WO2005009129A1

WO2005009129A1 - 1-n-arylpyrazole derivatives in prevention of arthropod-borne and mosquito-borne diseases

Info

Publication number: WO2005009129A1
Application number: PCT/US2004/005477
Authority: WO
Inventors: Mark Soll; Albert Boeckh
Original assignee: Merial Limited
Priority date: 2003-02-26
Filing date: 2004-02-25
Publication date: 2005-02-03
Also published as: EP1601249A4; US20040167175A1; CA2517135A1; EP1601249B1; CA2517135C; MXPA05009180A; ES2836108T3; EP1601249A1; US7262214B2

Abstract

This invention provides for a method for preventing or interrupting the transmission of anthropod and mosquito-borne diseases from a first actual or putative amplifying or incipient host to a second actual or putative amplifying or incipient host, which comprises applying or administering a formulation comprising an effective amount of at least one 1-N-arylpyrazole to said first actual or putative amplifying host and/or actual or putative amplifying or incipient host. This invention also provides for a method of using a bait placed in a bird station, the bait comprises an affective amount of at least one 1-N-arylpyrazole either alone or in combination with an antiparasitic, antihelmintic, or insecticidal agents. This invention also provides for an apparatus for delivering an effective amount of a formulation according to the present invention to a bird or animal in an environment where it resides.

Description

TITLE OF THE INVENTION 1-N-ARYLPYRAZOLE DERIVATIVES IN PREVENTION OF ARTHROPOD- BORNE AND MOSQUITO-BORNE DISEASES FIELD OF THE INVENTION This invention relates to spot-on formulations for preventing or interrupting the transmission of arthropod- and mosquito-borne diseases from an animal, bird or human, which may or may not be infected with the disease, to a second animal, bird or human. In particular, this invention provides for a method of preventing or interrupting the transmission of a mosquito-borne disease in an animal, bird or human to a second animal, bird or human by administering a formulation comprising an 1-N-arylpyrazole derivative. This invention also provides the use of a bait comprising at least one 1-N-arylpyrazole derivative and/or an IGR either alone or in combination with any antiparasitic, antihelmintic, or insecticidal agent placed in a commercially available bird station for preventing or interrupting the transmission of arthropod- and mosquito-borne diseases from an actual or putative amplifying or incipient host, such as an animal or bird (wild or domesticated), to a second actual or putative amplifying or incipient host, such as an animal, bird or human. This invention further provides an apparatus to administer a spot-on or pour-on formulation according to the present invention to animals, both domesticated and wild. All of the applications, as well as all documents cited herein and documents referenced or cited in documents cited herein, are hereby incorporated herein by reference. BACKGROUND OF THE INVENTION Mosquitoes act as vectors for a number of viral and protozoal infections in the world. It has been reported that mosquitoes carry diseases that potentially compromise the health of one-eighth of the world's population and impact the health and economy of approximately 300 million people per year. In addition to clinically significant diseases like malaria and yellow fever, mosquitoes are also implicated in the transmission of many arboviruses., infections with which cause symptoms ranging from nonspecific flu-like illnesses to encephalitis that may result in death. In addition to humans, domesticated animals such as dogs, cats, horses, cattle, sheep, pigs, as well as wild animals and birds may become infected and experience clinical disease as a result of that infection. Arboviruses that infect humans and other mammals are members of one of three virus families, Togaviridae, Flavividae, and Bunyaviridae, and include the agent responsible for Eastern Equine Encephalitis (EEE), Western Equine Encephalitis (WEE), St. Louis Encephalitis (SLE), La Crosse Encephalitis (LCE), and infection caused by Dengue Virus, and West Nile Virus (WNV). Worldwide, other arboviruses of medical importance include viruses responsible for Japanese Encephalitis (JE) and Venezuelan Equine Encephalitis. WNV has received significant attention in the United States since its outbreak on the East Coast in 1999 and 2000. Since that outbreak, CDC estimates that

WNV has been documented in forty-three of the lower forty-eight states including areas as geographically diverse as Alabama, Arkansas, California, Colorado, and North Dakota. From 1999 through 2001, there were 149 cases of WNV human illness reported to the CDC, including 18 deaths (see www.cdc.gov/ncidod/dvbid/westnile/background.htm). Transmission of WNV is similar to EEE, WEE, SLE viruses and may involve a cycle that includes mosquitoes and birds. Mosquitoes become infected with WNV when they feed on a bird carrying the virus in its blood. Birds act as amplifying hosts for the virus and, ten to fourteen days after initial infection, the virus can be transmitted to another bird, a human, or another animal host when the mosquito injects saliva containing the virus into that host during feeding. At present, the CDC reports that there are 110 species of birds that may act as amplifying hosts for WNV. Additionally, infected birds may facilitate the spread of the disease as birds can fly long distances after becoming infected. While humans and other animals may become clinically ill after infection with WNV, they are considered to be incidental hosts since they do not develop enough of the virus in the blood to infect other hosts. Arboviruses other than WNV have different amplifying hosts. For example, the amplifying hosts for JE virus are domestic pigs and wild birds (www.cdc. gov/nicidod/dvbid/i ecephalitis/qa.htm , while the amplifying hosts for the virus that causes La Crosse encephalitis are chipmunks and tree squirrels (www.cdc.gov/nicod/dsbid/ arbor/ardet.htm). Another emerging mosquito-borne disease of veterinary importance is heartworm disease, caused by infection with Dirofilaria immitis, and characterized by several developmental stages. Specifically, microfilariae are deposited by female heartworms into the bloodstream of a definitive host - primarily canines, but also felines and ferrets. Once ingested by a mosquito during feeding, the microfilariae develop into infective larvae which, when transmitted to the definitive host, migrate to heart where maturation into adult worms occurs. A number of drug treatments have been developed to treat heartworm. For example, US patent Serial No. 5,550,153 to Kerz discloses the use of Ivermectin for treating Dirofilaria immitis infection in canines. Other research has been directed to the control of heartworm and other arthropod-borne diseases by interfering with transmission cycles. For example, the most common method for controlling mosquitoes that transmit harmful viruses or other microorganisms involves spraying insecticides into areas where the mosquitoes breed. This approach is not without risk, however. For example, the use of insecticides may have a harmful environmental impact, especially to the wetland areas where mosquitos often reside (see, e.g., US 2002/021045 Al). Thus, there is a need for simple, low cost methods to abate arthropod populations, including mosquitos and ticks, and to prevent or impair the transmission of mosquito-borne diseases without widespread environmental damage. 1-N-arylpyrazoles as a class of chemicals are well known in the art, as are methods for their use in controlling parasites including insects, such as fleas or ticks, in mammals, such as domesticated livestock or companion animals, either alone or in combination with other pesticides such as insect growth regulators. See, e.g., EP- A-295,217, EP 295 177, EP-A-840-686, EP-A-352,944, WO 00/35844, WO 98/39972, U.S. Patent Nos. 5,122,530 5,236,938, 5,232,940, 5,576,429 5,814,652, 5,567,429, 6,090,751 and 6,096,329 as well as Publication No. US 2002-90381-A1. See also copending applications USSN 07/719,942; 08/933,016; 09/174,598; 08/863,182; and 08/863,692. The compounds of the families defined in these patents are extremely active and one of these compounds, 5-amino-3-cyano-l-(2,6-dichloro-4- trifluoromethylρhenyl)-4-trifluoromethylsulfinylpyrazole, or fipronil, is particularly effective, but not exclusively effective, against fleas and ticks. However, specific "results involving the effectiveness of these compounds against mosquitoes generally have not been reported. Various methods of formulating antiparasitical formulations are known in the art. These include oral formulations, baits, dietary supplements, powders, shampoos, etc. Formulations for localized topical applications of antiparasitical formulations are also known in the art. For example, pour-on solutions comprising 1-N-phenylpyrazole derivatives, such as fipronil, are known in the art and are described in copending application 08/933,016, now U.S. Patent 6,010,710, and U.S. Patent 6,413,542, issued July 2, 2002 and copending application 10/120,691, filed April 11, 2002 and herein incorporated by reference. Other methods of formulating antiparasitic agents include spot-on formulations. Spot-on formulations are well known techniques for topically delivering an antiparasitic agent to a limited area of the host. For example, U.S. Patent 5,045,536 describes such formulations for ectoparasites. Other spot-on formulations include U.S. Patent No. 6,426,333 and copending application USSN 09/221,470, now allowed, and 10/155,397, filed on May 24, 2002. WO 01/95715 describes a method for controlling ectoparasites in small rodents as well as interrupting or preventing the diseases caused by arthropods of small rodents, which comprise applying topical formulations, such as spot-on compositions, to the skin, or hair of the rodents. WO 01/95715 further provides an enclosure having one or more peripheral openings, which allows the entry and egress of rodents, and an applicator, which comprises the topical formulation and is arranged to contact a rodent. However, WO 01/95715 does not describe a method for preventing or interrupting the transmission of mosquito-borne diseases, in general, or the transmission of WNV, in particular, by administering a formulation comprising a 1-N- phenylpyrazole to a host, in general, or birds, in particular, thereby affecting a simple, low-cost method to abate mosquito populations and to prevent or impair the transmission of mosquito-borne diseases without widespread environmental damage. Baits are another method of formulating that is known in the art. For example, US patent application NO. 4,564,631 to Elbert gt al. relates to a process of preparing a bait containing Pyrethroids for combating Vermin. However, no methods are known to use a commercially available bird station (for example, see bird stations sold by Wild Bird Station, 2295 NW Broad street Murfreesboro, TN 37129 or visit info@wildbirdstation.com) having baits comprising 1-N-arylpyrazole derivatives and/or an IGR either alone or in combination with a known antiparasitic, antihelmintic or insecticidal agent to prevent or to interrupt the transmission of arthropod- or mosquito- borne diseases by birds or other small mammalian hosts. SUMMARY OF THE INVENTION The present invention provides for, inter alia, a method for preventing or interrupting the transmission of arthropod- or mosquito-borne diseases from a putative amplifying host, such as an animal, bird or human, to a second putative amplifying or incipient host, such as an animal, bird or human, which comprises applying or administering a formulation comprising an effective amount of at least one 1-N- arylpyrazole derivative to said first actual or putative amplifying or incipient host and/or second actual or putative amplifying or incipient host. This invention further provides for a method for preventing or interrupting the transmission of mosquito-borne diseases from an actual or putative amplifying or incipient host, such as an animal or bird (wild or domesticated), to a second actual or putative amplifying or incipient host, such as an animal, bird or human, by applying a spot-on formulation comprising: (a) an effective amount of at least one 1-N-arylpyrazole derivative; (b) a pharmaceutically or veterinary acceptable liquid carrier vehicle; (c) optionally, an insect growth regulator and/or a crystallization inhibitor to said first actual or putative amplifying host and/or to said second actual or putative amplifying or incipient hosts. This invention further provides for a method for preventing or interrupting the transmission from an actual or putative amplifying incipient host, such as a bird, animal or human, to a second actual or putative amplifying or incipient host, such as a bird, animal or human, by applying a pour-on formulation comprising: (a) an effective amount of at least one 1-N-arylpyrazole derivative; (b) a pharmaceutically or veterinary acceptable liquid carrier vehicle; (c) optionally, an insect growth regulator and/or a crystallization inhibitor to said first actual or putative amplifying or incipient host and/or second actual or putative amplifying or incipient host. This invention also provides the use of a commercially available bird station having a bait comprising an effective amount of at least one 1-N-arylpyrazole derivative and/or an IGR either alone or in combination with any known antiparasitic, antihelmintic, or insecticidal agent(s) including but not limited to Pyrethroids,

Avermectins, Organophosphates, Carbamates, Neonicotinoids or a mixture thereof. Also provided within scope of the present invention is an apparatus, as well as a method of using this apparatus, to administer the spot-on or pour-on formulations according to the present invention to birds or animals, both domesticated and wild, thereby preventing or interrupting the transmission of the mosquito-borne disease from said birds or animals to a second actual or putative amplifying or incipient host, which may be another bird or animal or a human. BRIEF DESRIPTION OF THE DRAWINGS A full and enabling disclosure of the present invention, including the best mode thereof, to one of ordinary slcill in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, wherein: FIG. 1 depicts one embodiment of an apparatus of the present invention for delivering a dose of a veterinary formulation to a bird or mammal; FIG. 2 depicts another embodiment of the inventive apparatus; FIGS. 3a and 3b depict a detailed view of one embodiment of the opening in an apparatus made according to the present invention. DETAILED DESCRIPTION Other objects, features and aspects of the present invention are disclosed in, or are obvious from, the following Detailed Description. It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only and is not intended as limiting the broader aspects of the present invention, which broader aspects are embodied in the exemplary construction, hi fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used in another embodiment to yield a still further embodiment. It is intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents. For convenience, certain terms employed in the Specification, Examples, and appended Claims are collected here. Definitions: As used herein, the term "comprising" in this disclosure can mean "including" or can have the meaning commonly given to the term "comprising" in U.S. Patent Law. Parasitic diseases may be caused by either endoparasites or ectoparasites.

