WO2006109069A1

WO2006109069A1 - Use of a metal ion chelating agent for the treatment of animal and human parasites

Info

Publication number: WO2006109069A1
Application number: PCT/GB2006/001350
Authority: WO
Inventors: Russell Taylor
Original assignee: Aq+Plc
Priority date: 2005-04-14
Filing date: 2006-04-13
Publication date: 2006-10-19
Also published as: EP1879576A1; GB0507490D0; JP2008535901A; AU2006235719A1; CA2606908A1

Abstract

Disclosed are uses of metal ion chelating compositions for the treatment or prophylaxis of parasitic infestations such as nematodes and other parasitic organisms, including protozoan species in human and non-human animals.

Description

TREATMENT OF ANIMAL AND HUMAN PARASITES

This invention relates to manufacture and applications of metal ion chelating compositions for the treatment of parasitic nematodes and (other) parasitic organisms which include the protozoan species and others in human and non-human animals; including horses, sheep, cattle, cats, and dogs .

There are many thousands of nematodes and whilst there are some 15,000 known species, there are thousands that occur even in a handful of soil; with a substantial number not yet named. They are prolific breeders with some containing many millions of eggs and laying up to 200,000 eggs per day. Amongst the various parasitic nematodes that affect animals, which may be mentioned are lungworms, whipworms, hookworms, threadworms, toxocara, and various filarial parasites. Other parasitic organisms in animals include, cestodes, notably tapeworms, and Bots.

Typically, a nematode has a long and narrow body, in some cases resembling a thread and the epidermis is a mass of cellular material and nuclei without separate membranes. This epidermis establishes a thick outer layer called the cuticle, which is very tough and flexible. Under the epidermis lie long muscles, which are aligned longitudinally, and this allows the nematode to bend its body from side to side. These muscles are activated by two nerves along its dorsal and ventral side.

The nematode can either feed through its head or various openings along its body where it can draw food in, crush it and then digest it. Waste is removed through excretory canals, which are on each side of the body.

Within the nematode family there are several blood sucking varieties together with the other varieties that rely either on bacteria for nutrition or other nutrients that may be available from the food eaten by the animal.

The blood sucking varieties can consume up to O.lmls of blood per day and with several thousand present in an animal drawing blood it can result in the infested animal having a lethargic condition.

A large family of parasitic nematodes (mainly round worms although flat worms may be present as well) inhabit the gut and intestinal passages of the animals and if not treated can lead to the occurrence of adverse medical and physical conditions.

Many nematodes can suspend their life processes when conditions become unfavourable, for example they can survive extreme drying, heat or cold and then commence life at a later stage; a condition known as cryptobiosis .

Intense farming practise developed over the years, means that nematodes are excreted with dung from infected animals in relatively confined areas, resulting in the situation that the fields become infested with nematodes or their eggs. This means that animals that are grazing on this land will then pick up the nematodes and/or their eggs and re-infection will occur immediately, creating a continual cycle.

Parasitic nematodes in animals will result in the animal becoming thin and in some extreme cases if the animal is not treated for nematodes, it will die from malnutrion as the nematodes compete for nutrition from what the animal eats and tries to digest .

Many parasitic nematodes that appear in animals are also present in humans, probably contracted from some animal source. They have a similar effect on humans as on the animals .

The animals that experience parasites and parasitic nematodes are mainly horses, cattle and sheep, although companion animals (pets) do experience infestation to a degree .

Within sheep for example, the main varieties that may be present are, Telodorsagia circumcinta, Trichostrongylus colubriformis, Haemonchus contortus ( Barber's pole or wire worm-blood sucker) , Ostertagia sp . up to several species of lungworm (Dictyocaulus filana) , tapeworms (Moniezia expansa) and at the same time, liver flukes - mainly Fasciola hepatica (a flatworm) .

Within cattle you will experience a range of Haemonchus spp . (Blood Suckers) not only contortus but also others like placei, together with other gut parasites Ostertagia ostertagi and Cooperia oncophora . Lungworms, Dictyocaulus viviparus and Dictyocaulus viviparous may also be present .

In horses the parasitic nematodes that may be present are

Oxyuris equi (pin worms) , Tarascaris Equorum (round worms) , Stongylus equines, Strόngylus edentatus (large) , Strongylus vularis (small) , Haemonchus contortus (blood suckers) and others together with the Bots eggs that hatch into larvae in the horse's stomach.

In dogs and cats the parasitic hookworm nematodes are Ancylostoma duodenale, and Toxocara canis in dogs and Ancylostoma tubeforme, and Toxocara cati in cats.

