WO2000045641A1

WO2000045641A1 - Control of mange

Info

Publication number: WO2000045641A1
Application number: PCT/AU2000/000041
Authority: WO
Inventors: Dudley Edwin Pinnock
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-02-02
Filing date: 2000-01-31
Publication date: 2000-08-10
Anticipated expiration: 2001-08-02
Also published as: AUPP841199A0; EP1154694A4; EP1154694A1

Abstract

The present invention relates to a method of preventing or controlling parasitic mite infestations of animals or birds comprising applying to the animal or bird an effective amount of a microbial preparation derived from or comprising a suitable bacterium of the genus Bacillus, or an araricidal metabolite thereof. Preferably, the bacterium is of the species Bacillus thuringiensis, Bacillus cereus or Bacillus moritai. The invention further relates to the microbial preparations for use in this method.

Description

CONTROL OF MANGE

BACKGROUND TO THE INVENTION

This invention relates to a novel method of control of mange caused by parasitic mite populations, and in particular to the control of parasitic mites on birds and animals. For example, the method of the present application is applicable to Trombidiform and Sarcoptiform mange and scab mites, such as the scab mite Psoroptes ovis on sheep.

Some parasitic mites are disease-causing or -spreading and all are generally undesirable. For example, infestations of Psoroptes ovis mites on sheep (known to veterinary practitioners as cases of psoroptic mange and to sheep farmers as scab) are notifiable conditions that are responsible for huge financial losses to the wool and sheepmeat industries. Other species of pest mites are potential carriers of disease organisms, and remain a threat to livestock, especially in intensive animal production units such as lambing pens and poultry houses.

Mange, scab and other Sarcoptiform and Trombidiform parasitic mite diseases are the cause of suffering and even death of infested animals and birds, and cause heavy economic costs in the livestock industries. For example, according to Lapage¹, Sarcoptiform sheep scab mites, Psoroptes ovis, "puncture the epidermis to suck lymph and stimulate a local reaction in the form of a small inflammatory swelling richly infiltrated with serum. The latter exudes on to the surface and coagulates, thus forming a crust. The altered conditions cause the wool to become loose and to fall out, or it is pulled out by the sheep in biting and scratching the lesion, which itches severely. The bare crusty patches are unsuitable for the mites, which therefore migrate to the margins of the lesion and thus extend the process outwards. The diseased condition of the skin, and probably also the constant irritation, lead to progressive emaciation and finally death of the sheep." The serious effects of scab mites are further exemplified by the passing in the

United Kingdom of special Ministerial Orders for scab control and movement of sheep, i.e. Statutory Instrument No. 968, 1997; The Sheep Scab Order, which came into force on the 1^st of July, 1997.

Bacillus thuringiensis

Bacillus thuringiensis is an aerobic Gram-positive spore-forming bacterium. It is distinguished from the closely related Bacillus cereus by the production during sporulation of one or more parasporal, crystalline protein inclusions².

In many strains or serotypes of Bacillus thuringiensis, the parasporal crystalline protein inclusions, when ingested by certain insects, are highly toxic to the insects, so that these crystalline inclusion proteins or "crystal proteins" have been called the Bacillus thuringiensis "delta-endotoxins" by some authors.

Prior Art Methods of Mite Control

The methods of mite control used heretofore have proved only partially effective. At present, these consist of the application to the infested animal or bird of highly toxic organophosphate and other chemical pesticides. In addition to the direct toxic effects on the animal or bird on to which they are applied, these very toxic chemicals may create a very serious occupational health hazard to the keepers, farmers and pest control personnel using them and be the cause of environmental pollution. For example, the organophosphate pesticide Diazinon^R - also known as Dimpylate^R, Basudin^R, Neocidol^R,Nucidol^R,Kayazinon^R or Spectracide^R - is used in plunge dips for control of scab mites, Psoroptes ovis, on sheep. Diazinon (IUPAC = 0,0-diethyl 0- 2-isopropyl-6-methylpyrimidin-4-yl phosphorothioate) is extremely hazardous to man and its continual use may result in cumulative poisoning of the human operator. Such pesticides may cause undesirable residues in the treated animal and/ or environmental contamination caused, for example, by improper disposal of the sheep dip liquid after use. Also, the use of chemical pesticides is generally unsound due to the short term protection which they provide and the evolution of resistance by the pests - e.g. the parasitic mites and/ or their nymphs - to the effects of these chemicals.