As used herein endoparasites refer to those parasites living inside the body of the host, either within an organ (such as the stomach, lungs, heart, intestines, etc.) or simply under the skin. Ectoparasites are those parasites that live on the outer surface of the host but still draw nutrients from the host. Endoparasitic diseases may further be subdivided based on class of parasite involved in the infection. For example, endoparasitic diseases generally referred to as belminthiasis are due to infection of the host with parasitic worms known as hehninths. Helminthiasis is a prevalent and serious worldwide economic problem due to infection of domesticated animals such as swine, sheep, horses, cattle, goats, dogs, cats, and poultry. Many of these infections, caused by the group of worms described as nematodes, cause diseases in various species of animals throughout the world. These diseases are frequently serious and can result in the death of the infected animal. The most common genera of nematodes infecting the animals referred to above include, but are not limited to, Haemonchus, Trichostrongylus, Ostertagia, Nematodirus, Cooperia, Ascaris, Bunostomum, Oesophagostomum, Chabertia, Trichuris, Strongylus, Trichonema, Dictyocaulus, Capillaria, Heterakis, Toxocara, Ascaridia, Oxyuris, Ancylostoma, Uncinaria, Toxascaris, and Parascaris. Many parasites are species specific (infect only one host) and most also have a preferred site of infection within the animal. Thus, Haemonchus and Ostertagia primarily infect the stomach while Nematodirus and Cooperia mostly attack the intestines. Other endoparasites reside in the heart, eyes, lungs, blood vessels, and the like while still others are subcutaneous parasites. Helminthiasis can lead to weakness, weight loss, anemia, intestinal damage, malnutrition, and damage to other organs. If left untreated these diseases can result in the death of the animal. Examples of endoparasites which infect animal and man include but are not limited to gastro-intestinal parasites of the genera Ancylostoma, Necator, Ascaris, Strongyloides, Trichinella, Capillaria, Trichuris, Enterobius, and the like. Other endoparasites which infect animal and man are found in the blood or in other organs. Examples of such parasites include but are not limited to filarial worms Wuchereria, Brugia, Onchocerca, and the like as well as extra-intestinal stages of the intestinal worms Strongylides and Trichinella. Ectoparasites which parasitize man include arthropods such as ticks, fleas, mites, lice, and the like and, as with domestic animals, infections by these parasites can result in transmission of serious and even fatal diseases. Infestations by ectoparasitic arthropods including but not limited to ticks, mites, lice, stable flies, hornflies, blowflies, fleas, and the like are also a serious problem. Infection by these parasites results not only in loss of blood and skin lesions, but also can interfere with normal eating habits thus causing weight loss. Ectoparasitic infestations of a host can also result in transmission of serious diseases including but not limited to encephalitis, anaplasmosis, babesiosis, rocky mountain spotted fever, lyme disease, ehrlichiosis, swine pox, and the like, many of which can be fatal to the host. Animals may be infected by several species of parasite at the same time since infection by one parasite may weaken the animal and make it more susceptible to infection by a second species of parasite. The compounds of this invention are also active against household pests including but not limited to cockroach, Blatella sp., clothes moth, Tineola sp., carpet beetle, Attagenus sp. and the housefly Musca domestica and against Solenopsis invicta (imported fire ants), termites, and the like. These compounds are furthermore useful against agricultural pests such as aphids (Acyrthiosiphon sp.) locusts, and boll weevils as well as against insect pest which attack stored grains such as Tribolium sp. and against immature stages of insects living on plant tissue. The compounds are also useful as anematodicide for the control of soil nematodes which may be agriculturally important. Antiparasitic agents are also useful for the treatment and/or prevention of helminthiasis in domestic animals such as cattle, sheep, horses, dogs, cats, goats, swine, and poultry. They are also useful in the prevention and treatment of parasitic infections of these animals by ectoparasites such as ticks, mites, lice, fleas and the like. They are also effective in the treatment of parasitic infections of humans. Antiparasitic agents as used herein including ecto- and endo-parsidicale agents include but are not limited to: albendazole, amitraz, amprolium, antimony, atovaquaone, benzimidazole, bunamidine, dichlorvos, diethylcarbamazine, diminazene aceturate, disophenol, dithiazanine iodide, epsiprantal, fenbendazole, fenthion, furazolidine, imidocarb dipropionate, ipronidazole, ivermectin, levamisole, lime sulfur suspension, lufenuron, mebendazole, meglumine antimonite, melarsomine HCI, metronidazole, milbemycin oxime, moxidectin, naproxen, niclosamide, mfurtimox, paromomycin, parvaquone, pentamidine isethionate, phenamidine isethionate, piperazine, praziquantel, primaquine phosphate, primaquine PO4, pyrantel pamoate, pyrimethamine, quinacrine, selamectin, skin so soft by avon, sodium stibogluconate, spiramycin, styrylpyridinium DEC, sulfadiazine, trimethoprim, sulfadimethoxine, sulfamethazine, tetramisole, thiabendazole, toltrazuril, toluene, trimetraxate glucuronate, trypan blue, and the like. Antihelmintics agents as used herein include, but are not limited to benzoimidazoles such as thiobendazole, mebendazole, albendazole and the like. Insecticidal agents as used herein include but are not limited to organophosphates such as coumaphos, carbamates such as propoxur, pyrethroids such as permethrin, arylpyrazoles such as fipronil, neonicotinoids such as imidaclopid and avermectins such as ivermectin and the like. As discussed above, the 1-N-arylpyrazole derivatives contemplated in the present invention as methods to formulate these compounds are known in the art. This class of insecticides is known to possess excellent activity against insects, such as ticks and fleas. The formulations contemplated in the method for preventing or interrupting the transmission of arthropod- and mosquito-borne diseases from an actual or putative amplifying host, such as an animal (domestic or wild), bird (domestic or wild) or human, to a second actual putative amplifying or incipient host comprise a therapeutically effective amount of at least 1-N-phenylpyrazole and optionally at least one diluent or carrier: the diluent or carrier would be well know to a practitioner of this art. Carriers include organic or inorganic materials, natural or synthetic, that facilitate the administration of the 1-N-arylpyrazole derivatives to the animal, bird or human.

Non-limiting examples of carriers include clays, silicates, silica, resins or waxes. Non- limiting examples of diluents include water, alcohols, ketones, oil solvent, polyethylene glycol and polar aprotic solvents such as corn oil, or dimethylsulfoxide. Preferred 1-N- arylpyrazole derivatives include those described below for the spot-on and pour-on formulations. Routes of administration include oral, parenteral, e.g., subcutaneous or intravenous, or topical, such as sprays. Preferred formulations for the inventive method comprise: A) an effective amount of at least one compound of the formula:

in which: Ri is a halogen atom, CN or alkyl; R₂ is S(O)_nR₃ or 4,5-dicyanoimidazol-2-yl or haloalkyl; R₃ is alkyl, alkenyl, alkynyl, haloalkyl, haloalkenyl or haloalkyl; R₄ is hydrogen, halogen, NR₅R<₅, S(O)_mR₇, C(O)R₇, C(O)OR₇, alkyl, haloalkyl , OR₈ or -N=C(R₉)(R₁₀) substituent; R₅ and R_ό independently represent a hydrogen atom, alkyl, haloalkyl, C(O)alkyl, S(O)_rCF₃ or alkoxycarbonyl or R₅ and R₆ together may combine to form a ring of 5 to 7 members. R₇ represents an alkyl or haloalkyl group; R₈ represents an alkyl, haloalkyl or a hydrogen; R₉ represents an alkyl or a hydrogen; R₁₀ represents an optionally substituted aryl or an optionally substituted heteroaryl group; Rπ and R₁₂ represent, independently of one another, hydrogen, halogen CN or NO₂; R₁₃ represents a halogen atom or a haloalkyl, haloalkoxy, S(O)_qCF₃ or SF₅ group; m, n, q and r represent, independently of one another, an integer equal to 0, 1 or 2; X represents a bivalent nitrogen atom or a C-R₁₂, the three other valencies of the carbon atom forming part of the aromatic ring; optionally with a pharmaceutically acceptable carrier or excipient. Preferred spot-on compositions to be used in the inventive method include, for example, spot-on formulations comprising: (a) an effective amount of at least one compound of the formula

in which: R_\ is a halogen atom, CN or methyl; R₂ is S(O)_nR₃ or 4,5-dicyanoimidazol-2-yl or haloalkyl; R₃ is alkyl, haloalkyl, haloalkenyl or haloalkynyl; ι represents a hydrogen or halogen atom or an NR₅R₆, S(O)_mR₇, C(O)R₇ or C(O)OR₇, alkyl, haloalkyl or OR₈ or an -N=C(R₉)(R₁₀) group; R₅ and Re independently represent a hydrogen atom or an alkyl, haloalkyl, C(O)alkyl, S(O)_rCF₃ or alkoxycarbonyl group or R₅ and R₆ together may form a ring of 5 to 7 members; R₇ represents an alkyl or haloalkyl substituent; R₈ represents an alkyl or haloalkyl or a hydrogen; R₉ represents an alkyl or a hydrogen atom; R₁₀ represents an optionally substituted aryl or an optionally substituted heteroaryl group; Rπ and R₁₂ represent, independently of one another, hydrogen, halogen CN or NO₂; R₁₃ represents a halogen atom or a haloalkyl, haloalkoxy, S(O)_qCF₃ or SF₅ group; m, n, q and r represent, independently of one another, an integer equal to 0, 1 or 2; X represents a trivalent nitrogen atom or a C-R₁₂, the three other valencies of the carbon atom forming part of the aromatic ring; with the proviso that, when R_! is methyl, then either R₃ is haloalkyl, I j is NH₂, Rπ is Cl, R₁₃ is CF₃ and X is N or else R₂ is 4,5- dicyanoimidazol-2-yl, R4 is Cl, Rπ is Cl, R₁₃ is CF and X is C-Cl; and/or (b) a pharmaceutically or veterinary acceptable liquid carrier vehicle; and (c) optionally, a crystallization inhibitor. More preferably, this invention provides for a method of preventing or interrupting the transmission of mosquitoes and mosquito-borne diseases wherein, for example, the spot-on or pour-on formulation comprises: (a) an effective amount of a compound of formula (I) wherein Ri is a halogen atom, CN or methyl; R₂ is S(O)_nR3 or 4,5-dicyanoimidazol-2-yl or haloalkyl; R₃ is CrCe-alkyl or Cι-C₆-haloalkyl; Rj represents a hydrogen or halogen atom; or NR₅R₆, S(O)_mR₇, C(O)R₇ or C(O)OR₇, alkyl, haloalkyl or OR₈ or -N=C(R₉) (Rio); R₅ and Re independently represent a hydrogen atom or a Cι-C₆ alkyl, Cι-C₆-haloalkyl, C(0)Cι-C₆-alkyl, S(O)_rCF₃, Q- C₆-acyl or Ci-Cβ-alkoxycarbonyl; R₅ and R₆ together may combine to form a ring of 5 to 7 members, which may include one or two divalent heteroatoms selected from the group consisting of oxygen or sulphur; R₇ represents a -C_δ-alkyl or -C_δ-haloalkyl; R₈ represents a Ci- -alkyl or Cι-C₆-haloalkyl or a hydrogen atom; R₉ represents a Ci-C_δ-alkyl or a hydrogen atom; R₁₀ represents an optionally substituted phenyl or optionally substituted heteroaryl group wherein the substituents are selected from the group consisting of halogen, OH, -O- C C_ό alkyl, -S- Ci-C_ό-alkyl, cyano or -Cό-alkyl; Rπ and R₁ , independently of one another represent hydrogen, halogen, CN or NO₂; R₁₃ represents a halogen, Cι-C₆-haloalkyl, -Ce-haloalkoxy, S(O)_qCl₃ or SF₅ group; and, m, n, q and r independently of one another are 0, 1, or 2. (b) the liquid carrier vehicle comprises a solvent and a cosolvent wherein the solvent is selected from the group consisting of acetone, acetonitrile, benzyl alcohol, butyl diglycol, dimethylacetamide, dimethylformamide, dipropylene glycol n-butyl ether, ethanol, isopropanol, methanol, ethylene glycol monoethyl ether, monomethylacetamide, dipropylene glycol monomethyl ether, liquid polyoxyethylene glycols, propylene glycol, 2-pyrrolidone, in particular N-methylpyrrolidone, diethylene glycol monoethyl ether, ethylene glycol, diethyl phthalate fatty acid esters, such as the diethyl ester or dusobutyl adipate, and a mixture of at least two of these solvents and the cosolvent is selected from the group consisting of absolute ethanol, isopropanol or methanol; (c) a crystallization inhibitor selected from the group consisting of an anionic surfactant, a cationic surfactant, a non-ionic surfactant, an amine salt, an amphoteric surfactant or polyvinylpyrrolidone, polyvinyl alcohols, copolymers of vinyl acetate and vinylpyrrolidone, polyethylene glycols, benzyl alcohol, mannitol, glycerol, sorbitol, polyoxyethylenated sorbitan esters; lecithin, sodium carboxymethylcellulose, and acrylic derivatives, or a mixture of these crystallization inhibitors. Especially preferred as spot-on formulations to be used in the inventive method are those wherein the 1-N-arylpyrazole derivative is a compound wherein the ring formed by the divalent alkylene substituent representing R₅ and R₆ and the nitrogen atom to which R₅ and R₆ are attached has 5, 6 or 7 members or wherein Ri is CN, R₃ is Ci-Cβ-haloalkyl, _t is NH₂, Rπ and R₁₂ are, independently of one another, hydrogen or halogen and R₁₃ is Cι-C₆-haloalkyl. Most especially preferred are formulations, including spot-on and pour- on compositions which are to be used in the inventive method, comprising: (A) 5-amino-3-cyano-l-(2,6-dichloro-4-trifluoromethylphenyl)-4- trifluoromethylsulfinylpyrazole; or (B) 1-N-phenylpyrazole derivative of the formula:

Other 1-N-arylpyrazole derivatives to be used in the formulation to the invention method which are preferred are those of the formula (II)

wherein: Rioi _s cyano, -C(O)alkyl, C(S)NH₂, alkyl, haloalkyl, C(=NOH)NH₂ or C(=NNH₂)NH₂; R 102 is S(O)_n'Rio3_. alkenyl, haloalkenyl, cycloalkyl, halocycloalkyl or alkynyl; Rl03 is alkyl, alkenyl, alkynyl, haloalkyl, haloalkenyl or haloalkynyl;

N(R₁₀₉)-C(R₁₀₅)=NR₁o₆; R₁₀₅ is hydrogen; alkyl; or alkyl substituted by halogen, alkoxy, haloalkoxy or -S(O)_raRιo5; R₁₀₆ and R₁₀ each independently represent hydrogen, alkyl, alkenyl or alkynyl, or alkyl substituted by one or more halogen, alkoxy, haloalkoxy, amino, alkylamino, dialkylamino, cyano or -S(O)_mRπ5_. or alkyl substituted by phenyl or pyridyl each of which is optionally substituted with one or more groups selected from halogen, nitro and alkyl group; or Ri₀ and R_o_ may form together with the nitrogen to which they are attached a 3- to 7- membered ring which may additionally contain one or more heteroatoms selected from oxygen, nitrogen or sulfur; R₁₀₈ is alkoxy, haloalkoxy, amino, alkylamino, dialkylamino, - C(O) R„4 or -S(O)_tR₁₁₀; Rιo_9. Rno and R₁₁₄ are alkyl or haloalkyl; Rπi and R₁₁₂ are independently selected from halogen, hydrogen, CN andNO₂ Rιi₃ is selected from halogen, haloalkyl, haloalkoxy, -

