GB2111830A - Devices for protecting animals from ectoparasites - Google Patents

Abstract

A device which is intended to be attached to an animal to control ectoparasite infections on the animal comprises a matrix of polymeric material having dispersed therein the pesticide, amitraz. Other pesticides may also be present eg carbamates, organo phosphates and pyrethroids. The device may be a collar, leg- or tail-band, or ear-tag. The matrix of polymeric material may contain a minor proportion of a polymeric material which is soluble in water.

Description

SPECIFICATION Devices for protecting animals from ectoparasites This invention relates to devices which are intended to be attached to animals to control ectoparasite infestations on the animals.

According to the present invention there is provided a device which is intended to be attached to an animal to control ectoparasite infections on the animal, the device comprising a matrix of polymeric material having dispersed therein the pesticide, amitraz.

Amitraz is a pesticide having the chemical formula 1,5-di(2,4-dimethylphenyl)-3-methyl-1,3,S4riazapenta- 1,4,diene which has a wide range of pesticidal properties as described in British Patent Specification 1,327,935. The amount of amitraz in the device of the present invention is conveniently in the range 0.5 to 30% by weight preferably in the range 5 to 20%.

The matrix of polymeric material may be a homopolymer or copolymer of a compound containing an ethylenic double bond. Suitable monomeric compounds include vinyl compounds such as vinyl chloride, vinyl acetate, vinyl acetal, vinyl alcohol, vinyl benzene, divinyl benzene, or vinylidene chloride, alkenes such as ethylene, propylene, butadiene, isoprene and acrylic and methacrylic acid and their esters. The preferred polymeric materials are homopolymers of vinyl chloride or copolymers of vinyl chloride with other vinyl monomers (e.g. vinyl acetate). Other suitable polymeric materials include polyurethanes, cellulosic plastics and synthetic or natural rubbers.

The polymeric material preferably contains one or more plasticisers for examples a phthalate, sebacate, adipate, citrate, phosphate or triglyceride. Plasticisers for use in the device of the present invention should be chosen so that there is no irritation to the animal on which the device is attached and so that the pesticidal activity of the amitraz is not diminished.

The matrix of polymeric material may contain a minor proportion of a polymeric material which is soluble in water. The water-soluble material is preferably blended with the remaining constituents of the polymeric material. Suitable water-soluble polymeric materials include polyethylene oxides, polyoxyethylene esters of fatty acids and of alicyclic carboxylic acids related to abietic acid, polyoxyethylene derivatives of sorbiton fatty acid esters (ethoxylated anhydrosorbitol esters), alkylphenoxypoly (ethyleneoxy)ethanols (ethoxylatedalkylphenols), alkylpoly(ethyleneoxy)ethanols (ethoxylated aliphatic alcohols) and polyvinylpyrrolidone.

Conveniently up to 20%, e.g. 1 to 15% by weight of the polymeric material is water-soluble.

The device may be in the form of a collar which can be attached to the animal around its neck; in the form of a band which can go around the leg of the animal; in the form of a member which can be secured to the tail of the animal or preferably in the form of a tag which can be attached to the ear of the animal. The device may additionally provide a means of identifying the animal.

The device can be used for treating ectoparasitic infections on domestic animals, e.g. dogs, pigs, sheep, goats and especially cattle, and is designed to control most infections normally controlled by amitraz and especially ticks, mange mites, lice and keds. If desired other pesticides may be included in the device to give a broader spectrum of control, e.g. carbamates, such as bendiocarb, propoxur and carbaryl; organophosphates, such as naled, dioxathion, phosmet, diazinon and dichlorvos; and pyrethroids such as permethrin, cypermethrin, fenvalerate, deltamethrin, cyhalothrin and cyfluthrin. Whilst the device gives good control of infection in the immediate vicinity where it is positioned, control may also be achieved remote from the device.Thus a tag attached to each ear and the tail of a cow according to the invention, can give complete tick control over the whole animal.

The invention will be illustrated by the following Examples of moulded polymeric bodies which are intended to be attached to the ears of cattle to control infestations of ticks.

Example 1 Polyethylene oxide (Polyox WSR-35) (5g) was added with stirring to di-n-butylphthalate (309) at 120-130"C.

