PRIORITY CLAEVI

[001] This application claims priority to Australian Provisional Patent Application 2016904719 filed on 18 November 2016, the content of which is hereby incorporated by reference.

FIELD

[002] The present disclosure relates to methods and products for reducing resistance to anti-parasitic agents in animals.

BACKGROUND

[003] Internal parasites such nematodes and fluke are a major problem in livestock. Of diseases endemic to livestock, parasites routinely present the highest cost burden to the industry. For example, infection of livestock with Haemonchus contortus may cause anaemia, diarrhoea, dehydration, and peripheral and internal fluid accumulation, and results in lower growth rates, reduced reproductive performance and higher rates of illness and death.

[004] Chemical agents have been developed to control parasitic infections in livestock. For example, a variety of agents have been developed to control gastrointestinal worms (helminthes). Such agents are referred to as "anthelmintics". Anthelmintics have become the mainstay of controlling parasitic worms in livestock. However, while anthelmintics are highly effective, easy to use and relatively economical, like many anti-parasitic agents resistance to these type of agents quickly develops.

[005] Because there are only a limited number of anti-parasitic agents available for use, and the fact that development of new anti-parasitic agents occurs infrequently, strategies to reduce the development of resistance are often employed. For example, use of a combination of two or more anthelmintics is often advocated to slow down the development of resistance of the parasites, rather than the use of individual agents alone. However, whilst such a strategy typically delays the development of resistance, it still eventually results in the development of parasites with resistance to multiple anthelmintic agents, further exacerbating the problem.

[006] Accordingly, there remains a need for new strategies to reduce the development of resistance to anti-parasitic agents in livestock, and/or to assist with the continuing use of current anthelmintic agents.

SUMMARY

[007] The present disclosure relates to methods and products for reducing resistance to anti-parasitic agents in animals.

[008] Certain embodiments of the present disclosure provide a method of reducing resistance to an anti-parasitic agent in an animal suffering from, or susceptible to, infection with parasites resistant to the anti-parasitic agent, the method comprising: treating the animal with an agent to reduce parasitic load in the animal;

inoculating the animal so treated with parasites susceptible to the anti-parasitic agent after parasitic load in the animal has reduced due to treatment with the agent; and

subsequently treating the animal after the parasitic load in the animal has increased with a further agent to again reduce parasitic load in the animal; thereby reducing resistance to the anti-parasitic agent in the animal.

[009] Certain embodiments of the present disclosure provide a method of increasing susceptibility of parasites infecting an animal to an anti-parasitic agent, the method comprising:

treating the animal with an agent to reduce parasitic load in the animal;

inoculating the animal so treated with parasites susceptible to the anti-parasitic agent after parasitic load in the animal has reduced due to treatment with the agent; and

subsequently treating the animal after the parasitic load in the animal has increased with a further agent to again reduce parasitic load in the animal; thereby increasing susceptibility of parasites infecting the animal to the antiparasitic agent.

[0010] Certain embodiments of the present disclosure provide a method of treating an animal suffering from, or susceptible to, an infection with parasites resistant to an antiparasitic agent, the method comprising:

treating the animal with an agent to reduce parasitic load in the animal;

inoculating the animal so treated with parasites susceptible to the anti-parasitic agent after parasitic load in the animal has reduced due to treatment with the agent; and

subsequently treating the animal after the parasitic load in the animal has increased with a further agent to again reduce parasitic load in the animal; thereby treating the subject

[0011] Certain embodiments of the present disclosure provide a method of reducing anthelmintic resistance in an animal suffering from, or susceptible to, infection with anthelmintic resistant parasites, the method comprising:

treating the animal with an anthelmintic agent;

inoculating the animal so treated with anthelmintic susceptible parasites after parasitic load in the animal has reduced due to treatment with the anthelmintic agent; and

subsequently treating the animal with a further anthelmintic agent after parasitic load in the animal has again increased;

thereby reducing anthelmintic resistance in the animal.

[0012] Certain embodiments of the present disclosure provide a method of reducing anthelmintic resistance in an animal suffering from, or susceptible to, infection with anthelmintic resistant parasites, the method comprising:

drenching the animal with an anthelmintic agent;

inoculating the animal after at least 14 days with anthelmintic susceptible parasites; and

drenching the animal with a further anthelmintic agent after parasite load in the animal has increased;

thereby reducing anthelmintic resistance in the animal.

[0013] Certain embodiments of the present disclosure provide use of parasites susceptible to an anti-parasitic agent for treatment of an animal to reduce resistance to the anti -parasitic agent in the animal.

[0014] Certain embodiments of the present disclosure provide a kit for reducing resistance to an anti-parasitic agent in an animal, the kit comprising:

parasites susceptible to the anti-parasitic agent; and

optionally one or more of the following:

reagents and/or instructions for preparing the parasites for inoculation of the animal;

reagents and/or instructions for inoculating the animal with the parasites; and reagents and/or instructions for measuring the level of parasites in the animal.

[0015] Certain embodiments of the present disclosure provide a combination product for reducing resistance to an anti-parasitic agent in an animal, the combination product comprising the following components:

parasites susceptible to the anti-parasitic agent; and

an anti-parasitic agent.

[0016] Other embodiments are described herein. BRIEF DESCRIPTION OF THE FIGURES

[0017] Certain embodiments are illustrated by the following figures. It is to be understood that the following description is for the purpose of describing particular embodiments only and is not intended to be limiting with respect to the description. [0018] Figure 1 shows the percentage of fecal eggs remaining in dung 14 days after treatment as a percentage of the count on the day of treatment. The light grey indicates the fecal egg count of the group treated with Levamisole and the dark grey indicates the group which did not receive a drench (control). The two columns on the left are the results before receiving the susceptible strain of worm. The two columns on the right are the results after treatment with the susceptible strain of parasite.

[0019] Figure 2 shows the efficacy of 3 anthelmintic products before and after treatment with the drench susceptible strain of parasite. Numbers on the Y Axis are expressed as percentage fecal egg count reduction as compared to an undrenched control group.

[0020] Figure 3 shows the efficacy of 3 anthelmintic products before and after treatment with the drench susceptible strain of parasite. Numbers on the Y Axis are expressed as percentage fecal egg count reduction as compared to an undrenched control group.

[0021] Figure 4 shows the rate dependence of the proportion of genetics in the hybrid population originating from the introduced strain of parasite (y axis) and the proportion of the full dose of parasites given (x axis).

DETAILED DESCRIPTION

[0022] The present disclosure relates to relates to methods and products for reducing resistance to anti -parasitic agents in animals.

[0023] The present disclosure is based, at least in part, on the recognition that selective pressures can be applied to a population of undesirable organisms to cause the population to become less problematic overtime. In particular, it has been found that a combination of selective pressures applied to problematic parasitic organisms, in conjunction with the introduction of benign parasites into that population at certain times, can be used to modify the parasitic population.

[0024] Certain embodiments of the present disclosure provide a method of reducing resistance to an anti-parasitic agent in an animal. [0025] Certain embodiments of the present disclosure provide a method of reducing resistance to an anti-parasitic agent in an animal suffering from, or susceptible to, an infection with parasites resistance to the anti-parasitic agent, the method comprising: treating the animal with an agent to reduce parasitic load in the animal;

inoculating the animal so treated with parasites susceptible to the anti-parasitic agent after parasitic load in the animal has reduced due to treatment with the agent; and

subsequently treating the animal after the parasitic load in the animal has increased with a further agent to again reduce parasitic load in the animal; thereby reducing resistance to the anti-parasitic agent in the animal.

