Transcript Guinea Pig Diseases - Yola

Guinea Pig Diseases
Antibiotic toxicity
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Antibiotics may suppress clinical
signs but usually do not eliminate
the organism and fatal antibioticinduced enterocolitis is always a
concern in treating guinea pigs.
Antibiotics implicated include
penicillin, aminoglycoside,
erythromycin, clindamycin,
lincomycin, chlonetracycline,
estreptomycin, bacitracin, and
dihydrostreptomycin.
BACTERIAL AND FUNGAL DISEASES
Bacterial and fungal agents are
responsible for some of the most
significant diseases of guinea pigs
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Bacterial diseases
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Several primary respiratory diseases of
the guinea pig are of bacterial origin, with
Bordetella bronchiseptica and
Streptococcus pneumoniae being the
most important.
Other infectious agents act as
opportunistic invaders in traumatized
tissue (Streptococcus zooepidemicus),
and contribute to enteric disease
(Clostridium piliforme and Salmonella
spp) and dermatitis (Trichophyton
mentagrophytes).
Bordatella
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Pneumonic lungs, seen
here as the dark-colored
tissue, may have one or
more areas of
consolidation and
hemorrhage. Bordetella
bronchiseptica,
Streptococcus
pneumoniae, or other
bacteria frequently cause
pneumonia in guinea
pigs. Affected animals
may have no clinical
signs, or exhibit nasal
discharge, sneezing,
dyspnea, weight loss, or
sudden death
Bordetella
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Bordetella bronchiseptica is
a small gram negative rod.
Incidence of Bordetella
bronchiseptica infection in
guinea pigs may be high
because many animal
species such as rabbits,
dogs and cats carry the
organism in nonclinical
infections. For this reason,
rabbits and guinea pigs
should not be housed
together.
Transmission between
animals is by direct contact,
aerosol, or contaminated
fomites
Bronchopneumonia
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Lesions include rhinitis,
tracheitis and pulmonary
consolidation. Typical
histopathologic lesions of
purulent bronchitis and
bronchopneumonia with
large accumulations of
neutrophils and
intraluminal debris
(arrow) are shown here
Head tilt
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Otitis media may also
occur with Bordetella
infections. Severe
otitis media may be
accompanied by head
tilt (torticollis).
One may detect
suppurative otitis
media through
radiographic
examination of the
tympanic bulla, as
illustrated in this
unilaterally affected
animal (arrow).
Bordatella
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Treatment of Bordetella
bronchiseptica infection is often
unrewarding. Antibiotics of choice
include chloramphenicol,
sulfamethazine and trimethoprimsulfa.
Effective prevention includes good
husbandry and maintenance of a
closed Bordetella free colony
Streptococcus pneumoniae
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Fibrinopurulent pericarditis, shown
here, can be caused by
Streptococcus pneumoniae. It may
be accompanied by fibrinous
pleuritis and bronchopneumonia. S.
pneumoniae is a gram positive.
Mortality is high
Clinical signs are similar to those
seen in other bacterial
pneumonias. Otitis media, metritis
and other suppurative processes
may occur.
Transmission of Streptococcus
pneumoniae is by aerosol or direct
contact with diseased or
asymptomatic carrier guinea pigs,
rats or humans
Lymphadenitis
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Cervical lymphadenitis is
caused most commonly by
Streptococcus
zooepidemicus. Other
Streptococcus spp and
Streptobacillus moniliformis
are rarely implicated.
The organism may be an
asymptomatic inhabitant of
the upper respiratory track
that opportunistically
invades damaged mucosa.

Bite wounds or
aerosol spread
onto mucosal
surfaces are the
primary modes of
transmission.
Cervical lymph
nodes become
swollen, abscess
and often rupture.
Lymphadenitis
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Lymph nodes progress to
encapsulated abscesses
filled with yellow-white
purulent exudate.
Diagnosis is based on
clinical signs and culture of
the organism from lesions.
Treatment may include
drainage and lavage of
lesions and antibiotic
therapy with
chloramphenicol or
trimethoprim-sulfa.
