COMMON DISEASES

uf :Dumestic

,.---TEXAS A&M UNIVERSITY-----.TEXAS AGRICULTURAL EXTENSION SERVICEJ. E. HUTCHISON, DIRECTOR. COL.L.EGE STATION. TEXAS

8-256

COMMON DISEASES OF DOMESTIC RABBITS!Everett E. Lund, Parasitolo~ist, Animal Dlsease and Parasite Research Branch, A~ricultural Research Center,

Beltsville, Maryland

The table on the following pages presents in a concise fonn useful infonnation on the more common rlisor-ders of the domestic rabbit. In certain cases more extensive consideration of a particular subject is avail-able in other pamphlets. NUmbers in the column 'Insease and synonyms' and corresponding footnotes give thesereferences.

There are certain principles, some of Which may appear to be self-evident, that are so generally applic-able that space would .not pennit their repetitious presentation in the table. These together with certain re-levant comments are, therefore, enumerated here.

1. Insease is in a sense a natural phernnenon mich can never be conpletely eliminated.2. Purposeful ancl intelligent practice may usually keep it at a low level.3. Prevention is vastly to be preferred to treabnent and possible cure.4. ~gh natural resistance, long life and high p~tivity are as certainly inheritable as other traits

such as size, color, ear length etc. but not necessarily in as simple a pattern. Persistent selection ofbreeding stock on the basis of superior perfonnance will pay well for the trouble expetlded.

5. Observe good practices of nutrition to permit the greatest expression of superior inheritable traits.6. Ih not overcrov.d }'Our animal s.7. Provide plenty of draft-free ventilation. up-drafts through self-cleaning floors result from over-

enclosure of the sides; and these drafts are particularly objectionable.8. Permit your animals plenty of access to sunlight, if not attended by great heat. Shade RUst be pro-

vided al so so instinct may direct the animal's cooice.9. Keep all eqJipment a..EAN and IRY, and to minimize the possibi li ties of injury, keep it in good repair.10. Avoid unnecessary handling of animals, their feed, containers for food and water, or any equipment

wi th ..mich they come in contact. The clothing and hands of the attendant may spread disease.11. Isolate animal s suspected of having infectious diseases, and care for such animal s~ the normal

ones have had their attention.12. Isolate all stock being brought into }'Our herd, mether it be a new introduction or one of your own

animals that has been in possible contact with other rabbits, directly or through equipment and handlers.13. Protect your animals from disturbing influences, particularly night prowlers. Allow }'Our animals as

complete rest during the day as routine care will permi t.14. If rabbits are sold on regular schedule to a nealer, have marketable stock segregated and confined

outside of the rabbitry or at its entrance. The pickup man visits many rabbitries in rapid succession, andwill appreciate }'Our cooperation in minimizing the possibility of his beconUng a factor in the spread of dis-ease.(1) This is a reprint of AHRD Correspondence Aid No. 23 by the same title ao:l formerly designated as U.S. Fishand Wildlife Service Conservation Bulletin 31. Several OOditions have been included as suggested by Karl W.Hagen, Jr., bacteriologist, U. S. Rabbit Exoerirrent Station, Agricultural Research Service, Fontana, Ca~ifornia.

Cooperative Extension Work in Agriculture and Home Economics, Texas A&M University and United States Depart-ment of Agriculture cooperating. Distributed in furtherance of the Acts of Congress of May 8, 1914, as amended, andJune 30, 1914.

PART OFOODY

AFFECTED

SKIN

DISEASEAND

SYNONYMS

Earmange

miteso~

Earcanker

Skinmange

Favus(Ring-worm)

Sore 1hocks

CAUSE

Mites (one oftwo similarforms)

Very contagious

Mites

A fungus ormold-likeorganism

Very contagious

Bruised orchafed areasthat mayor maynot becomeinfected

GmERAL SYMPTOMS

Shaking of head and flappingof ears. Scratching at earswith hind feet. Yellow-whitescales in opening at base ofear, with scaly crust pro-gressing up inner surface ofear in advanced cases.

Reddened, scaly skin, hairtending to fall, and evidenceof intense itching by per-sistent scratching or biting.Yellow crusts of dried bloodserum may be present.

Patches of scaly skin withnumerous red, pinhead eleva-tions surrounding hair fol-licles. Hair breaks off or isshed from older patches.Usually starts on head,butmay appear around hind feet.Advanced cases may involve anypart of body. Early cases donot itch enough to provokemuch scratching, but laterones may do so.