These parasitic nematodes go through various cycles of life within the animal and they may be present as eggs, larvae or fully-grown nematodes. When present in the gut and intestines of the animal they lodge in the gut wall and intestinal wall tissue and can live there for an indefinite period of time, adversely affecting the animal concerned. They control the growth of young animals as with parasitic nematodes being present nutrition is denied to the growing animal .

The current treatment for these nematode infestations are with chemicals called, Moxidectin (Macrocyclic Lactone - affects the chloride channels in the nervous system) ,

Ivermectin (Macrocyclic Lactone - binds to the glutamate gated chloride channels in the parasites nervous system) , Oxibendazole ( Benzimidazole family- binds to tubulin subunit and interferes with microtubule formation) , Fenbendzole (Benzididazole family - interferes with the nervous system) and Pyrantel pamoate (Imidazothiazole - acts as a blocking agent on muscle activity)

Parasitic nematodes and parasites have, over a period of time, started to become resistant to the action of these chemicals with the result that they are no longer effective in treating animals for these conditions at the set dosage rate. If the dosage rate were to be increased to overcome the resistance problems, the toxicity of a lot of these chemicals would exceed the safe limits imposed for the treatment of animals so this is clearly not a realistic option.

With this level of resistance building, animals have an increasing load of parasites, which can affect the growth of the animal and its well-being. This means for, example, that meat-breeding animal's development ceases and in some cases if they cannot be treated they will die from malnutrion. In horses the development of the parasite load will seriously affect their capability of specialist activities like racing, or even being available for general duties.

It has been shown that if animals are not treated for nematode infestation then eventually, due to the fact that the animals are not receiving sufficient nutrition from the food they eat, they will consume their own body fat and then after that, their muscle tissue. This is a muscle wasting disease called Cachexia. The body goes into a shock syndrome, consuming all the muscle tissue resulting in the animal not being able to stand or move. Such an animal will eventually die of malnutrition.

It is an object of the present invention to avoid or minimize one or more of the above problems.

Other parasitic organisms that may be present in animals and humans are Protozoan parasites and Brucella.

The Protozoan's that may be present are Amoeba and flagellates, Trichomonas vaginalis, Acanthamoeba, Giardia, Cryptosporidium, Entamoeba, Isospora, Balantidium Equine Protozoal Myeloencephalitis, Coccidia, Leishmania, Trypanosoma, Naegleria, Toxoplasma and

Plasmodium especially in humans.

Brucella may be present in animals as Brucella abortus, in seals as Brucella maris and in humans as Brucellosis.

In all cases the Parasitic Protozoan's and Brucella depend on Ferric and/or Ferrous ions and in all cases they enter the bloodstream to have access to the red blood cells to survive.

With Trichomonas protozoan, this can be present in equines to an extent as a sexually transmitted disease and the female equine will be emitting a white secretion from the genital tract, as well as losing weight and if the animal is used for breeding it will not become pregnant with this condition present. In humans Trichomonas vaginalis is treated as a sexually transmitted disease and if not treated, it produces various medical conditions within the vagina that will give vaginal discharge and itchiness.

Trichomonas vaginalis can also be present in males in the urethra transmitted through sexual contacts. Other transmission of the Trichomonas protozoa can be by soiled towels, lavatory seats, sports clubs facilities and saunas .

Coccidia and Giardia are two protozoans' that do invade and inhabit the lining of the small intestines in cats and dogs and create severe watery discharges or bloody diarrhoea .

Equine protozoal myeloencephalitis is a condition that affects the nervous system of the equine, as it creates - 1 ~ inflammation of the brain tissue and damage to the spinal cord. The source of the parasite which creates this situation is Sarcocystis neurona normally derived from opossum faeces and this infective form is a "sporocyst" . The sporocyst is ingested by the horse from the grass it consumes and then the sporocyst enters the blood stream and enters the brain and forms lesions on the brain tissue and spinal cord. When the equine is infected its coordination is erratic and has very little ability in moving its legs in a coordinated fashion.

Acanthamoeba and Naegleria species are found worldwide and they are mainly in fresh water sources like lakes, rivers , hot springs and in hot tubs . They can be found in heating, venting and air conditioning units. Acanthamoeba infections of the eye can result in being transmitted through the use of soft contact lenses as well as the contact lens solutions not been clean and with this situation eye infections where the Acanthamoeba enters the eye through a cornea cut or sore and a corneal ulcer can result . Acanthamoeba can enter the skin through a cut, wound, or through the nostrils. Once inside they can travel to the lungs through the bloodstream and to other parts of the body, especially the nervous system. In the case of nervous system infections, these can be fatal.