[0026] In certain embodiments, the animal subject is a livestock animal (such as a horse, a cow, a sheep, a goat, a pig, a deer, poultry), a domestic animal (such as a dog or a cat) or another types of animal such as a primates, a rabbit, a rat, mouse, or a bird. Other types of animals are contemplated. Veterinary applications of the present disclosure are also contemplated.

[0027] In this regard, it will be understood that while the present disclosure refers to the term "animal", the methods and products of the present disclosure are also suitable for reducing resistance in humans, if so desired.

[0028] In certain embodiments, the animal is a ruminant or a pseudoruminant. Examples of ruminants include cows, sheep, goats and deer. Examples of pseudomminants include horses. In certain embodiments, the animal is a monogastric animal, such as a pig.

[0029] In certain embodiments, the animal is a selected from one of a sheep (an ovine animal), a cow (a bovine animal), a goat (a caprine animal), or a horse (an equine animal).

[0030] In certain embodiments, the animal is an avian species, such as a chicken, turkey, goose, fowl or duck. [0031] In certain embodiments, the animal is suffering from an infection with parasites resistance to the anti-parasitic agent. In this embodiment, the method provides a method of treating an animal to reduce the load of resistant parasites in the animal, treating a population of animals to reduce the load of resistant parasites in the population, or treating an animal to maintain a low load of resistant parasites in the animal.

[0032] In certain embodiments, the animal is susceptible to an infection with parasites resistance to the anti-parasitic agent. In this embodiment, the method provides a method of prophylactically treating an animal to reduce the load of resistant parasites in the animal that may develop, or prophylactically treating a population of animals to reduce the load of resistant parasites in the population that may develop.

[0033] The term "parasite", or related terms such as "parasitic", as used herein refers to an organism which has a non-mutually symbiotic relationship with a host. In many cases, parasites can have a detrimental effect on animals, such as reducing growth rates, reducing reproductive rates, reducing health and/or fitness, reducing milk production, and reducing fleece quality.

[0034] Examples of parasites include nematodes (roundworms), cestodes (tapeworms), and trematodes (flatworms). Other types of parasites are contemplated.

[0035] Examples of parasites in sheep and/or goats include Haemonchus spp. (eg (Haemonchus contortus), Ostertagia spp (eg Teladorsagia (Ostertagia) circumcincta, Trichostrongylus axei, and Ostertagia trifurcate), Trichostrongylus spp. (eg Trichostrongylus colubriformis, Trichostrongylus vitrinus, Trichostrongylus rugatus), Nematodirus spp, Bunostomum spp. (eg Bunostomum trigonocephalum, Oesophagostomum spp. (eg Oesophagostomum columbianum), Cooperia curticei, Strongyloides papillosus, Trichuris ovis, Gaigeria spp. (eg Gaigeria pachyscelis), and Chabertia ovina.

[0036] Examples of parasites in cattle include Haemonchus placet, Ostertagia ostertagi, and Trichostrongylus axei, Cooperia spp (eg. Cooperia punctata, Cooperia oncophora, and Cooperia pectinate), Bunostomum phlebotomum, Strongyloides papillosus, Neamtodirus spp. (eg Nematodirus helvetianus, Nematodirus spathiger and Nematodirus battus), Toxocara vitulorum, Oesophagostomum radiatum, Chabertia ovina, Trichuris spp., Moniezia expansa and Moniezia benedeni.

[0037] In certain embodiments, the parasite comprises a nematode, a cestode or a trematode.

[0038] In certain embodiments, the parasite comprises a nematode.

[0039] In certain embodiments, the parasite comprises one or more of a Haemonchus spp., a Trichostrongylus spp., and a Teladorsagia spp.

[0040] In certain embodiments, the parasite comprises a Haemonchus spp, such as Haemonchus contortus.

[0041] Methods for determining the extent or level of resistance to anti -parasitic agents are known in the art. For example, for worms a test such as a fecal egg count reduction test may be utilised to assess the extent or level of resistance.

[0042] The term "anti-parasitic agent" as used herein refers to an agent that may be used to treat a parasitic infection in an animal, and may be used for example, to eradicate infection by a parasites, to kill the parasites, or to reduce or slow growth, reproduction or spread of parasites. Various types of agents are contemplated, including for example, drugs, small molecules, natural or synthetic agents, nucleic acids, herbs, vaccines, and extracts from natural products, and mixtures thereof.

[0043] In certain embodiments, the animal comprises an animal with parasites having resistance to one anti -parasitic agent. In certain embodiments, the animal comprises an animal with parasites having resistance to one or more anti-parasitic agents. In certain embodiments, the animal comprises an animal with parasites having resistance to multiple anti-parasitic agents.

[0044] In certain embodiments, the resistance to an anti-parasitic agent comprises resistance to an anthelmintic agent. In certain embodiments, the resistance to an antiparasitic agent comprises resistance to one or more anthelmintic agents. In certain embodiments, the resistance to an anti-parasitic agent comprises resistance to multiple anthelmintic agents.

[0045] In certain embodiments, the resistance to an anti-parasitic agent comprises resistance to one or more of a benzimdzole, albendazole, mebendazole, thiabendazole, fenbendazole, triclabendazole, flubendazole, abamectin, diethylcarbamazine, ivermectin, suramin, pyrantel pamoate, levamisole, salicylanilides, niclosamide, nitazoxanide, oxyclozanide, praziquantel, octadepsipeptides, emodepside an aminoacetonitrile, monepantel, spiroindoles, derquantel, and pelletierine sulphate. Other types of anti-parasitic agents are contemplated.

[0046] In certain embodiments, the resistance to an anti-parasitic agent comprises at least 0.001% resistance of the parasites in the animal to an anti-parasitic agent, at least 0.01%) resistance of the parasites in the animal to an anti-parasitic agent, at least 0.1%> resistance of the parasites in the animal to an anti-parasitic agent, at least 1%> resistance of the parasites in the animal to an anti-parasitic agent, at leastl0%> resistance of the parasites in the animal to an anti-parasitic agent, at least 20% resistance of the parasites in the animal to an anti-parasitic agent, at least 30%> resistance of the parasites in the animal to an anti-parasitic agent, at least 40% resistance of the parasites in the animal to an anti-parasitic agent, at least 50% resistance of the parasites in the animal to an antiparasitic agent, at least 60% resistance of the parasites in the animal to an anti-parasitic agent, at least 70% resistance of the parasites in the animal to an anti-parasitic agent, at least 80%) resistance of the parasites in the animal to an anti-parasitic agent, at least 90% resistance of the parasites in the animal to an anti-parasitic agent, or at least substantially all of the parasites being resistant in the animal to an anti-parasitic agent. In certain embodiments, the aforementioned levels of resistance are resistance of the parasites in the animal to multiple anti-parasitic agents. In certain embodiments, the aforementioned levels of resistance are resistance of the parasites in the animal to one or more anthelmintic agents. In certain embodiments, the aforementioned levels of resistance are resistance of the parasites in the animal to multiple anthelmintic agents.