Tendency to tread with hindfeet, even when sitting. Rest-ing in positions favoring thesoles of hind feet. Ball ofhind feet shows elevated,tender area, losing pad of furor developing scaly crust overnaked area. May bleed. Badcases may be spongy with pus,or open and draining. Inadvanced cases animal shiftsmuch of weight to front feet,and they break down, as hindones did.

TREAnmIT

Swab thoroughly with the fol-lowing lotion:Mixture of 1 part iodoform,10 parts of ether, 25 partsof olive oil or other vege-table oil.

Wash affected region with soapand warm water, clip hair backto healthy skin and apply mix-ture of 1 part flowers of sul-phur and 3 of lard. Repeatafter 4-6 days, as required.

Clip or shear 1/2 inch outsideaffected area. Bathe in warmsoapy water and dry. Applytincture of iodine or 10 per-cent salicylic acid in 70 per-cent alcohol.

Front as well as hind feetinvolved - dispose of animal.Otherwise - 1. Det~rmine andremove contributing factors(see 'Prevention'). 2. Placeanimal on ground or turf, butwhere it is undisturbed, or3. Grease pads with an oint-ment, preferably with a lano-lin base. Repeat daily, Ifinfected, sulfathiazole oint-ment or Calomel-lanolin (see'Urine burn') is good.4. Penicillin 'shots' clearup some cases.

P~ION

Clean up and disinfect hutchesused by and near infectedanimals. Treat all ~nimals

adjacent to or in contact withinfected animals. Do not in-troduce into herd any infectedstock nor equipment from ques-tionable sources.

Same as above.

1. Disposal of all affectedanimals by burning or de~p

burial. 2. Disinfection ofall exposed hutches and equip-ment. 3. Use of gloves andclothing that can be boiled ordisposed of after handling af-fected animals and theirequipment. 4. Care to avoidinfection of hands or faceespecially through cuts orscratches. S. Do not introduceanimals or equipment from un-known sources.

1. Keep hutch floors clean anddry, and in good repair~ 2. Usea type of flooring, especiallyfor healthy animals, that givesas much support as possiblewithout compromising on clean-liness and dry condition.3. Protect animals from dis-turbing influences that incitestamping. Dispose of per-sistent stampers that exciteherd, or at least isolate themin remote corner of rabbitryseldom visited.

REldARKS

Wry neck w-y be acomplicabon.

See below under'Miscellaneous.

Positive identifica-tion may requirelaboratory test. Com-pare symptoms with'Favus' below.

Positive identifica-tion depends on micro-scopic examination ofskin or scraping andfinding of fungus.Not all animals norall humans are equallysusceptible. Somecases in each can bevery seriov~.

Sore hocks underminehealth and predispnseto other diseases.Nervous does excitetheir young, and morenervous stock is theresult if young aresaved from suchlitters. Raise quietanimals, give themprotection, and keepfloors clean.

I'Sore hocks in domestic rabbits' A.H.D. Leaflet No. 83

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PAIrr OFmDY

AFFECTED

DISEASEAND

SYNONYMSCAUSE GENERAL SYMPTOMS TREA'IldENl' PREVENTIOO RD4ARKS

WISTANDMUCOOSMEMBRANES

IUrine Anyone ofburn several skin(Hutch bacteria infect-burn, ing chappedsore membranes.vent, Early cases'Vent sometimes notDisease' infected

Inflammation of delicate mem-branes near sex organs andsometimes anal opening also.Yellow or brownish crusts maycover areas, and swelling,cracking, bleeding or dis-charge of pus may be present.In males the penis and sheathmay swell or show chappingand cracking. Glandularpockets to either side ofvent may be involved, butpresence of moderate amountsof a thick, whitish secretionin these is normal.

Mild cases recover withouttreatment if faulty conditionsare corrected (see 'Preven-tion'). 4 or S daily appli-cations of lanolin rubbed wellinto affected area will hastenrecovery. In more severecases, or if infection iscertain, treat daily for 4 -Sdays with mixture of 1 partcalomel and 3 parts lanolin.After that, lanolin may beused alone for several daysif needed.

Keep hutch floors clean anddry. Avoid the 'soiled corner'to which animal may go tourinate, for urine splashesback, soiling coat and mem-branes about vent, finallychapping them and admittinggerms into skin. Solid floorsmust be kept very clean and dryand bedding must be changedfrequently, if necessary. Avoidsolid rails about hutches atlevels permitting urine tosplash back on animals.

