Classifications

• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
  • A01N57/00—Biocides, pest repellants or attractants, or plant growth regulators containing organic phosphorus compounds
  • A01N57/10—Biocides, pest repellants or attractants, or plant growth regulators containing organic phosphorus compounds having phosphorus-to-oxygen bonds or phosphorus-to-sulfur bonds
  • A01N57/16—Biocides, pest repellants or attractants, or plant growth regulators containing organic phosphorus compounds having phosphorus-to-oxygen bonds or phosphorus-to-sulfur bonds containing heterocyclic radicals
• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
  • A01N25/00—Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application, e.g. seed treatment or sequential application; Substances for reducing the noxious effect of the active ingredients to organisms other than pests
• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
  • A01N51/00—Biocides, pest repellants or attractants, or plant growth regulators containing organic compounds having the sequences of atoms O—N—S, X—O—S, N—N—S, O—N—N or O-halogen, regardless of the number of bonds each atom has and with no atom of these sequences forming part of a heterocyclic ring

Definitions

• the present invention relates to a combination of an anti-parasitic agent and fresh water for use in the treatment or prevention of a marine parasite infection in a fish.
• the invention also provides methods of enhancing the effectiveness of an anti-marine parasitic agent, reducing the resistance of marine parasites to an anti-marine parasitic agent, treating a marine parasite infection in a fish, and preventing re-infection of a fish with a marine parasite.
• Marine parasites include Neoparamoeba perurans, gill flukes, skin flukes and Cymothoidae.
• Parasitic sea lice arguably present the most significant challenge at present to control and treat in Atlantic salmon.
• the term sea lice refers to a number of closely related species of parasitic copepods in the family Caligidae (caligid copepods). There are three major genera of sea lice: Pseudocaligus, Caligus and Lepeophtheirus.
• the species Lepeophtheirus salmonis is responsible for most disease outbreaks on farmed salmonids and is responsible for indirect and direct losses in aquaculture in excess of US $100 million annually. In the southern hemisphere, the species Caligus rogercresseyi is more prevalent.
• Caligid copepods consist of two free-living planktonic nauplius stages, one free-swimming infectious copepodid stage, four to six attached chalimus stages, one or two pre-adult stages, and one adult stage. Each of these developmental stages is separated by a moult. Once the adult stage is reached, caligid copepods do not undergo additional moults. In the case of L. salmonis, eggs hatch into the free-swimming first nauplius stage, which is followed by a second nauplius stage, and then the infectious copepodid stage. Once the copepodid locates a suitable host fish it continues its development through four chalimus stages, first and second pre-adult stages, and then a final adult stage.
• a variety of chemical treatments have also been used to control parasites in fish farms. These include compounds such as hydrogen peroxide, organophosphates (e.g., dichlorvos and azamethiphos), ivermectin (and related compounds such as emamectin benzoate), insect moulting regulators and pyrethrins. Most marine parasite treatments can be classified into groups including treatments administered by bath (e.g. organophosphates, pyrethrins) and treatments administered orally (e.g. ivermectin).
• organophosphates e.g., dichlorvos and azamethiphos
• ivermectin and related compounds such as emamectin benzoate
• insect moulting regulators ethrins.
• Most marine parasite treatments can be classified into groups including treatments administered by bath (e.g. organophosphates, pyrethrins) and treatments administered orally (e.g. iver
• azamethiphos has been found to effectively kill adult and pre-adult sea lice (mobile stage), but has been found to be relatively ineffective at killing juvenile sea lice (attached stage).
• Azamethiphos is an organophosphate that acts as an acetylcholinesterase inhibitor. Juvenile stage sea lice are thought to have no or low levels of cholinesterase, and therefore are not significantly affected by this treatment.
• Fresh water treatments have been found to kill all stages of sea lice. However, the required treatment times are in the range of 7-9 hours. Thus, for example, Stone et al. (Journal of Fish Diseases 25: 371-373, 2002) indicates that exposure to fresh water for three hours is an ineffective treatment for controlling sea lice in fish. Furthermore, often not all sea lice are removed or killed after fresh water treatment. Due to the length of treatment time required, fresh water treatment has generally been accepted in the industry as an inefficient de-lousing treatment, with chemical baths and immunogenic treatments being preferred. There therefore remains a need for improved or alternative treatments for marine parasite infections in fish, particularly for parasites that have become resistant to existing treatments.