[0047] In certain embodiments, the anti-parasitic agent comprises an anthelmintic agent. In certain embodiments, the anti-parasitic agent comprises one or more anthelmintic agents. In certain embodiments, the anti-parasitic agent comprises multiple anthelmintic agents. [0048] In certain embodiments, the anti-parasitic agent comprises an anthelmintic agent selected from one or more of a benzimdzole, albendazole, mebendazole, thiabendazole, fenbendazole, triclabendazole, flubendazole, abamectin, diethylcarbamazine, ivermectin, suramin, pyrantel pamoate, levamisole, salicylanilides, niclosamide, nitazoxanide, oxyclozanide, praziquantel, octadepsipeptides, emodepside an aminoacetonitrile, monepantel, spiroindoles, derquantel, and pelletierine sulphate. Other anthelmintic agents are contemplated.

[0049] Treating the animal with the agent (ie a first agent) reduces parasitic load in the animal, prior to inoculation with susceptible parasites. In certain embodiments, the agent for treating the animal comprises an anthelmintic agent. Anthelmintic agents are commercially available.

[0050] Examples of anthelmintic agents include one or more of a benzimdzole, albendazole, mebendazole, thiabendazole, fenbendazole, triclabendazole, flubendazole, abamectin, diethylcarbamazine, ivermectin, suramin, pyrantel pamoate, levamisole, salicylanilides, niclosamide, nitazoxanide, oxyclozanide, praziquantel, octadepsipeptides, emodepside an aminoacetonitrile, monepantel, spiroindoles, derquantel, and pelletierine sulphate. Other anthelmintic agents are contemplated.

[0051] In certain embodiments, the agent comprises one or more anthelmintic agents. In certain embodiments, the agent comprises multiple anthelmintic agents.

[0052] The animal is treated with a further agent (ie a second agent) after allowing parasitic load in the animal to increase. The further agent then reduces the parasitic load in the animal again. In certain embodiments, the further agent comprises an anthelmintic agent. Anthelmintic agents are commercially available.

[0053] Examples of anthelmintic agents include one or more of a benzimdzole, albendazole, mebendazole, thiabendazole, fenbendazole, triclabendazole, flubendazole, abamectin, diethylcarbamazine, ivermectin, suramin, pyrantel pamoate, levamisole, salicylanilides, niclosamide, nitazoxanide, oxyclozanide, praziquantel, octadepsipeptides, emodepside an aminoacetonitrile, monepantel, spiroindoles, derquantel, and pelletierine sulphate. Other anthelmintic agents are contemplated. [0054] In certain embodiments, the further agent comprises one or more anthelmintic agents. In certain embodiments, the further agent comprises multiple anthelmintic agents.

[0055] In certain embodiments, the agent and the further agent are the same. In certain embodiments, the agent and the further agent are different.

[0056] In certain embodiments, the agent comprises an anthelmintic agent and/or the further agent comprises an anthelmintic agent.

[0057] Parasites of animals and appropriate anti-parasitic agents for treatment, are generally as described in The Merck Veterinary Manual 11 ^th Edition. Merck Publishing, editor Susan E. Alello.

[0058] Parasites in cattle include: stomach worm and lungworm and the use of the anthelmintics levamisole, fenbendazole, oxfendazole, albendazole, eprinomectin, doramectin, ivermectin, moxidectin; tapeworm and use of the anthelmintics oxfendazole, albendazole; and liver fluke and the use of anthelmintic clorsulon.

[0059] Parasites in pigs include: large roundworm (Ascarids) and the use of anthelmintics ivermectin, fenbendazole, levamisole, pyrantel, dichlorvos, piperazine (adult stage), fenbendazole (migrating, infective); fenbendazole, pyrantel (infective); whipworm and the use of the anthelmintics fenbendazole and dichlorvos; nodular worm and the use of anthelmintics ivermectin, fenbendazole, levamisole, pyrantel, dichlorvos, piperazine; lungworm and the use of the anthelmintics fenbendazole, ivermectin, and levamisole; kidneyworm (adult) and the use of the anthelmintics: fenbendazole and levamisole; lungworm and the use of the anthelmintic fenbendazole; strongyloides and use of the anthelmintics ivermectin, and levamisole.

[0060] Parasites in poultry include roundworm (Ascarids) and the use of anthelmintics albendazole, ivermectin, levamisole, and piperazine; cecal worms and the use of the anthelmintics albendazole, ivermectin, and levamisole; threadworms (Capillaria) and the use of the anthelmintics albendazole, ivermectin, and levamisole; tapeworms and the use of the anthelmintic albendazole. [0061] Parasites in horses include large strongyle (Strongylus vulgaris, S. equinus and S. endentatus) or bloodworm and the use of the anthelmintics moxidectin, ivermectin and fenbendazol for migrating phase; small strongyle (cyathostome) and the use of the anthelmintics ivermectin and moxidectin for adult stages and moxidectin; roundworms (Ascarid) and the use of the anthelmintics ivermectin, moxidectin, fenbendazole, and pyrantel pamoate; Gasterophilus intestinalis and the use of the anthelmintics ivermectin, and moxidectin; pinworm (Oxyuris equi, common pinworm; Probstmayria vivipara, minute pinworm) and the use of the anthelmintics ivermectin, moxidectin, and fenbendazole; tapeworm (Anoplocephala perfoliata, A. magna) and the use of the praziquantel.

[0062] Parasites in small ruminants include Haemonchus contortis and the use of the anthelmintics ivermectin, moxidectin, levamisole, fenbendazole, and albendazole; small brown stomach worm (Ostertagia circumcinta) and the use of the anthelmintics ivermectin, moxidectin, levamisole, fenbendazole, and albendazole; tapeworm and use of the anthelmintics benzimidazoles; lungworm and use of the anthelmintics ivermectin, and moxidectin; liver fluke and use of the anthelmintics albendazole, and clorsulon; Coccidia and the use of the anthelmintics sulfa drugs, and amprolium; meningeal worm or deer or brain worm (a parasite of the white tail deer; Paralaphostrongylus tenius) and use of the anthelmintics levamisol, ivermectin, albendazole, fenbendazole, and thiabendazole.

[0063] In certain embodiments, the treating of the animal with an agent to reduce parasitic load comprises oral administration of the agent In certain embodiments, the agent(s) is administered via injection. In certain embodiments, the agent(s) is administered intravenously. In certain embodiments, the agent(s) is administered parenterally. In certain embodiments, the agent(s) is administered nasally. In certain embodiments, the agent(s) is administered by direct introduction to the lungs, such as by aerosol administration, by nebulized administration, or by being instilled into the lung. In certain embodiments, the agent(s) is administered by implant. In certain embodiments, the agent(s) is administered by suppository. In certain embodiments, the agent(s) is administered rectally, intranasally, vaginally, or transdermally.

[0064] Oral administration is a route of administration where a substance is taken through the mouth, and includes buccal, sublabial and sublingual administration. Typical forms for oral administration include administration of liquids, or solid forms tablets or capsules. Oral formulations are known in the art.

[0065] In certain embodiments, the agent is administered by drenching.