Often confused withSpirochetosis or trueVent disease. Thebreeder need notdistinguish betweenthem for treatment issimilar.

Infectedeyes -severalforms:Wateryeyes,Weepingeyes,Running(pus)eyes

Infectednose orlips( 'ScabbyNose')

Irritation,usually followedby or accompa-nied with in-fection wi th anyof several com-mon bacteria

Anyone ofseveral germs

Usually sameas 'Urine burn'

Rubbing of eye or face withfront feet. Discharge fromeye, which, if considerable,may flow across face, wettingand matting iur, and latercausing fur to fallout.Discharge may be thin andclear, or thick and yellowor white. If eye bulges, in-fection is deep-seated, oftenin orbit or socket.

Inflammation and swelling, orchapping and cracking of noseor lips, with yellow or brownscales forming sometimes to agreat thickness.

Very early cases may clear upif sources of irritation areremoved (see ·PreventionW).

Treat early with ophthalmic(eye) solution of sulfathia-zole and/or sulfadiazine, threeto four times daily, or similardrugs in ointment, twice daily.Argyrol, silver oxide ointment,yellow oxide of mercuryointment or other ophthalmicpreparations may have to betried. An aqueous suspension of200,000 units of penicillin Gplus 0.25 grams dihydrostrepto-mycin sulfate per cc droppedinto the infected eye has beeneffective for mixed infections.No one drug affects all typesof germs and old infections areoften mixed.No local medication can be kepton. If the case justifies theuse of penicillin, inject 150,000 units of penicillin Gprocaine in oil into the thickmuscles of the hind leg for a10 to 12-pound rabbit. Followwith a second injection after72 hours.

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1. Protect animals from exces-sive dust, chemicals in paintsand sprays, smoke, industrialfumes and other irritants.2. Keep equipment in repair soinjuries are not frequent.3. Feed wholesome rations withample roughage in form ofleguminous hay and freshgreens, to keep resistance toinfection high.4. Keep equipment clean andotherwise discourage flies byremoval of refuse, and use ofrepellants or insecticides, ifrequired.S. Admit plenty of sunlight.6. Protect healthy animalsfrom infected ones.

Clean up cases of Urine burn,and prevent reappearance ofthat disorder. Except forinjuries that get infected,most cases are contracted frominfected vents.

Severe cases deepseated in the socketsshould not be treated,unless skillful useof sulfa drugs orpenicillin, internal-ly, is justified.Chronic cases oftenshow sinus involve-ments, and treatmentas for other deep-seated infections isonly alterndtive tonatural recovery.Doe or one animal inlitter often a sourceof infection toothers.

Rabbits normally pluckone type of droppingsfrom the anus, andconsume theM. Indoing so, the nose andlips are exposed toinfection from sorevents.

PART OFBODY

AFFECTED

MAMMARYOR

MILKGLANDS

DISEASEAND

SYNONYMS

Cakedbreast(Cakedudder)

Masti tis(Breastinfec-tion,'Bluebreast')

CAUSE

Milk not drawnfrom glands asfast as formed

Too few youngor young notbeing nursedsuff iciently

Bacteriausuallystaphylo-coccus orstrepto-coccus

VeJ:y con-tagious, insome cases

GmERAL SYMP1'adS

Early cases, one or morebreasts, firm, pink andfeverish to touch. Con-gested. Later cases,quite firm or even hardwith knots or bunches atsides of one or morenipples. Very late casesmay turn dark, skin become-ing naked, dry and stiff,or cracking open, so part-ly dried milk, of cottagecheese consistency escapes.Nipples may be bruised.

In mature does, few .excep-tions. Feverish, temperaturegoes above normal (102.7+0.5)to lOS or more. Appetitepoor, activity poor. Earsfeel hot. Animal may cravewater. Early cases, breastspink and feverish. Nipplesmay be red or dark. Spreadsrapidly from breast tobreast. Turn red or purple.Milk usually will flow butmay not in more advancedcases.

TREAnrmT

Prevention is most important,so correct faulty management.Reduce concentrates sharply,end provide generously of hayand greens. Allow plenty ofexercise. Rub lanolin wellinto nipples in early cases,massage to start milk flow,and encourage young to nurse.Recovery in advanced casesmay be hastened by softeningcrusts with lanolin and al-lowing drainage. Lancing ishazardous.

