Transcript SYRIAN HAMSTERS: Viral, Parasitic, and Noninfectious Diseases

SYRIAN HAMSTERS:
Viral, Parasitic, Bacterial and
Noninfectious Diseases
HAMSTERS
• More likely to bite
• Signs of an angry
hamster
– Roll on back
– Stand on hind limbs
– Vocalizing
VIRUSES
• Compared with laboratory mice, relatively few
naturally acquired viral infections have been
reported for the Syrian hamster. However,
Syrian hamsters can be infected with several
of the viruses that infect laboratory mice and
rats.
• In most cases, viral infections in Syrian
hamsters are subclinical—there is no overt
disease.
• Most viral infections in Syrian hamsters are
poorly described, unlike similar infections in
laboratory mice and rats
Sendai and pneumonia viruses
• Two respiratory viruses, Sendai virus
and pneumonia virus of mice (PVM),
have been shown by serologic surveys
to commonly infect laboratory hamsters
These RNA viruses are of the family
Paramyxoviridae.
• These viral infections involve both the
upper and lower respiratory system and
are spread by direct contact with nasal
secretions and aerosol in rats and mice
Diagnosis & Control
• Diagnosis of Sendai virus or PVM infection is
made by testing sera for specific antiviral
antibodies in either an enzyme-linked
immunosorbent assay (ELISA) or indirect
immunofluorescent antibody (IFA).
• Control Both Sendai virus and PVM infection
can be eliminated from a hamster population
by isolating the animals and letting the
infection run its natural course
LCMV
• Lymphocytic choriomeningitis virus (LCMV),
an arenavirus of the wild house mouse, can
infect hamsters, monkeys, dogs, guinea pigs,
rabbits, chickens, and people. Both pet and
laboratory hamsters have been shown to
harbor the virus. Naturally-occurring LCMV
infection of hamsters is chronic, persistent,
usually subclinical, and characterized by
prolonged viral excretion in the urine
LCMV
• LCMV is a serious zoonotic agent. It can be
spread from hamsters to people both by
aerosol and by direct contact. Outbreaks in
people have occurred from contact with
infected pets as well as laboratory hamsters.
• Symptoms in humans- Infection in people
may be either subclinical or clinical with
symptoms including fever, headache,
myalgia, nausea, vomiting, sore throat, and
photophobia
Bacterial Diseases
Tyzzer’s Disease
• Occasionally reported in hamsters and other
rodent species, Clostridium piliforme
• Clinical signs:anorexia, dehydration, watery
diarrhea, and sudden death.
• See mice info..
C piliforme
Clostridial Enteritis
• Enteric disease associated with variable
morbidity and mortality may result from
overgrowth of Clostridium perfringens,
C. difficile, and perhaps C.
spireforme. These anaerobic bacteria
produce toxins that cause edema and
hemorrhage, and occasionally mucosal
dysfunction and necrosis.
Clostridial enteritis manifests as 2
syndromes.
• The first is acute diarrheal disease in hamsters with
cecal bacteria dysbiosis from dietary changes,
antibiotic therapy, concurrent diseases or other
physiologic stressors that can disrupt the cecal
microbiota.
• The second syndrome occurs in older (>6 mo)
hamsters usually on experimental studies that often
do not involve changes in diet or oral
medication. Hamsters slowly lose weight and die
without developing diarrhea. Gross lesions include
mild dehydration and thickening of the cecal wall
with thick to watery cecal contents
Clostridial enteritis
Colibacillosis
1. Etiology: E. coli recovered from hamsters
with colibacillosis has virulence factors that allow
for adherence to mucosal cells and production of
enterotoxins or invasion. The incidence of
disease is moderate.
• 2. Transmission: The disease is transmitted
via direct contact, fecal-oral and fomite
contamination.
• 3. Predisposing Factors: A high carbohydrate
or vitamin imbalanced diet, exposure to infected
animals, shipment stress, overcrowding, and
lack of fresh water are stressful events that
precipitate disease
•
Clinical Signs
• Generally the disease is
acute in onset, with 2to 4-week-old hamsters
developing a profuse
yellow watery diarrhea
that mats the area
around the
tail. Dehydration and
death quickly ensues.
Diagnosis: Culture of the gut with recovery of pure
culture of E. coli is strong evidence for disease.
Treatment: Supportive treatment for dehydration with
lactated Ringer's solution given SQ (5% to 15% of body
weight) and Kaopectate (1-2 ml PO) for diarrhea may be
effective. Antimicrobial therapy may actually worsen the
bacterial population imbalance and lead to development
of a fatal enteritis.
Control: Even though colibacillosis outbreaks are
generally associated with stress every effort should be
made to prevent cage to cage transmission of
feces. Strict sanitation practices.
Salmonellosis
Etiology: Salmonella enterica serovars
Typhimurium and Enteritidis are Gram-negative,
invasive enteric bacteria. Incidence of infection
and disease is low.