[0066] Intravenous administration is the administration of substances directly into a vein. Compositions suitable for intravenous administration may be formulated by a skilled person, and typically contain a carrier or excipient such as isotonic saline. Intravenous formulations are known in the art.

[0067] In certain embodiments, it may be desirable to administer the agent(s) directly to the airways in the form of an aerosol. Formulations for the administration of aerosol forms are known.

[0068] In certain embodiments, the agent(s) may also be administered parenterally or intraperitoneally. For example, solutions or suspensions of the agent(s) in a non-ionised form or as a pharmacologically acceptable salt can be prepared in water suitably mixed with a surfactant such as hydroxy-propylcellulose. Dispersions can also be prepared in glycerol, liquid polyethylene glycols and mixtures thereof in oils. Under ordinary conditions of storage and use, these preparations typically contain a preservative to prevent the growth of microorganisms. Such formulations are known in the art.

[0069] In certain embodiments, the agent(s) may also be administered by injection. Forms suitable for injectable use include sterile aqueous solutions or dispersions and sterile powders for the extemporaneous preparation of sterile injectable solutions or dispersions. The carrier can be a solvent or dispersion medium containing, for example, water, ethanol, polyol (e.g., glycerol, propylene glycol and liquid polyethylene glycol), suitable mixtures thereof, and vegetable oils. Injectable formulations are known in the art.

[0070] In certain embodiments, the agent(s) may also be administered by way of rectal administration, such as by way of a suppository. Suppository formulations may be made from traditional materials, including cocoa butter, with or without the addition of waxes to alter the suppository's melting point, and glycerin. Water soluble suppository bases, such as polyethylene glycols of various molecular weights, may also be used. Rectal formulations are known in the art.

[0071] In certain embodiments, the treating of the animal with the agent comprises drenching. Drenching and methods for drenching are known in the art.

[0072] Dosages for administration of agents to animals to reduce parasitic load are known in the art, for example as described in in The Merck Veterinary Manual 11th Edition. Merck Publishing, editor Susan E. Alello. For commercially available agents, dosages may be selected as per the supplier's instructions.

[0073] For example, typical concentrations for the administration to sheep of benzimidazoles is 5 mg/kg body weight, avermectins is 0.2 mg/kg body weight, moxidectin is 0.2 mg/kg body weight, and levamisole is 7.5 mg/kg body weight, and typical concentrations for the administration to goats is benzimidazoles is 10 mg/kg body weight, avermectins is 0.3 mg/kg body weight, moxidectin is 0.4 mg/kg body weight, and levamisole is 12 mg/kg body weight.

[0074] Inoculating the animal with parasites susceptible to the anti-parasitic agent results in the inoculation of the animal with susceptible parasites after parasitic load in the animal has been reduced.

[0075] In certain embodiments, the inoculating of the animal with parasites susceptible to the anti-parasitic agent comprises a period of at least 7 days, at least 14 days, at least 21 days, or at least 28 days after treatment with the agent. In certain embodiments, the inoculating of the animal with parasites susceptible to the antiparasitic agent comprises a period of greater 7 days, greater than 14 days, greater than 21 days, or greater than 28 days after treatment with the agent.

[0076] In certain embodiments, the inoculating of the animal with parasites susceptible to the anti-parasitic agent comprises a period of 7 to 28 days after treatment with the agent, 7 to 21 days after treatment with the agent, 7 to 14 days after treatment with the agent, 14 to 28 days after treatment with the agent, 14 to 21 days after treatment with the agent, or 21 to 28 days after treatment with the agent.

[0077] In certain embodiments, the inoculating of the animal with parasites susceptible to the anti-parasitic agent comprises a period of 7 to 14 days after treatment with the agent.

[0078] Other periods of time suitable for the inoculating of the animal with parasites susceptible to the anti-parasitic agent may be determined based on the characteristics of a particular parasite and the agent used.

[0079] Methods for determining when parasitic load in the animal has reduced due to treatment with the agent may be determined by a method known in the art, such as use of fecal egg counts.

[0080] In certain embodiments, the inoculating of the parasites susceptible to the antiparasitic agent comprises oral administration. In certain embodiments, the inoculating of the parasites susceptible to the anti-parasitic agent comprises drenching.

[0081] In certain embodiments, the inoculating of the parasites susceptible to the antiparasitic agent comprises rectal administration. In certain embodiments, the inoculating of the parasites susceptible to the anti-parasitic agent comprises nasal administration.

[0082] Other routes of administration may be selected based on the characteristics and/or lifecycle of the parasite. Methods of administration are known in the art, including methods of drenching animals.

[0083] In certain embodiments, the administration of the parasites susceptible to the anti-parasitic agents comprises use of a carrier, such as a liquid. In certain embodiments, the administration of the parasites susceptible to the anti-parasitic agents comprises administering a composition comprising the parasites, such as a liquid composition comprising the parasites.

[0084] In certain embodiments, the inoculating of the animal with parasites susceptible to the anti-parasitic agent comprises inoculating the animal with larval parasites. Other forms of the parasite may be selected dependent upon infective lifestyle stages of a parasite.

[0085] In certain embodiments, the inoculating of the animal with parasites susceptible to the anti-parasitic agent comprises inoculating the animal with less than 2000 parasites.

[0086] In certain embodiments, the inoculating of the animal with parasites susceptible to the anti-parasitic agent comprises inoculating the animal with 1 to 1000 parasites. For example, for Haemonchus contortus inoculating the animal with approximately 100 parasites is generally suitable.

[0087] In certain embodiments, the inoculating of the animal with parasites susceptible to the anti-parasitic agent comprises inoculating the animal with 1 to 1000 parasites, 10 to 1000 parasites, 100 to 1000 parasites, 1 to 100 parasites, 10 to 100 parasites or 1 to 10 parasites. Other numbers of parasites are contemplated.

[0088] The parasites may be diluted to a suitable concentration for administration.

[0089] In certain embodiments, the inoculating of the animal with parasites susceptible to the anti-parasitic agent comprises inoculating with parasites with a characteristic of reaching maturity later than the resident parasites.

[0090] In certain embodiments, multiple inoculations with parasites susceptible to the anti-parasite agent may be undertaken.

[0091] The subsequent treating of the animal with a further agent after parasitic load in the animal has increased results in reducing the parasitic load in the animal a further time. Dosages for administration of further agents to animals to reduce parasitic load are known in the art, for example as described in in The Merck Veterinary Manual 11th Edition. Merck Publishing, editor Susan E. Alello. Dosages may be selected as per the supplier's instructions.

[0092] In certain embodiments, the method comprises treating the animal with the further agent at least 14 days, at least 1 month, at least 2 months, at least 3 months, at least 4 months, at least 5 months or at least 6 month following inoculation with the susceptible parasites. Other time periods are contemplated. Multiple treatments are contemplated.

[0093] Methods for treating with further agents are as described herein for the treatment of agents generally.

[0094] In certain embodiments, the method comprises determining the parasitic load in the animal prior to treatment with the further agent. Methods for determining parasitic load are known in the art. In certain embodiments, the determining of the parasitic load comprises measuring fecal egg count.

[0095] In certain embodiments, the method does not comprise determining the parasitic load in the animal prior to treatment with the further agent. In this case, a suitable amount of time may be chosen to allow the parasitic load to increase.