S(O)_q.CF₃, and -SF₅; Rπ ₅ is alkyl or halo alkyl; X is selected from nitrogen and C-Ri ₁₂; Z is O, S(O)_a.; orNR₁₀7; a', m', n' and q' are independently selected from 0, 1, and 2; and is 0, 1 or 2; and veterinarily acceptable salts thereof. Another preferred 1-N-arylpyrazole derivatives to be used in the method of the present invention are those compounds of formula (III):

wherein: R₂₀ι is cyano, C(O)alkyl, C(S)NH₂, alkyl, C(=NOH)NH₂ or C(=NNH₂)NH₂; R202 is S(O)_hR203, alkenyl, haloalkenyl, cycloalkyl, halocycloalkyl or alkynyl; R₂o₃ is alkyl, alkenyl, alkynyl, haloalkyl, haloalkenyl or haloalkynyl; R₂₀₄ is -N(R₂₀₅)C(O)CR₂₀₆R207R208, -N(R₂₀₅)C(O)aryl, or -N(R₂₀₅)C(O)OR₂₀7; R ₀₅ is alkyl, haloalkyl, cycloalkyl, halocycloalkyl, cycloalkylalkyl, halocycloalkylalkyl, alkoxyalkyl, haloalkoxyalkyl, alkenyl, haloalkenyl, alkynyl, haloalkynyl; R₂₀₆ s hydrogen, halogen, alkoxy, haloalkoxy, alkoxyalkyl, haloalkoxyalkyl, formyloxy, alkylcarbonyloxy, haloalkylcarbonyloxy, alkylthio, haloalkylthio, alkylsulfinyl, haloalkylsulfinyl, alkylsulfonyl, haloalkylsulfonyl, alkylamino, dialkylamino, haloalkylamino, di(haloalkyl)amino, cycloalkyloxy, halocycloalkyloxy, alkoxyalkoxy, haloalkoxyalkoxy, alkoxyalkoxyalkoxy, aryloxy, or arylalkoxy; R ₀₇ and R₂o₈ are independently hydrogen, alkyl, haloalkyl, cycloalkyl, or halocycloalkyl; or R₂o₇ and R₂o₈ may form together with the carbon to which they are attached a 3- to 7- membered ring which additionally may contain one or more heteroatoms selected from nitrogen, oxygen and sulfur; X₁ is selected from nitrogen and C-R₂₁₂; R₂₁₁ and R₂₁₂ are independently selected from halogen, hydrogen, CN and NO₂; R₂₁₃ is selected from halogen, haloalkyl, haloalkoxy, - S(O)_kCF₃, and -SF₅; and h and k are independently selected from 0, 1, and 2; and veterinarily acceptable carrier, excipients and salts thereof. A preferred class of compounds of formula (II) for use in the inventive method are those wherein: Rioi is cyano or alkyl; R102 is S(O)_nR₁₀₃; R₁₀₃ is alkyl or haloalkyl; R₁₀ is -N=C(R₁₀₅)-Z- R₁₀₆; R₁₀₅ is hydrogen, alkyl or haloalkyl; Z is O, S(OV; or NR₁₀₇; Rιo₆ and Rιo₇ are independently selected from hydrogen and unsubstituted or substituted alkyl; or R₁₀₆ and R₁₀₇ may form together with the nitrogen to which they are attached a 3- to 7- membered ring which may additionally contain one or more heteroatoms selected from oxygen, nitrogen or sulfur; X is selected from nitrogen and C-R₁₁₂; Riπ and Rπ₂ are independently selected from halogen, hydrogen, CN and NO₂; Rιi₃ is selected from halogen, haloalkyl, haloalkoxy, - S(O)_q.CF₃, and -SF₅; a', n' and q' are independently selected from 0, 1, and 2. Preferably Rioe is alkyl which is substituted by one or more halogen, alkoxy, haloalkoxy, amino, alkylamino, dialkylamino, sulfide, sulfoxide, sulfone, or phenyl or pyridyl moieties of wliich each phenyl or pyridyl moiety is optionally substituted with one or more groups selected from halo, nitro, and alkyl. Preferably the compound useful in the method of the invention has one or more of the following features: Rj.oi is cyano; Rιo is -N=C(R₁₀₅)-Z-R₁₀₆ and Z is -NR₁₀7. X is C-Rn₂; Rπi and R₁₁₂ represent a chlorine atom; and Rπ3 is CF₃, OCF₃, or -SF₅; R112 is -S(O)_n.CF₃ and n is 0, 1, or 2. ^' A further preferred class of compounds to be used in the inventive methods or approaches are those of formula II wherein: R101 is cyano or alkyl; R₁₀ is -N=C(R₁₀₅)-Z-R₁₀₆; and R₁₀₅ is hydrogen or C₁-C₃ alkyl. The compounds of formula (II), preferably have one or more of the following features : R₁₀ι is cyano or methyl; Ri_θ is halomethyl (preferably CF₃); Rπi and R112 each independently represent a halogen atom;

Rπ3 is haloalkyl (preferably CF₃ haloalkoxy (preferably

OCF₃), or -SF5; or n' is 0, 1 or 2 (preferably 0 or 1). A further preferred class of compounds of formula (II) for use in the control of parasites in animals are those wherein: Rιo_ is cyano; R₁₀ is S(O)nR₁₀₃; R1₀₃ is halomethyl;

R₁₀₅ is hydrogen or alkyl; R₁₀₆ and R₁₀₇ each independently represent hydrogen, alkyl, alkenyl or alkynyl; or alkyl substituted by one or more halogen, alkoxy, haloalkoxy, amino, alkylamino, dialkylamino, cyano or -S(O)_mRι₅; or alkyl substituted by phenyl or pyridyl which rings are optionally substituted with one or more groups selected from halogen, nitro and alkyl; X is selected from nitrogen and C-Rn ; Rioβ and Ri ι₂ each independently represent a halogen atom; Rm is selected from haloalkyl, haloalkoxy and -SF₅; R₁₁₅ is alkyl or haloalkyl; and m' and n' are independently selected from 0, 1, and 2. A further preferred class of compounds of formula (II) is that wherein: R101 is cyano; R₁₀₂ is S(OVCF₃; R₁₀ is

or -N=C(R₁₀₅)-N(R₁₀7)-Rιo8;

R₁₀₅ is hydrogen or alkyl; Rιo₆ and R₁₀₇ each independently represent hydrogen, alkyl, alkenyl or alkynyl; or alkyl substituted by one or more halogen, alkoxy, haloalkoxy, amino, alkylamino, dialkylamino, cyano or -S(O)Rπ₅; or methyl substituted by phenyl or pyridyl which rings are optionally substituted with one or more groups selected from halogen, nitro and alkyl; Rios is alkoxy, haloalkoxy, amino, alkylamino, dialkylamino or -S(O)_tRιιo; X is selected from nitro gen and C-Rn₂; R-10₉, Rπo and R114 independently represent alkyl or haloalkyl; Rπi and R each represent a chlorine atom; Rπ₃ is CF₃ or -SF₅; and m' and n' are 0, 1 or 2; and is 0 or 2. A further preferred class of compounds of formula (II) are those wherein: Rioi is cyano; Z is NR10 ; R₁₀₅ is hydrogen or methyl; Rιo₆ and R₁₀₇ each independently represent hydrogen, alkyl, alkenyl or alkynyl; or alkyl substituted by one or more halogen, alkoxy, haloalkoxy, amino, alkylamino, dialkylamino, cyano or -S(O)_m>Rπ₅; or alkyl substituted by phenyl or pyridyl which rings are optionally substituted with one or more groups selected from halogen, nitro and alkyl;

Rm and R each represent a chlorine atom; R₁₁₃ is CF₃ or -SF₅; m' is zero, one or two; and 11' is O or l. A further preferred class of compounds of formula (II) is those wherein: R101 is cyano; R102 is S(O)_n€F₃; Rι₀₄ is -N=C(Rιo₅)-Z-Rι₀₆; Z is R.107; Rios and R₁₀₇ each represent a hydrogen atom; Rιo_<5 is alkyl or haloalkyl;

Rm and Rπ₂ each represent a chlorine atom; Rm is CF₃ or-SF₅; and n' is 0. Compounds of formula (III) which are preferred according to the present invention are those wherein: R201 is cyano; R₂₀₂ is S(O)_hR₂₀₃; R₂₀₃ is alkyl or haloalkyl; R₂₀₄ is - N(R₂₀₅)C(O)CR20₆R207R208. R₂₀₅ is alkyl, haloalkyl, cycloalkyl, cycloalkylal yl and halocycloalkylalkyl; R₂o₆ is alkoxy, haloalkoxy, or hydrogen; R₂₀₇ and R₂o₈ are independently hydrogen, alkyl, or haloalkyl; or R₂.₀₇ and R₂o₈ may form together with the carbon to which they are attached to a 3- to 7- membered ring wliich additionally may contain one or more heteroatoms selected from nitrogen, oxygen and sulfur; Xi is selected from nitrogen and C-R₂ι₂; R₂n and R₂₁₂ are independently selected from halogen, hydrogen, CN and NO₂; R₂₁₃ is selected from halogen, haloalkyl, haloalkoxy, - S(O)_kCF₃, and -SF₅; and h and k are independently selected from 0, 1, and 2. A preferred group of compounds of formula (III) is that wherein the ring which is formed by R₂₀₇ andR₂o₈ contains one or more heteroatoms, more preferably one oxygen atom. The compounds of formula (HI) of the present invention preferably have one or more of the following features: R201 is cyano; R203 is halomethyl, preferably CF₃; R₂π and R₂ι₂ are independently halogen; Xi is C-R₂ι₂; R₂i₃ is haloalkyl, haloalkoxy or -SF₅; or h is 0 or 1, or 2, preferably 0 or 1. A preferred class of compounds that wherein R₂o₄ is N(R₂₀5)C(O)CR₂o₆R207R208. Another preferred class of compounds that wherein R₂₀ is N(R₂₀₅)C(O)aryl. Another preferred class of compounds that wherein R₂o₄ is N(R₂₀₅)C(O)OR₂₀7. Preferably R₂₀₅ is Cι-C₄ alkyl, more preferably Cι-C₂ alkyl, most preferably methyl. Preferably R₂₀₆ is alkoxy, most preferably methoxy, ethoxy or propoxy. Preferably R₂₀₇ and R₂₀₈ are both hydrogen. Another especially preferred group of 1-N-arylpyrazole derivative is 4- thiocarbonylpyrazole derivatives of the formula:

in which R ,3^J0^U1¹ is H₂N-C(S)-, R ,3³0⁰2² is halogenoalkyl, halogenoalkenyl or halogenoalkynyl, R³⁰³ is hydrogen, amino or one of the following groups

where R³⁰⁴ represents alkyl, halogenoaUcyl, aUcoxyalkyl or in each case optionally substituted phenyl or pyridyl, R³⁰⁵ represents hydrogen or alkyl, R³⁰⁶ represents hydrogen, alkyl or in each case optionally substituted phenyl or pyridyl and R³⁰⁷ represents alkyl, alkenyl, alkinyl, formyl, alkylcarbonyl, halogenoalkylcarbonyl or alkoxycarbonyl; Ar represents in each case optionally substituted phenyl or pyridyl and n represents a number 0, 1 or 2. Especially preferred derivatives of formula (IV) are those wherein R³⁰¹ represents H₂N-C(S)-; R³⁰² preferably represents (Cι-C₆)-halogenoaUcyl having 1 to 12 halogen atoms; (C₂- C₆)-halogenoalkenyl having 1 to 8 halogen atoms or (Cι-C₆)-halogenoalkinyl having 1 to 6 halogen atoms; R³⁰³ preferably represents hydrogen, amino or one of the following groups:

-NHR^Jl

wherein: R , 304 represents (Cι-C₆)-aUcyl, (Cι-C₆)-halogenoaUcyl having 1 to 3 halogen atoms, (Cι-C₆)-alkoxy-(Cι-C₆)-alkyl, or represents phenyl or pyridyl, each of which is optionally monosubstituted to trisubstituted by identical or different substituents from the group consisting of cyano, nitro, halogen, Cι-C₆-alkyl, Cι-C₆-aUcoxy, Cι-C₆-alkylthio, Cι-C₄-halogenoalkyl, Cι-C₄ halogenoalkoxy or Cι-C₄- halogenoalkylthio having in each case 1 to 5 halogen atoms, R³⁰⁵ represents hydrogen or (Cι-C₆)-alkyl, R³⁰⁶ represents hydrogen, (Cι-C₆)-aUcyl, phenyl which is optionally monosubstituted to trisubstituted by identical or different substituents from the group consisting of cyano, nitro, halogen, Cι-C₆-alkyl, Cι-C₆-alkoxy, C i -C₆-aUcylthio, C i -C -halogenoaUcyl, Cι-C₄-halogenoalkoxy or Cι-C₄-halogenoaUcylthio having in each case 1 to 5 halogen atoms or hydroxyl, or represents pyridyl which is substituted by cyano, nitro, halogen, Cι-C₆-alkyl, Cι-C₆-alkoxy, Cι-C₆-aUcylthio, Cι-C₄-halogenoaUcyl, Cι-C₄-halogenoaUcoxy or Cι-C₄- halogenoalkylthio having in each case 1 to 5 halogen atoms, and R³⁰⁷ represents (Cι-C₆)-aUcyl, (C₂-C₆)-alkenyl, (C₂-C₆)-aUcynyl, formyl, (Cι-C6)-aUcylcarbonyl, (Cι-C₆)-halogenoaUcylcarbonyl having 1 to 6 halogen atoms or (Cι-C₆)-aUcoxycarbonyl; 5 Ar preferably represents phenyl or pyridyl, each of which is optionally monosubstituted to trisubstituted by identical or different substituents from the group consisting of halogen halogeno(Cι-C₆)aUcyl, halogeno(Cι-C₆) alkylthio, halogeno(Cι-C₆)alkoxy, (Cι-C₆)alkoxy, methoxy, 10 hydrazine, (Cι-C₆)-dialkylhydrazino, amino, (Cι-C₆)alkylamino, di(Cι-C₆)alkylamino, (Cι-C₆) alkylimino, cyano, (Cι-C₆)alkylthio or the group

in which 15 R³⁰⁸ and R³⁰⁹ are identical or different and represent hydrogen or (Cι-C₆)-aUcyl n¹¹¹ preferably represents a number 0, 1 or 2. R³⁰¹ represents H₂N-C(S)-; R³⁰² particularly preferably represents (Cι-C₄)-halogenoaUcyl 20 having 1 or 9 identical or different halogen atoms from the group consisting of fluorine, chlorine and bromine, (C₂-C₄)-halogenoalkenyl having 1 to 5 identical or different halogen atoms from the group consisting of fluorine, chlorine or bromine or (C₂-C₄)-halogenoaUcynyl 25 having 1 to 5 identical or different halogen atoms from the group consisting of fluorine, chlorine and bromine; R³⁰³ especially preferably represents hydrogen, amino or one of the following groups:

where 5 R³⁰⁴ represents (Cι-C₄)-aUcyl, (Cι-C₄)-halogenoaUcyl having 1-3 halogen atoms, (Cι-C₄)-alkoxy(Cι-C )-alkyl, or phenyl which is optionally monosubstituted to trisubstituted by identical or different substituents from the group consisting of hydroxyl, cyano, nitro, halogen, 10 Cι-C₄-alkyl, Cι-C₄-aUcoxy, (Cι-C₂-halogenoalkyl, Cι-C₂-halogenoalkoxy or Cι-C₂-halogenoalkylthio having in each case 1 to 3 halogen atoms, R³⁰⁵ represents hydrogen or (Cι-C₄)-alkyl, R³⁰⁶ represents hydrogen, (Cι-C₄)-alkyl or phenyl which is 15 optionally monosubstituted or disubstituted by identical or different substituents from the group consisting of hydroxyl, cyano, nitro, halogen, Cι-C₄-aUcyl, Cι-C₄- alkoxy, Cι-C₂-halogenoaUcyl, C₁-C2 halogenoaUcoxy or Cι-C₂ halogenoaUcylthio having in each case 1 to 3 20 halogen atoms, in particular 4-hydroxy-3-methoxy-phenyl, and R³⁰⁷ represents (Cι-C₄)-alkyl, (C₂-C₄)-alkenyl, (C₂-C₄)-alkynyl, formyl, (Cι-C₄)-aUcylcarbonyl, (Cι-C₄,)-halogenoaUcylcarbonyl having 1 to 5 identical or different halogen atoms from the group consisting of fluorine, chlorine or bromine or (Cι-C₄)-alkoxycarbonyl; Ar especially preferably represents phenyl or pyridyl, each of which is optionally monosubstituted to trisubstituted by identical or different substituents from the group consisting of fluorine, chlorine, trifluoromethyl, trifluoromethylthio, trifluoromethoxy, methoxy, hydrazine, dimethylhydrazino, amino, methylamino, dimethylamino, iminomethyl, cyano, methylthio or the group

where R and R are identical or different and represent hydrogen or (Cι-C₄)-alkyl; xι^m especially preferably represents a number 0, 1 or 2. Compounds of formula (IV) which are most preferably preferred are those where R³⁰¹ represents H₂N-C(S)-; R³⁰² most preferably represents one of the following groups: -CF₃, -CHF₂ -CF2-CH3 -CF₃-CHF₂, -CF₂CHFC1, -CH₂-CF₃, -CH2CF2CI, -CH2-CF2-CHF2, -CF2-CFCI-CF3, -C(C1)(CF₃)-CF₂C1, -C(C1)(CF₃)-CHC1-CF₃, -C(CF₃)=CC1₂ R³⁰³ most preferably represents hydrogen, amino or one of the groups: -NH-CO-CH₃, -NH-CO-C₂H₅, -N=CH-NH₂, -N=C(CH₃)-NH₂, -N=CH-N(CH₃)₂, -N=C(CH₃)-N(CH₃)₂,

-NHC₂H₅ or -NH-CH₂-CH=CH₂. Ar most preferably represents (1) phenyl which is disubstituted or trisubstituted by identical or different substituents, where fluorine or chlorine occupies the 2-position, trifluoromethyl the 4-position and fluorine, chlorine, cyano, methoxy, methylthio, trifluoromethyl, trifluoromethoxy, trifluoromethylthio or hydrazino the 6-position; or (2) a 2-pyridyl substituent which is substituted in the 4-position by trifluoromethyl and in the 6-position by fluorine or chlorine. n ^1U most preferably represents one of the integers 0, 1 or 2. A most especially preferred compound is one wherein R is -CF₃, R is amino, Ar is a phenyl which is trisubstituted and the substituents are a 2- position chloro group, a 4-position trifluoromethyl group and a 6- position chloro group, and n¹¹¹ is 1. Especially prefeπed compounds are those of the formulae.

Other preferred 1-N-arylpyrazoles include the following compounds:

Especially preferred 1-N-arylpyrazoles derivative in addition to fipronil include fipronil thio

and fipronil sulfone

In addition to the patent discussing 1-N-arylpyrazoles derivatives discussed previously, one skilled in the art could make these compounds by adopting procedures described in DE 19928155, DE 19853560, WO 2000031043, DE 19650197, WO 9824769, US 6265430, US 2001007876, all of which are herein incorporated by reference. Insect growth regulating (IGR) compounds are another class of insecticides or acaricides, which are provided for in the bait formulations in this invention. Compounds belonging to this group are well known to the practitioner and represent a wide range of different chemical classes. These compounds all act by interfering with the development or growth of the insect pests. Compounds with an ovicidal and/or larvicidal effect on the immature stages of various ectoparasites are already known, for example from U.S. Patent No. 5,439,924. Among these compounds described are those IGR compounds which act either by blocking the development of the immature stages (eggs and larvae) into adult stages, or by inhibiting the synthesis of chitin. Insect growth regulators are described, for example, in U.S. Patent 3,748,356; U.S. Patent 3,818,047; U.S. Patent 4,225,598; U.S. Patent 4,798,837; and U.S. Patent 4,751,225, as well as in EP 179,022 or U.K. 2,140,010. French Patent No. A-2,713,889 generally describes an IGR combination comprising at least one compound with juvenile hormone activity and chitin synthesis inhibitors, with at least one of three N- arylpyrazole compounds, in particular fipronil, to control many harmful insects belonging to very varied orders. Examples of IGR compounds which may be used in this invention include compounds which mimic juvenile hormones, in particular: azadirchtin - Agridyne diofenolan (Ciba Geigy now Novartis) fenoxycarb (Ciba Geigy now Novartis) hydroprene (Sandoz now Novartis) kinoprene (Sandoz now Novartis) methoprene (Sandoz now Novartis) pyriproxyfen (Sumitomo/Mgk) tetrahydroazadirachtin (Agridyne) 4-chloro-2-(2-chloro-2-methylpropyl)-5-(6-iodo-3- pyridylmethoxy)pyridizin-3(2H)-one and chitin-synthesis inhibitors, in particular: chlorfluazuron (Ishihara Sangyo) cyromazine (Ciba Geigy now Novartis) diflubenzuron (Solvay Duphar) fluazuron (Ciba Geigy now Novartis) flucycloxuron (Solvay Duphar) flufenoxuron (Cyanamid) hexaflumuron (Dow Elanco) lufenuron (Ciba Geigy now Novartis) tebufenozide (Rohm & Haas) teflubenzuron (Cyanamid) triflumuron (Bayer). These compounds are defined by their international common name (The Pesticide Manual, 10^th edition, 1994, Ed. Clive Tomlin, Great Britain). Chitin-synthesis inhibitors also include compounds such as l-(2,6- difluorobenzoyl)-3-(2-fluoro-4-((trifluoromethyl)) phenylurea, 1 -(2,6-difluorobenzoyl)- 3-(2-fluoro-4-(l, 1,2,2 -tetrafluoroethoxy))phenylurea and l-(2,6-difluorobenzoyl)-3-(2- fluoro-4-trifluoro-methyl)phenylurea. Novaluron (Isagro, Italian company) is also an example of an IGR compound. Preferred IGR compounds include methoprenes, pyriproxyfens, hydroprene, cyromazine, lufenuron, l-(2,6-difluorobenzoyl)-3-(2-fluoro-4- (trifluoromethyl)phenylurea and novaluron. The alkyl groups of the definition of the compounds (1) of the formula (I) generally comprise from 1 to 6 carbon atoms. The ring formed by R₅ and R₆ and the nitrogen atom to wliich they are attached is generally a 5-, 6- or 7-membered ring. Unless otherwise specified, aUcyl and alkoxy groups are generally lower alkyl and alkoxy groups, that is having from one to six carbon atoms, preferably from one to four carbon atoms. Generally, the haloalkyl, haloaUcoxy and alkylamino groups have from one to four carbon atoms. The haloalkyl and haloalkoxy groups can bear one or more halogen atoms; preferred groups of this type include -CF₃ and -OCF₃. Cycloalkyl groups generally have from 3 to 6 carbon atoms, preferably from 3 to 5 carbon atoms, and may be substituted by one or more halogen atoms. Alkenyl, haloaUcenyl, aUcynyl, and haloalkynyl groups generally contain from 3 to 5 carbon atoms. By the term aryl is generally meant phenyl, pyridyl, furyl, and thiophenyl, each of which is optionally substituted by one or more halogen, alkyl, haloaUcyl, nitro, alkoxy, haloaUcoxy, hydroxy, amino, aUcylamino or dialkylamino. In compounds of formulae (1) to (III), by the term substituted aUcyl is meant aUcyl which is substituted by, for example, one or more halogen, alkoxy, haloaUcoxy, amino, aUcylamino, diaUcylamino, cyano or -S(O)_mRn₅; or aUcyl substituted by phenyl or pyridyl each of which is optionally substituted with one or more groups selected from halogen, nitro and alkyl; wherein Rn₅ is aUcyl or haloalkyl and m is zero, one or two. Preferably in compounds of formula (I), alkyl groups are generally substituted by from one to five halogen atoms, preferably from one to three halogen atoms. Chlorine and fluorine atoms are preferred. Compounds of formula wherein Rι₀₄ is -N=C(Rι₀₅)~Z-Rιo₆, Z is NR₁₀₇ and Rioe represent a hydrogen atom may exist as the tautomeric double bond isomer form -NH-C(Rιo₅)=N-Rιo₇. It is to be understood that both such forms are embraced by the present invention. In compounds of formula (III) the following examples of substituents are provided: An example of cycloalkylalkyl is cyclopropylmethyl; an example of cycloalkoxy is cyclopropyloxy; An example of alkoxyalkyl is CH₃OCH₂-; An example of alkoxyalkoxy is CH₃OCH O-; An example of alkoxyalkoxyaUcoxy is CH₃OCH₂OCH₂O-; An example of aryloxy is the phenoxy group; and An example of the arylalkoxy group is benzyloxy or 2-phenylethoxy. Generally, in diaUcylamino or di(haloalkyl)amino groups, the alkyl and haloaUcyl groups on nitrogen may be chosen independently of one another. A preferred class of compounds of formula (I) comprises the compounds such that Ri is CN, R₃ is haloalkyl, Rt is NH₂, Rπ and Rι₂ are, independently of one another, a halogen atom and Rι₃ is haloalkyl. Preferably still, X is C-Rι . A compound of formula (I) wliich is very particularly preferred in the invention is 5-amino-3-cyano- 1 -(2,6-dichloro-4-trifluoromethylphenyl)-4-trifluoromethylsulfinylpyrazole or fipronil. Compounds of formulae (I) - (III) can be prepared according to one or other of the processes described in Patent Applications WO 87/3781, 93/6089 and 94/21606, and 00/59862 or European Patent Application 295,117 or any other process coming within the competence of a person skilled in the art who is an expert in chemical synthesis. For the chemical preparation of the products of the invention, a person skilled in the art is regarded as having at his disposal, inter alia, the entire contents of "Chemical Abstracts" and of the documents which are cited therein. Administration of the inventive formulation may be intermittent in time and may be administered daily, weekly, biweekly, monthly, bimonthly, quarterly, or even for longer durations of time. The time period between treatments depends upon factors such as the parasite(s) being treated, the degree of infestation, the type of mammal or bird and the environment where it resides. It is well within the skill level of the practitioner to determine a specific admimstration period for a particular situation.

This invention contemplates a method for combating mosquitoes in an environment in which the animal is subjected to strong mosquito pressure where the administration is at a frequency far below a daily administration in this case. For example, it is preferable for the treatment according to the invention to be carried out monthly on dogs and on cats and or birds. Spot-on and pour-on formulations may be prepared by dissolving the active ingredients into the pharmaceutically or veterinary acceptable vehicle. Alternatively, the spot-on formulation can be prepared by encapsulation of the active ingredient to leave a residue of the therapeutic agent on the surface of the animal. These formulations will vary with regard to the weight of the therapeutic agent in the combination depending on the species of host animal to be treated, the severity and type of infection and the body weight of the host. The compounds maybe administered continuously, particularly for prophylaxis, by known methods. Generally, a dose of from about 0.001 to about 10 mg per kg of body weight given as a single dose or in divided doses for a period of from 1 to 5 days will be satisfactory but, of course, there can be instance where higher or lower dosage ranges are indicated and such are within the scope of this invention. It is well within the routine skill of the practitioner to detennine a particular dosing regimen for a specific host and parasite. Preferably, a single formulation containing the 1-N-arylpyrazole derivative in a substantially liquid carrier and in a form which makes possible a single application, or an application repeated a small number of times, will be administered to the animal over a highly localized region of the animal, preferably between the two shoulders. Most preferably, this localized region has a surface area of less than 10 cm², especially between 5 and 10 cm² area. Remarkably, it has been discovered that such a formulation is highly effective against the mosquito, thereby preventing or interrupting the transmission of the mosquito-borne disease. The treatment is preferably carried out so as to administer to the host, on a single occasion, a dose containing between about 0.001 and about 100 mg/kg of 1-N- arylpyrazole derivative and, in particular, a dose that is topically administered. The amount of 1-N-arylpyrazole for birds and animals which are small in size is preferably greater than about 0.01 mg and in a particularly preferred way between about 1 and about 50 mg/kg of weight of animal. It also may be preferable to use controlled-release formulations. With regard to formulations wliich comprise both 1-N-arylpyrazole and

IGR compounds, it is preferable to administer the two classes of compounds concomitantly and, most preferably, simultaneously. Preferably, the treatment is carried out so as to administer to the- animal a dose of from about 0.1 to about 40 and in particular from about 1 to about 20 mg/kg of 1-N-phenylpyrazole and a dose of from about 0.1 to about 40 and in particular about 1 to about 30 mg/kg of IGR compound. The preferred doses are from about 5 to about 15 mg/kg of 1-N- arylpyrazoles and from about 0.5 to about 15 mg kg for the prefeπed IGR compounds, or about 10 to about 20 mg/kg for the other IGR compounds. In another embodiment of the method according to the invention, the 1-