If early, while temperatureis still up, but not over106 degrees, and the casejustifies it, use penicillinas directed under "InfectedNose or Lips."

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PREVENTION

Do not wean young from heavilymilking doe abruptly. Iflitter is lost, rebreed doeat once. Breeding heavymilkers a few days beforelitter is weaned may help drythem up. Correct faultyequipment (nest boxes, etc.)that may bruise or injurenipples so doe refuses to letyoung nurse. Protect doe fromdisturbing influences. Thisis very necessary for propernursing.

Allow no questionable animalsto enter herd. Accept no usednest boxes from questionablesources. Destroy by burningall bedding, nest boxes, andlow cost material used byinfected animals. NEVERtransfer young from aninfected doe to any other.Isolate suspicious animaisand destroy untreated sick.

REMARKS

Caked breasts, sorehocks, neglectedyoung, kindlings onfloor, paralyzed.hind quarters andtrampled young oftenpoint to disturbancesat night.

Occasionally in-fections frombacteria of commonoccurrence mayfollow injury tonipples. Faultyequipment or cakedbreasts may causescratched or bruisednipples.

PART OFOODY

AFFECI'ED

RESPIRA-TORYSYSTEM

DISEASEAND

SYNONYMS

Coldsandsnuf £les(Somereservelatterterm forinfec-tionswithPasteur-ellaand/orBrucellaof cer-tainspecies)

PneumoniaParticu-larlyprevalentin veryyoung(nest boxage) andyoungdoescarryingornursing1st or2ndlitters

CAUSE

Any of severaltypes of bacte-ria and possi-bly viruses,too

Any of severaltypes of bac-teriaUsually ap-pears as com-plication toother disease,a hazard ofpregnancy andlactation ora result ofexposureNot usuallyhighly conta-gious but sometypes are

GmERAL SYMPTOMS

Sneezing, rubbing nose vigor-ously with front feet. Per-sistent, not to be confusedwith temporary irritationfrom inhalation of dust fromfeed trough or manger. Nasaldischarge may be thin andclear, or heavy and mucus-like.Mats fur on inner side offront feet. Cases may becomechronic, clear up, or breakinto blood stream or go tolungs, and high temperatureand death may result.

Labored breathing, often withnose held high. Temperaturerises, ears feel hot. Feedmayor may not be consumed.Craving for water sometimesnoted. Activity restricted.Late cases show bluishcoloration of eyes and ears(cyanosis). Temperature fallssome hours before death. Theremay be diarrhea in last fewhours, seldom otherwise un-less other disorders arepresent too. Lungs show con-gestion, and may be white aswith pus ~usually prolongedcases) or bluish purple, red,fiery pink or mottled.

TREATMmT

Reduce concentrates, and feedplenty of fresh greens. Sun-light and exercise are bene-ficial in early cases. Peni-cillin injections help somecases, depending on germspre sen t. 'No se drops' 0 f t enspread infection to bronchiand lungs, and if used at allmust be given sparingly.Since germ is not specific,treatment cannot be either.

Must be detected early, be-fore too much damage is done.Lighten load (if nursing doe)but watch for caked breasts.Keep at uniform temperature.Reduce concentrates and pro-vide greens. 200,000 unitspenicillin G procaine plus0.25 grams dihydrostrepto-mycin sulfate injectedintramuscularly into thehind legs is specific forseveral of the germs knownto cause pneumonia. Repeatin 72 hours. Some types can-not be cured. Late cases arefatal.

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PREVmTION

Keep r&sistance of animalshigh by selection of stockfrom resistant provenparents. Feed for maximumdevelopment of inherited re-sistance by using roughage(good hay and fresh greens)generously. Provide plentyof draft-free ventilation,sunlight (if not great heat)and plenty of opportunity forexercise.

Avoid crowding.

As above, in general, and1. Give ~oes special protec-tion and attention 10-14 daysbefore and after kindling.2. Don't save breeding stockfrom unproven lines, or fromanimals having to be nursedthrough pregnancy andlactation periods.3. Keep nest box materialclean and dry, to avoid ex-posure of infants.4. Eliminate ear mange, sorehocks, animals with longincisors, abscessed navels,abscessed molar teeth andother predisposing factors.