[0096] In certain embodiments, the steps of treating with a first agent, inoculating and treating with a further agent, may be repeated one or more times.

[0097] In certain embodiments, the method reduces the level of resistance in the animal to a single anti -parasitic agent to less than 60%, less than 50%, less than 40%, less than 30%, less than 25%, less than 20%, less than 10%, less than 5%, less than 2% or less than 1%.

[0098] In certain embodiments, the method reduces the level of resistance in the animal to multiple anti-parasitic agents to less than 60%, less than 50%, less than 40%, less than 30%, less than 25%, less than 20%, less than 10%, less than 5%, less than 2% or less than 1%.

[0099] In certain embodiments, a method as described herein may be used to increase susceptibility of parasites infecting an animal to an anti-parasitic agent; to reduce anthelmintic resistance in an animal suffering from, or susceptible to, infection with anthelmintic resistant parasites; to treat a subject suffering from, or susceptible to, an infection with parasites resistant to an anti-parasitic agent; and to reduce anthelmintic resistance in an animal suffering from, or susceptible to, infection with anthelmintic resistant parasites. [00100] In certain embodiments, the present disclosure provides a composition comprising parasites susceptible to an anti-parasitic agent.

[00101] Certain embodiments of the present disclosure provide a composition comprising parasites susceptible to an anti-parasitic agent, for use in the methods and products of the present disclosure.

[00102] In certain embodiments, the composition comprises less than 2000 parasites. In certain embodiments, the composition comprises 1000 or less parasites.

[00103] In certain embodiments, the composition comprises 1 to 1000 parasites, 10 to 1000 parasites, 100 to 1000 parasites, 1 to 100 parasites, 10 to 100 parasites or 1 to 10 parasites. Other numbers of parasites are contemplated.

[00104] In certain embodiments, the composition is a liquid composition, such as an aqueous composition.

[00105] The composition comprising parasites may contain one or more other additives, for example additives to assist with maintaining viability of the parasites.

[00106] In certain embodiments, the present disclosure provides a method of reducing resistance to an anti-parasitic agent in an animal suffering from, or susceptible to, an infection with parasites resistant to the anti-parasitic agent.

[00107] Methods for growing and using parasites for use in a composition are known in the art.

[00108] Certain embodiments of the present disclosure provide a method of reducing resistance to an anti-parasitic agent in an animal suffering from, or susceptible to, an infection with parasites resistant to the anti-parasitic agent, the method comprising: inoculating an animal treated with an agent to reduce parasitic load in the animal with parasites susceptible to the anti-parasitic agent; and

subsequently treating the animal after the parasitic load in the animal has increased with a further agent to again reduce parasitic load in the animal; thereby reducing resistance to the anti-parasitic agent in the animal. [00109] Certain embodiments of the present disclosure provide a method of reducing resistance to an anti-parasitic agent in an animal suffering from, or susceptible to, an infection with parasites resistant to the anti-parasitic agent, the method comprising: inoculating an animal with parasites susceptible to the anti-parasitic agent, wherein the animal has been treated with an agent to reduce parasitic load in the animal; and

subsequently treating the animal after the parasitic load in the animal has increased with a further agent to again reduce parasitic load in the animal; thereby reducing resistance to the anti-parasitic agent in the animal.

[00110] Certain embodiments of the present disclosure provide a method of reducing resistance to an anti-parasitic agent in an animal suffering from, or susceptible to, an infection with parasites resistance to the anti-parasitic agent, the method comprising: reducing parasitic load in the animal;

inoculating the animal with parasites susceptible to the anti-parasitic agent; allowing parasitic load in the animal to increase; and

reducing the parasitic load in the animal again;

thereby reducing resistance to the anti-parasitic agent in the animal.

[00111] In certain embodiments, the present disclosure provides a method of increasing susceptibility of parasites infecting an animal to an anti-parasitic agent, using a method as described herein.

[00112] Certain embodiments of the present disclosure provide a method of increasing susceptibility of parasites infecting an animal to an anti-parasitic agent, the method comprising:

treating the animal with an agent to reduce parasitic load in the animal;

inoculating the animal so treated with parasites susceptible to the anti-parasitic agent after parasitic load in the animal has reduced due to treatment with the agent; and

subsequently treating the animal after the parasitic load in the animal has increased with a further agent to again reduce parasitic load in the animal; thereby increasing susceptibility of parasites infecting the animal to the antiparasitic agent.

[00113] In certain embodiments the present disclosure provides a method of treating an animal suffering from, or susceptible to, an infection with parasites resistant to an antiparasitic agent.

[00114] Certain embodiments of the present disclosure provide a method of treating an animal suffering from, or susceptible to, an infection with parasites resistant to an antiparasitic agent, using a method as described herein.

[00115] Certain embodiments of the present disclosure provide a method of treating a subject suffering from, or susceptible to, an infection with parasites resistant to an antiparasitic agent, the method comprising:

treating the animal with an agent to reduce parasitic load in the animal;

inoculating the animal so treated with parasites susceptible to the anti-parasitic agent after parasitic load in the animal has reduced due to treatment with the agent; and

subsequently treating the animal after the parasitic load in the animal has increased with a further agent to again reduce parasitic load in the animal; thereby treating the subject.

[00116] In certain embodiments the present disclosure provides a method of reducing anthelmintic resistance in an animal suffering from, or susceptible to, infection with anthelmintic resistant parasites.

[00117] Certain embodiments of the present disclosure provide a method of reducing anthelmintic resistance in an animal suffering from, or susceptible to, infection with anthelmintic resistant parasites, using a method as described herein.

[00118] Certain embodiments of the present disclosure provide a method of reducing anthelmintic resistance in an animal suffering from, or susceptible to, an infection with anthelmintic resistant parasites, the method comprising: treating the animal with an anthelmintic agent;

inoculating the animal so treated with anthelmintic susceptible parasites after parasitic load in the animal has reduced due to treatment with the anthelmintic agent; and

subsequently treating the animal with a further anthelmintic agent after parasitic load in the animal has again increased;

thereby reducing anthelmintic resistance in the animal.

[00119] Certain embodiments of the present disclosure provide a method of reducing anthelmintic resistance in an animal suffering from, or susceptible to, an infection with anthelmintic resistant parasites, using a method involving drenching as described herein

[00120] Certain embodiments of the present disclosure provide a method of reducing anthelmintic resistance in an animal suffering from, or susceptible to, an infection with anthelmintic resistant parasites, the method comprising:

drenching the animal with an anthelmintic agent;

inoculating the animal after at least 14 days with anthelmintic susceptible parasites; and

drenching the animal with a further anthelmintic agent after parasite load in the animal has increased;

thereby reducing anthelmintic resistance in the animal.

[00121] Certain embodiments of the present disclosure provide one or more animals treated by a method as described herein. Animals are as described herein. In certain embodiments, the present disclosure provides a product from an animal as treated by a method as described herein. Methods for producing animal products are known in the art.

[00122] In certain embodiments the present disclosure provides use of parasites in a method as described herein.

[00123] Certain embodiments of the present disclosure provide use of parasites susceptible to an anti-parasitic agent for treatment of an animal to reduce resistance to the anti-parasitic agent in the animal, as described herein.