Pre-existing Bacillus thuringiensis Pest Control Technologies

A wide variety of products, produced from sporulated cultures of Bacillus thuringiensis and containing the parasporal crystalline inclusion proteins, have been manufactured as sprays, granules, powders etc and are applied as biological pesticides for control of pests such as caterpillars and mosquito larvae³.

Asporogenous mutants of Bacillus thuringiensis also have been produced by treatment of the Bacillus thuringiensis cells with mutagenic chemicals and/ or radiation. In these mutants, spores are not produced, but the crystalline inclusion proteins may still be produced and used as above.

In many cases, the Bacillus thuringiensis genes encoding these crystalline inclusion proteins, the so-called crystal or "cry" genes, have been isolated and sequenced. Using genetic engineering techniques, one or more of these Bacillus thuringiensis "cry" genes may be inserted into other, recipient bacteria, or into crop plants. In the recipient bacteria or plants, the Bacillus thuringiensis "cry" gene(s) then may be expressed so that the Bacillus thuringiensis pesticidal inclusion protein(s) are produced.

In the case of recipient bacteria, these bacteria, after growth and expression of the protein, may be chemically fixed and processed to microencapsulate the Bacillus thuringiensis crystalline inclusion protein. Biopesticides containing this microencapsulated inclusion protein have been formulated as sprays, powders or granules, and these have been claimed to have some pest control advantages over the native Bacillus thuringiensis product.

In a genetically modified plant, expression of the Bacillus thuringiensis inclusion protein(s) by and within the plant may confer a degree of protection of the plant against attack by certain insect pests. Cotton, corn, tobacco and several other crop plants have been genetically modified in this manner.

These two methods of pest control both rely for their pesticidal effect on the ingestion by the pest of the Bacillus thuringiensis parasporal crystalline inclusion protein(s). The two methods differ only in the manner by which this is achieved - ie by applying the native protein directly as a biopesticide in a spray, powder or granule, or by the expression of the protein in a genetically modified bacterium or plant.

It will be apparent that these prior art methods have a single, common mode of action - for their pesticidal effect, both rely on the target pests ingesting the Bacillus thuringiensis parasporal crystalline inclusion protein.

To date, these methods of pest control using the Bacillus thuringiensis crystalline inclusion protein have been applied commercially for control of insect larvae of the Orders Lepidoptera, Diptera and Coleoptera. These methods have not been trialed against parasitic mites.

The Object of This Invention

The main object of this invention is to provide a novel method which overcomes at least some of the prior art disadvantages, and which is effective in controlling pest parasitic mite populations, including those which cause mange, scab and other diseases of animals (including sheep, cattle and dogs) and birds. The present invention provides a novel microbial treatment method for treating animals or birds (in particular, domestic animals or birds), which are either infested with, or likely to be infested with, mange, scab or other parasitic mites.

The microbial preparation used is harmless to man and other vertebrates and is therefore safe for the animals and birds under treatment and for the human operator. Because the parasitic mites are controlled by biological, i.e. microbial means, there is a smaller risk of resistance developing in the mite populations. The method of the present invention is effective in the prevention or treatment of such conditions as sheep scab, mange and other diseases caused by parasitic mites.

THE PRESENT INVENTION

The present invention relates to a novel method of control of mange and other ectoparasitic diseases of animals and birds caused by ectoparasites such as mites. For example, the method is applicable to the control of Sarcoptiform and Trombidiform mange and scab mites, such as the scab mite (Psoroptes ovis) on sheep.

The present invention stems from the applicant's discovery of the toxic effects of certain living organisms to mites. The precise biochemical mode of action in killing the mites and their nymphs remains only partially known at the present time.

This novel method of control is by the use of selected strains (eg of Bacillus thuringiensis, Bacillus cereus or Bacillus moritai) which, placed on the animal or bird in the vicinity of the mange mites, produce, or have produced in their vegetative growth phase, diffusable, nucleotide and other low molecular weight, pesticidal metabolites.

