CA2113342A1 - Use of natamycin for the control and prevention of poultry aspergillosis - Google Patents

Abstract

Post-hatch diseases in poultry caused by Aspergillus fumagitus) are controlled and prevented by exposing the poultry environment to an effective quantity of natamycin.

Description

WO 93/~091 1 Pcr/lJs92/05790 TL,E

USE OF NATAMYCIN FOR THE CONTROL AND PRE\IENTION OF POULTRY ASPERGILLOSIS

ELD QF THE INVlENTl(:)N
The present invention relates to a method or preventing and treating post-hatch asperg~llosis in poultry by apply~ng an effectiYe amount of ll~tamyc~n to the litter and/or respiratory system of the poul~.

0 ~
Aspergillosis is a common poultry fungal disease th~t us~ally attacks the respirato~ system~ although o~her sites may be involved. AspergDlosis is ~pically c~used byAsp~rgillus f ~magit~s mold, which is a mem~er ~ the ~ungus family. As~e~llus ~uma~ will proliferate in aerobi~ environme~ts~ parti~lar~y ~lS with a high humidity and a temperature ~ver about 25(:. Moldy litter, ~ai~ a~d feed, dust and unclean hatching equipme:nt have been associated Wit}l aspergil~osis outbreaks. :
Inhala~ion of the spores of Asp~rgillus~rn~gi~s appears ~o be the -.
primary route of exposllre, with young chick and poults being the DSt susceptilble 2 0 to an infectio~
Post-hatch aspergillos;s can also be egg bome, with the fu~gi gro~nng inside the egg. (:hieks hatching from such eggs have a~high disease risk. ~u~her, ~utbreaks of aspergil}osis are common in young birds, usual~y occumng~withi~ 3 weeks of age. A mortali~r rate of 1~50~o~is usual in an outbreak of aspergillosis. -~
~: ~25 ~ymptomsoftheaspergillosisdiseaseare: s~ of:growth, gaspi~g, rapid respiratior~ rate, le~ y and increased ~hirs~. HoweYer, the prese~ce of one or more of these symptoms is not coIlelusivc of an aspergillosis i~e~i~. ~
Cli~ical identific~tion of the fungus in af~ected birds is the 021]y positive:di~ osis.
~s discussed by F.T.W. lordan in '~oultry Diseases", Bailliere l['indall, 3rd Edition, at present there is no feasible treatment for asperg;llosis. Affected and infe~e~
birds normally are destroyed and the infected environment must be cleaned rigorously and disinfected.
In the past eggs have been disinfected with a number of agents including natamycin (U.S. Patent No. 3,343,968). Treating eggs wi~h llataymcin is 3 5 help~ul but does not control aspergillosis at$ributable to post-hatching environmental conditions.

wo ~3/009l l Pcr/uss2/os7sl) Natamycin is a member of the polyene family of antimycotics. The compound natamycin is a te~raene with a mole~lar weight of about 666, empirical ~ormula corresponding generally to C33Hq7N013, and contairls a glycosidically-linked carbohydrate moiety, mycosamine. It has an isoelectric point of pH 6.5. The structure of natamycin t~rpically exists in two configurations: the enol-structure and the keto-structure.
Natamycin is known as an antibiotic in humans which is dis~ussed ;n Florey, i'~a~ytical Pro~lles of Drug Substances", Vol. 10, 1981. As repor~ed in '~harmacology", Natamy~n ~Pimaricin) by Wol~gang P. Raab, 1972, Georg ~ieme 0 Publishers, S~ut~gar~, pages 18 & 19, yeasts and 1 nolds which infect humans usually exhibit susceptibilit~ to natamycin. The disclosure of each of the above publications is hereby incorpor~ted by re~erence.
It is an ob3ect of the present irlven~ion to use natamycin ~or controlling and preveIltiI g diseases associated wit~ the Aspergillusfum~itus mold.
i5 The enviromnental characteristics o~ ~he sites on hllmans and poultry7 which may be infected byAsper~llus fumagitu3, are diverse and, according3y, the e~ectiveness of rlatamycin against a poult~ ection of Aspe~illus ~magitus wa~ a surprising discove~ e surprising ef~ectiveness of natamyc~n agaiI s~ diseases in poultry associated withAspergillusff~m~tus is emphasized when considering t!he anatomical, metabolic, etc., differences between humans and poultry.
lt is another object of the present invent;on to prevent and treat an infection of Aspergil~usfumagitus by including ~atamycin in the litter and/or atmosphere of ~he poultry husbandry environment.
Allhough particular emphasis is placed upon controlling and 2 5 preventing diseases associated with the particular strain of Aspergillu$ ~maginls which a~f~cts poultly, other avians (e.g., duclcs, tllrlceys~ pheasants, etc.~ may be e~ecthrely treated in accordance with the present inveneion. ln addition, the invention may be use~ to control and prevent dise~es caused by molds which are related to Asper~illus ~magiPls.
3g -:

The present invention is a method for controlling and preventing diseases associated with Asp~rgillus ~4magzh~s (hereinafter referred to as ",4spergillu~"). A disease in poultry known as asperg;l}osis, can be controlled and 3 5 prevented by exposing ~he poultry ~e.g., respira~ory system) and/or ~heir ellv~ronment to an e~fective amount of natamycin.

WO ~3/0091 ~ P~/IJS92/05790 ln one aspect of the inventiorl, aspergillosis caused an infection of Aspergillus may be controlled and prevented by contacting the poultry's litter with nat~nycin.
ln another aspect of the invention7 aspergillosis caused by an infec~ion of Aspergillus may be prevented alld controlled by exposing the respirato~y ~ystem of the poultry to an effective ~nount of natamycin.
Moreover, early treatment with natamycin can prevent a mold infection. Tberefore, it is desirable to treat the litter and newly hatched chicks or poults ~e.g., within three weeks of hatching) with natamycin which may be ~ll~wed by periodic treatmellt throughout the life of ~he poultry.

D T~ULED DE~R~pIlo~l~N
The method of the present invention relates broadly to the control and prevention ~ diseases associated with an undesired mold known as~pe~gillus ~15~ ~miga~us(h~reinafter referred ~o as "A5pergill~ . The undesired mold may invade the bodies of the poultry to create diseases(e.g., aspergillosis)9 which are contagious and normally fatal. The in~rention achieves control and prevention of diseases associated withAspergillzls by inhibiting, if not eliminating, grou th of the undesired mold.
2 o T~e undes;red mold t~pically grows within and upon the )itter that is used by ~he poult~y. In turn, the Aspergilf,~ may infect the respirato~y system of the poultry due to the ~lose proximity of the poultry to the litter. For example, the ~:
Aspergillus within Ihe litter can produce spores which may become air-borne and ::
carried to the nearby poultry. The spor~s may be inhaled by the pollltry and infec~
z5 the respiratory system of the poultry to cause aspergillosis.
The method of the inven~iorl is achieved by exposing the litter and/or the poultry to ~1l effective dosage of natamycin to cont~ol and prevent disease associated withAspe~illus. An e~fective dosage of natamycin typically ranges rom about 1.0 parts per million (ppm~ through about 70 ppm and normally about 5-30 3 o ppm of the environment being treated. However, ~he exact dosage which is su~ficient to be effective agairlst the Aspergillus is de.pendent upon the speci~ic environment which contains the undesired mold. ln accordance with the invention,~he te~TI "enviror~nent" in intended to refer to the litter infection site vf the poult~y, etc., which may be adversely af~cted byAsper~llus. If the environment is favorable 3 5 for the metabolic activities of the mold, a relatively large dosage of natamyein may be required ~o be effective against the mold ~e.g., 20~30 ppm of natamycin~
environment which is warm, possesses a neutral pH~ contains oxygen, includes a wo 93/00911 " ; ~ Pcr/uss2/o579o substrate which enhances mold growth, etc., would require a relatively large dosage of natamycin to be effective against the undesired mold. The amount of natamycinwhich is necessaly to prevent growth and a possible infection of the undesired mold is le~s than the amount of natamycin which is necessary to treat an existing mold 5 infection. l~erefore, it is advantageous to trea~ the environment and/or poultry in acsordance with the invention while ~he chicks or poults are in the early stages of their development (e.g., treat the chicks in~nediately after hatching to prevent an infection of the undesired mold~.
More~ver, although it is preferred to practice the invention ~y usi~
10 natamyci~ pha~naceutically accep~able derivatives of natamycin (~.g., calcium and sodium salts, and esters of natamycin), which are effective to control and prevent exposure of the poult~y to Aspergillus, may be used in the invention alone or inconjun~ion with natamycin. The prefelTed morphology of the natamycin is crystalline, however, any morphologieal state is acceptable in the irlvention which is ~5 effective againstAs~e~llus. Further, the natamycin used in the invention may be -:~
preseIlt in one or more hydr~te forms (e.g., mono-, di and tr;-hydrates3. The tr}-hydrate ~orm is advantageous for some appl;ca~iQns due ~o its s~ability. In some~ases it may be desirable to increase the effectiveness of the nata~nycin ~y co~nuting or grinding the natamycin to increase ~he surface area of ~he 20 natarnycin.