N-arylpyrazoles and the IGR compounds may be applied in a distinct and separate manner over time. In this case, it is preferred to alternate the applications with an interval, for example of one month between two applications, the first application preferably being made with the 1-N-arylpyrazole. It is understood that the dosage values which are thus indicated are average values which may vary within a wide range, since, in practice, a formulation having defined doses of 1-N-arylpyrazole-type derivative and of an IGR compound will be administered to animals having relatively different weights. Consequently, the doses actually applied are often smaller or larger by a factor wliich may be up to 2, 3 or 4 relative to the prefeπed dose, without entailing any toxic risk for the animal in the case of an overdose, and while at the same time retaining real efficacy, possibly of shorter duration, in the case of an underdose. While not wishing to be bound by theory, it is believed that the invention spot-on formulation works by the dose dissolving in the natural oils of the host's skin, fur or feathers. From there, the therapeutic agent(s) distribute around the host's body through the sebaceous glands of the skin. The therapeutic agent also remains in the sebaceous glands. Thus, the glands provide a natural reservoir for the therapeutic agent wliich allows for the agent to be drained back out to the follicles to reapply itself to the skin and hair feathers. This, in turn, provides for longer time periods between applications as well as not having to re-administer the dose after the host becomes wet because of rain, baths, etc. Moreover, the inventive formulations have the further advantage in self- grooming animals of not being directly deposited on the skin or fur where the animals might orally ingest the therapeutic agent, thereby increasing the safety margin. The spot-on formulations of the present invention provide for the topical admimstration of a concentrated solution, suspension, microemulsion or emulsion for intermittent application to a spot on the animal, generally between the two shoulders (solution of spot-on type). It has been discovered that the inventive formulations are especially active against parasites when the formulations are applied to mammals and birds, especially poultry, dogs, cats, sheep, pigs, cattle zebras, horses, donkeys, mice, chipmunks and tree squiπels. These formulations comprise a composition of an effective amount of compound (1) and/or IGR compound dissolved in a pharmaceutical or veterinary-acceptable carrier vehicle where a crystallization inhibitor is optionally present. The N-arylpyrazoles can advantageously be present in the formulations in a proportion of about 1 to about 20%, preferably of about 5 to about 15% (percentages as weight by volume = W/V). The liquid carrier vehicle comprises a pharmaceutically or veterinary acceptable organic solvent and optionally an organic cosolvent. Also contemplated are the pharmaceutically or veterinary-acceptable acid or base salts, where applicable, of the active compounds provided for herein. The term "acid" contemplates all pharmaceutically or veterinary acceptable inorganic or organic acids. Inorganic acids include mineral acids such as hydrohalic acids, such as hydrobromic and hydrochloric acids, sulfuric acids, phosphoric acids and nitric acids. Organic acids include all pharmaceutically or veterinary-acceptable aliphatic, alicyclic and aromatic carboxylic acids, dicarboxylic acids, tricarboxylic acids and fatty acids. Prefeπed acids are straight chain or branched, saturated or unsaturated Cι-C₂₀ aliphatic carboxylic acids, which are optionally substituted by halogen or by hydroxyl groups, or C₆-Cι aromatic carboxylic acids. Examples of such acids are carbonic acid, formic acid, fumaric acid, acetic acid, propionic acid, isopropionic acid, valeric acid, α- hydroxy acids, such as glycolic acid and lactic acid, chloroacetic acid, benzoic acid, methane sulfonic acid, and salicylic acid. Examples of dicarboxylic acids include oxalic acid, malic acid, succinic acid, tataric acid and maleic acid. An example of a tricarboxylic acid is citric acid. Fatty acids include all pharmaceutically or veterinary- acceptable saturated or unsaturated aliphatic or aromatic carboxylic acids having 4 to 24 carbon atoms. Examples include butyric acid, isobutyric acid, sec-butyric acid, lauric acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, and phenylsteric acid. Other acids include gluconic acid, glycoheptonic acid and lactobionic acid. The term "base" contemplates all pharmaceutically or veterinary acceptable inorganic or organic bases. Such bases include, for example, the alkali metal and aUcaline earth metal salts, such as the lithium, sodium, potassium, magnesium or calcium salts. Organic bases include the common hydrocarbyl and heterocyclic amine salts, which include, for example, the morpholine and piperidine salts. The organic solvent for the liquid carrier vehicle will preferably have a dielectric constant of between about 10 and about 35, preferably between about 20 and about 30, the content of this solvent in the overall composition preferably representing the remainder of 100% of the composition. It is well within the slcill level of the practitioner to select a suitable solvent on the basis of these parameters. The organic cosolvent for the liquid carrier vehicle will preferably have a boiling point of less than about 100°C, preferably of less than about 80°C, and will have a dielectric constant of between about 10 and about 40, preferably between about 20 and about 30; this cosolvent can advantageously be present in the composition according to a weight/weight (W/W) ratio with respect to the solvent of between about 1/15 and about 1/2; the cosolvent is volatile in order to act in particular as drying promoter and is miscible with water and/or with the solvent. Again, it is well within the slcill level of the practitioner to select a suitable solvent on the basis of these parameters. The organic solvent for the liquid carrier includes the commonly acceptable organic solvents known in the formulation art. These solvents may be found, for example, in Remington Pharmaceutical Science, 16^th Edition (1986). These solvents include, for example, acetone, ethyl acetate, methanol, ethanol, isopropanol, dimethylformamide, dichloromethane or diethylene glycol monoethyl ether

(Transcutol). These solvents can be supplemented by various excipients according to the nature of the desired phases, such as C₈-Cιo caprylic/capric triglyceride a hydro genated or fractionated coconut oil (Estasan or Miglyol 812), oleic acid or propylene glycol. The liquid carrier may also comprise a micro emulsion. Microemulsions are also well suited as the liquid carrier vehicle. Microemulsions are quaternary systems comprising an aqueous phase, an oily phase, a surfactant and a cosurfactant. They are translucent and isotropic liquids. Microemulsions are composed of stable dispersions of microdroplets of the aqueous phase in the oily phase or conversely of microdroplets of the oily phase in the aqueous phase. The size of these microdroplets is less than 200 mn (1000 to 100,000 nm for emulsions). The interfacial film is composed of an alternation of surface-active (SA) and co-surface-active (Co-SA) molecules which, by lowering the interfacial tension, allows the microemulsion to be formed spontaneously. The oily phase can in particular be formed from mineral or vegetable oils, from unsaturated polyglycosylated glycerides or from triglycerides, or alternatively from mixtures of such compounds. The oily phase preferably comprises triglycerides and more preferably medium-chain triglycerides, for example C₈-Cιo caprylic/capric triglyceride. The oily phase will represent, in particular, from about 2 to about 15% more, particularly from about 7 to about 10%, preferably from about 8 to about 9%,

V/V of the microemulsion. Suitable oils for the oily phase are known in the art and are described, for example, in U.S. Patent 6,036,394; U.S. Patent 5,580,574; U.S. Patent 6,174,540 and WO 97/37653, herein incorporated by reference. The aqueous phase includes, for example, water or glycol derivatives, such as propylene glycol, glycol ethers, polyethylene glycols or glycerol. Propylene glycol, diethylene glycol monoethyl ether and dipropylene glycol monoethyl ether are especially prefeπed. Generally, the aqueous phase will represent a proportion from about 1 to about 4% V/V in the microemulsion. Surfactants for the microemulsion include diethylene glycol monoethyl ether, dipropylene glycol monomethyl ether, polyglycolysed C₈-Cιo glycerides or polyglyceryl-6 dioleate. In addition to these surfactants, the cosurfactants include short- chain alcohols, such as ethanol and propanol. Some compounds are common to the three components discussed above, i.e., aqueous phase, surfactant and cosurfactant. However, it is well within the slcill level of the practitioner to use different compounds for each component of the same formulation. The cosurfactant to surfactant ratio will preferably be from about 1/7 to about 1/2. There will preferably be from about 25 to about 75% V/V of surfactant and from about 10 to about 55% V/V of cosurfactant in the microemulsion. Likewise, the co-solvents are also well known to a practitioner in the formulation art. Prefeπed co-solvents are those which are promoters of drying and include, for example, absolute ethanol, isopropanol (2-propanol) or methanol. The crystallization inhibitor can in particular be present in a proportion of about 1 to about 20% (W/V), preferably of about 5 to about 15%. The inhibitor preferably coπesponds to the test in which 0.3 ml of a solution comprising 10% (W/V) of the compound of formula (I) in the liquid carrier and 10% of the inhibitor are deposited on a glass slide at 20°C and allowed to stand for 24 hours. The slide is then observed with the naked eye. Acceptable inhibitors are those whose addition provides for few or no crystals, and in particular less than 10 crystals, preferably 0 crystals. Although this is not prefeπed, the formulation can optionally comprise water, in particular in a proportion of 0 to about 30% (volume by volume V/V), in particular of 0 to about 5%. The formulation can also comprise an antioxidizing agent intended to inhibit oxidation in air, this agent being particularly present in a proportion of about 0.005 to about 1% (W/V), preferably of about 0.01 to about 0.05%. Crystallization inhibitors which can be used in the invention include:

- polyvinylpyπolidone, polyvinyl alcohols, copolymers of vinyl acetate and of vinylpyπolidone, polyethylene glycols, benzyl alcohol, mannitol, glycerol, sorbitol or polyoxyethylenated esters of sorbitan; lecithin or sodium carboxymethylcellulose; or acrylic derivatives, such as methacrylates and others,

- anionic surfactants, such as alkaline stearates, in particular sodium, potassium or ammonium stearate; calcium stearate or triethanolamine stearate; sodium abietate; aUcyl sulphates, in particular sodium lauryl sulphate and sodium cetyl sulphate; sodium dodecylbenzenesulphonate or sodium dioctyl sulphosuccinate; or fatty acids, in particular those derived from coconut oil, cationic surfactants, such as water-soluble quaternary ammonium salts of formula N^IRR"R"'R""Y^~, in which the R radicals are identical or different optionally hydroxylated hydrocarbon radicals and Y^~~ is an anion of a strong acid, such as halide, sulphate and sulphonate anions; cetyltrimethylammonium bromide is one of the cationic surfactants which can be used,

- amine salts of formula N^RR 'R'", in which the R radicals are identical or different optionally hydroxylated hydrocarbon radicals; octadecylamine hydrochloride is one of the cationic surfactants which can be used,

- non-ionic surfactants, such as optionally polyoxyethylenated esters of sorbitan, in particular Polysorbate 80, or polyoxyethylenated alkyl ethers; polyethylene glycol stearate, polyoxyethylenated derivatives of castor oil, polyglycerol esters, polyoxyethylenated fatty alcohols, polyoxyethylenated fatty acids or copolymers of ethylene oxide and of propylene oxide, amphoteric surfactants, such as substituted lauryl compounds of betaine, or preferably a mixture of at least two of the compounds listed above. In a particular prefeπed embodiment, a crystallization inhibitor pair will be used. Such pairs include, for example, the combination of a fihn-forming agent of polymeric type and of a surface-active agent. These agents will be selected in particular from the compounds mentioned above as crystallization inhibitors. Particularly prefeπed film-forming agents of polymeric type include: - the various grades of polyvinylpyπolidone, - polyvinyl alcohols, and - copolymers of vinyl acetate and of vinylpyπolidone. Especially prefeπed surface-active agents, include those made of non- ionic surfactants, preferably polyoxyethylenated esters of sorbitan and in particular the various grades of polysorbate, for example Polysorbate 80. The film-forming agent and the surface-active agent can in particular be incorporated in similar or identical amounts within the limit of the total amounts of crystallization inhibitor mentioned elsewhere. The pair thus constituted secures, in a noteworthy way, the objectives of absence of crystallization on the coat and of maintenance of the cosmetic appearance of the fur, that is to say without a tendency towards sticking or towards a sticky appearance, despite the high concentration of active material. Particularly prefeπed antioxidizing agents are those conventional in the art and include, for example, butylated hydroxyanisole, butylated hydroxytoluene, ascorbic acid, sodium metabisulphite, propyl gallate, sodium thiosulphate or a mixture of not more than two of them. The formulation adjuvants discussed above are well known to the practitioner in this art and may be obtained commercially or through known techniques. These concentrated compositions are generally prepared by simple mixing of the constituents as defined above; advantageously, the starting point is to mix the active material in the main solvent and then the other ingredients or adjuvants are added. The volume applied can be of the order of about 0.3 to about 1 ml, preferably of the order of about 0.5 ml, for cats and of the order of about 0.3 to about 3 ml for dogs, depending on the weight of the animal. The formulations according to the invention are extremely effective for long durations of time in the treatment of parasites, such as mosquitoes in mammals and, in particular, of small mammals, such as dogs and cats. The inventive formulations also exhibit a degree of effectiveness against other parasitic insects, in particular, fleas, ticks, mites and flies. Another method of formulating antiparasitical formulations in this invention is a bait formulation that comprises a at least one 1-N-arylpyrazole derivative and or an IGR either alone or in combination with an antiparasitic, antihelmintic, or insecticidal agent placed in a commercially available bird station for preventing or interrupting the transmission of arthropod- or mosquito-borne diseases from an actual or putative amplifying or incipient host, such as an animal or bird (wild or domesticated), to a second actual or putative amplifying or incipient host, such as an animal, bird or human. This invention further provides for an apparatus, which is a chamber comprising an opening, the interior of which includes an applicator that is attached to a reservoir by a conduit said conduit comprising an actuator to deliver a metered dose of a veterinary formulation comprising a 1-N-arylpyrazole, as well as a method for using the apparatus to prevent or interrupt the transmission for a mosquito-borne disease from a first actual or putative amplifying host, wherein said first host is a bird or animal, to a second actual or putative amplifying or incipient host in an environment where said first host resides by applying a metered dose of the veterinary formulation to the feathers, fur or skin of the bird or animal. FIGS. 1 and 2 depict two non-limiting examples of the apparatus. To construct apparatuses of different sizes to accommodate a specific bird or animal would be well within the routine slcill of the practitioner. The apparatus (1) comprises a top, (2) a bottom (3), at least one wall (4), which connects the top (2) to the bottom (3), thereby creating an interior space (5), and at least one opening (6), which connects the environment (12) to the interior space (5) of the apparatus. The materials used for the top (2), bottom (3) and walls (4) would be well known to the practitioner and include, for example, wood, plastics, etc. FIG. 1 depicts a prefeπed embodiment of the apparatus that has four walls (4), one of which is removable (41) so one has the option of inserting bait or food (8). FIG. 2 depicts an alternative prefeπed embodiment, which has one wall (4), two openings (6), where the wall has a door (42) to insert the bait or food (not shown). The interior space (61) of the opening (6) has an applicator (62) attached thereto. FIGS. 3(a) and 3(b) depict a detailed view of two prefeπed embodiments of the opening. The applicator (62) is attached to the reservoir (7), which contains the formulation (71) by a conduit (9), which conducts flow of the formulation (71) to the applicator (62). The applicator (62) comprises any material which will retain the formulation and transfer it to the bird or animal. Examples of suitable materials for an applicator would be a sponge or a moisture-sensitive membrane. Likewise, the reservoir and the conduit may be made of any material suitable for this purpose such as metal or plastic, and the size and shape depend on the particular dimensions of the apparatus. Such determinations for particular materials, size and shape are well within the review of the skilled practitioner. In FIGS. 3(a) and 3(b) the conduit (9) comprises an actuator (10) which administers the metered dose of the formulation when the bird or animal enters the apparatus. The activator may be, for example, a pressure sensitive device (not shown) or a light beam (11), which controls the release of the fonnulation to the applicator when the bird or animal enters or leaves the apparatus, thereby administering the metered dose of the formulation to the animal. The opening (6) may be of any size or shape and is configured to permit the entry or egress of the bird or animal into the apparatus. The determination of the coπect size would be well within the slcill level of the practitioner and is dependent on the size of the bird or animal. Other advantages and characteristics of the invention will become apparent on reading the following description, given by way of non-limiting examples. Example 1 : Mosquito Mortality (Spray) The ability of formulations to kill mosquitoes after feeding and thereby preventing or inhibiting the spread of a mosquito-borne disease was tested by comparing the mortality of mosquitoes who feed on dogs treated with a formulation comprising a 1-N-arylpyrazole derivative with dogs which were not treated. Four beagles, two males and two females, were randomly assigned to one of two treatment groups. Group I was not treated and Group II was treated with a fipronil spray at a rate of 6 ml/kg on Day 0 and Day 30. Assessment of mosquito mortality was conducted by exposing the dogs of the two groups with non-infected mosquitoes on Days 3, 10, 17, 24, 31, 38, 45, 52 and 59. Mosquito mortality was determined by counting the number of dead mosquitoes 7 after exposure. The data is summarized in Table 2.