The vegatative cells of the selected strains of Bacillus are motile and, in an exemplified case, the control of the sheep scab mite Psoroptes ovis, are applied in liquid suspension and thus can move into, or in very close proximity to, the feeding sites of the mites. The pesticidal metabolites diffuse into the feeding sites of the mites and, ingested with the cells, produce a lethal effect, killing the mites or preventing their reproduction so that the treated animal's mange or disease is mitigated and controlled.

The low molecular weight metabolites which are specified in this application are produced during the vegetative phase of growth of selected strains of Bacillus, and these are chemically distinct and entirely different from the crystalline inclusion protein also produced by Bacillus thuringiensis during the later sporulation stage.

Therefore, the method of control using low molecular weight metabolites is clearly different and distinct from the prior art pre-existing technologies which rely for their pesticidal effect on the ingestion by the pest of the crystalline inclusion protein produced only in sporulated cultures of Bacillus thuringiensis, or in genetically modified bacteria, or in crop plants expressing a Bacillus thuringiensis gene. Furthermore, those pre-existing technologies have not been trialed against parasitic mites.

Broadly, according to this invention, the population of the relevant parasitic mites, such as Trombidiform and Sarcoptiform mites, including the scab mite species Psoroptes ovis on sheep, is controlled by treating the infested animal or bird with an effective amount of a pesticidal preparation derived from a bacterium of the genus Bacillus or, more specifically, the species Bacillus thuringiensis (Author - Berliner 1915), Bacillus cereus (Author - Frankland and Frankland 1887) or Bacillus moritai (Author - Aizawa and Fujiyoshi 1968).

More particularly, there is provided a method of preventing or controlling parasitic mite infestations on sheep, cattle, other animals (eg dogs) or birds comprising applying to the animal or bird an effective amount of a microbial preparation derived from or comprising a suitable bacterium of the genus Bacillus, or an acaricidal metabolite thereof.

The term "preparation" means material comprising or containing bacterial cells, spores, metabolites and/ or toxins, plus conventional excipients or additives, chemicals with a synergistic or additive effect (including other pesticides), plus any inert carriers or fillers. The term "microbial preparation" pertains to cells, spores, metabolites (including both the prior-mentioned low molecular weight metabolites and crystalline inclusion proteins) or toxins derived from cultures of the bacteria, and which are instrumental in causing toxicity to, and death of, the parasitic mites.

Selection of the Suitable Bacteria by Bioassay

Suitable bacteria are those having anti-mite activity. The selection of candidate strains of the Bacillus species for anti-mite activity is made by employing appropriate bioassays and/ or tests, for example, as described hereinafter.

The microbial strains employed in this invention can be determined by bioassay. Serial concentrations or dilutions of microbial preparations and/ or formulations are administered to target mites in one or more appropriate bioassay systems, such as the examples described below. The bioassays consist of treating or exposing replicated samples of the pest mites to a graded range of dilutions or doses of the microbial preparations or formulations derived from the candidate bacterial strains. In general, no less than sixty mites per replicate, per dose, are used, and no less than five graded dose levels are tested with a minimum of two, and preferably four, replicates of each dose.

From the resulting mite mortality data, the mortality response, for example the corrected LD50, LC50 or LT50, is calculated, as required. Such calculations are in general and widespread use and are well known to persons familiar with bioassays, who will have no difficulty in performing them.

In general, for a given mite species, the bacterial strain showing the highest potency, eg the lowest LD50 or LC50, and/ or most rapid mite mortality, eg the lowest LT50, is selected as the strain to be used for implementation of this invention for control of that mite species. Depending on the species of mite, the bioassay procedures may involve a three step process. The first step is to bioassay on artificial or semi-natural diet, where one is available for that mite species. The second step is to follow up with bioassays on a simulated substrate, for example, sheepskin for sheep scab mites; the third and final step is, for this example, to bioassay on mite-infested sheep.

For other species of mites, preliminary bioassays and subsequent bioassays are made along similar lines, but on different, appropriate substrates and on the appropriate hosts. For example, in these bioassays, the doses derived from the candidate bacterial strains may be administered to the mites living on a substrate such as simulated pelage, fleece or plumage, skin, soiled wool and/ or skin scrapings of the host. Depending on the target species of mite, serum may be added to reduce mortality caused by starvation which could otherwise confound the results. As mentioned above, mite mortality is measured, the corrected LD50, LC50 or LT50 calculated and, in general, the most potent bacterial strain used for the implementation of this invention for control of that mite species on that host.