Naegleria entering the nasal passages of humans can cause a fatal situation.

With Entamoeba, Cryptosporidium, Isospora, Balantidium, and Giardia are all associated with giving humans diarrhoea. The source of Balantidium is associated with pigs . The source of Isospora is normally associated with Aids patients from Haiti and Africa.

Tryanosoma the cause of the condition called African sleeping sickness and is conveyed by the Tsetse fly (Glossina) . The infection is developed in the blood stream which results in bouts of fever and malaise, a classical sleeping sickness syndrome.

With Toxoplasma protozoan is found in mainly felines in the intestinal system but upon transmission to humans can end up creating cogenital toxoplamosis (toxoplasma encephalitis) .

Leishmania is widespread and produces zoonotic infections in dogs and rodents.

With Plasmodium this is the protozoan parasite that induces Malaria in humans. This protozoan has four known species "vivax" , "malariae" , "ovale" and "falciparum" of which falciparum is the most common and deadliest species. The Plasmodium parasite is world wide and is transmitted by the Anopheles mosquito. When a human is infected from a mosquito bite the

Plasmodium parasite enters the bloodstream and goes straight to the liver where it is safe and where it replicates itself many thousand times over within a two week period. The Plasmodium parasite requires Ferric and/or Ferrous ions to multiply so it attacks a plasma protein called "Transferrin" that transports Ferric/Ferrous ions through the blood to the liver, spleen and bone marrow. Brucella is an parasitic bacteria that causes Brucellosis in its various forms in sheep, goats, cattle, deer, elk, pigs, dogs and humans who come into contact with diseased animals. With humans brucellosis can cause a range of symptoms like, fevers, sweats, backaches, headaches and physical weakness . Transmission by humans is rare but lactating females can transmit the infection to their baby, and also it is reported that transmission by sexual activity has been recorded.

There has previously been proposed in our earlier Patent publication WO 03/032944, various topical chelating compositions suitable for use in combating antibiotic- resistant infections and contamination of the skin and open wounds. There has been no previous suggestion, however, of the possible utility of such compositions for other conditions.

We have now found that compositions based on the use of chelating compounds as disclosed in WO 03/032944 (the contents of which are hereby incorporated herein by reference thereto) , are effective in the treatment of various parasite infestations for animals and humans in one or more different ways, further discussed herein below.

More particularly we have found that these compositions have the capability of killing nematodes over a period of time, allowing the animal to regain control over its digestive system and establish a healthy condition. We have also found these compositions to be effective in the treatment of bot larvae infestations .

We have found as well that these compositions have the capability of entering the blood stream and attacking various Protozoan parasite and also Brucella present in the blood stream by chelating the Ferric and Ferrous ions . The chelate that has been formed denies the Ferric and Ferrous ions to the protozoan parasite and brucella. In the case of Plasmodium the chelate also actually enters the diseased cell and exerts a profound biological effect on it resulting in the death of the diseased cell .

In a first aspect the present invention provides the use of a metal ion chelating agent for the manufacture of a medicament for the treatment or prophylaxis of a parasitic infestation, wherein the parasite is susceptible to coating by said metal ion chelating agent or being attacked by the chelate formed.

In a second aspect the present invention provides the use of a metal ion chelating agent for the manufacture of a medicament for the treatment or prophylaxis of a parasitic infestation, wherein the parasite is nutritionally dependent on a host bacterial population and wherein said metal ion chelating agent has a metal ion chelating capacity for metal ions on which said host bacterial population is dependent for viability.

For example, the treatment or prophylaxis may be in respect of nematodes, and their bacterial food sources wherein said metal ion chelating agent provides a metal ion chelating capacity for at least one metal ion on which the said nematodes and their bacterial food sources are dependent for viability. In a third aspect the present invention provides the use of a metal ion chelating agent for the manufacture of a medicament for the treatment or prophylaxis of a parasitic infestation, wherein the parasite is susceptible to paralysis by said metal ion chelating agent .

In a fourth aspect the present invention provides the use of a metal ion chelating agent for the manufacture of a medicament for the treatment or prophylaxis of a parasitic infestation, wherein the parasite is a bloodsucking or blood dependent parasite, and wherein said metal ion chelating agent has a metal ion chelating capacity for ferric and/or ferrous ions.

In a further aspect the present invention provides the use of a metal ion chelating agent for the manufacture of a medicament for the treatment or prophylaxis of a nematode, cestode, bot larvae infestation or Protozoan parasite or Brucella infestation.