RF1dARKS

In general, colds inrabbits resemblecolds and sorethroats in humans inthat more than onegerm may be present.The infections areprevalent, strikewhen resistance islow, and medicinesare often useless.

Pneumonia is usuallya secondary disease,caused by organismsthat are ever-present,but strike the animalweakened by anyfactor. Seek andeliminate suchfactors.

PART OFOODY

AFFECTED

DISEASENID

SYNONYMSCAUSE GENERAL SYMPTOMS TREATMENr PREV»lTION REMARKS

DIGESTIVESYSTEld

Long 2teeth(Buckteeth,Wolfteeth ormaloc-clusion

Some types in-hed table,others frominjury or dis-eases

Incisors not worn away as fastas they grow, so mouth doesnot close properly. Upper in-cisors curl back, lower pro-trude.

None, except advanced fryersmay be kept to marketablesize by trimming teeth withside cutting pliers.

Save no breedIng stock fromparents showing long teethunless source of long teethis known to be accidental.

Most cases snoW by8 weeks, tut someappear much later.

In adults many casesaccompany disordersof molars and face.

Infectedmolars

Some unknown;others, in-juries fromforeign bodiesin food

Animal chews abnormally, favor-ing affected side. May drinkwith head to one side. Drool-ing is common. Later, swell-ings on jaw may appear.

None. None, except to avoid use ofequipment that allows fine wireto get in mouth, and avoid feedwith excessive beards andburrs.

Because of cautiouschewing, long teethoften follow.Pneumonia usuallysets in.

Livercoccidi-osis

A speci fic one-celled animal·parasite

Usually no symptoms except ap-pearance of white, circularspots on and through liver.Heavy cases, poor appetite,loss of flesh, and enlargementof liver to extent it can befelt in living animal. Onautopsy, liver much enlarged,and permeated with nodules.Egg-like oocysts in droppingsrevealed by microscopic ex-amination.

Mild cases are self-healing,but scars remain in liverfor many weeks. Extremelysevere cases are fatal. Liversfrom affected animals shouldnot be marketed, although mancannot contract the disease.A ration containing 0.025percent sulfaquinoxaline fedcontinuously for 30 days willeliminate infective stages ofcoccidiosis.

Use equipment for feed andwater that cannot become con-taminated with droppings. Kee.phutch floors clean and dry.Remove manure frequently. Donot handle animals or equipmentunnecessarily. Do not con-taminate food, fur, or utensilswith any material you mQY carryon your hands or clothing.

Drug control is effec-tive but must be accom-panied by managementpractices mentionedunder ·PreventionW toattain full effective-ness.

Developing and maturestock may be affected.

Few cases are noted innest box babies, andthe greatest incidence(by mortality records)is near the close ofthe sixth week.

Whereas liver coccidi-osis can be virtuallyeliminated by goodmanagement, intestinalcoccidiosis can onlybe kept at low levels,but these can be en-tirely compatiblewi th profi tableproduction.

Observe principles of sanita-tion,to reduce hazards of com-plications.

As above, but even greaterprecautions are required toavoid contamination of feed,water, utensils, hutch floorsor the fur of animals. Hand-ling, as during sexing andselection of breeding stockprovides great opportunityfor spread. Drug control(see treatment for livercoccidiosis) will reduce thenumbers of oocysts of in-testinal types and, whenfollowed with good manage-ment practices, coccidiosiscan be kept at a low level.No specific recommendations.

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No specific recommendations.Rations with antibioticshave varying and unpredic-table results. Aureomycin,terramycin, penicillin andbacitracin have been effec-tive at times but are notconsistent.

The four types are distinct.

Usually none. If reinfectiondoes not occur, the diseaseruns its course in from 4 or5 days (after first appearanceof symptoms) to 10 - 14 days.Reinfection is possible, andfrequent. Resistance isdeveloped so no symptoms needbe shown, but the animal maystill contract the disease andvoid the egg-like oocysts inthe droppings.

Loss of appetite, hunched pos-ture, little activity, earsprone, eyes squinted and dull,even on provocation. Coatrough, hair erect, abdomenoften bloated. Frequent sip-ping of water. Temperatureusually normal or subnormal.Often diarrhea or mucus. Maygrind teeth. Dead show muchwater in stomach. Intestinesshow hemorrhage, are empty, orwith fluid or muc~s~ I I I

Mild cases - no symptoms ex-cept on microscopic examina-tion of droppings, intestinalcontent, or wall. Moderatecases - tendency to softdroppings or diarrhea. Failureto gain, hunched position withhind feet far forward. Littleinterest. in food. Eyes alertwhen animal aroused. Severecases - profuse diarrhea rapidloss of flesh, hunched posi-tion. Mucus may be voided.'Pot belly' on recovery. Pneu-monia often sets in.