Where appropriate, and following successful performance in artificial diet and simulated pelage, fleece or plumage bioassays, the microbial preparations are bioassay ed on the host animal or bird. This involves treatment of the mite-infested animal or bird with the microbial preparation. The numbers of mites are recorded before and after treatment of the animal or bird with the microbial preparation or formulation. The results are read subsequently as the LC50, LT50, the rate of mortality of the mites over time, or duration of prevention of re-establishment of infestation.

Alternatively, strains may be selected by appropriate tests for the metabolites, such as HPLC, LPLC or spectrographic analysis. In general, the strains yielding the highest levels of the metabolites will be selected. Method of Application

The method of application used to effect the treatment may vary according to husbandry conditions or circumstances, the host species, the species and developmental stage of the mite being controlled, and the microbial preparation being employed. To accommodate a wide range of application methods, the microbial preparations can be formulated as aqueous or non-aqueous concentrates, emulsifiable concentrates, wettable powders suitable for application with or without dilution as a spraying, jetting or dipping liquid or shampoo, or as a powder or dust.

For example, when controlling scab mites (Psoroptes ovis) on sheep, the microbial preparation can be formulated and applied in a plunge dip. For other applications, for example on birds, the microbial preparation may be incorporated in an inert carrier material and applied in the form of a powder or dust. For application on mammalian species, the microbial preparation may be formulated as a powder or dust, as a sprayable liquid or as a shampoo which is applied to the coat or pelage of the animal.

DETAILED DESCRIPTION OF THE INVENTION

In order to further explain the invention, reference is now made to specific examples of the method of the invention. These examples are illustrative, but not restrictive, of the invention.

In a first embodiment, sheep with psoroptic mange are treated by a plunge dipping method with a liquid formulation containing a microbial preparation derived from one or more selected strains of bacteria of the genus Bacillus, specifically Bacillus thuringiensis, Bacillus cereus or Bacillus moritai. The liquid formulations contain, or are derived wholly or in part from, one or more of the aforementioned microbial preparations derived from selected Bacillus strains, either alone or augmented by additives, excipients and/ or one or more chemical acaricides. For plunge dipping, the sheep are plunged into a suitably large trough or vessel containing an effective concentration of the liquid formulation at such a depth that the sheep can be totally submerged. A preferred method is to employ a sufficiently long dip so that the sheep have a minimum swim length of ten metres and are submerged three times, once when plunging into the dip, and twice more during their swim.

In a second embodiment, the sheep or animal is sprayed or jetted with the microbial formulation, which is pumped at approximately 560 kpa (70psi) through a hand wand to thoroughly wet the animal, so that the formulation penetrates to the skin.

In an alternative method, the liquid microbial formulation is poured along the backline of the animal from a hand-held nozzle or applicator.

Alternatively, a spray dipping technique can be used, which is similar to the jetting technique, except that the whole animal is exposed to jets spraying the formulation. For spray dipping, spray nozzles are positioned so that the spray is directed from above, below and to the sides of the animal. Pressures are about the same as with jetting (560 kpa). Animals can be treated individually, as they are made to run through a race, or can be treated in batches in a larger enclosure. The run-off liquid may be recirculated by a pump.

In another embodiment, which is especially suitable for use on birds, use is made of dust or granules. The microbial preparations are dried and formulated into an inert carrier material, such as finely powdered talc, bentonite, kaolin, celite or similar inert dust material. The dust formulation acts as a carrier for the preparations, and also acts as a screening agent to protect the preparations from degradation due to solar radiation and, in particular, ultra-violet radiation. A granular formulation, consisting of the above materials, may be compressed into small granules of a suitable size, or microencapsulated by biological or chemical means, to provide a gradual release of the active material in appropriate environments.

In another variation of the method, the bacterial cells, spores and/ or their metabolic products derived from the bacteria are incorporated in animal or bird feeds so that the effective acaricidal compound or compounds is or are passed systemically throughout the animal to control the mites.