This invention also provides a method for the treatment or prophylaxis, in a human or non-human, animal, of: a parasitic infestation, and especially of a parasitic infestation selected from a nematode, cestode and bot larvae, infestation, Protozoan and Brucella.

The Protozoan's that may be present are Amoeba and flagellates, Trichomonas vaginalis, Acanthamoeba,

Giardia, Cryptosporidium, Entamoeba, Isospora, Balantidium Equine Protozoal Myeloencephalitis, Coccidia, Leishmania, Trypanosoma, Naegleria, Toxoplasma and Plasmodium especially in humans. Brucella may be present in animals as Brucella abortus, in seals as Brucella maris and in humans as Brucellosis.

In more detail, we have found that when nematodes gain prominence in the animal's stomach and intestines, it appears that the pH level in each area is altered considerably. Where a stomach will normally have a pH level of 1 to 2 to support the digestion of food, it has been shown that a nematode infestation results in a pH level of around 7. The pH in the intestinal tract has also being altered due to the presence of these nematodes. It appears that the nematodes have reduced the amount of bacteria working on the food to be digested by absorbing the bacteria themselves as a food source. Altered pH and fewer digestive bacteria means that the food for the animal is not properly digested and the nutrients are not available to the animal to survive.

Treatment of animals for nematodes with the current treatments removes a proportion of the nematodes. After this treatment, a dose of active bacteria is required to achieve balance within the stomach and intestinal system to allow digestion of the food eaten.

Nematodes and other parasitic organisms appear to have developed resistance to current treatments by blocking the effect of these treatments entering into their bodies; probably by coating themselves with a further resistant coating.

The metal ion chelating composition appears to coat the nematodes and, at the same time, completely paralyse them so they cannot move or feed. In so doing it prevents the nematodes from eating all the digestive bacteria present .

After a period of time, with the nematodes unable to eat, they will die. The nematodes are in various stages of development within the stomach and intestinal system and they are all affected.

The other mode of attack is that the metal ion chelating composition also coats the bacteria present and chelates the metal ions present that the bacteria relies on to survive. This means that, with the bacteria being coated or smothered and then starved to death, the food source for the nematodes has been eliminated and the nematodes will die.

With regards to the blood sucking nematodes: it is thought that the metal ion chelating composition, once in contact with and coating these nematodes' skin, shrinks the outer skin due to the chelating action seeking the ferric ions associated with the blood that they rely on for food. This type of nematode appears to have very high ferric or ferrous iron content from the blood consumption.

Thus preferred chelating agents can chelate various different metal ions and thereby attack the nematodes by multiple, direct and indirect, routes. More particularly, it is preferable for the metal ion chelating agent to form a chelate with a plurality of metal ions selected from Mg²⁺, Fe²⁺, Cu²⁺, Zn²⁺, Mn²⁺, Ni²⁺, and Se²⁺. 8-hydroxyquinoline has been found to have a particularly broad spectrum of activity, chelating most metals apart from sodium, potassium and calcium. Upon treatment of equines with this metal ion chelating agent on a planned program dosage, no dead nematodes appear in their faeces for the first 3 days. The first dead nematodes and other parasites (such as bots) will then start to appear and will continue for typically another 6 days after which normally no more can be located in the dung. A great majority of the eggs are also emitted during that period.

It has been shown (by post-mortem analysis of a horse after death from other causes) that after this treatment, the stomach and intestinal system contains virtually no nematodes .

Once this treatment has been completed then administration of a pro-biotic may be beneficial to assist the development of the natural bacteria population in the digestive system re-establishing itself.

Typically the metal ion and the metal ion chelating agent form together a stable complex such that the metal ion is effectively removed for a sufficient period of time to prejudice microbe viability and overcome the infection and/or to maintain a coating on the nematode, before the metal ion chelate dissociates. In general the metal ion and metal ion chelating agent should form a stable chelate under physiological conditions, and especially conditions prevailing in the intestinal tract where blood-sucking nematodes tend to be attached.

Typically the metal ion and the metal ion chelating agent form together a stable complex such that the metal ion is effectively removed or chelated to prejudice the viability of the Protozoan parasites and Brucella. Preferably the metal ion chelating agent is a heteropolar compound comprising at least one unsaturated heterocyclic six-membered ring in which at least one heteroatom moiety acts as a hydrogen acceptor and in which said compound also comprises at least one hydrogen donor moiety, conveniently a hydroxyl group, said heteropolar compound having no substituent which by itself or together with another substituent or substituents creates such steric hindrance and/or renders the molecule so basic or acidic or so alters the steric geometry of the molecule as to prevent interaction of the hydrogen donor and acceptor moieties of one molecule of heteropolar compound with the hydrogen donor and acceptor moieties of another molecule of said heteropolar compound.