The resulting solution was heated to 140-145 C and amitraz (159) was then added. This was immediately followed by an even addition of a polyvinylchloride/polyvinylacetate copolymer (50g, ICI-Corvic C47/488 containing 15% of polyvinylacetate) with intensive stirring, keeping the temperature at 140-1450C. The addition of the PVC/PVA copolymer was completed within 10 minutes. The resulting hot mixture was poured into aluminium foil moulds (55mm x 37mm x 15mm) and left to cool. The surface of the moulded bodies was treated by dipping in a fine PVC powder.

Example 2 Further moulded bodies were prepared in a similar manner to that described above in Example 1 and had the following composition.

50 g Polyvinyl chloride/Polyvinyl acetate copolymer (ICI-C47/488) 5 g Polyethleneoxide (Polyox WSR-35) 30 g Trixlyl phosphate technical (BDH) 15 9 Amitraz Example 3 Further moulded bodies were prepared in a similar manner to that descrined above in Example 1 and had the following composition.

50g PVC/PVA copolymer (ICI-C47/488) 5g Polyoxyethyleneoxide (Polyox WSR-35) 30g Tritolyl phosphate 1 5g Amitraz The moulded bodies of Examples 1, 2 and 3 were tested in vitro against the larvae of Boophilus microplus (Biarra strain) and Rhipicephalus appendiculatus. The moulded bodies were lightly rubbed on filter papers and the first of a pair of treated papers was placed in the inverted top of a 5.5cm disposable Petri dish and an annular cardboard washer inserted. 30 to 50 unfed week-old larvae were transferred to the filter paper inside the cardboard ring and covered with the second treated paper. The bottom of the Petri dish was then placed on top of the second paper and secured by means of elastic bands. Thus the tick larvae were confined to the narrow space between the two treated filter papers.Four replicates were set up for each of the Examples.

The Petri dishes were maintained at 269C at approximately 70% relative humidity for 48 hours and the number of dead larvae was ascertained. A control body having no amitraz was also prepared and this was tested in a similar manner to the bodies of the Examples. The results obtained are shown in the following Table.

% Mortality after 48 hours incubation v. B.microplus larvae v. R.appendiculatus larvae Example 1 100 100 Example 2 100 100 Example3 100 100 Control 0 0 The moulded body of Example 2 was attached to the pinna of the left ear of a Friesan/Hereford bullock.

After three days ear bags were attached to each ear of the bullock and each ear was inoculated with approximately 500 larvae of R. appendiculatus. Two days later about 20 live larvae were found in the untreated ear bag but no live larvae were found in the treated ear bag and 150-200 dead larvae were found.

25 male and 25 female unfed adults of R. evertsiwere then introduced into each ear of the bullock. Five days later no live ticks were observed in the treated ear but live ticks were observed deep inside the untreated ear.

After a further eight days live ticks were observed in the untreated ear but no live ticks were observed in the treated ear.

143 days after attachment of the tag, both ears of the bullock were reinfested with the following unfed adult ticks: 20 male and 20 female R. app en diculatus 100 male and 100 female R. evertsi 6 male and 6 female Amblyomma hebraeum and 5 male and 5 female Hyalomma rufipes.

Five days later, the ear bags were removed. On the treated ear a few R. Evertsiwere attached and 41 ticks were found in the bag. The untreated ear was heavily infested and a few ticks found in the bag. Two days later the bullock was slaughtered and the ears examined. No ticks were attached to the inside of the treated ear whereas 22 were attached to the inside of the untreated ear.

The results of these tests show that polymeric bodies containing amitraz are capable of killing certain ectoparasites and that when used on animals they can control ectoparasite infestations.

Claims (7)

1. A device which is intended to be attached to an animal to control ectoparasite infections on the animal, the device comprising a matrix of polymeric material having dispersed therein the pesticide amitraz.

2. A device as claimed in claim 1 wherein the polymeric material is a homopolymer or copolymer of a compound containing an ethylenic double bond, a polyurethane, a cellulosic plastics material or a synthetic or natural rubber.

3. A device as claimed in either of the preceding claims wherein the polymeric material contains a minor proportion of a polymeric material which is soluble in water.

4. A device a claimed in claim 3 wherein up to 20% by weight of the polymeric material is water soluble.

5. A device is claimed in claim 4 wherein 1 to 15% by weight of the polymeric material is water soluble.

6. A device as claimed in any one of the preceding claims in the form of a collar attached to the animal round its neck; in the form of a band around the leg of the animal; in the form of a member secured to the tail of an animal or in the form of a tag attached to the ear of the animal.

7. A device as claimed in claim 6 in the form of a tag which can be attached to the ear of the animal.