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LABORATORY ANIMAL MEDICINE
Introduction
Laboratory animals are animals used in the laboratory for
scientific researches e.g.
Rabbit, mouse, Rat, Guinea pigs, Hamsters, Girbils etc.
Lab animal medicine is more of prevention than curative. It
is easier to prevent diseases than to cure.
When not prevented, the diseases can kill a whole colony of
pets or research animals
Involves good management e.g. hygiene, good, balanced
diet, good and adequate housing(free from draught,
dampeness, direct sunlight and extreme temperatures.)
(a)INFECTIOUS MYXOMATOSIS:
Caused by a poxvirus.
 Characterized by high mortality (40-100%).
fibromas.
It occurs as
 Enzootic in Eastern and Western United States, Europe, South
America and Australia.
 The situation in Africa is still unknown.
 Transmitted mechanically by
o Mosquitoes and biting insects e.g. fleas
o Direct contact from the cotton tail to domestic rabbits
where the disease ranges from peracute, fatal to transitory
and single fibromas.
Clinical Signs
 All ages are susceptible but younger ones (1 month – 1 year) are less
susceptible.
 Characterized by conjunctivitis with milky ocular discharges
listlessness, anorexia, fever (1080F).
 In severe cases death may occur within 48 hours.
 Survivors after this become progressively, depressed, develop rough
coat, edematous eyelids, nose, lips and ears giving rise to the
characteristic “big head”.
 Edematous and inflamed vent in the male, the scrotum becomes
swollen.
 Drooping ears due to edema.
 Purulent nasal discharges and laboured respiration followed by coma
and death which usually occurs 1-2 weeks after the appearance of clinical
signs.
Diagnosis
o Clinical signs, Virus isolation and serology
Treatment
o None
Control and prevention
o Control of vectors
o Quarantine of new animal in insect proof
quarters for 2 weeks.
o Vaccinate animals with a live attenuated
myxomatosis virus vaccine.
BACTERIAL DISEASES
Common in domestic rabbits.
PASTEURELLOSIS
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Snuffles
Enzootic pneumonia
Otitis media
Genital infection
Abscesses
Conjunctivitis
Septicaemis
Pyometra
Orchitis
1) Snuffles (Nasal catarrh)
Aetiology: Pasteurella multocida
Characterized by
Rhinitis, pneumonia, otitis media and conjunctivitis.
Used to describe rhinitis and paranasal sinusitis characterized
by serous, mucous or mucopurulent nasal discharges.
Usually complicated by such bacteria as Staph. aureus and
Bordetella bronchiseptica.
Symptomatic carriers may come down due to stress (change in
weather, pregnancy, concurrent diseases, experimentation)
Spread is by direct contact or through aerosol.
Clinical Signs
May be acute, subacute or chronic characterized by nasal
discharges which may be serous, mucous or mucopurulent.
Sick rabbits paw with the inside of the front legs causing
matting of the fur around that area, sneezing coughing are usual.
Snuffles is common at kindling period or during low resistance.
 Death may occur while recovered animals become carriers.
Treatment
Penicillin and streptomycin, Sulphaquinoxaline, furazolidone
may be administered.
2. ENZOOTIC PNEUMONIA
Aetiology P. multocida
Usually complicated by other bacteria like
o klebsiella pneumomae,
o Bordetella bronchiseptica
o Pneumococci.
Clinical signs
Starts with nasal infection, anorexia, fever
(400C) dyspnea.
There may be diarrhea and weakness.
 Death may occur within 4 days.
 Some animals may die without showing
clinical signs.
Treatment
As for snuffles. Tetracyclines may be used.
OTITIS MEDIA
P. Multocida is the usual causative agent but
Staph spp and Bordetella spp may also be
found.
oTransmission is by
odirect contact,
oformites
respiratory route
Clinical signs:Torticollis. In severe cases the rabbis may not
be able to eat or drink resulting in weight loss
and dehydration. If the meninges are affected
incordination and other nervous signs may
occur.