In general the preferred metal ion chelating agent is a hetero aryl compound having at least one nitrogen in the ring structure and at least one hydroxyl substituent disposed on the ring structure so as to provide together, a chelating function. Preferred metal ion chelating agents are selected from optionally substituted 2,3- dihydroxypyridine; 4 , 6-dihydroxypryrimidine; 2- pteridinol; 2 , 4-quinolindiol ; 2 , 3-dihydroxyquinoxalin; 2 , 4-pteridinediol ; 6-purinol; 3-phenanthridinol ; 2- phenanthrolinol ; 2-phenazinilol, and most preferred is 8- hydroxyquinoline . 8-hydroxyquinoline has the advantage of forming metal ion chelates with a particularly broad range of different metal ions.

In a further aspect the present invention provides an orally ingestible pharmaceutical composition suitable for use in the treatment or prophylaxis of a parasitic infestation (such as a nematode, cestode, bot larvae infestation, protozoan parasites or brucella) , said composition comprising a physiologically acceptable metal ion chelating agent and a pharmaceutically acceptable carrier therefore, in which composition said metal ion chelating agent has at least one of: a metal ion chelating capacity for metal ions on which a host bacterial population providing nutrition to the parasite, is dependent for viability; a capability for coating the parasite; a capability for paralysing the parasite; and a metal ion chelating capacity for ferric and ferrous ions .

The compositions of the present invention for internal application will generally comprise from 0.000001% to 0.2% w/w, preferably from 0.00001 to 0.1, % w/w, conveniently from 0.0005 to 0.05 % w/w, of the chelating agent, depending on the particular administration route selected (e.g. admixed with dry feedstuff or drinking water, or administered as a liquid or paste-form drench etc) . Using a chelating agent concentration of around 0.05% w/w, a convenient dosage of a liquid formulation suitable for incorporating into feed etc, would typically be around 10 mis. Where it is preferred to administer the composition directly to the animal, then it is conveniently presented as a paste at a dosage of around 100 mis, using a chelating agent concentration of around 0.005% w/w.

For example, in the case of small animals such as cats and dogs the dose rate of the liquid compound is according to their actual weight and may vary from about 5mls per day to about 20mls per day. For the case of treating humans the dose may vary from about 10mls at a time to about 20 mis at a time twice a day depending on the Protozoan parasite or Brucella and may be for a period of time from about 5-6 days to about 45-50 days.

For example, on treatment of humans for Brucella, the period is typically for about 42 days dosing at the rate of about 20 mis per day.

For example, on the treatment of Plasmodium, the period is typically for about 5 days dosing at the rate of about 20 mis per day.

For example, on treatment of Trichomonas vaginalis in equines, treatment may be for a period of about 5 days with a vagina flush and then application of the paste in the vagina .

For example, treatment of Trichomonas vaginalis in humans is typically for a period of about 5 days inserting the paste in the vagina or in the penis in the case of the male .

Treatment of Acanthamoeba infections normally in the eye typically use about 10 mis of liquid compound per eye in a eyewash glass typically followed by application of about 5 mis of the paste around the eyelid for a period of about 5 days .

Treatment of Equine Protozoal Myeloencephalitis is typically by adding about 50 mis per day to the equine feed and this treatment is for about 42-50 days. The doses and dose regimes used are readily determined by the skilled practitioner.

Various forms of orally ingestible composition may be used in accordance with the present invention. Preferably there is used an aqueous based liquid composition, which can be readily mixed in with dry feedstuff, incorporated in drinking water etc. Alternatively there may be used a paste formulation, or in encapsulated form e.g. using capsules of suitable material which are readily available, e.g. based on starch, gum and alginate.

It will be appreciated that the choice of other components of the composition may be limited by the nature of the metal ion chelating agent. Thus, for example, since the preferred metal ion chelating agent 8- hydroxyquinoline is generally insoluble or only poorly soluble in aqueous solution. Suitable aqueous based compositions of 8-hydroxyquinoline can be prepared by using an intermediate solvent such as a polyolol, including glycols, preferably propylene glycol, glycerine, or sorbitol, and a wetting agent. Those skilled in the art will appreciate that a wide range of wetting agents are available that may be used which would give solubility of the metal ion chelating agent in glycol, including inter alia Polyoxyethylene Sorbitan Fatty Acid Ester T20, T40, T60 and T80 (Polysorbate) , and C9-C11 Alcohol ethoxylate (Symperonic 91/6,91/8) .