[00124] Certain embodiments of the present disclosure provide use of a composition comprising parasites susceptible to an anti -parasitic agent in a method as described herein. Compositions comprising parasites are as described herein.

[00125] Certain embodiments of the present disclosure provide use of a composition comprising parasites susceptible to an anti-parasitic agent for treatment of an animal to reduce resistance to the anti-parasitic agent in the animal, as described herein.

[00126] In certain embodiments the present disclosure provides a kit or product for performing a method as described herein.

[00127] A kit or product may, for example, comprise one or more reagents as described herein and/or may also comprise instructions for performing a method as described herein.

[00128] Certain embodiments of the present disclosure provide a kit for reducing resistance to an anti-parasitic agent in an animal, the kit comprising:

parasites susceptible to the anti-parasitic agent; and

optionally one or more of the following:

reagents and/or instructions for preparing the parasites for inoculation of the animal;

reagents and/or instructions for inoculating the animal with the parasites; and reagents and/or instructions for measuring the level of parasites in the animal.

[00129] Reagents and/or instructions for preparing parasites for inoculation of the animal are as described herein.

[00130] Reagents and/or instructions for inoculating an animal with parasites are as described herein.

[00131] Reagents and/or instructions for measuring the level of parasites in the animal are as described herein. [00132] The kit may further comprise one or more anti -parasitic agents and/or instructions for using the agents. Anti-parasitic agents are as described herein.

[00133] In certain embodiments the present disclosure provides a combination product.

[00134] Certain embodiments of the present disclosure provide a combination product for reducing resistance to an anti-parasitic agent in an animal, the combination product comprising the following components:

parasites susceptible to the anti-parasitic agent; and

an anti-parasitic agent.

[00135] Parasites susceptible to the anti -parasitic agent and anti -parasitic agents are as described herein.

[00136] Certain embodiments of the present disclosure provide a method of reducing resistance to an anti-parasitic agent in an animal suffering from, or susceptible to, an infection with parasites resistant to anti-parasitic agent, the method comprising using a kit or product as described herein to reduce the resistance to the anti-parasitic agent in the animal.

[00137] Standard techniques may be used for the methods and procedures as described herein, such as the propagation of parasites, handling of parasites, storage of parasites, preparation of parasites for inoculation, animal husbandry, testing for the presence of parasites, assessing animal health, and veterinary procedures. The foregoing techniques and procedures may be generally performed according to conventional methods well known in the art

[00138] The present disclosure is further described by the following examples. It is to be understood that the following description is for the purpose of describing particular embodiments only and is not intended to be limiting with respect to the above description. EXAMPLE 1 - Treatment of sheep to reduce resistance of barber's pole worm to anthelmintics

[00139] Methods

[00140] Sheep were identified as being infected with Haemonchus contortus and resistant to varying degrees to the following anthelmintics: levamisole, moxidectin, albendazole, closantel and napthalaphos. This was accomplished by assessing the faecal egg count as discussed below.

[00141] Sheep carrying resistant parasites were treated with a first anthelmintic (for example monepantel - trade name ZOLVIX from Novartis Animal Health Australia, a broad spectrum anthelmintic of the amino-acetonitrile derivative class of drenches). Sheep were treated at the manufacturer's recommended dosages. For example, sheep treated with ZOLVIX were treated at lmL per 10kg body weight (corresponding to 2.5 mg monepantel per kg) in a drench solution, as per the supplier's instructions.

[00142] Sheep were then either held in yards overnight or for a couple of days, or put straight into a spelled paddock.

[00143] Two weeks after treating the sheep with the first anthelmintic, 100 L3 infective larvae of Haemonchus contortus were given to each animal. The larvae were suspended in water and given via an oral dose. L3 larvae were produced by collecting eggs from sheep known to be susceptible to the action of the anthelmintics from a separate property. Larvae were grown from the eggs and collected at the L3 larval stage. Methods for propagating parasites are known in the art, for example as described in Coyne CP. and Brake D. (2001) Int. J. Parasitol. 31(4): 359-376.

[00144] Following treatment, sheep were returned to the same spelled paddock that they had been held in when first drenched.

[00145] The above methodology was conducted in autumn, as the heat of summer reduces required paddock spelling time for the clean paddock. In addition there is a reduced risk of the administered parasite burden accumulating and becoming problematic in this part of the year. Typically, a month is considered a reproductive cycle/reinfection cycle for Haemonchus.

[00146] Fecal egg counts were then monitored once a month. Once total parasitic egg counts began to rise again (600-800), second stage drenching occurred with a second anthelmintic, such as levamizole (eg available from Virbac Australia) at 8 mg/kg body weight or napthalaphos (eg available from Virbac Australia) at 35 mg/kg.

[00147] Results

[00148] We initially tested the level of resistance to various anthelmintics in a population of sheep used for the trial, which was performed by measuring the level of fecal egg counts before and after treatment, over a period of 10 to 14 days.

Table 1 : Levamizole resistance in individual sheep

[00149] Table 1 shows that significant resistance, and little sensitivity, to levamisole and was broadly found in the sheep as tested.

[00150] In a control set of sheep in the same mob, which were not subject to any treatment, the level of parasite load before and the study was also assessed and the results are shown in Table 2.

Table 2: Untreated resistance in control sheep

[00151] These results show that there was no significant trend to changes in parasitic load generally over the course of the study, reflecting a range of immunologic states present in the sheep.

[00152] Table 3 also shows the level of resistance to albendazole (BZ), closantel (CLOS), napthalaphos (NAP) and moxidectin (MOX) in different groups of sheep used in the trial, which was performed by measuring the level of fecal egg counts before and after treatment, over a period of 10 to 14 days. Horizontal data does not reflect measurement in the same sheep.

Table 3 : Resistance to Anthelmintics in sheep

[00153] Table 3 shows that significant resistance, and little sensitivity, to the various anthelmintics tested was broadly found in the sheep as tested.

[00154] Table 4 shows the results for the treatment protocol using Zolvix as the first anthelmintic, inoculating with sensitive parasites and then treating with napthalaphos as the second anthelmintic, and testing resistance in individual sheep (as indicated by a specific sheep identifier) for number of eggs without treatment to levamisole or after treatment.

Table 4: Eggs counts using treatment protocol

[00155] The results show that the treatment protocol resulted in an extensive reduction in anthelmintic resistance in the sheep. The extent of resistance is provided in Table 5. [00156] Table 5: Eggs counts using treatment protocol

[00157] Table 6 shows the results for the treatment protocol using Zolvix as the first anthelmintic, inoculating with sensitive parasites but not subsequently treating with a second anthelmintic, and testing individual sheep (as indicated by a specific sheep identifier) for number of eggs without before or after treatment to generally. Table 6:

[00158] Table 6 serves as a control and shows that in the absence of the treatment of the second anthelmintic, generally parasitic load in the sheep is not adversely affected.

[00159] As a further consideration, the treatment with susceptible worms was performed on about 200 wethers. This was conducted on an isolated part of the property. Once this data had been collected, the wethers were no longer run in isolation, mixing with about 200 ewes also running on the property, with the ewes and wethers no longer in isolation. This changed the resistance status of the worms. It would be expected that this would dilute the resistance in the ewes to about half for each active class of anthelmintic. Another fetal egg count resistance test was conducted, this test included 3 individuals that had been treated with a combination of anthelmintics from 4 classes.