• a first aspect of the invention provides a combination of an anti-parasitic agent and fresh water for use in the treatment or prevention of a marine parasite infection in a fish, wherein the use is sequential, separate and/or simultaneous.
• the use is sequential, and the anti-parasitic agent is applied after an initial period in the fresh water.
• the anti-marine parasitic agent may be applied in fresh water, brackish water or sea water, preferably fresh water.
• the present invention has been found to enhance the effectiveness of anti-parasitic agents against all stages of sea lice (attached, mobile, juvenile, pre-adult & adult lice).
• the present invention provides a total treatment time of less than half of known fresh water treatments and with an efficacy of 100% removal of sea lice, even of sea lice that are genetically resistant to known chemical treatments.
• the present invention has been found to prevent resettlement of sea lice and thus prevent reinfection of fish treated according to the method.
• the effectiveness of the present invention will help to prevent resistance development to chemical bath treatments.
• the fresh water has a salinity of less than 29 ppt, less than 20 ppt, less than 10 ppt, less man S ppt, or less than 2 ppt.
• the fresh water has a salinity of around 0 ppt, or 0 ppt (i.e. no measurable salinity).
• the initial period in the fresh water may be at least IS minutes, at least 30 minutes, at least 1 hour, at least 2 hours, or at least 3 hours.
• the initial period in the fresh water may be less than 4 hours, less than 5 hours, less than 6 hours, or less than 7 hours.
• the initial period may be longer than 6 or 7 hours, but this would typically achieve no further technical effect.
• the anti-parasitic agent should typically be applied for the period of time recommended for the agent as a standalone treatment agent (i.e. for a treatment regime without an initial period in fresh water; the label indicated dose time). In practice, the anti-parasitic agent may be applied for at least 15 minutes, at least 30 minutes, at least 1 hour, at least 2 hours, or at least 3 hours. The anti-parasitic agent may be applied for less man 4 hours, less than 5 hours, less than 6 hours, or less than 7 hours.
• the fish are held in fresh water for an initial period of around 2 hours, then the anti-parasitic agent is applied in fresh water for around 1 hour.
• the fish is a salmonid, preferably Salmo salar.
• the fish is sea bass, sea bream, Seriola sp., grouper, Asian sea bass, cod, lumpsucker fish (Cyclopteridae), or Wrasse sp.
• the anti-parasitic agent may be one or more agents selected from the group consisting of: an organophosphate; azamethiphos; diclorvos; pyrnethroid; deltamethrin; cypermethrin; pyrethrin; carbamate; eonicitinoid; imidacloprid; thiocloprid; avermectins; emmamectin; doramectin; ivomectin; spinosad; teflubenzuron; di-flubenzuron; lufenuron; hexaflumuron; milbamycin; cyromazine; praziquantel; formalin; hydrogen peroxide; boric acid; propionic acid; and bronopol.
• the anti-parasitic agent is azamethiphos.
• the anti-parasitic agent is applied at 5% to 500% of the recommended treatment dose.
• the anti-parasitic agent is azamethiphos, which is applied at a dose of 0.005 to 0.5 mg/L or 0.05 to 0.2 mg/L, for example around 0.1 mg/L, which is the recommended treatment dose for sea lice (the label indicated dose is 0.2 mg/L for Salmosan ® Vet, which is 50 % w/w azamethiphos).
• the parasite is one or more parasites selected from the group consisting of: a copepod; Lepeophtheirus sp.; Caligus sp.; Lepeophtheirus salmonis; Caligus rogercresseyi; Caligus clemensi; amoebic gill disease [Neoparamoeba perurans); gill fluke (monogeneans); Dactylogyrus sp.; skin fluke; Gyrodactylus sp.; Cymothoidae; and Cymothoa exigua.
• a copepod Lepeophtheirus sp.
• Caligus sp. Lepeophtheirus salmonis
• Caligus rogercresseyi Caligus clemensi
• amoebic gill disease [Neoparamoeba perurans); gill fluke (monogeneans); Dactylogyrus sp.; skin fluke; Gyrodact
• the parasite is Lepeophtheirus salmonis, Caligus rogercresseyi or Caligus clemensi.
• a second aspect of the invention provides a method of enhancing the effectiveness of an anti-marine parasitic agent, the method comprising the steps: (i) contacting the marine parasite with fresh water; and (ii) contacting the marine parasite with the anti-marine parasitic agent.
• step (ii) follows step (i).
• the invention provides a more reliable effective treatment.
• a third aspect of the invention provides a method of reducing the resistance of marine parasites to an anti-marine parasitic agent, the method comprising the steps: (i) contacting the marine parasite with fresh water; and (ii) contacting the marine parasite with the anti- marine parasitic agent.
• step (ii) follows step (i).