It will be appreciated that a range of different proportions of the various components of the aqueous based compositions may be used depending on the solubilities of the metal ion chelating agents used, the final concentration required etc. In general we have found that the amount of wetting agent used is relatively sensitive. In the case of the intermediate solvent (glycol etc) , once a required minimum amount sufficient for solubilisation of the metal ion chelating agent in the water is present, then the amount of this intermediate solvent can be readily increased further, though there is normally no particular advantage in doing so .

Advantageously there is also included a pH controller, in order to ensure an alkaline pH in the composition, most preferably a pH in the region of 9.2 to 9.4. The pH controller may simply be KOH or NaOH. Preferably, though, there is used EDTA, conveniently in the form of the DiSodium or TetraSodium salt .

In the case of 8-hydroxyquinoline we have found that suitable proportions which may be used in a liquid, aqueous-based, composition of the invention suitable for use in the treatment of nematode (and other parasitic organisms - especially bots) , Protozoa parasites and Brucella infestations, would in general have the following composition:

Component Weight

Metal ion chelating agent 1 part Wetting agent 4 +/- 5% parts

Diluent at least 20 preferably 40

Deionised Water as required to obtain the final concentration required. pH controller as required to achieve a pH of 9.2 to 9.4.

Further preferred features and advantages of the present invention will appear from the following detailed examples given by way of illustration of some preferred embodiments .

Example 1 - Method of Preparation of concentrate

10 gm of 8-hydroxyquinoline was dissolved at 65 degrees centigrade in 50 grammes of a wetting agent selected from: Polyoxyethylene Sorbitan Fatty Acid Ester T20, T40, T60 and T80 (Polysorbate) , and C9-C11 Alcohol ethoxylate (Symperonic 91/6,91/8), with 200 grams of a water soluble non-aqueous diluent selected from Propylene Glycol, Glycerine and Sorbitol . Once solution has been achieved, a further quantity of the glycol or glycerine or Sorbitol diluent was added to make up to a solution of 500 grammes and then cooled giving 500 g of 2% w/w 8-hydroxyquinoline concentrate .

Example 2 - Preparation of Veterinary Treatment Composition for nematodes and other parasites.

Take one part of the 2% w/w 8-hydroxyquinoline concentrate from Example 1 and dilute in 159 parts of deionised water, then the pH of this composition is adjusted to 9.2 to 9.4 by the addition of Tetra Sodium Ethylene Diamine Tetra Acetic Acid.

The strength of this preparation is 125 ppm of 8- Hydroxyquinoline, whereby each millilitre contains 125 micrograms of the chelating agent. Estimated dosage rate of this composition for the following animals is as follows; a) Horses: 3.5 to 4.0 microgram per kg body weight for 9 days. This liquid can be put into their daily oats or hay that they consume .

b) Cattle: 3.5 to 4.0 micrograms per kg body weight for 10 days. This liquid can be placed into their daily feed or else it can be dosed into their water troughs .

c) Sheep: 3.5 to 4.0 micrograms per kg body weight for 6 days. This liquid can be placed in their daily feed.

d) Dogs : 3.0 to 4.0 micrograms per day/ estimated body weight for 5 days. This liquid can be placed in their daily food.

e) Cats: 3.0 to 4.0 micrograms per kg body weight for 3 days. This liquid can be placed in their daily food.

Example 3 -Preparation of Protozoan parasites and Brucella Treatment composition.

Take one part of the 2% w/w 8-hydroxyquinoline concentrate from Example 1 and dilute in 39 parts of deionised water, then the pH of this composition is adjusted to 9.2 to 9.4 by the addition of Tetra Sodium Ethylene Diamine Tetra Acetic Acid.

The strength of this liquid preparation is 500 ppm of 8- hydroxquinoline, whereby each millilitre contains 500 micrograms of the chelating agent .

For the manufacture of the paste 98.8 grams the above liquid is taken and a 1.2 grams of thickener added being being either hydroxypropylcellulose of dehydoxanthan gum to produce 100 grams the paste with the desired viscosity.

Estimated dosage rate of these compositions for the following applications is as follows;

a) Equine Protozoal Myeloencephanlitis in equines .

50 mis per day of the liquid compound with their feed.

An infected horse which was losing motor neuron control of its back legs was treated with 2OmIs of the composition per day with its feed, and within 7 weeks the horse showed very little sign of the infection. However, it was evident that the lesions associated with this infection on the brain and spinal cord were still there. A post mortem revealed no EPM present, but some lesions remained on the brain mass and the spinal cord. b) Plasmodium (malaria parasite) in humans.