Table 1: Mosquito Mortality [engorged females]

* Dogs are treated on day 0 and day 30. The data demonstrates that there was an increase in the mortality of the mosquitoes that fed on dogs treated with a formulation comprising fipronil.

Example 2: Mosquito Mortality (Spot-on Formulation) The ability of a spot-on formulation comprising a 1-N-arylpyrazole derivative to kill mosquitoes in treated dogs was compared with untreated dogs. Sixteen beagles were placed in two groups of eight dogs each. The dogs in group I were untreated and the dogs in group H were treated with topical fipronil, a spot-on formulation comprising 10% w/v of fipronil and 9% w/v of (s)-methoprene. The dogs were sedated and placed individually in mosquito proof containers. Approximately 100 mosquitoes, A. aegypti four to five days old were releases into the container. After approximately 30 minutes, all of the engorged and non-engorged mosquitoes were aspirated into a separate container using a vacuum pump and the number was recorded. Exposures occurred in days 1, 2, 7, 14, 21 and 28. Mosquitoes recovered from individual animals at each exposure were placed in separate containers (engorged and non-engorged) and kept in an insectary maintained at approximately 20°C and 80% relative humidity for 2 days. At day 1 after exposure, all dead mosquitoes were removed and counted. At day 2, all dead mosquitoes were counted. The data is summarized below in Table 2.

The results show that topical fipronil was effectively killing 95% of the mosquitoes at 3 weeks. The above description is intended to be illustrative and not-limiting. Various changes or modifications in the embodiments described herein may occur to those skilled in the art. These can be made without departing from the scope or spirit of the invention. The invention will now be further described by the following number paragraphs 1. A method for preventing or interrupting the transmission of mosquito-borne diseases from a first actual or putative amplifying or incipient host to a second actual or putative amplifying or incipient host, which comprises applying or administering a formulation comprising an effective amoxmt of at least one 1-N- arylpyrazole to said first actual or putative amplifying host and/or actual or putative amplifying or incipient host. 2. The method according to paragraph 1, wherein the formulation comprises an effective amount of at least one 1-N-arylpyrazole is a compound of the formula

in which Ri is a halogen atom, CN or alkyl; R₂ is S(O)_nR₃ or 4,5-dicyanoimidazol-2-yl or haloalkyl; R₃ is alkyl, alkenyl, alkynyl, haloaUcyl, haloalkenyl, or haloaUcynyl; R4 represents a hydrogen or halogen atom or an NR₅R₆, S(O)_mR₇, C(O)R₇₎ C(O)OR₇, alkyl, haloalkyl, OR₈, or an - N=C(R₉)(Ri₀) group; R₅ and R independently represent a hydrogen atom or an alkyl, haloalkyl, C(O)aUcyl, S(O)_rCF₃ or aUcoxycarbonyl radical or R₅ and R₆ may form a ring of 3 to 7 members which is optionally interrupted by one or two divalent heteroatoms; R₇ represents an aUcyl or haloaUcyl group; R₈ represents an aUcyl or haloaUcyl group or a hydrogen atom; 51 00177425.DOC R₉ represents an alkyl radical or a hydrogen atom; Rio represents an optionally substituted aryl or an optionally substituted heteroaryl group; Rπ and Rι represent, independently of one another, hydrogen, halogen CN or NO₂; Rι₃ represents a halogen atom or a haloaUcyl, haloalkoxy, S(O)_qCF₃ or SF₅ group; m, n, q and r represent, independently of one another, an integer equal to 0, 1 or 2; X represents a bivalent nitrogen atom or a C-Rι₂ radical, the three other valencies of the carbon atom forming part of the aromatic ring; with the proviso that, when Ri is methyl, then either R₃ is haloaUcyl, i is NH2, Rπ is Cl, Rι₃ is CF₃ and X is N or else R is 4,5-dicyanoimidazol-2-yl, R₄ is Cl, Rπ is Cl, Rι₃ is CF₃ and X is C-Cl, optionally with a pharmaceutically acceptable caπier or excipient. 3. The method according to paragraph 2, wherein the formulation comprises an effective amount of a compound of formula (I) wherein: Ri is a halogen atom, CN or methyl; R₂ is S(O)_nR₃ or 4,5-dicyanoimidazol-2-yl or haloalkyl; R₃ is Cι-C₆-aUcyl or Cι-C₆-haloaUcyl; R₄ represents a hydrogen or halogen atom; or a group NRsR_ό, S(O)_mR₇, C(O)R₇ or C(O)OR₇, aUcyl, haloalkyl or OR₈ or a group

R₅ and R₅ independently represent a hydrogen atom or a Cι-C₆- aUcyl, Ci- C₆-haloalkyl, C(O)d-C₆-aUcyl, S(O)_rCF₃, Cι-C₆-acyl or C^Ce-alkoxycarbonyl group; or R₅ andR₆ together may form a ring of 3- to 7-membered which additioanlly may contain one or more heteroatoms selected from the group consisting of oxygen or sulphur. 4. The method according to paragraph 1, wherein the formulation comprises an effective amount of at least 1-N-arylpyrazole is a compound of the formula

(II) wherein: Rioi is cyano, -C(O)alkyl, C(S)NH₂, alkyl, haloalkyl,

C(=NOH)NH₂ or C(=NNH₂)NH₂; Rι₀₂ is S(O)_nRιo₃, aUcenyl, haloalkenyl, cycloaUcyl, halocycloalkyl or alkynyl; Rio₃ , is aUcyl or haloaUcyl;

Rios is hydrogen, aUcyl, alkyl substituted by halogen, alkoxy, haloaUcoxy or -S(O)_m>Rιo₅; Rιo₆ and R₁₀₇ each independently represent hydrogen, alkyl, aUcenyl, alkynyl, alkyl substituted by one or more substituents selected from the group consists of halogen, aUcoxy, haloaUcoxy, amino, alkylamino, diaUcylamino, cyano, - S(O)_mRπs_. phenyl and pyridyl, said phenyl or pyridyl being optionally substituted with one or more substituents selected from the group consisting of halogen, nitro and aUcyl, or Rio_ό and R₁₀₇ may form together with the nitrogen to wliich they are attached a 3- to 7-membered ring which may additionally contain one or more heteroatoms selected from the group - consisting of oxygen, nitrogen or sulfur; Rios is alkoxy, haloalkoxy, amino, alkylamino, dialkylamino,

Rπ₄CO or -S(O)_tRιιo; R₁₀₉, Rno and Rπ₄ are alkyl or haloalkyl; Rm and R are independently selected from the group consisting of halogen, hydrogen, CN and NO₂ Rm is selected from the group consisting of halogen, haloalkyl, haloalkoxy, -S(O)_q>CF₃, and -SF₅; R₁₁₅ is aUcyl or haloalkyl; X is selected from nitrogen and C-Ri ι₂; Z is O, S(O)_a., or NRι₀₇; a', m', n' and q' are independently 0, 1, or 2; and t' is 0 or 2; optionally with a pharmaceutically acceptable caπier or excipient. 5. The method according to paragraph 1, wherein the formulation comprises an effective amount of at least one 1-N-arylpyrazole of the formula:

wherein: R₂oι is cyano, C(O)alkyl, C(S)NH₂, aUcyl, C(=NOH)NH₂ or C(=NNH₂)NH₂; R202 is S(O)hR203_. alkenyl, haloaUcenyl, cycloalkyl, halocycloalkyl or alkynyl; R₂₀₃ is alkyl, alkenyl, alkynyl, haloalkyl, haloalkenyl, or haloalkynyl; R₂₀₄ is -N(R₂o5)C(O)CR₂o₆R207R208, -N( ₂₀s)C(O)aιyl, or -

N(R₂₀₅)C(O)OR₂₀₇; R₂₀₅ is alkyl, haloaUcyl, cycloalkyl, halocycloaUcyl, cycloaUcylaUcyl, halocycloalkylalkyl, aUcoxyalkyl, haloalkoxyalkyl, alkenyl, haloalkenyl, aUcynyl, haloalkynyl; R oe is hydrogen, halogen, aUcoxy, haloalkoxy, alkoxyalkyl, haloalkoxyalkyl, formyloxy, aUcylcarbonyloxy, haloaUcylcarbonyloxy, alkylthio, haloaUcylthio, alkylsulfinyl, haloaUcylsulfinyl, aUcylsulfonyl, haloalkylsulfonyl, aUcylamino, diaUcylamino, haloaUcylamino, di(haloaUcyl)amino, cycloalkyloxy, halocycloaUcyloxy, aUcoxyaUcoxy, haloalkoxyaUcoxy, aUcoxyaUcoxyalkoxy, aryloxy, or arylalkoxy; R207 and R₂₀₈ are independently hydrogen, alkyl, haloalkyl, cycloalkyl, or halocycloaUcyl; or R o₇ and R₂o₈ may form together with the carbon to which they are attached a 3- to 7-membered ring which additionally may contain one or more heteroatoms selected from nitrogen, oxygen and sulfur; Xi is selected from nitrogen and C-R₂ι₂; R2₁₁ and R ι₂ are independently selected from the group consisting of halogen, hydrogen, CN and NO ; R2₁₃ is selected from the group consisting of halogen, haloalkyl, haloaUcoxy, -S(O)_kCF₃, and -SF₅; and h and k are independently selected from 0, 1, and 2; optionally with a pharmaceutically acceptable caπier or excipient. 6. The method according to paragraph 5, wherein the formulation comprises an effective amount of at least 1-N-arylpyrazole of the formula (III), wherein R201 ^l is cyano; R₂₀₃ is halomethyl; R₂₀₄ is N(R₂₀₅)C(O)CR₂o₆R207R208; R21₁ and R₂i₂ are independently halogen;

R₂₁₃ is haloalkyl, haloalkoxy or -SF₅; or h is O or l. 7. The method according to paragraph 1, wherein the formulation comprises an effective amount of at least one 1-N-arylpyrazole that is a compound selected from the group consisting of

59

and

8. A method for preventing or interrupting the transmission of mosquito-borne diseases from an actual or putative amplifying or incipient host, to a second actual or putative amplifying or incipient host, by applying a spot-on formulation comprising: (a) an effective amount of at least one 1-N-arylpyrazole derivative; (b) a pharmaceutically acceptable liquid carrier vehicle; (c) optionally, a crystallization inhibitor to said first actual or putative amplifying or incipient host and/or second actual or putative amplifying or incipient host. 9. The method according to paragraph 8 wherein the spot-on formulation comprises: (a) an effective amount of at least one compound of the formula

in winch Ri is a halogen atom, CN or alkyl; R₂ is S(O)_nR3 or 4,5-dicyanoimidazol-2-yl or haloaUcyl; R₃ is alkyl, alkenyl, alkynyl, haloalkyl, haloalkenyl, or haloalkynyl; i represents a hydrogen or halogen atom or an NR₅R₆, S(O)_mR₇, C(O)R₇, C(O)OR₇, aUcyl, haloalkyl, OR₈, or an - N=C(R₉)(Rιo) group; R₅ and Re independently represent a hydrogen atom or an aUcyl, haloaUcyl, C(O)alkyl, S(O)_rCF₃ or aUcoxycarbonyl radical or R₅ and R₆ can together form a divalent aUcylene radical which is optionally interrupted by one or two divalent heteroatoms; R represents an alkyl or haloaUcyl group; R₈ represents an aUcyl or haloalkyl group or a hydrogen atom; R₉ represents an alkyl group or a hydrogen atom; Rio represents an optionally substituted aryl or an optionally substituted heteroaryl group; Rπ and R₁₂ represent, independently of one another, hydrogen, halogen CN or NO₂; R₁₃ represents a halogen atom or a haloalkyl, haloaUcoxy, S(O)_qCF₃ or SF₅ group; m, n, q and r represent, independently of one another, an integer equal to 0, 1 or 2; X represents a bivalent nitrogen atom or a C-Rι₂ radical, the three other valencies of the carbon atom forming part of the aromatic ring; with the proviso that, when Ri is methyl, then either R₃ is haloalkyl, t is NH₂, Rii is Cl, Rι₃ is CF₃ and X is N or else R is 4,5-dicyanoimidazol-2-yl, t is Cl, R_n is Cl, R_J3 is CF₃ and X is C-Cl; (b) a pharmaceutically or veterinary acceptable liquid carrier vehicle; and (c) optionally, a crystallization inhibitor. 10. The method according to paragraph 8 wherein - the liquid carrier vehicle comprises a solvent and a cosolvent wherein the solvent is selected from the group consisting of acetone, acetonitrile, benzyl alcohol, butyl diglycol, dimethylacetamide, dimethylformamide, dipropylene glycol n-butyl ether, ethanol, isopropanol, methanol, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, monomethylacetamide, dipropylene glycol monomethyl ether, liquid polyoxyethylene glycols, propylene glycol, 2- pyπolidone, diethylene glycol monoethyl ether, ethylene glycol, diethyl phthalate fatty acid esters, and a mixture of at least two of these solvents and the cosolvent is selected from the group consisting of absolute ethanol, isopropanol or methanol. - the crystallization inhibitor selected from the group consisting of an anionic surfactant, a cationic surfactant, anon-ionic surfactant, an amine salt, an amphoteric surfactant or polyvinylpyπolidone, polyvinyl alcohols, copolymers of vinyl acetate and vinylpyπolidone, polyethylene glycols, benzyl alcohol, mannitol, glycerol, sorbitol, polyoxyethylenated sorbitan esters, lecithin, sodium carboxymethylcellulose, and acrylic derivatives, and a mixture of these crystallization inhibitors. 11. The method according to paragraph 9, wherein the formulation comprises an effective amount of a compound of formula (I) wherein Ri is a halogen atom, CN or methyl; R₂ is S(O)_nR₃ or 4,5-dicyanoimidazol-2-yl or haloaUcyl; R₃ is Cι-C₆-aUcyl or Cι-C₆-haloaUcyl; R_t represents a hydrogen or halogen atom; or a group NR₅R₅, S(O)_mR₇, C(O)R₇ or C(O)OR₇, alkyl, haloalkyl or OR₈ or a group -N=C(R₉) (Rιo); R₅ and Re independently represent a hydrogen atom or a Cι-C₆- allcyl, d- Ce-haloalkyl, C(O)Cι-C₆-aUcyl, S(O)_rCF₃, Cι-C₆-acyl or Cι-C₆-alkoxycarbonyl group; or R₅ and R₆ may together form a divalent alkylene group which may be interrupted by one or two divalent hetero atoms selected from the group consisting of oxygen or sulphur. 12. The method according to paragraph 10, wherein the formulation comprises an effective amount of at least one 1-N-arylpyrazole is a compound of the formula

wherein: Rioi is cyano, -C(O)aUcyl, C(S)NH₂, alkyl, haloaUcyl, C(=NOH)NH₂ or C(-NNH₂)NH₂; Ri₀₂ is S(O)_nRιo₃, alkenyl, haloaUcenyl, cycloaUcyl, halocycloaUcyl or alkynyl; R₁₀₃ is aUcyl, alkenyl, aUcynyl, haloalkyl, haloaUcenyl, or haloalkynyl;