[00160] In relation to the issue of the two strains possibly not mixing again, in theory, if the strains hadn't mixed, the 4 way combination treatment of anthelmintics should result in the same level of fecal egg reduction as any of the single actives, since all the single actives started at 0% effective. If there was inter breeding between the two strains, that would indicate that drenching with a 4 way active anthelmintic would have an additive effect in reducing the fecal egg output, i.e. 50% + 25% + 12.5% +6.25% = 93.25% for the 4 way active if the single actives were diluted to 50% active (because of the untreated ewes and treated wethers running on the same land.

[00161] However, it was found that there was clearly genetic mixing, because a multicombination drench (commercially available as the product Q-drench from Jurox) which contains the actives (Abamectin, Albendazole, Closantel and Levamisole hydrochloride) works at 98.6% and the other actives work at 45% - 86% (approximately 50%).

[00162] Accordingly, these studies demonstrate that reducing resistance to an antiparasitic agent in an animal may be achieved by first reducing parasitic load in the animal, inoculating the animal with parasites susceptible to the anti-parasitic agent, allowing the parasitic load in the animal to increase again; and then reducing the parasitic load in the animal again.

EXAMPLE 2 - Efficacy of Treatment

[00163] The following data utilises a fecal egg count reduction test (FECRT). The data involves identifying groups of 10 sheep - one group for each active you would like to test, plus an additional "undrenched" or "control" group.

[00164] The sheep were marked in a way that makes it easy to identify the active which those sheep were drenched with. On the day of drenching, fecal egg counts were taken from each individual sheep. 10 - 14 days later, fecal egg counts were again taken for each sheep. Reductions in fecal egg count were recorded and drench efficacies were calculated as a percentage fecal egg count reduction compared with initial fecal egg count results. This fecal egg count reduction is averaged across all animals within a treatment which gives the efficacy of each particular drench active.

[00165] The control or "untreated" group was used to observe any change in the fecal egg counts had the sheep not been drenched. There is a degree of variability between animals using this type of test. In some cases, a 95% confidence interval (CI) was provided to show how variable the records were for a particular treatment.

[00166] The results of the trial are provided in Figure 1. This data represents the average worm egg counts 10 - 14 days after drenching with Levamizole as compared with the undrenched group. The graph shows that there was little apparent difference between the Levamizole treated sheep and the untreated sheep. In fact, the worm egg counts increased to almost 400% of what they were when the sheep were drenched 2 weeks prior.

[00167] After identifying that Levamizole didn't work, the sheep were treated with susceptible parasites. After some months, the sheep were drenched several times with Napthalaphos (Rametin). Another FECRT was performed, using Levamizole. The results are presented in Figure 1. The data shown is the average fecal egg count 10 - 14 days after drenching. The control group FEC had increased to over 900% of what it was measured at the time of drenching. The Levamizole group however showed only 2.5% of the initial FEC, demonstrating over 97% efficacy of Levamizole.

[00168] Figure 2 shows the results of another trial conducted in the same way as the previous trial. First, we established the drench efficacy of Moxidectin, Albendazole and Levamizole. The product was then applied according. Some months passed and the sheep were drenched with a Closantel, Abamectin, Albendazole and Levamizole combination (available as Q Drench) to kill the artificial infection. Once worm egg counts had increased again, drench efficacies were re-evaluated using FECRT. As can be seen in Figure 2, the drenches reduced the FEC by a greater amount after the treatment had been applied.

[00169] Figure 3 shows the results of a further trial to evaluate the efficacies of three drenches, namely Levamizole, Closantel, and a combination of Levamizole and Albendazole. Initially the Levamizole worked at 78%, the Closantel worked at 88%> and the Levamizole Albendazole combination worked at 95.9%. After using the treatment, the Levamizole worked at 99.78%, the Closantel worked at 99.69%> and the Levamizole and Albendazole combination worked at 99.9%. It is also important to note that when undertaking the larval differentiation only 6 Haemonchus contortus (barbers pole worm) larvae were retrieved from approximately 15g of dung culture from the combination drench treatment.

[00170] As this data shows, the product is highly effective in restoring on farm drench susceptibility to Haemonchus contortus.

EXAMPLE 3 - Treatment of sheep with a mixture of susceptible parasites

[00171] A study similar to that described in Example 1 was undertaken, except in this case instead of the pure Haemonchus strain applied, a mix of Haemonchus (97%), Teladorsagia (1%) and Trichostronglyus (2%) was applied to each sheep.

[00172] The protocol involved the inoculation of 39 mixed parasites per sheep which used the proportions of parasites described above. The sheep were inoculated in April and testing of the levels of resistance undertaken after a six month interval.

[00173] As a control, the levels of parasite load were determined in sheep that were not inoculated with parasite nor exposed to drenching. These results are provided in Table 7.

Table 7: Untreated resistance in control sheep

[00174] The data provided in Table 7 reflects the parasitic load in the control sheep. As anticipated, the sheep demonstrated different loads of parasite before and after, and which was dependent resistance in the sheep population was also assessed by treating the sheep with a broad spectrum drench containing 4 actives, namely Q drench (Abamectin 1.0 g/L; Albendazole 25.0 g/L, Closantel 37.5 g/L and Levamisole hydrochloride 40.0 g/L) brand name Q drench, available from Jurox) and Moxidectin and assessing the efficacy of treatment of a control (no treatment with susceptible parasites) and using the treatment protocol. [00175] The percentage efficacy is shown in Table 8 for Trichostronglysis columbriformis and in Table 9 for Teladorsagia circumcinta.

Table 8 {Trichostronglysis columbriformis)

[00176] For Trichostronglysis columbriformis, it was found that the Q drench had nearly 100% efficacy, whereas treatment with Moxidection had a 70.6% efficacy, indicating the presence of Trichostronglysis resistant to Moxidectin.

[00177] For Teladorsagia circumcinta, it was found that the Q drench had 86% efficacy, and treatment with Moxidection had a 0% efficacy, whereas after the treatment protocol the efficacy rose to 100% for Q drench and 49.6% for Moxidectin.

[00178] For sheep treated with susceptible parasites according to the protocol, results for individual sheep are provided in Table 10 (Q drench) and Cydectin (Table 11). Table 10: Resistance in sheep

Identifier Egg counts

11 0

12 0

13 40

14 0

15 0

16 0

17 0

18 0

19 0

20 0

Table 11 : Resistance in sheep

[00179] The results provided in Tables 8 and 9 demonstrate that the treatment protocol restored sensitivity of the parasites to the anthelmintic agent. For example, for resistance to Q drench there is almost complete sensitivity as compared to a 86% efficacy with Telasorsagia in the absence of treatment.

[00180] Given that resistance tests are in a mixed population, drench efficacies were calculated by identifying the species present before drenching, then identifying species present in each drench treatment group after drenching. [00181] Table 12 shows the percentage of parasite types for the treatment groups 1-10, 11-20 and 21-30. Oes. = Oesophagostomumm.

Table 12

[00182] In the study, drench efficacy was restored to 100% in 3 of the 4 treatment groups, no Teladorsagia or Trichostronglylis were present in these groups after drenching.