Treatment
Tympanocentesis plus antibiotic (antibiotic
alone may not be effective).
GENITAL INFECTION
Caused mainly by P. multocida
complicated by other organisms.
Common in adults, more common in
does than in bucks.
Transmission is through coitus.
Clinical signs
o May be acute or subacute inflammation of the reproductive
track.
o Causes pyometra in females characterized by mucoid vaginal
discharges.
o It may also be purulent, thick yellowish-grey in colour.
o In bilateral cases there is sterility but if only one horn is
affected there may be normal litter.
o In the male a purulent penile discharge, orchitis also occurs.
Treatment
o Antibiotics which may be of little value. Ovariohysterectomy
in pets plus antibiotic.
Control
o Cull all affected animals.
o Regularly examine the genitalia of breeding stock.
o Bucks with low conception rate should be culled also females
that consistently fail to conceive.
ABSCESSES
P. multocida predisposed by wounds which may result from light by
males, scratches from other rabbits or sharp wire from the cage.
Clinical signs
Subcut swelling, abscesses of internal organs which may result in
septicaemia and death.
Treatment
Lancing and draining antibiotic treatment both topically and
systemically.
Control
Eliminate affected animals, remove predisposing factors.
CONJUNCTIVITIS
oCaused by P. multocida, other organism may be incriminated.
Common in young ones than in adults but both are quite
susceptible.
Clinical signs
oSwollen eye lids gumed together by exudates.
oInflamed conjunctiva, mucoid later mucopurulent ocular
discharges. Affected animals rub the eyes with their front legs.
o Inflammation may become chronic with edema subsiding but
discharges continue resulting in epiphora.
oPathological overflow of tears on to the cheek.
Treatment
oPenicillin or chloramphenicol eye ointment.
 SEPTICAEMIA
o Caused by P. multocida:- may be from other Pasteurella
infection.
 Clinical signs
o May not be detected as the animal dies suddenly but may be
noticed if other forms of pasteurellosis have been
incriminated.
 Treatment
o Usually not practicable as animal dies suddenly.
Control:o Avoid infection by P. multocida, eliminate affected animal.
Prevent stress.
PARASITIC DISEASE
Coccidiosis
Major intestinal but self limiting disease of rabbit
Recovered animals become carriers.
There are two forms of the disease in rabbit, liver and
intestinal coccidiosis.
Liver form is caused by Eimeria stiedae
The intestinal form is caused by a variety of spp – E.
megna, E. irresidua, E. media, E perforans.
Nasal coccidiosis is due to contamination of mucous
membranes of the nose while practicing coprophagy.
Clinical signs
Older animals may be able to cope with the infection
but become carriers. The young ones succumb easily.
Hepatic coccidiosis:- There may be no clinical signs but
severe infection results in cachexia, abdominal
distension and death as a result of hepatic
dysfunction.
Intestinal coccidiosis
Vary from inapparent to poor weight gain. May be acute
or chronic. Common signs are enteritis, diarrhea
which may be unformed stool or watery, catarrhal or
bloody fluid. In acute cases there is rapid weight loss
severe dehydration, polydipsia, anorexia but at times
with ravenous appetite. In some cases when young
ones are affected with virulent organisms e.g. E.
irresidua or E magna may die with no clinical signs.
Diagnosis is based on finding oocysts in the faeces but
there could be oocysts without clinical signs. In case
of sudden death oocysts may not be seen but all the
stages may be found in the intestinal mucosa.
Treatment
Sulphamerazine 0.02% in drinking water
Sulphaquinoxaline 0.05% in drinking water or 0.03% in
feed (for 2 weeks).
Control
Hygiene, eliminate carriers, screen incoming rabbits for
oocysts. Avoid contamination of food and water with
faeces. Separate the young ones from the adults.