Rios is hydrogen, alkyl, or alkyl substituted by halogen, aUcoxy, haloaUcoxy, or -S(O)m'Rι₀₅; Rιo₆ and R₁₀₇ each independently represent hydrogen, aUcyl, alkenyl or aUcynyl, alkyl substituted by one or more substituents selected from the group consisting of halogen, alkoxy, haloaUcoxy, amino, alkylamino, diaUcylamino, cyano -S(O)_mRn₅, phenyl and pyridyl, said phenyl or pyridy being is optionally substituted with one or more substituents selected from the group consisting of halogen, nitro and alkyl; or Rιo₆ and R₁₀₇ may form together with the nitrogen to which they are attached a 3- to 7-membered ring which may additionally contain one or more heteroatoms selected from the group consisting of oxygen, nitrogen or sulfur; Rιo₈ is aUcoxy, haloaUcoxy, amino, alkylamino, dialkylamino, Rπ₄CO- or -S(O)fRno; Rio₉, Rno and Rπ are alkyl or haloalkyl; Rm and R are independently selected from the group consisting of halogen, hydrogen, CN and NO_2; R 113 is selected from the group consisting of halogen, haloalkyl, haloalkoxy, -S(O)_q>CF₃, and -SF₅; Rll5 is aUcyl or haloaUcyl; X is nitrogen or C-Rπ₂; z is O, S(O)a_', orNRι₀₇; a', in', n' and q' are independently 0, 1, or 2; and t' is 0 or 2; optionally with a pharmaceutically acceptable caπier or excipient. 13 The method according to paragraph 10, wherein the formulation comprises an effective amount of at least one 1-N-arylpyrazole of the formula:

wherein: R₂₀ι is cyano, C(O)aUcyl, C(S)NH₂, aUcyl, C(=NOH)NH₂ or C(=NNH₂)NH₂; R202 is S(O)hR₂₀₃, alkenyl, haloaUcenyl, cycloaUcyl, halocycloaUcyl or aUcynyl; R203 is alkyl, alkenyl, alkynyl, haloaUcyl, haloaUcenyl, or haloalkynyl; R ^■204 is -N(R₂o₅)C(O)CR₂o₆R207R208, -N(R₂₀₅)C(O)aryl, or -

N(R₂₀₅)C(O)OR₂₀₇; R205 is alkyl, haloaUcyl, cycloaUcyl, halocycloaUcyl, cycloaUcylaUcyl, halocycloalkylaUcyl, alkoxyaUcyl, haloaUcoxyalkyl, aUcenyl, haloalkenyl, alkynyl, haloalkynyl; R206 is hydrogen, halogen, aUcoxy, haloaUcoxy, alkoxyaUcyl, haloaUcoxyalkyl, formyloxy, alkylcarbonyloxy, haloalkylcarbonyloxy, alkylthio, haloaUcylthio, aUcylsulfinyl, haloalkylsulfinyl, alkylsulfonyl, haloalkylsulfonyl, alkylamino, diaUcylamino, haloalkylamino, di(haloalkyl)amino, cycloaUcyloxy, halocycloalkyloxy, aUcoxyaUcoxy, haloalkoxyalkoxy, alkoxyalkoxyalkoxy, aryloxy, or arylalkoxy; R₂o₇ and R₂os are independently hydrogen, alkyl, haloaUcyl, cycloaUcyl, or halocycloalkyl; or R2₀₇ and R2os may form together with the carbon to which they are attached a 3- to 7- membered ring which additionally may contain one or more heteroatoms selected from the group consisting of nitrogen, oxygen and sulfur; Xi is nitrogen or C-R₂ι₂; R₂₁₁ and R₂₁₂ are independently selected from the group consisting of halogen, hydrogen, CN and NO₂; R₂i₃ is selected from the group of consisting of halogen, haloaUcyl, haloaUcoxy, -S(O)_kCF₃, and -SF₅; and h and k are independently selected from 0, 1, and 2; optionally with a pharmaceutically acceptable caπier or excipient. 14. The method according to paragraph 13, wherein the fonnulation comprises an effective amount of at least one 1-N-arylpyrazole of the formula (III), wherein R201 is cyano; R₂₀₃ is halomethyl; R₂₀₄ is N(R₂0₅)C(O)CR20₆R207R208; R₂π and R₂ι₂ are independently halogen; Xi is C-R₂ι₂; R₂i₃ is haloalkyl, haloalkoxy or -SF₅; or h is 0 or 1. 15. The method according to paragraph 10, wherein the formulation comprises an effective amount of at least one 1-N-arylpyrazole selected from the group consisting of

69

70

and

16. The method according to paragraph 15, wherein the formulation further comprises an insect growth regulator. 17. The method according to paragraph 1, wherein the formulation is a pour-on formulation. 18. The method according to paragraph 17, wherein the pour-on formulation comprises: (a) an effective amount of at least one 1-N-arylpyrazole derivative; (b) a pharmaceutically or veterinary acceptable liquid carrier vehicle which comprise a solvent and a cosolvent wherein the solvent is selected from the group consisting of acetone, acetonitrile, benzyl alcohol, butyl diglycol, dimethylacetamide, dimethylformamide, dipropylene glycol n-butyl ether, ethanol, isopropanol, methanol, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, monomethylacetamide, dipropylene glycol monomethyl ether, liquid polyoxyethylene glycols, propylene glycol, 2-pyrrolidone, diethylene glycol monoethyl ether, ethylene glycol, diethyl phthalate, fatty acid esters and a mixture of at least two of these solvents and the cosolvent is selected from the group consisting of absolute ethanol, isopropanol and methanol; (c) a crystallization inhibitor selected from the group consisting of an anionic surfactant, a cationic surfactant, a nonionic surfactant, anamine salts, amphoteric surfactant, polyvinylpyπolidone, polyvinyl alcohols, copolymers of vinyl acetate and vinylpyπolidone, polyethylene glycols, benzyl alcohol, mannitol, glycerol, sorbitol, polyoxyethylenated sorbitan esters; lecithin, sodium carboxymethylcellulose, acrylic derivatives and a mixture of these crystallization inhibitors; (d) optionally, an antioxidant. 19. The method according to paragraph 18 wherein the 1 -N- arylpyrazole is

l-[2,6-Cl₂-4-CF₃ ρhenyl]-3-CN-4-[SO-CF₃]-5-NH₂ pyrazole; or

20. The method according to paragraph 18 wherein the 1-N- arylpyrazole is

75



Claims

WHAT IS CLAIMED IS: 1. A method for preventing or interrupting the transmission of arthropod- or mosquito-borne diseases from a first actual or putative amplifying or incipient host to a second actual or putative amplifying or incipient host, which comprises applying or administering a formulation comprising an effective amount of at least one 1-N-arylpyrazole derivative to said first actual or putative amplifying host and/or actual or putative amplifying or incipient host.

2. The method according to claim 1, wherein the formulation comprises an effective amount of at least one 1-N-arylpyrazole is a compound of the formula:

in which Ri is a halogen atom, CN or aUcyl; R₂ is S(O)_nR₃ or 4,5-dicyanoimidazol-2-yl or haloalkyl; R₃ is alkyl, aUcenyl, alkynyl, haloaUcyl, haloalkenyl, or haloalkynyl; R. represents a hydrogen or halogen atom or an NR₅R₆, S(O)_mR₇, C(0)R₇, C(O)OR₇, alkyl, haloaUcyl, OR₈, or an ^■ N=C(R₉)(Rιo) group; R₅ and R_δ independently represent a hydrogen atom or an aUcyl, haloalkyl, C(O)alkyl, S(O)_rCF₃ or aUcoxycarbonyl group or R₅ and R₆ together may form a ring of 3 to 7 members which is optionally interrupted by one or two divalent heteroatoms; R₇ represents an aUcyl or haloaUcyl group; R₈ represents an aUcyl or haloaUcyl group or a hydrogen atom; R₉ represents an aUcyl group or a hydrogen atom; Rio represents an optionally substituted aryl or an optionally substituted heteroaryl group; R₁₁ and Rι₂ represent, independently of one another, hydrogen, halogen CN or NO₂; R₁₃ represents a halogen atom or a haloalkyl, haloaUcoxy, S(O)_qCF₃ or SF₅ group; m, n, q and r represent, independently of one another, an integer equal to 0, 1 or 2; X represents a trivalent nitrogen atom or a C-R₁₂ substituent, the three other valencies of the carbon atom fonning part of the aromatic ring; with the proviso that, when Ri is methyl, then either R₃ is haloalkyl, _t is NH2, Rπ is Cl, R13 is CF₃ and X is N or else R₂ is 4,5- dicyanoimidazol-2-yl, _t is Cl, Rπ is Cl, Rι₃ is CF₃ and X is C-Cl, optionally with a pharmaceutically acceptable caπier or excipient.

3. The method according to claim 2, wherein the 1 -N-arylpyrazole derivative is 5-amino-3-cyano-l-(2,6-dichloro-4-trifluoromethylphenyl)-4- trifluoromethylsulfinylpyrazole, or a compound of the formula:

4. The method according to claim 1, wherein the fonnulation is administered to the first actual or putative amplifier or incipient host or to the second actual or putative amplifier or incipient host by spraying.

5. The method according to claim 1, wherein the formulation is administered to the first actual or putative amplifier host orally.

6. The method according to claim 1, wherein the first actual or putative amplifier host is a bird and the second actual or putative incidental host is a human or domestic animal and the mosquito-borne disease is caused by a virus.

7. The method according to claim 6, wherein the domestic animal is a cat or dog.

8. The method according to claim 6, wherein the virus is the West Nile virus.

9. The method according to claim 1, wherein the mosquito-borne disease is malaria or yellow fever.

10. The method according to claim 1, wherein the first actual or putative amplifier host is a pig and the second actual or putative incidental host is a domestic animal or human and the mosquito-borne disease is caused by JE virus.

11. A method for preventing or interrupting the transmission of mosquito-borne diseases from an actual or putative amplifying or incipient host, to a second actual or putative amplifying or incipient host, by applying a spot-on formulation comprising: (a) an effective amount of at least one 1-N-arylpyrazole derivative; (b) a pharmaceutically acceptable liquid carrier vehicle; (c) optionally, a crystallization hihibitor to said first actual or putative amplifying or incipient host and or second actual or putative amplifying or incipient host.

12. The method according to claim 11 wherein the spot-on formulation comprises (a) an effective amoxmt of at least one compound of the formula

in which Ri is a halogen atom, CN or alkyl; R₂ is S(O)_nR₃ or 4,5-dicyanoimidazol-2-yl or haloalkyl; R₃ is alkyl, alkenyl, aUcynyl, haloalkyl, haloalkenyl, or haloalkynyl; R4 represents a hydrogen or halogen atom or an NR₅R₆, S(O)_mR₇, C(O)R_7> C(O)OR₇, alkyl, haloaUcyl, OR₈, or an - N=C(R₉)(Rιo) group; R₅ and R independently represent a hydrogen atom or an aUcyl, haloaUcyl, C(O)alkyl, S(O)_rCF₃ or aUcoxycarbonyl radical or R₅ and R₆ can together form a divalent alkylene radical which is optionally interrupted by one or two divalent heteroatoms; R₇ represents an alkyl or haloaUcyl group; R₈ represents an aUcyl or haloalkyl group or a hydrogen atom; R₉ represents an alkyl group or a hydrogen atom; Rio represents an optionally substituted aryl or an optionally substituted heteroaryl group; Rπ and R ₂ represent, independently of one another, hydrogen, halogen CN orNO₂; R₁₃ represents a halogen atom or a haloalkyl, haloalkoxy, S(O)_qCF₃ or SF₅ group; m, n, q and r represent, independently of one another, an integer equal to 0, 1 or 2; X represents a bivalent nitrogen atom or a C-Rι₂ radical, the three other valencies of the carbon atom forming part of the aromatic ring; with the proviso that, when Ri is methyl, then either R₃ is haloalkyl, _t is NH₂, Rii is Cl, R₁₃ is CF₃ and X is N or else R₂ is 4,5-dicyanoimidazol-2-yl, R_t is Cl, R₁1 is Cl, R1₃ is CF₃ and X is C-Cl; (b) a pharmaceutically or veterinary acceptable liquid carrier vehicle; and (c) optionally, a crystallization inhibitor.

13. The method according to claim 11 wherein the liquid carrier vehicle comprises a solvent and a cosolvent wherein the solvent is selected from the group consisting of acetone, acetonitrile, benzyl alcohol, butyl diglycol, dimethylacetamide, dimethylformamide, dipropylene glycol n-butyl ether, ethanol, isopropanol, methanol, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, monomethylacetamide, dipropylene glycol monomethyl ether, liquid polyoxyethylene glycols, propylene glycol, 2- pyπolidone, diethylene glycol monoethyl ether, ethylene glycol, diethyl phthalate fatty acid esters, and a mixture of at least two of these solvents and the cosolvent is selected from the group consisting of absolute ethanol, isopropanol or methanol. the crystallization inhibitor selected from the group consisting of an anionic surfactant, a cationic surfactant, a non-ionic surfactant, an amine salt, an amphoteric surfactant or polyvinylpyπolidone, polyvinyl alcohols, copolymers of vinyl acetate and vinylpyπolidone, polyethylene glycols, benzyl alcohol, mannitol, glycerol, sorbitol, polyoxyethylenated sorbitan esters, lecithin, sodium carboxymethylcellulose, and acrylic derivatives, and a mixture of these crystallization inhibitors.