• a fourth aspect of the invention provides a method of treating a marine parasite infection in a fish, the method comprising the steps: (i) contacting the infected fish with fresh water; and (ii) contacting the infected fish with an anti-marine parasitic agent.
• step (ii) follows step (i).
• a fifth aspect of the invention provides a method of preventing re-infection of a fish with a marine parasite, the method comprising the steps: (i) contacting the infected animal with fresh water, and (ii) contacting the infected animal with an anti-marine parasitic agent
• step (ii) follows step (i).
• tests were carried out on a well-boat comprising two 550 m 3 wells; the first well at starboard side (SB) and the second well at port side (PS).
• Atlantic salmon averaging 600-700 g were loaded from the sea into SB and PS wells containing fresh water having an initial salinity of 0 ppt (grams of salt in 1 kilogram of seawater).
• CO 2 strippers and 4 kg of bicarbonate of soda were used to control the pH in the well water to levels appropriate for the well-being of the fish.
• the pH was maintained to around 6.35.
• the fish were released from the PS and SB wells to a new saltwater site.
• Table 1 shows the average number of sea lice on each fish pre- and post-treatment at the stated four stages of the lice lifecycle. For example, a count of 0.2 indicates an average of one attached sea louse per five fish.
• the treatment showed 100% clearance of sea lice infection up to 2 days post-treatment with no resettlement on the fish. A few sea lice were still attached post-treatment, but these were picked off and no recovery of the sea lice was observed.
• a control comprising 7 cages stocked with Atlantic salmon receiving Salmosan ® Vet (azamethiphos 50% w/w powder) and H2O 2 was also trialled in parallel, but in contrast only achieved an average of 70% reduction in sea lice infection.
• Tests were carried out on a well-boat that was different to that used for Example 1, which boat comprised two 550 m 3 wells; the first well at starboard side (SB) and the second well at port side (PS).
• Atlantic salmon were stocked into both the SB and PS wells. 35,343 fish averaging 1.4S kg were loaded into the PS well containing water having an initial salinity of around 2 ppt. 19,922 fish averaging 836 g were loaded into the SB well containing an initial salinity of around 4 ppt
• Salmosan ® Vet azamethiphos 50% w/w powder
• the pH, salinity and CO 2 levels in the well water were monitored and maintained throughout the treatment. As no CO 2 stripper was available on the well-boat, a total of 75 kg of bicarbonate of soda was used to regulate the pH. The resulting pH was between 6.S and 7.S. The salinity remained at 4 ppt for the starboard well, and varied only slightly (within 1 ppt unit) for the port side well. Oxygen levels were also monitored and adjusted to the appropriate level as required. The CO 2 level was measured as 40.98 mg/L for the port side well, and as 36.79 mg/L for the starboard well.
• Live sea lice were collected from a Scottish marine location, and were transported and held overnight for at least 18 hours at 10°C in gently aerated normal seawater to ensure that only those lice that were considered healthy and active were studied ( ⁇ 80% male to 20% female).
• Each of two perforated holding chambers were stocked with lice, and were immersed in 1- litre beakers containing test solutions of varying salinities 0 ppt (freshwater), 9 ppt, 18 ppt and 35 ppt (normal seawater) for varying periods of time, from 30 to 240 minutes (table 2) prior to treatment with nil active (control), azamethiphos (0.1 ppm) or imidacloprid (20 ppm).
• nil active control
• azamethiphos 0.1 ppm
• imidacloprid 20 ppm.
• Live sea lice were collected from a Scottish marine location, and were transported and held overnight for at least 18 hours at 10°C in gently aerated normal seawater to ensure that only those lice that were considered healthy and active were studied ( ⁇ 80% male / 20% female).
• Each of two or three perforated holding chambers were stocked with lice, and were immersed in 1 -litre beakers containing test solutions of sea-water at 35 ppt containing azamethiphos at 0.1 ppm or 0.3 ppm. After treatment for 60 minutes, lice were rinsed and placed in beakers containing fresh seawater for a further 180 minutes. Lice were then rinsed and subsequently placed in beakers containing fresh seawater.

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• 2016
  • 2016-06-13 GB GBGB1610275.8A patent/GB201610275D0/en not_active Ceased
• 2017
  • 2017-06-13 DK DKPA201970010A patent/DK201970010A1/en not_active Application Discontinuation
  • 2017-06-13 WO PCT/GB2017/051715 patent/WO2017216541A1/en not_active Ceased
  • 2017-06-13 EP EP17732156.9A patent/EP3468367A1/de not_active Withdrawn
  • 2017-06-13 CA CA3027534A patent/CA3027534A1/en not_active Abandoned
• 2018
  • 2018-12-06 CL CL2018003495A patent/CL2018003495A1/es unknown

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