Control is accomplished by
culling affected animals
prior to rupture of lesions
and separating new stock
from an existing colony
Tyzzer’s disease
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This image shows the
multiple gray-white
foci often found in the
liver of guinea pigs
with Tyzzer's disease.
See mice info….
Salmonellosis
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Salmonella typhimurium and
other Salmonella spp will infect
guinea pigs. Sporadic
outbreaks with high mortality
are the rule, with guinea pigs
becoming most susceptible
around parturition, weaning, or
other times of physiologic
stress.
Clinical signs of salmonellosis
include anorexia, rough
haircoat, lethargy, weight loss,
soft feces, reproductive
inefficiency and abortion.
Transmission
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Many animal species harbor
Salmonella organisms which are
shed intermittently in the feces.
Transmission is fecal-oral;
organisms often are introduced in
contaminated foods such as fresh
fruits and vegetables, or through
the water supply.
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Necropsy findings
may include gas
and fluid contents
in the
gastrointestinal
tract as seen here.
Enlargement of
the liver, spleen
and lymphoid
tissues may also
be found.
Salmonella
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Management Culture-positive
animals should be removed from
the colony. The room and
equipment should be disinfected
and restocked with clean animals.
Dermatophytosis
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This animal has dermatophytosis and may
also show some signs of barbering.
Trichophyton mentagrophytes is the most
common cause of dermatophytosis
(ringworm) in the guinea pig and rabbit
causing patchy alopecia
While clinical infections are uncommon,
asymptomatic carriers are abundant. Spores
may be found in hair, bedding and soil
Diagnosis
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Culture of hair shafts from a lesion
onto dermatophyte test media may
also be used to confirm a diagnosis.
Topical antifungal creams used daily
for 2 to 4 weeks, or griseofulvin at
25 mg/kg daily in the water for 14
days or 20mg/kg in feed for 25
days, are generally effective
treatments.
Prevention of outbreaks may be
accomplished by strict sanitation,
screening suspect animals and
culling affected animals.
Trichophyton mentagrophytes is
infective to humans and other
animal species.
Mastitis
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Mastitis is common in lactating sows. Milk provides an
excellent media for the growth of bacteria that may invade
when young traumatize the teats. Multiple agents have been
implicated, including Pasteurella spp, Klebsiella spp,
Staphylococcus spp, Streptococcus spp and others. Mammary
glands become warm, enlarged and hyperemic, as illustrated
on the image.
The milk may appear bloody; depression and even death may
follow. Diagnosis is based on clinical signs.
Treatment includes hot packs and antibiotic therapy
VIRAL AND CHLAMYDIAL
DISEASES
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Some viral and chlamydial disease
agents are documented, but they
are of limited importance
Conjunctivitis
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Overt signs of inclusion
body conjunctivitis, as
seen in this image, are
found primarily in one to
three week old guinea
pigs. Spontaneous
resolution of the disease
is complete by four
weeks of age in most
animals. Chlamidia
psittaci, the infective
agent, is transmitted via
feces, saliva and nasal
secretions; infections
may be spread by direct
contact or aerosol
Zoonotic
Lymphosarcoma
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A type Oncornavirus is
the etiologic agent
responsible for the
leukemia found in
aged guinea pigs.
Cavian leukemia virus
is widespread and
usually transmitted
transplacentally,
remaining dormant in
the animal until aging
or stress trigger
disease expression.
Hepatomegaly
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Hepatomegaly,
splenomegaly and
diffuse
lymphadenopathy are
found frequently in
guinea pigs with viralinduced leukemia/
lymphosarcoma.
Enlarged organs
appear mottled and
light in color. Anemia
and leukocytosis are
often present
PARASITES
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Many parasites are known to infect
guinea pigs, but as a rule, parasites
are more a problem in hobby and
breeding colonies than in the
research setting.
Ectoparasites
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Common ectoparasites of the
guinea pig include the mites
Trixicaris caviae and Chirodiscoides
caviae, as sell as the lice, Gliricola
porcelli and Gyropus ovalis.
Acariasis
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Acariasis in guinea
pigs is primarily
associated with two
species of mite,
Trixacaris caviae and
Chirodiscoides caviae.