One or more offour commonone-celledanimal para-si tes mul tiply-ing in thelining of theintestine ofdomesticrabbi ts

Never demon-strated to becontagious, butoften confusedwith contagiousdiseases

Unknown

Intesti-nalcoccidi-osis

Mucoidented tis(Scours,Diarrheaor Bloat)

2 'Malocclusion, or 'buck teeth,' in rabbits' A.H.D. No. 109.

PART OFlDDY

AFFECTED

DISEASEAND

SYNONYMSCAUSE GmERAL SYMPTOMS TREATMENT PREVENTION REMARKS

DIGESTIVE ITapewormSYSTEM larva(continued) (Bladder-

worms)

Larval stageof dog and cattapeworm

White streaks in liver. Clear,bubble-like cysts of pin headto small pea size on membranesintestines or other organs,External symptoms not, speci f ic,or absent in light cases.

None.If infection of this sortexists in herd, make sure nodogs or cats have access toviscera of any of your animals

Keep dogs and cats away from feed,water, bedding and utensi Is. Eggs 1of tapeworm in dog or cat droppingsor on fur must not reach rabbits.Do not let dogs or cats consumerabbit viscera or they may de-velop mature worms.

MISCEL-LANEOUS

Uter ineInfec-tion(Metd ti sor Whitedischarge)

Myx~m!­tOSlS(Bighead,Mosquitodisease)

Mi lkweedpoison-ing(Headdowndisease)

Para-lyzedhind-quarters

Wry neck(Twistedneck. orLimber-neck

Any of severalbacteriaMost not highlycontagious

A fi 1terablevirus. Oftentransmitted bymosqui tos

Usually fatal

Consumingwoolly-podmilkweed infeed or bedding

Broken back,injury tospinal cord

Infection oforgans ofbalance ofinner ear

White, sticky discharge underhutch. Not to be confusedwith thick urine, which is notsticky. Found in one or bothuteri. Often detectable bypalpation~

Inflammation, and grotesque,bulbous swellings about eyes,nose, ears, and genitals.Ears may swell enough to droopfrom weight. Discharge fromeyes, loss of appetite, heavybreathing, death.

Paralysis of neck muscles andloss of coordination. Headdroops between front legs.Animal can eat and drink ifhead is supported. In ad-vanced cases paralysis may begeneral.

Hindquarters drag, lie to oneside or at least cannot sup-port weight. Break may oftenbe felt in small of back.Bladder fills but does notempty readily.

Head twfsted to one side,often followed by animalsrolling over, after whichthe process may be repeated.

None is practical.

Market the animal to avoidcontamination of buck.

None.

Destroy affected animals byburning or deep burial.

Moderate caaes - support headof animel and get it to drinkand to eat greens and carrots.Get as much fluid down aspossible. Advanced cases arehopeless.

None.

Very few could recover. Thereis internal hemorrhage in mostcases and permanent damage tonerve cord.

None.

After organs of balance aredestroyed or badly damaged,complete recovery does notfollow.

Breed only clean animals. Dis-pose of infected animals, anddisinfect contaminated equip-ment.

Keep flies down.

Keep down mosquitos by drain-ing, oil spray on marshes, andusual precautions. Screen oruse insecticide to keep adultmosquitos down.

Search hay and especially bed-ding for light, greenish-yellowstems and leaves of woolly-podmilkweed. Use only if free ofthis weed.

Provide animals protectionfrom disturbing influences,particularly night prowlersand visitors that startleanimals badly.

Eliminate ear mange from herd.It is most common initialfactor. Cases following in-jury are usually in nest boxbabies, and attributable topure accident or disturbinginfluences.

Some few cases resultfrom decomposition ofretained afterbirth.Occasionally theserecover.

Limited to West Coast,Mexico, and SouthAmerica, as knownfrom reports.

Woolly-pod milkweed(Asclepias eriocarpa)reported only fromPacific Southwest.

May follow ear mange,accidental perfora-tion of ear drum, orthroat infection.

3 'Infectious myxomatosis of domestic rabbits' W. L. leaflet 213.- 7 -