In general, the invention is directed to bacilli of the species Bacillus thuringiensis, Bacillus cereus and Bacillus moritai.

The specific details required for any one or group of infecting organisms can best be ascertained by empirical means.

The invention relates generally to a method of control of parasitic mites on animals or birds, and is not limited to the control of Trombidiform and Sarcoptiform mites, nor of Psoroptes ovis scab mites on sheep.

Production of the Microbial Preparations

The following examples set forth details of production of the bacterial preparations. It should be understood that the specific materials and techniques set forth hereinafter are exemplary only and may vary, so that the following is presented as illustrative, but not restrictive, of the present invention.

The selected strain of Bacillus may be produced by standard or conventional fermentation procedures, for example by growing the cells in a suitable liquid medium in a stirred fermenter. During production by fermentation, the following parameters are maintained: pH = 7.2; pθ2 = 70-90%; Temperature = 32.5 °C.

The production of the microbial preparation may follow one of two pathways:-

Pathway 1. The fermentation broth or culture is harvested when the Bacillus cells are in the vegetative stage, prior to sporulation. The timing of this harvesting will depend on the Bacillus strain under culture and on the fermentation medium. In general, harvesting will occur when the cell population reaches the "plateau" stage of the fermentation - typically at 7 to 10 hours post-inoculation, if an inoculum of 10% of fermenter volume containing 5 x 10⁹ cells per millilitre is used.

Harvesting may be accomplished by one or more standard procedures such as centrifugal separation, filtration, co-precipitation or membrane concentration. The harvested material, which includes the vegetative Bacillus cells and the fermentation broth metabolites, is then formulated with conventional excipients to produce a stabilised, aqueous, non-aqueous or emulsifiable liquid concentrate which maintains cell viability, or the material is dried by one or more conventional processes, such as by vacuum drying, spray drying or freeze-drying, or by air-drying the harvested material after addition of two volumes of acetone. Following homogenisation of the dried material to a fine powder, the material is then formulated with conventional excipients to form an aqueous, non-aqueous or emulsifiable concentrate, a dispersible suspension, a shampoo or a wettable powder. Alternatively, the material may be thoroughly mixed, milled or blended with a carrier dust, such as finely powdered talc, bentonite, kaolin or celite, and other excipients or additives, to produce a dust or powder formulation.

Pathway 2. After about 28 to 30 hours' fermentation, and following sporulation, the culture is harvested by one or more standard procedures, eg by centrifugal separation, filtration, co-precipitation or membrane concentration. The harvested material, which includes the sporulated Bacillus cells and/ or spores and fermentation broth metabolites, is then formulated with conventional excipients to produce a stabilised, aqueous, non-aqueous or emulsifiable liquid concentrate which maintains cell viability, or the material is dried by one or more conventional processes, such as by vacuum drying, spray drying or freeze-drying, or by air-drying the harvested material after addition of two volumes of acetone. Following homogenisation of the dried material to a fine powder, the material is then formulated with conventional excipients to form an aqueous, non-aqueous or emulsifiable concentrate, a dispersible suspension, a shampoo or a wettable powder.

Alternatively, the material may be thoroughly mixed, milled or blended with a carrier dust, such as finely powdered talc, bentonite, kaolin or celite, and other excipients or additives, to produce a dust or powder formulation. The resulting dust formulation contains about 2x10¹⁰ viable spores per gram. Mode of Action of the Invention

The selected strains of Bacillus thuringiensis, Bacillus cereus and Bacillus moritai produce a complex of metabolites, such as enzymes and nucleotides, in their vegetative growth stages⁴. The most notable is the adenine nucleotide thuringiensin, and the molecular structure of this is shown in Figure 1. Thuringiensin is a potent inhibitor of RNA polymerase, an essential enzyme in the mite, and this is a major contributor to the pesticidal effect of the microbial preparations. When ingested by the pest mites, the pesticidal effect of these metabolites, plus (where it occurs) the invasion of the mites' alimentary canal by the Bacillus thuringiensis, Bacillus cereus or Bacillus moritai cells, causes the death or severe debilitation of the mites. In this way, the mite infestation is controlled, and thus the mange, scab or disease caused by the mites is controlled.