Mild to severe
alopecia may be seen,
as illustrated in the
image
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Trixacaris caviae, a
burrowing mite, poses
a significant threat to
the health of a guinea
pig colony.
Trixicaris caviae tend
to distribute on the
neck, shoulders, lower
abdomen, and inner
thighs, whereas
Chirodiscoides caviae
distribute more
randomly
Trixacaris caviae
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Trixacaris caviae, a sarcoptid mange mite,
burrows through the keratin layer of the
epidermis causing alopecia, crusting, and an
intense pruritus that may lead to self
mutilation, debility and death.
Chirodiscoides caviae
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Chirodiscoides caviae, a fur mite, may cause
few or no clinical signs in infested animals.
Mites are transmitted by direct contact with the
host, animal bedding, or hair and debris.
Treatments
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Reported treatments for acariasis
include pyrethroid flea powder
dusts, lime sulfur dips and
injections with ivermectin.
Lice
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Guinea pig lice, Gliricola porcelli (left) and
Gyropus ovalis (right) are chewing lice that cause
occasional alopecia and mild pruritus with heavy
infestations; Gliricola porcelli is seen more
commonly. Lice are spread by direct contact with
the host or contaminated bedding.
Noninfectious Disease
NONINFECTIOUS DISEASES OF
GUINEA PIGS
The noninfectious diseases of guinea
pigs may be placed in four
categories:
 Nutritional and metabolic diseases
 Management-related diseases
 Other noninfectious diseases
 Neoplasia
NUTRITIONAL AND METABOLIC
DISEASES
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Nutritional and metabolic diseases,
our first category, represent a
major cause of illness in guinea
pigs. These diseases present as
clinical or, usually, subclinical
entities. The diseases discussed
here are hypovitaminosis C (or
scurvy), pregnancy toxemia and
metastatic mineralization.
Vitamin C Deficiency “Scurvy”
“I’m reluctant to move”
“I have
joint
pain”
“I’m lame”
Scurvy
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Hypovitaminosis C is a common and frequently
unrecognized or subclinical problem in guinea pigs.
The guinea pig seen here has swollen hind limbs and
moves with difficulty.
Scurvy
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Signs of scurvy include
enlarged costochondral
junctions (illustrated
here), swollen limbs
(seen previously),
increased vocalizations
(due to pain when
moving or handled),
anorexia, weakness,
delayed healing of
wounds, and death in two
to three weeks due to
starvation and/or
secondary bacterial
infections.
Joint hemorrhages
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Cartilaginous,
muscular (seen
here), periosteal,
and subcutaneous
hemorrhages are
observed
frequently on
postmortem
examination
Treatment/ prevention
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Clinically ill guinea pigs should receive
vitamin C daily until improvement is seen.
The amount of vitamin C added to the
diet will vary, but is approximately 50
mg/kg. A daily source of ascorbic acid
should be provided to every guinea pig at
a dosage rate of 10 mg/kg per day for
normal guinea pigs and 30 mg/kg per day
for pregnant sows.
Sources of vitamin C
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A daily source of vitamin C is provided by
use of high quality, commercially
available guinea pig diets that have been
stored in a cool, dry place. The diet
should be used within 90 days of the
milling date. Good sources of vitamin C
include a handful of kale or cabbage, 1/4
fresh orange or green pepper, or the
addition of ascorbic acid to the drinking
water (200-400 mg per liter of water,
prepared daily).
Pregnant guinea pig
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Pregnancy toxemia or ketosis,
similar to that seen in sheep, is
a metabolic/nutritional disease
of obese female guinea pigs. It
is most commonly associated
with a sudden dietary change
Clinical signs of pregnancy
toxemia appear in the last one
to two weeks of gestation or the
first week postpartum.
Signs include anorexia,
depression, dyspnea,
convulsions, stillbirths, and
abortions
Pregnancy Toxemia
Renal disease
Fatty
liver
Uterine hemorrhages
MANAGEMENT-RELATED
DISEASES
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A number of other noninfectious diseases
occur in guinea pigs, many of which are
related to the management of the
animals. Those to be discussed include
antibioticinduced enterotoxemia, dystocia,
heat stress, pododermatitis, cage trauma,
vaginitis, and preputial plugs
Diarrhea
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Antibiotic-induced
enterotoxemia, also called
hemorrhagic typhlitis
This disease is produced by
overgrowth of
enterotoxinproducing enteric
bacteria, or increased
enterotoxin production, most
commonly associated with
the administration of certain
antibiotics.