Take 20 mis per day of the liquid compound before a meal for 5 days .

Several human subjects were selected and treated with the composition after which no Plasmodium parasite was recorded in the bloodstream of the subjects .

c) Trichomonas vaginalis with equines

Irrigation of the vagina with 100 mis of the liquid compound followed by the application of 20 mis of the paste.

Two female horses (mares) with Trichmonas infections were selected and treated with 20 mis of paste composition each day for 5 days, by insertion in the vagina. Examination showed that the infection had gone after this treatment.

d) Trichomonas vaginalis with humans.

With females insertion of approximately 10 mis of paste per day for 5 days in the vagina.

With males insertion of paste up in the penis for 5 days .

e) Trichomonas in towels etc. Place 50 mis of the Liquid compound per gallon of wash water in the washing machine to eliminate the presence of Trichomonas in soiled towels.

f) Trichomonas on Toilet seats and facilities.

Place the liquid compound on a soft damp cloth and wipe around the areas of concern. This will leave a residual film that will be active for some time.

g) Acanthamoeba (protozoan parasite) infections in eyes .

Use 10 mis of the liquid compound in washing the eyeball with a glass eyewasher. Then application of 5 mis of the Paste applied around the eyelids.

h) Acanthamoeba and Naeglaria infections in the human body.

Take 20 mis per day of the liquid compound before a meal

i) Acanthamoeba and Naeglaria presence in air Conditioning units.

Establish a water wick system where the filter pad for the air conditioning unit is immersed in a trough of the liquid compound. This allows the liquid to move up in the filter media which will catch the amoeba in the air and then kill it. j ) Acanthamoeba and Naegleria presence in hot tubs .

For every gallon capacity of the hot tub, use 2OmIs of the liquid compound to overcome the protozoa that may have developed in the tub.

k) Acanthamoeba and Naegleria presence in saunas .

Wash the sauna walls and floor with the liquid compound which will kill the protozoa and let dry.

When the treated surface becomes damp again the residue from the compound will become active again and kill any protozoan presence.

1) Coccidia and Giardia infections in small pets.

Dose the animal with 10 mis of the liquid compound per day for 6 days with their food,

m) Entamoeba, Cryptosporidium and other Protozoas associated with inducing diarrhoea in humans.

Take 20 mis per day of the liquid compound for 5 days .

n) Tryanosoma Protozoa.

Take 20 mis twice per day of the liquid compound for 5 days .

o) Brucella (Brucellosis parasite) in humans.

Take 20 mis twice a day of the liquid compound for about 45 days. A human subject was chosen who had contracted Brucellosis after attending to a litter of Jack Russell pups. The subject had the infection for over 5 years, which was being treated with

Tetracycline. The treatment with the liquid composition was for 6 weeks taking 10 mis in the morning, and 10 mis in the afternoon.

p) Brucella (Brucellosis parasite) in small animals.

Give 10 mis a day of the liquid compound with food.

q) Brucella (Brucellosiis parasite) in large animals.

Give 50 mis per day of the liquid compound with food.

Claims

1. Use of a metal ion chelating agent for the manufacture of a medicament for the treatment or prophylaxis of a parasitic infestation.

2. Use according to claim 1, wherein the parasite is nutritionally dependent on a host bacterial population and wherein said metal ion chelating agent has a metal ion chelating capacity for metal ions on which said host bacterial population is dependent for viability.

3. Use according to claim 1, wherein the parasite is a bloodsucking or blood dependent parasite, and wherein said metal ion chelating agent has a metal ion chelating capacity for ferric and/or ferrous ions.

4. Use according to any preceding claim, wherein the parasite is a nematode, cestode or bot larvae infestation.

5. Use according to any one of claims 1 to 3 , wherein the parasite is a Protozoan parasite or Brucella infestation.

6. Use according to claim 5, wherein the Protozaon parasite is selected from the group consisting of amoeba, flagellates, Trichonomas vaginalis, Acanthamoeba, Giardia, Cryptosporidium, Entamoeba, Isospora, Balantidium Equine Protozoal Myeloencephalitis , Coccidia, Leishmania, Trypanosoma, Naegleria, Toxoplasma or Plasmodium.

7. Use according to any preceding claim, wherein said metal ion chelating agent is used together with a calcium ion chelating agent having a chelating capacity for calcium ions .

8. Use according to claim 7, wherein the calcium ion chelating agent comprises ethylenediaminetetraacetic acid

(EDTA) .