Methods of Implementation of the Invention

The exposure of the parasitic mites to the Bacillus thuringiensis, Bacillus cereus or Bacillus moritai pesticidal metabolites is achieved by one or more of the following methods of implementation of this invention:-

Implementation Method 1. The microbial preparation or formulation applied to the animal or bird host contains a sufficient quantity of the active metabolites described above so that, when ingested by the parasitic mites, the mites are killed and/ or unable to reproduce. These metabolites originate in the fermenter broth harvested with the selected Bacillus thuringiensis, Bacillus cereus or Bacillus moritai strain. The pesticidal effect of the metabolites may be augmented by the invasion of the mites' alimentary canal by the Bacillus cells. The elimination of the parasitic mites is the means whereby the disease, scab or mange is controlled.

Implementation Method 2. The microbial preparation or formulation contains viable, vegetative cells of the selected Bacillus thuringiensis, Bacillus cereus or Bacillus moritai strain. After application onto the animal, these cells grow on the animal, with or without the aid of nutrients added in the formulation or to the tank mix. These cells are motile, and as they move and grow in, or in very close proximity to, the feeding sites of the parasitic mites, these vegetative cells produce the pesticidal metabolites in situ (ie the enzymes and other metabolites described above). These metabolites then diffuse or move into the feeding sites where they are ingested by, and kill, the parasitic mites. The pesticidal effect of the metabolites may be augmented by the invasion of the mites' alimentary canal by the

Bacillus cells. The elimination of the parasitic mites is the means whereby the disease, scab or mange is controlled.

Implementation Method 3. The microbial preparation or formulation contains viable spores of the selected Bacillus thuringiensis Bacillus cereus or Bacillus moritai strain. These spores may be "potentiated" by heat treatment so that, when wetted, they will quickly germinate in the presence of an appropriate inducer. Prior to application onto the infested animal, a spore germination inducer, such as L- alanine, adenosine, glucose or calcium dipicolinate, is added to the microbial preparation or formulation so that the spores rapidly germinate and produce vegetative cells on the treated animal. As in Implementation Method 2 (above), these vegetative cells then grow, produce the pesticidal metabolites and so kill the parasitic mites. The pesticidal effect of the metabolites may be augmented by the invasion of the mites' alimentary canal by the Bacillus cells. The elimination of the parasitic mites is the means whereby the disease, scab or mange is controlled.

Implementation Methods and/or Bacterial Strains May Be Combined

A further embodiment of this invention is the combination of one or more of the aforementioned implementation and/ or application methods and/ or one or more Bacillus thuringiensis, Bacillus cereus or Bacillus moritai strains. Such combinations may be advantageous when employing this invention for control of more than one parasitic mite species or stage and/or parasitic mites on more than one host species.

While the present invention has been described in terms of preferred embodiments in order to facilitate better understanding of the invention, it should be appreciated that various modifications can be made without departing from the principles of the invention. Therefore, the invention should be understood to include all such modifications within its scope.

References

1 Lapage, G. 1962, Monnig's Veterinary Helminthology and Entomology, Bailliere, Tindall and Cox, London, p. 525 et seq.

2 Buchanan, R.E. and N.E. Gibbons Eds. 1974, Bergey's Manual of Determinative Bacteriology, Williams and Wilkins Company, Baltimore, USA, p. 536 et seq.

3 Entwistle, P.E., J.S. Cory, M.J. Bailey and S. Higgs 1993, Bacillus thuringiensis, An Environmental Biopesticide: Theory and Practice, John Wiley and Sons, Chichester, England.

4 Luthy, P and H.R. Ebersold 1981, The Entomocidal Toxins of Bacillus thuringiensis, Pharmac. Ther. 13 : 257 - 263.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A method of preventing or controlling parasitic mite infestations of animals or birds comprising applying to the animal or bird an effective amount of a microbial preparation (as defined herein) derived from or comprising a suitable bacterium of the genus Bacillus, or an acaricidal metabolite thereof.

2. A method according to claim 1, wherein the bacterium is of the species Bacillus thuringiensis, Bacillus cereus or Bacillus moritai.