Clinical signs may include
anorexia, rapid weight loss,
dehydration, depression,
diarrhea, and death
Antibiotics to avoid
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Antibiotics implicated include
penicillin, erythromycin, lincomycin,
chlortetracycline, oxytetracycline,
bacitracin, and dihydrostreptomycin
Ptyalism
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Guinea pigs are highly susceptible to heat stress.
One of the signs of heat stress is excessive salivation
(or ptyalism), as seen in this image.
Heat stress may occur even at moderate
environmental temperatures, particularly if the animal
is housed in a confined, humid and poorly ventilated
space
Treatment
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Treatment is usually unrewarding
but would include rapid cooling with
cool running water or ice water,
steroids and administration of
supportive care.
Pododermatitis
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Pododermatitis, also
known as bumblefoot,
occurs when guinea pigs
are overweight or housed
in cages with rough,
unsanitized floors. Wire
floored cages or pens are
particularly troublesome.
This condition is
produced by trauma to
the feet with secondary
bacterial invasion.
The most common
offending organisms are
staphylococcal species
Histopathology
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Histologic
examination of the
tissue reveals
fibrotic,
granulomatous
inflammation.
Diagnosis is
obtained from the
history and clinical
signs.
Management
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Affected guinea
pigs should be
moved to cages
with solid floors
covered with soft
bedding. The feet
may be treated
with astringents or
with povidone
iodine and
bandaged
Stampede
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Cage trauma may be
observed in any
guinea pig, but is
more commonly seen
in young guinea pigs
kept in cages with
wire mesh floors. The
wires may be far
enough apart to trap
the guinea pig's foot
or leg.
Vagina impacted with bedding material
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Occasionally, wood chips,
sawdust, or other types
of bedding adhere to the
vulva, vagina and
prepuce and will produce
a foreign body reaction in
these areas. Vaginal
debris with inflammation
and infection will be seen
in sows.
When this debris is
observed, it should be
removed and the area
washed with a mild soap
and water
Smegma
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a secretion of
mammalian genitals
is a combination of
exfoliated (shed)
epithelial cells,
transudated skin oils,
and moisture
In boars, sometimes
develop smegma, a
cheesy and smelly
secretion from the
sebaceous glands that
collects around the
penis
Barbered guinea pig
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Barbering or hair pulling
among cage mates and
transient hair loss of
weanlings will affect small
areas, regions, or the
entire body. A diagnosis
of a specific type of
alopecia is based on
history and clinical signs.
Treatment involves
separating offending
guinea pigs
Overgrown incisors
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Skull of a rare “Guinea mammoth”
Guinea pigs are
similar to other
rodents in that they
have open-rooted
incisors, but differ in
that they also have
open-rooted molars
and premolars. In the
guinea pig, the
anterior most cheek
teeth tend to become
overgrown and
maloccluded first
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Malocclusion is common
in guinea pigs and is
easily overlooked at the
time of clinical
examination because
the cheek teeth are
difficult to see.
Excessive salivation,
halitosis, chronic weight
loss, and trauma to the
tongue are frequently
observed.
Overgrown molars
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While the guinea pig
is sedated, the
offending teeth
(overgrown molars in
this image) should be
trimmed by filing or
cutting with small
trimming instruments;
all sharp edges should
be smoothed.
Urinary calculi
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Urinary calculi may
occur in guinea pigs,
but are a rather
uncommon incidental
finding. Clinical signs
are observed if
obstruction
(evidenced here as an
enlarged urinary
bladder) or
inflammation occurs
Urinary calculi
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Clinical signs can
include uremia,
anuria or oliguria,
pyuria, depression,
and anorexia.
Hematuria may be
observed even
without
obstruction.
Resources
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Center for Laboratory Animal
Medicine and Care
University of Texas Houston
Health Sciences Center