14.The method according to claim 13, wherein the 1-N-arylpyrazole derivative is 5-amino-3-cyano-l-(2,6-dichloro-4-trifluoromethylphenyl)-4- trifluoromethylsulfinylpyrazole or a compound of the fonnula

or aUcyl substituted by halogen, alkoxy, haloalkoxy, or

15. The method according to claim 13, wherein the formulation further comprises an antioxidant.

16. The method according to claim 15, wherein the antioxidant is selected from the group consisting of butylated hydroxyanisole, butylated hydroxytoluene, ascorbic acid, sodium metabisulphite, propyl gallate and sodium thiosuphate.

17. The spot-on formulation according to claim 13, wherein water is present in a proportion of from 0 to about 30%. V/V.

18. The spot-on formulation according to claim 13, wherein the crystallization inhibitor is present in an amount from about 1 to about 20% W/V.

19. The spot-on formulation according to claim 12 which comprises a crystallization inhibitor.

20. The spot-on formulation according to claim 13, wherein the anionic surfactant is alkaline stearates, sodium abietate; aUcyl sulphates; sodium dodecylbenzenesulphonate, sodium dioctylsulphosuccinate; and fatty acids; the cationic surfactant is water-soluble quaternary ammonium salts of formula IST'R'R'R' ^MR" " Y^~ in which the radicals R independently are hydrocarbon radicals, optionally hydroxylated, and Y^~ is an anion of a strong acid; the amine salt is an amine salt of N^R'R'R' " in which the radicals R independently are optionally hydroxylated hydrocarbon radicals; the non-ionic surfactant is optionally polyoxyethylenated sorbitan esters, polyoxyethylenated alkyl ethers; polyethylene glycol stearate, polyoxyethylenated derivatives of castor oil, polyglycerol esters, polyoxyethylenated fatty alcohols, polyoxyethylenated fatty acids, copolymers of ethylene oxide and propylene oxide; and the amphoteric surfactant is lauryl-substituted betaine compounds.

21. The spot-on fonnulation according to claim 13, wherein the crystallization inhibitor is a crystallization inhibitor system comprising a polymeric film-forming agent and a surfactant.

22. The spot-on formulation according to claim 13, wherein the polymeric film-forming agent is polyvinylpyrrolidone, polyvinyl alcohols, or a copolymer of vinyl acetate and polyvinylpyπolidone and the surfactant is a non-ionic surfactant.

23. The spot-on formulation according to claim 22, wherein the crystallization inhibitor system is a mixture of polyvinylpyπolidone and polyoxethylene (20) sorbitan mono-oleate.

24. The method according to claim 15, wherein the 1-N-arylpyrazole is 5-amino-3-cyano- 1 -(2,6-dichloro-4-trifluoromethylρhenyl)-4- trifluoromethylsulfinylpyrazole, the liquid carrier vehicle comprises diethylene glycol monomethylether and ethanol, the crystallization inhibitor is a mixture of polyvidone and Tween 80, and the antioxidant is butylhydroxytoluene

25. The method according to claim 19, wherein the cosolvent is ethanol, the crystallization inhibitor is a mixture of polyvinylpyπolidone and Tween 80, the organic solvent is diethylene glycol monomethylether and said formulation further comprises an antioxidant wliich is butylhydroxytoluene.

26. A method for preventing or interrupting the transmission of mosquito-borne disease from an actual or putative amplifier or incipient host to a second actual or putative amplifying or incipient host by applying to said first actual or putative amplifying or incipient host and/or second actual or putative amplifying or incipient host, wherein at least one host is an animal, which comprises applying to said animal a spot-on formulation comprising: (a) an effective amount of at least one 1-N-arylpyrazole derivative; (b) a pharmaceutically acceptable liquid carrier vehicle wherein said vehicle contains an organic solvent, an organic cosolvent and/or a crystallization inhibitor wherein: the crystallization inhibitor selected from the group consisting of polyvinylpyπolidone, copolymers of vinyl acetate and vinylpyπolidone, polyoxyethylenated sorbitan esters and mixtures thereof; - the organic solvent comprises acetone, ethyl acetate, methanol, ethanol, isopropanol, dimethylformamide, dichloromethane or diethyl glycol monoethyl ether; said solvent optionally supplemented by C₈-Cι₀ caprylic/capric triglyceride, oleic acid or propylene glycol; and the organic cosolvent selected from the group consisting of ethanol, isopropanol, and methanoj; whereby the formulation is applied between the shoulders of the animal and there is a prolonged release of the 1-N-arylpyrazole derivative in or on the body of the animal.

27. The method according to claim 26, wherein the first actual or putative amplifier host is a bird and the second actual or putative incipient host is a cat or dog.

28. The method according to claim 11, wherein the first actual or putative amplifier host is a bird and the second actual or putative incidental host is a human or domestic animal and the mosquito-borne disease is caused by a virus.

29. The method according to claim 28, wherein the virus is the West

Nile virus, the virus that causes EE, WEE, or the virus that causes SLE.

30. The method according to claim 29 wherein the domestic animal is a cat or dog.

31. The method according to claim 30, wherein the virus is the West Nile virus.

32. The method according to claim 11, wherein the first actual or putative amplifier host is a pig and the second actual or putative amplifying or incidental host is a domestic animal or human and the mosquito-borne disease is caused by JE virus.

33. The method according to claim 11 , wherein the virus is the La

Crosse encephalitis virus, the first actual or putative amplifies host is a chipmunk or a free squiπel and the second actual putative host is a human or a domesticated animal.

34. The method according to claim 11, wherein the formulation further comprises an insect growth regulator.

35. The method according to claim 34, wherein the insect growth regulator mimics juvenile hormones.

36. The method according to claim 35, wherein the insect growth regulator is selected from the group consisting of azadirachtin, diofenolan, fenoxycarb, hydroprene, kinoprene, methoprene, pyriproxyfen, tetraliydroazadirachtin, and 4- chloro-2-(2-chloro-2-methyl-propyl)-5-(6-iodo-3 -pyridylmethoxy)pyridizine-3 (2H)- one.

37. The method according to claim 35 wherein the insect growth regulator is selected from the group consisting of chlorfluazuron, cyromazine, diflubenzuron, and fluazuron.

38. The method according to claim 14, wherein the formulation further comprises an insect growth regulator.

39. The method according to claim 38, wherein the 1-N-arylpyrazole is fipronil and the insect growth regulator is (s)-methoprene.

40. The method according to claim 1, wherein the formulation is a pour-on formulation.

41. The method according to claim 40, wherein the pour-on formulation comprises: (a) an effective amount of at least one 1-N-arylpyrazole derivative; (b) a pharmaceutically or veterinary acceptable liquid carrier vehicle which comprise a solvent and a cosolvent wherein the solvent is selected from the group consisting of acetone, acetonitrile, benzyl alcohol, butyl diglycol, dimethylacetamide, dimethylfoπnamide, dipropylene glycol n-butyl ether, ethanol, isopropanol, methanol, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, monomethylacetamide, dipropylene glycol monomethyl ether, liquid polyoxyethylene glycols, propylene glycol, 2-pyπolidone, diethylene glycol monoethyl ether, ethylene glycol, diethyl phthalate, fatty acid esters and a mixture of at least two of these solvents and the cosolvent is selected from the group consisting of absolute ethanol, isopropanol and methanol; (c) a crystallization inhibitor selected from the group consisting of an anionic surfactant, a cationic surfactant, anonionic surfactant, anamine salts, amphoteric surfactant, polyvinylpyπolidone, polyvinyl alcohols, copolymers of vinyl acetate and vinylpyπolidone, polyethylene glycols, benzyl alcohol, mannitol, glycerol, sorbitol, polyoxyethylenated sorbitan esters; lecithin, sodium carboxymethylcellulose, acrylic derivatives and a mixture of these crystallization inhibitors; (d) optionally, an antioxidant.

42. The method according to claim 41, wherein the formulation further comprises an insect growth regulator.

43. The method according to claim 42, wherein the insect growth regulator is a compound which mimics juvenile hormone.

44. The method according to claim 43, wherein the insect growth regulator is selected from the group consisting of azadirachtin, diofenolan, fenoxycarb, hydroprene, kinoprene, methoprene, pyriproxyfen, tetrahydroazadirachtin, and 4- chloro-2-(2-chloro-2-methyl-propyl)-5-(6-iodo-3-pyridylmethoxy)pyridizine-3(2H)- one.

45. The method according to claim 43 wherein the 1-N-arylpyrazole derivative is fipronil, the insect growth regulator is (s)-methoprene, the pharmaceutically or veterinary acceptable carrier comprises diethylene glycol monoethyl ether, as the solvent and ethanol as the cosolvent, the crystallization inhibitor is a mixture of polyvidone and Tween 80 and the oxidant is butyl hydroxytoluene.

46. The method according to claim 42, wherein the insect growth regulator is a chitin synthesis inhibitor.

47. The method according to claim 46, wherein the chitin synthesis inhibitor is selected from the group consisting of chlorfiuazuron, cyromazine, diflubenzuron, and fluazuron.

48. The method according to claim 42, wherein the formulation comprise from about 2 to about 10 mg / kg of body weight of 1-N-arylpyrazole and from about 2 to about 20 mg / kg of body weight of insect growth regulator.

49. The method according to claim 42 wherein the mosquito borne disease is caused by a virus.

50. The method according to claim 49, wherein the virus is the West Nile virus, the first actual or putative amplifier host is a bird and the second actual or putative incipient host is a human or domestic animal.

51. The method according to claim 50 wherein the domestic animal is a cat or dog.

52. The method according to claim 49 wherein the virus is the Japanese encephalitis virus, the first actual or putative amplifier host is a domestic pig and the second putative or actual incipient host is a human or domestic animal.

53. The method according to claim 49 wherein the virus is the La Crosse encephalitis viruses, the amplifying host is a chipmunk or a tree squiπel and the second actual putative incipient host is a human or a domesticated animal.

54. The method according to claim 1 wherein at least one 1-N- arylpyrazole derivative is a compound of the formula

in which _R301 represents H₂N-CS-, R³⁰² represents halogenoaUcyl, halogenoaUcenyl or halogenoaUcinyl, R³⁰³ represents hydrogen, amino or one of the following groups:

where R³⁰⁴ represents alkyl, halogenoaUcyl, alkoxyalkyl or in each case optionally substituted phenyl or pyridyl, R³⁰⁵ represents hydrogen or alkyl, R represents hydrogen, alkyl or in each case optionally substituted phenyl or pyridyl and ^( 7 R represents alkyl, aUcenyl, aUcinyl, formyl, alkylcarbonyl, halogenoalkylcarbonyl or alkoxycarbonyl; Ar represents in each case optionally substituted phenyl or pyridyl and n represents a number 0, 1 or 2.

55. The method according to claim 13, wherein at least one 1-N- arylpyrazole is a compound of the formula

in which R³⁰¹ represents H₂N-CS-, R³⁰² represents halogenoaUcyl, halogenoaUcenyl or halogenoaU inyl, R³⁰³ represents hydrogen, amino or one of the following groups:

where R 304 represents aUcyl, halogenoaUcyl, alkoxyalkyl or in each case optionally substituted phenyl or pyridyl, R 305 represents hydrogen or alkyl, R 306 represents hydrogen, alkyl or in each case optionally substituted phenyl or pyridyl and R 307 represents alkyl, alkenyl, alkinyl, formyl, alkylcarbonyl, halogenoaUcylcarbonyl or alkoxycarbonyl; Ar represents in each case optionally substituted phenyl or pyridyl and n represents a number 0, 1 or 2.

56. The method according to claim 54 wherein at least one 1-N- arylpyrazole derivative is a compound wherein: R³⁰² is CF₃; _R303 is amino; Ar is a phenyl which is trisubstituted and the substituents are a 2-chlorine atom; a 4-position trifluoromethyl group; and a 6-position chlorine atom; and n -ill is l.

57. The method according to claim 54 wherein at least one 1-N- arylpyrazole is a compound wherein: R³⁰² is CF₃; R ^{3 3} is amino; Ar is a phenyl which is trisubstituted and the substituents are a 2-chlorine atom; a 4-position trifluoromethyl group; and a 6-position chlorine atom; and n¹¹¹ is 1.

58. A method for preventing or interrupting the transmission of a mosquito-borne diseases from a first actual putative amplifying or incipient host, to a second actual putative amplifying or incipient host, which comprises applying to a bait placed in a commercially available bird station an effective amount of at least one 1-N- arylpyrazole derivative and/or an IGR in combintion with an antiparasitic, antihelmintic, or insecticidal agent or a mixture thereof.

59. A method for preventing or interrupting the transmission of a mosquito-borne disease from a first actual or putative amplifying or incipient host, wherein said first host is a bird or animal, to a second actual putative amplifying or incipient host in an environment where said first host resides which comprises administering a formulation according to one of claims 11, 34 or 41 to said first host by placing at least one apparatus, which admimsters an effective amount of the formulation to the feathers, fur or skin of the bird or animal during the entry of the bird or animal into the apparatus and/or egress of the bird or animal from the apparatus into said environment; said apparatus comprising a top, bottom, at least one wall, which connects the top to the bottom thereby creating an interior space, and at least one opening, which has an interior surface and com ects the environment to the interior space of the apparatus, said opening, comprising an applicator on the interior surface that is connected to a reservoir, which contains the formulation, by a conduit that is attached to the reservoir and the applicator and comprises an actuator that permits an effective amount of the formulation to flow onto the applicator, and said opening being of sufficient size to permit the entry and egress of the bird or animal into and from the interior of the apparatus while still allowing the feathers, fur or skin of the bird or animal to come into contact with the applicator, thereby permitting the administration of a metered dose of the formulation.

60. The method according to claim 59, wherein the interior of the apparatus contains food or bait.

61. The method according to claim 60, wherein the apparatus comprises at least three walls, one of which is removable to insert the food or bait.

62. The method according to claim 59, wherein the device has four walls.

63. The method according to claim 59, wherein the host is a wild bird.

64. The method according to claim 59, where the host is a chipmunk or tree squiπel.

65. The method according to claim 59, wherein the wall is cylindrical.

66. An apparatus for delivering a metered dose of a veterinary formulation to a bird or animal in an environment where it resides which comprise a top, bottom and at least one wall, which connects the top to the bottom thereby creating an interior space, and at least one opening, which has an interior surface and connects the environment to the interior space of the apparatus, said opening comprising an applicator on the interior surface that is connected to a reservoir, which contains the formulation, by a conduct that is attached to the reservoir and the applicator and comprises an actuator that pennits an effective amount of the formulation to flow onto the applicator, said opening being of sufficient size to permit the entry and egress of the bird or animal into and from the interior of the apparatus while still allowing the feather, fur or skin of the animal to come into contact with the applicator, thereby delivering a metered dose of the veterinary formulation to said bird or animal.