[00183] Figure 4 show data for rate dependence on allergic substitution, knowing that the levamisole and albendazole resistance is recessively inherited, and by separate genes, allows for the calculation of parental allocation of the relative proportions of alleles in the new population using the hardy Weinberg principle:

A ² + 2AB + B ² = 1; where A and B are alleles on the same gene

[00184] The values on the X axis are /100 (X by 100 to get total number of infective larvae introduced into each sheep).

EXAMPLE 4 - Description of the technology

[00185] A description of the technology as used, and some of its benefits, is provided below.

[00186] In agriculture, there is a large range of pests which can reduce the profitability and/or viability of an enterprise. For many of these pests there has been a reliance on chemicals to kill the pests, thereby reducing their negative impact on production.

[00187] In sheep and other livestock, internal nematode parasites, often referred to as "worms" cause substantial production loss and even death. For sheep, roundworms cause the highest animal health cost in the Australian sheep industry. These worms have been successfully controlled by chemicals in the form of drenches since about the 1970's when very safe and highly effective drenches started to be invented.

[00188] However, it wasn't long until the worms evolved "resistance" to these drenches and new drenches were invented to continue the job. Over the years, the costs in developing drenches have increased, while the value of agricultural commodities have remained relatively constant, or even declined in relative terms. It is clear that it may not be possible to continuously develop new drenches, so there it is important to prolong the use of existing drenches as long as possible.

[00189] The use of a method as described herein is a solution to prolong the use of existing drenches.

[00190] The product has been shown to be extremely useful in not only slowing the development of drench resistance, but in reversing it.

[00191] For example, the product may contain a quantified amount of a H. contortus strain which is not only highly susceptible to MLs, BZs, Closantel and Levamisole, but it is also much less virulent than most H. contortus strains on farms. In addition, the strain when used according to directions has reliably increased ML and Levamizole susceptibility to greater than 95%, even if drenches were very ineffective initially.

[00192] It also produces a marked increase in the efficacy of BZ drenches, albeit not to the same extent in a single application (about 85% effective). The product also boosts the initial and sustained efficacy of Closantel. The product has also proven very good at restoring Moxidectin LA sustained activity at a high efficacy to 80 days in lactating ewes. Because the product is being replenished from stock which is not under selection pressure from drenches, it could in theory prolong the use of highly efficacious drenching indefinitely.

[00193] We have also compared the production cost of inoculating with the product with the use of an 80% effective drench. Over the 3 month inoculation period, sheep inoculated with the product (n=60) produced an average of 130g more wool than the sheep treated with an 80% effective Closantel (n=~600). So the product while having the benefit of being a measured amount of parasites, can also minimizing production losses.

EXAMPLE 5 - Kits and Products

[00194] Examples of a product or kit for use in some embodiments as described herein are set out below.

[00195] A product/kit may contain one or more of the following components:

• Isolated parasites, typically in the larval stage, which are susceptible to identified anthelmintics.

• A container of sterile water or other suitable solution for dilution of the parasites to a suitable working concentration for drenching (oral administration).

• Instructions for preparing the susceptible parasites for drenching and/or instructions for drenching of the animal.

• One or more anthelmintic agents for administration to animal.

• Instructions for preparation and/or administration of the anthelmintic agent(s).

• Instructions for animal handling before, during and/or after the treatment regime.

• Reagents and/or instructions for measuring the level of parasites in the animal.

• Components may be provided in suitable containers. [00196] For example, instructions for using a product for treating livestock are as follows (with reference, by way of example, to the treatment of sheep):

[00197] 1) In the three months leading up to treatment with the product, quarantine the sheep in sufficient paddocks to support treated animals for at least 1 month.

[00198] 2) Treat all sheep on the property with Zolvix according to manufacturer's guidelines. Sheep may be put immediately into the paddock immediately after treatment with Zolvix. Alternatively, sheep may be held on grating or in yards for up to 24 hours before being put into the paddock.

[00199] 3) Fourteen days (14 days) following Zolvix treatment inoculate with susceptible parasites. Sheep may be returned to the same paddock.

[00200] 4) Graze paddocks as per normal management. Aim to have paddocks "sheep free" for 3 summer months or 6 winter months before being grazed with treated sheep.

[00201] 5) Sheep must either have a detectable worm egg count before being moved into an unexposed paddock or remain undrenched since the initial inoculation with the susceptible parasites. The term "unexposed" is used here in the context of any paddocks which have not been exposed to sheep carrying the current treatment of the product.

[00202] 6) Drench only when egg counts begin to rise. If all paddocks have been grazed since the initial inoculation, the program is complete and drenching can be carried out as desired.

[00203] Product mixing instructions:

[00204] 1) Remove the composition containing susceptible parasites from refrigeration and allow to stand for 1 - 6 hours at room temperature. Do not sit in direct sunlight.

[00205] 2) Rock container 3 - 4 times gently until sediment is thoroughly suspended.

[00206] 3) Pour contents into a 5 litre drenching pack (Caution: do not use packs, hoses or guns which at any time have come into contact with any drench or pesticide as this may result in destruction of the prodi

[00207] 4) Rinse product container 2 - 3 times and pour rinsings into the 5 litre drenching pack.

[00208] 5) Gently fill the 5 litre pack with water to the 5 litre mark. Product is now ready for administration to animals.

[00209] 6) Administer to animals at a rate of lOmL per animal orally 14 - 16 days post treating with Zolvix.

[00210] Although the present disclosure has been described with reference to particular embodiments, it will be appreciated that the disclosure may be embodied in many other forms. It will also be appreciated that the disclosure described herein is susceptible to variations and modifications other than those specifically described. It is to be understood that the disclosure includes all such variations and modifications. The disclosure also includes all of the steps, features, compositions and compounds referred to, or indicated in this specification, individually or collectively, and any and all combinations of any two or more of the steps or features.

[00211] Also, it is to be noted that, as used herein, the singular forms "a", "an" and "the" include plural aspects unless the context already dictates otherwise.

[00212] Throughout this specification, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element or integer or group of elements or integers but not the exclusion of any other element or integer or group of elements or integers.

[00213] Reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that this prior art forms part of the common general knowledge in any country.

[00214] The subject headings used herein are included only for the ease of reference of the reader and should not be used to limit the subject matter found throughout the disclosure or the claims. The subject headings should not be used in construing the scope of the claims or the claim limitations.

[00215] The description provided herein is in relation to several embodiments which may share common characteristics and features. It is to be understood that one or more features of one embodiment may be combinable with one or more features of the other embodiments. In addition, a single feature or combination of features of the embodiments may constitute additional embodiments.

[00216] All methods described herein can be performed in any suitable order unless indicated otherwise herein or clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the example embodiments and does not pose a limitation on the scope of the claimed invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential.

[00217] Future patent applications may be filed on the basis of the present application, for example by claiming priority from the present application, by claiming a divisional status and/or by claiming a continuation status. It is to be understood that the following claims are provided by way of example only, and are not intended to limit the scope of what may be claimed in any such future application. Nor should the claims be considered to limit the understanding of (or exclude other understandings of) the present disclosure. Features may be added to or omitted from the example claims at a later date.