9. Use according to any preceding claim, wherein the metal ion chelating agent is able to form a chelate with a plurality of metal ions selected from Mg²⁺, Fe²⁺, Cu²⁺, Zn²⁺, Mn²⁺, Ni²⁺, and Se²⁺.

10. Use according to any preceding claim, wherein the metal ion chelating agent is a heteropolar compound comprising at least one unsaturated heterocyclic six- membered ring in which at least one heteroatom moiety acts as a hydrogen acceptor and in which said compound also comprises at least one hydrogen donor moiety, said heteropolar compound having no substituent which by itself or together with another substituent or substituents creates such steric hindrance and/or renders the molecule so basic or acidic or so alters the steric geometry of the molecule as to prevent interaction of the hydrogen donor and acceptor moieties of one molecule of heteropolar compound with the hydrogen donor and acceptor moieties of another molecule of said heteropolar compound.

11. Use according to claim 10, wherein said metal ion chelating agent is a hetero aryl compound having at least one nitrogen in the ring structure and at least one hydroxyl substituent disposed on the ring structure so as to provide together, a chelating function.

12. Use according to claim 11 wherein said metal ion chelating agent is selected from the group consisting of optionally substituted 2 , 3-dihydroxypyridine; 4,6- dihydroxypryrimidine; 2-pteridinol; 2 , 4-quinolindiol ; 2,3- dihydroxyquinoxalin; 2 , 4-pteridinediol ; 6-purinol; 3- phenanthridinol ; 2-phenanthrolinol ; 2-phenazinilol; and 8- hydroxyquinoline .

13. Use according to claim 12, wherein said metal ion chelating agent is 8-hydroxyquinoline .

14. Use according to any preceding claim, wherein the medicament includes a wetting agent.

15. Use according to any preceding claim, wherein the medicament includes an intermediate solvent in the form of a non-aqueous water soluble solvent.

16. Use according to claim 15, wherein said intermediate solvent is a polyol .

17. Use according to claim 16, wherein said intermediate solvent is selected from monoethylene glycol, propylene glycol, glycerine and sorbitol.

18. Use according to any preceding claim, wherein the medicament includes a thickener.

19. Use according to claim 18 wherein said thickener is a hydroxypropylenecellulose thickener.

20. Use according to claim 18 wherein said thickener is a dehyroxanthan gum thickener.

21. Use according to any preceding claim, wherein the medicament comprises 1 part by weight of 8- hydroxyquinoline, 4 +/-5% parts by weight of wetting agent, at least 20 parts by weight of glycol, and water.

22. Use according to any one of claims 1 to 20, wherein the medicament is in the form of a liquid, spray, cream, gel or paste.

23. Use according to any preceding claim, in which said metal ion chelating agent is present in the medicament at a concentration of from 0.0031% to 0.20% w/w of the chelating agent .

24. Use according to claim 23, in which said metal ion chelating agent is present in the medicament at a concentration of from 0.02 to 0.1% w/w of the chelating agent .

25. Use according to any preceding claim, wherein said medicament includes a pH controller to provide an alkaline pH.

26. Use according to claim 25, wherein the pH is in the range of 7.5 to 10.

27. Use according to claim 26 wherein the pH is in the range of 9.2 to 9.4.

28. Use according to any one of claims 25 to 27, wherein the pH contoller is selected from the group consisting of potassium hydroxide, sodium hydroxide or EDTA.

29. A method of treatment or prophylaxis of a parasitic infestation, comprising administering to a human or animal in need thereof, an effective dose of a metal ion chelating agent .

30. A method of treatment or prophylaxis according to claim 29, wherein the parasitic infestation is selected from the group consisting of a nematode, cestode or bot larvae infestation.

31. A method of treatment or prophylaxis according to claim 29, wherein the parasitic infection is a Protozoan parasite or Brucella infestation.

32. A method of treatment or prophylaxis according to claim 29, wherein the Protozoan parasite is selected from the group consisting of amoeba, flagellates, Trichonomas vaginalis, Acanthamoeba, Giardia, Cryptosporidium, Entamoeba, Isospora, Balantidium Equine Protozoal Myeloencephalitis, Coccidia, Leishmania, Trypanosoma, Naegleria, Toxoplasma or Plasmodium.

33. A method of treatment or prophylaxis according to any one of claims 29 to 32, wherein said treatment is followed by administering a dose of active bacteria.

34. A method of treatment or prophylaxis according to any one of claims 29 to 32, wherein said treatment is followed by administering a pro-biotic.