In one embodiment of the invention, the litter which is used by the poultry may be treated with natamycin. A suitable litter comprises at least one :-~
naember of the ~ollowing group: clay, hard wood planks, wood shaviDgs, etc. The ~-natamycin (e.g., in a c~ystalline form) may be applied direetly to the li~ter in any 2 5 expedient mamler. For example, the natamycin may be suspended within a non-~oxic carrier liquid and sprayed upon the litter. Shnuld a non-toxîc carrier liquid be ~:
used to apply the nataymcin to the litter~ the carrier liquid should not be a solvent for the natamycin. However, certain pharmaceutically accept~ble de~statives of natamycin may be soluble within the non-to~ic carrier liquid. Suitable non-toxic3 o carrier liquids comprise at least one member of the following group: alcohols such a~ m2thaDol, water, etc. When an ef~ective amount of natamycin is used to treat the litter, growth (e.g., sporation) of Aspe~gfllus is reduced, if not elim~nated, which tends to prevent an Aspergilllls infection in the respiratory systsm of the poult~y.
Moreover, depending upon the concentration of Aspe~illus in the 3 5 litter, it may be desirable to treat the litter with natamycin before and during use by the poultTy. Further, in certain situations it may be advantageous to continue to treat the litter with natamycin after the soiled ïitter has been removed for disposal WO 9~/00~1 1 PCI /VS92/05790 2:113~2 (e.g., any disposed litter which is stored near the poultry may release spores capable of infecting the respirato~y sys~em of the poultry with Aspe~gillus).
In another embndiment of the invention, the respirato~y systems of the poultry may be contac~ed with na~amycin to prevent and/or control an S Aspergillus infection. When the nataymcin is applied effectively to the respiratory -sys~em, arl Aspergillus infection can be prevented and an existing infection can be con~rolled, ;f not elimiIIa~ed. I'he natarnycin may be applied in any suitable manne~
which irltroduces an effective amount of ~atamycin into the respirato~y system of the poultry. A convenient and e~ective manner for applying the natamycin to ~he poult~y comprises introducing an air-borne suspension of rlataymcill(e.g.9 an aerosol, a fog, mist~ etc.), into a confined area or chamber (e.g., a so-called "spray cabinet' through which the poultry passes. The poultry may be transported towards, passedthrough and away ~rom the confined area by any accep~able means, such as, for example, a corlveyor belt. The poultly, whiie withi~ the confined area, inhale the ~t5 air-bome natamycin which contacts directly their respirato~y systems. Tl;e poultly should remain within the confined area containing natamycin for a period which is sufficient to permi~ the poultry to inhale a quanti~ of nataymcin tha~ is effectiYe to prevent and/or control a~,4spergill~s infection.
The natarnycin susperlsion(~ .g., an aerosol, fog, mist, etc.), may be 2 0 crea~ed by first forming a suspgnsion of natamycin within an appropriate c~er liquid. The calTier liquid should be non-tlDxie and IlOt a solvent for the natamy~
An appropriate ~uId comprises at least olle member of the following group:
alcohols, such as methanol, water, etc.
The llatamycin suspension discussed above may be converted to an ~5 aerosol, a fog, mise, etc., by any ~echnique which creates a respirable ~orm of nat~mycin for the poulti~. For example, an a~eous suspension of nata~ycin may be pumped through a nozzle, which is in communication with the confined area co~taining the poultly, at a rate which is sufficient to in~roduce a respirable form of natamycin. Generally, a natamycin suspe~.ion ha~ring fine particles enhances the3 o penetration of the natamycin into the respiratory system of the poultry which hlcreases the effectiveness of the natamycin.
Moreover, in certain sltuations it may be desirable to treat the entire poultAy-husbandly environment (e.g., to reduce the activity of any air-borne fungal spores). For example, the natamycin may be introduced into the ventilation 3 5 equipment(e.g., the heatinglcooling system of the st~.~cture which houses the poultly), in a manner which ef~ectively fumigates the poultry husbandly enviFonment to combat an extreme outbreak of Aspergillus.