3. A method according to claim 1 or 2, wherein the bacterium is selected for anti - mite activity by bioassay.

4. A method according to any one of claims 1 to 3, wherein the microbial preparation comprises cells, spores, metabolites or toxins derived from a culture of the bacterium, or a combination thereof.

5. A method according to any one of claims 1 to 4, wherein the metabolite is a product of the vegetative growth stage of the bacterium.

6. A method according to any one of claims 1 to 5, wherein the metabolite is selected from enzymes, nucleotides, crystalline inclusion proteins and combinations thereof.

7. A method according to any one of claims 1 to 6, wherein the metabolite is thuringiensin.

8. A method according to any one of claims 1 to 7, wherein the microbial preparation is formulated as a dust, a powder, a granular formulation, a microencapsulated product, a liquid, an aqueous, non-aqueous or emulsifiable concentrate, a dispersible suspension, a shampoo or a wettable powder.

9. A method according to any one of claims 1 to 8, wherein the bacterial preparation is applied to the animal or bird by spraying, jetting, dipping, powdering or dusting, is applied as a shampoo to the coat or pelage of the animal, or is incorporated into animal or bird feeds

10. A method according to claim 9, wherein the bacterial preparation is applied by plunge dipping or spray dipping.

11. A method according to any one of claims 1 to 10, wherein the microbial preparation comprises about 2 x 10¹⁰ viable spores per gram.

12. A method according to any one of claims 1 to 11, wherein the microbial preparation further comprises one or more chemical acaricide(s).

13. A method according to any one of claims 1 to 12, wherein the microbial preparation further comprises a spore germination inducer.

14. A method according to claim 13, wherein the spore germination inducer is L- alanine, adenosine, glucose or calcium dipicolinate.

15. A method according to any one of claims 1 to 14, wherein the mite is a Sarcoptiform or Trombidiform mite.

16. A method according to any one of claims 1 to 15, wherein the mite is a mange or scab mite.

17. A method according to claim 15 or 16, wherein the mite is Psoroptes ovis.

18. A method according to any one of claims 1 to 17, wherein the animals are sheep, cattle, dogs or other domestic animals.

19. A composition for preventing or controlling parasitic mite infestations of animals or birds comprising an effective amount of a microbial preparation (as defined herein) derived from or comprising a suitable bacterium of the genus Bacillus, or an acaricidal metabolite thereof.

20. A composition according to claim 19, wherein the bacterium is of the species Bacillus thuringiensis, Bacillus cereus or Bacillus moritai.

21. A composition according to claim 19 or 20, wherein the bacterium has been selected for anti-mite activity by bioassay.

22. A composition according to any one of claims 19 to 21, wherein the microbial preparation comprises cells, spores, metabolites or toxins derived from a culture of the bacterium, or combination thereof.

23. A composition according to any one of claims 19 to 22, wherein the metabolite is a product of the vegetative growth stage of the bacterium.

24. A composition according to any one of claims 19 to 23, wherein the metabolite is selected from enzymes, nucleotides, crystalline inclusion proteins and combinations thereof.

25. A composition according to any one of claims 19 to 24, wherein the metabolite is thuringiensin.

26. A composition according to any one of claims 19 to 25, which is in the form of a dust, a powder, a granular formation, a microencapsulated product, a liquid, an aqueous, non-aqueous or emulsifiable concentrate, a dispersible suspension, a shampoo or a wettable powder.

27. A composition according to any one of claims 19 to 26, wherein the microbial preparation comprises about 2 x 10¹⁰ viable spores per gram.

28. A composition according to any one of claims 19 to 27, which further comprises one or more chemical acaricide(s).

29. A composition according to any one of claims 19 to 28, which further comprises a spore germination inducer.

30. A composition according to claim 29, wherein the spore germination inducer is L-alanine, adenosine, glucose or calcium dipicolinate.

31. A composition according to any one of claims 19 to 30, wherein the mite is a Sarcoptiform or Trombidiform mite.

32. A composition according to any one of claims 19 to 31, wherein the mite is a mange or scab mite.

33. A composition according to claim 31 or 32, wherein the mite is Psoroptes ovis.

34. A composition according to any one of claims 19 to 33, wherein the animals are sheep, cattle, dogs or other domestic animals.