Transmission: Food, water and bedding may be
contaminated by infected feces from wild
rodents.
Clinical Signs: The disease may only be
manifest as acute death. Clinical signs are seen
primarily in pregnant or recently delivered
females and infant or weanling
hamsters. Diarrhea is usually not present but
pregnant females may abort and become
cachexic.
Parasites
Hamsters can harbor several different endoand ectoparasites.
The commonly seen protozoa, pinworm,
tapeworm, and mite infestations.
Protozoa
• Spironucleus muris (left photo), Giardia sp.,
Tritrichomonas sp., and Entamoeba sp. (right photo) are
protozoa which commonly inhabit the small and large
intestine without causing clinical signs. When the
luminal contents become more fluid, as in the case of
bacterial enteritis, these protozoa take advantage of the
opportunity to replicate, and frequently aggravate the
inflamed intestinal tract
Pinworms
• Etiology: Syphacia mesocricetus is the hamster
pinworm (see photo). Syphacia obvelata and
Syphacia muris are also capable of infecting
hamsters. Prevalence of a pinworm infection is
low, however the incidence of parasitism within
individual colonies may be high.
Pinworms
• Transmission: Syphacia sp.
deposit eggs in the perianal
region. Transmission of
infection occurs via ova
ingestion.
• Clinical signs: No signs are
usually seen. Heavy parasite
loads may lead to rectal
prolapse or perianal irritation.
• Gross Pathology: Pinworms
are easily recognized as white
hair-like nematodes in the
cecum.
• Diagnosis: Direct exam of
cecal contents to identify adult
worms, and fecal flotation, and
perianal tape test for ova (see
photo) are routinely used
diagnostic methods.
Treatment & Control
• If treatment is desired, two doses of
piperazine (10 mg/ 1ml water) for 7 days
followed by 5 days without treatment is
effective. Thiabendazole at 0.1% in the feed
for 3 to 4 weeks is also effective.
• Rigid sanitary procedures, and use of filter
hoods should be employed to prevent aerosol
transmission. Regular ova examinations with
treatment may control the parasitism.
Mange Mites
• Etiology: Demodex criceti and
Demodex aurati are mange mites of
hamsters. High incidence of infestation
occurs without clinical signs. The mites
are generally found together. Demodex
criceti is considered non-pathogenic and
is found in the epidermis. Demodex
aurati, the more pathogenic mite, is
found in the pilosebaceous component
of the skin
• Transmission: Demodex infestations
are thought to be spread by direct
contact.
• Predisposing factors are considered
necessary for the development of
clinical signs including malnutrition,
concurrent systemic disease, and age
Clinical Signs
• Clinical signs can
range from none to
alopecia, dry,
scaly, scabby
dermatitis, and
rough hair
coat. Alopecia
generally occurs
over the rump and
back.
Demodicosis
Alopecia
Alopecia
Dermatitis
Diagnosis
• Diagnosis: Skin scrapings of alopecia skin will reveal
mites. Demodex criceti has a shorter body length and is
scraped from epidermal pits (A.). Demodex aurati is
longer that Demodex criceti, and is squeezed from the
hair follicles (B.).
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Miscellaneous Maladies
Antibiotic-associated Enterocolitis
• Administration of
antibiotics selective for
gram-positive bacteria
such as lincomycin,
clindamycin, ampicillin,
vancomycin,
erythromycin,
gentamicin, penicillin,
and cephalosporins may
cause a fatal
enterotoxemia with
profuse diarrhea and
high mortality within 210 days.
Proliferative Enteritis (“wet tail”)
• Proliferative enteritis is a frequent cause of diarrhea in hamsters.
• Recently, the causative agent was determined to be identical to
Lawsonia intracellularis , a bacteria that causes proliferative enteritis
in swine.
• Precipitating factors include recent transport, overcrowding,
surgery, and dietary changes
Proliferative Enteritis (“wet tail”)
• Clinically, it is more
common in younger
hamsters with
sudden onset, high
morbidity and
mortality, and signs
of watery diarrhea
and matting of fur
around the tail and
ventral abdomen.
• Transmission is by
the fecal-oral route.
• Gross pathology
may include ileal
thickening, enlarged
mesenteric lymph
nodes, peritonitis,
and abdominal
adhesions.
Hyperemic ileum
Treatment
• Treatment includes supportive fluids
(oral electrolyte solutions or lactated
Ringer’s solution, SC) for dehydration
(5-15% body wt), 1-2 mL bismuth
subsalicylate, PO, and appropriate
antibiotics such as enrofloxacin,
metronidazole, or trimethoprim-sulfa,
which can be administered via the
drinking water
Amyloidosis
• Amyloidosis is a
condition whereby
proteins produced
by the body are
deposited in various
organs, primarily the
liver and kidneys.
• Kidney and liver
failure
Amyloidosis
Malocclusion
Neoplasia
• Lymphosarcoma
• Adrenal cortex tumors
• Malignant melanoma