Wo 93/oo~ l 1 2 1 1 3 3 1 2 rl~r/us92/os7'~i The ability of ~he natamyciIl to prevent and treat an infection of A3pe~11us wilhin ~e poultry is due in part ~o the unique anatomy of the poultry.For example, the anatomy of a chicken is such that inhalation of natamycin is ef~ective to preveIlt or con~rol an infec~ion of Asp~illus throughout a significan~ :~
5 portion of the poultry's body(e.g., inhalation of na~amycin may trea~ the respiratory syst~m, crop, certain portions of the digestive system, etc., for aspergillQsis).
While nvt wishiIlg to be bound by any theory or explana~ion, it is believed that na~amycin is active or eifective against growth of mold, but not against ba~eria. C)ne explanatiom may be that molds (but not bacteria) contain e~osterolo iIl their membralles.
In general the mold will grow, if the erl~ironment is appropnate, until conta~ting the natamycin. l~e theorized mechaI~sm of natamycin action is a :~
binding of ~he natamycill molecule and ergosterol presen~ in the cell membrane of the mold. The complexing with ergosterol is substantiated by the nelltralizing ~5 e~ects of ergosterol addi~ion on the antifungal activities of natamycin against the :-~
Aspergillr~ fumngii~s. A complex be~reen natamycin and the cell membrane of the mold i5 believed to alter membrane permeabili~ since na~amy~n is a relatively large molecule which creates an increaseld xurface pressure which may tend to induce a reorientation of the ergosterol present in the membrane, thus altering 2 o permeability o~ the cell and resulting in osmo~ic shoek. This osmotic shosk is sufficient to inter}upt, if not hal~, the metabolic activities of theAsper~ s(e.g., the natamycin may cause irregular mold grou/th, sporation~ etc.).
In certain aspec~s o~ the invention, it may be advantageous to use the natamycin in conjunction with other processes and/or substances. For example, 2 5 the natamycin susper~ion may be intro~uced into the spray eablnet along with a vaccine in order to treat a plurali~r of poultry ailmen~s.
The natamydn which has been added to the litter and/or formed into a suspension ~ically possesses an acceptable shelf-life. Depending upon the storage condi~ions, natamycin c~n be expected ~o be ei~fective against the undesired 3 0 mold for several weeks or months. However, to er~ure macimum e~ectiveness ofthe natamycin, any umlsed natayTncin suspension or treated litter should be shielded from extended exposure to light (e.g., a natamycin suspension should be stored in ~he dark prior to introduction into the spray cabinet).
Any natamycin which is consumed (e.g., inhaled) by the poultry is normally n~t retained by the poultry. As a result, the natamycin is generally ~ot incorporated into the flesh or eggs of the poultry and, accordingly, does not affect human consumption of any treated eggs or poultry. ln contrast, poultry which are wo ~3/009l l 3 3 ~ 2 Pcr/us~2/os7su exposed to the undesired fungi (e.g., Asper~illus mold) may incorporate the moldand/or toxins thereof into ~heir eggs and flesh. Such molds and/or toxins may beharmful to humans which co:nsume the eggs and poultry flesh; making it is desirable to prevent ~d treat any signi~icant mold exposure of the poultry. Therefore, the 5 present inYention permits enhaIIced production of eggs ~d poultry which are not contamina~ed with mold and anti-mold agents.
Although a few aspects and embodiments of the invention have been described in detail, ~hose skilled in the art will readily appreciate that the present invention embraces many eombinati~ns, equivalents and variatior~s other ~han ~hose ~ -o exemplified.

Claims (8)

AMENDED CLAIMS
[received by the International Bureau on 22 January 1993(22.01.93);
original claim 7 cancelled;
original claims 1, 4, 5 and 9 amended;
other claims but renumbered accordingly (1 page)]

1. The method for controlling disease caused by Aspergillus fumagitus comprising:
treating at least one member of the following group consisting of the poultry litter and the respiratory system of the poultry, by exposure to a quantity of natamycin which is sufficient to reduce growth of the Aspergillus fumagitus.

2. The method of Claim 1 wherein the natamycin is applied by exposing the poultry to a finely divided suspension of natamycin in the air.

3. The method of Claim 2 wherein the natamycin is an aqueous mist.

4. The method of Claim 1 wherein the poultry is a chicken.

5. The method of Claim 1 wherein the poultry is a turkey.

6. The method of Claim 1 wherein said treating comprises spraying natamycin onto the poultry litter.

7. The method of Claim 1 wherein the sufficient quantity of natamycin comprises about 1.0 ppm through about 70 ppm.

8. The method of Claim 1 further comprising treating poultry which are infected with Aspergillus fumigatus.