Rodent Infectious Diseases

This page is a "laundry list" of rule-outs for various infectious diseases of rodents. For more information consult the appropriate pages for bacterial, viral and parasitic diseases. For rats and mice, the rule-outs are listed by system rather than by infectious organism.

Guinea Pigs    Peromyscus    Chinchillas

Hamsters        Gerbils     Meadow voles     Rats    Mice

Guinea Pigs{3984}

Guinea Pig Bacterial Diseases

Guinea Pig Viral Diseases

Limited importance in guinea pigs; Chlamydia, cytomegalovirus, LCM, lymphosarcoma or cavian leukemia from type C retrovirus, guinea pig adenovirus. The guinea pig is one of the natural hosts for Sendai virus.

Guinea Pig Parasitic Diseases

Guinea Pigs: Non-infectious Diseases{3985}

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Chinchillas

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Hamsters

Bacterial and mycotic diseases

            Viral diseases

Parasitic diseases

Hamster bacterial diseases{3991, 4758}

The FELASA list suggests monitoring hamsters for Tyzzer's, Pasteurellaceae and Salmonella every 3 months; Helicobacter and Corynebacterium kutscheri annually.

Proliferative ileitis: "wet tail", regional enteritis, terminal ileitis, atypical transmissible ileal hyperplasia. Cause= intracellular bacteria (now Lawsonia intracellulare), which causes a similar disease in swine; in fact, cross-species transmission has been shown. Signs= may be self-limiting with no signs, but in those that do get sick, watery diarrhea is the major sign. Death may result in 50-90% of affected hamsters.  The disease may also be chronic, with mild diarrhea and weigt loss. Gross= marked thickening of terminal jejunum and ileum, serosal hyperemia and enlargement, peritonitis, adhesions, suppuration of mesenteric and ileocecal lymph nodes, may have intussusception or rectal prolapse. Histo= hyperplasia of crypt and villous epithelium, loss of villous architecture, villar necrosis, inflammation of lamina propria, crypt abscesses in intestinal wall, mucosal edema, lymphoid hyperplasia. Increased mitotic activity and cell immaturity in crypt epithelium. Warthin Starry silver stain shows brown haze of organisms in apical cytoplasm of mucosal and crypt epithelial cells. Serological tests are "under development". Treatment= Remove affected hamsters and improve sanitation, or eliminate the colony. Antibiotics (tetracycline, enrofloxacin, or trimethoprim-sulfa) can be used.

Clostridium difficile enterocolitis and enterotoxemia: overgrowth from antibiotic use (penicillin, ampicillin, erythromycin, lincomycin, tetracycline). Anorexia, rough haircoat, profuse watery diarrhea, marked dehydration, death. Hemorrhagic distal small intestine and distended cecum. Marked mucosal hemorrhage, submucosal edema, loss of mucosal architecture. If chronic, may get cecal and colonic mucosal hyperplasia and cholangiohepatitis and amyloidosis. Prevent by not using antibiotics in hamsters.

Tyzzer’s disease: Hunched posture, rough haircoat, diarrhea that is pale and watery. C. piliforme is obligate intracellular, flagellated, spore-former. Variable gross lesions including hepatomegaly and multifocal hepatic necrosis, loss of ileal tone, serosal edema in cecum leading to ileocecal distension, multiple white nodules in the heart. Liver lesions: focal necrosis bordered by PMNs, on silver stain organisms are pick-up sticks in dying hepatocytes. Intestine: distorted mucosal epithelium, inflammation and submucosal edema. Serologic tests are available to pick up subclinical cases. Remove hamsters and clean with bleach as a sporicide, use microisolators.

Salmonella: rare, S. typhimurium and S. enteriditis. Lethargy, rough haircoat, anorexia, weight loss, fast respiratory rate. Gross: pulmonary hemorrhage, multiple small white liver spots, hyperemic lymph nodes. Surprisingly, there is no enteritis. Histo: thrombosis of pulmonary venules by septic emboli (unusual in hamsters), multifocal interstitial pneumonia, hepatic necrosis. Treatment: Eliminate due to zoonosis.

Campylobacter jejuni: no disease, fecal shed for months, zoonosis.

E. coli: varied lesions

Yersinia pseudotuberculosis: caseous nodules in intestine, liver, spleen, lymph nodes and lungs from contaminated bedding or food.

Streptococcus: pneumonia, cervical lymphadenitis, septicemia, mastitis

Respiratory: from strep or Pasteurella.

Mastitis: Strep, Pasteurella, E. coli

Fight wound abscesses: drain, flush, "treat systemically with appropriate antibiotic" although they just told us not to do that.

Mycotic: Microsporum

Hamster Viral Diseases

Few, including adenovirus, Sendai, PVM, LCMV{3988}. There was a recent outbreak of parvovirus causing domed cranium and malformed incisor teeth. The old blue book has a table of most common viral diseases from a 1967 survey; it indicates that, in order, the viral diseases of concern are: PVM, Sendai, SV5, reovirus 3, mouse polio (GDVII), and polyoma virus.{3566} The 2002 edition is different: it says that LCMV, PVM, Reo 3, Sendai, and simian virus 5 (note, this is from the older FELASA recommendations, no known infections) should be monitored serologically. The 2001 FELASA list includes only LCMV and Sendai among the viruses to be monitored. 

LCMV can either be asymptomatic or cause wasting disease in hamsters due to immune complex glomerulonephropathy. Hamsters shed large quantities of virus in the urine for months, a zoonotic risk. The source is often contaminated tumor cell cultures, since hamsters are often used in cancer studies.

Sendai virus causes only subclinical disease in hamsters; it is significant only when hamsters are housed in proximity to mice.{4758}

Adenoviral intranuclear inclusion bodies are reported to have been spotted in the intestinal epithelium of young hamsters. Natural infection with MAd-2 (K87) has been reported, but was asymptomatic.{4758}

Explosive outbreaks of mesenteric lymphoma in young hamsters is diagnostic of infection with hamster polyomavirus. Older hamsters may get multiple epitheliomas in haired skin.{4773}

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Hamster Parasitic Diseases

Hymenolepis nana{3988}, Tritrichomonas muris, Syphacia obvelataand Syphacia muris; mites are Demodex cricetus and D. aurati.{3566}

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Gerbil Diseases{4635}

Bacterial diseases

Viral diseases: none

Parasitic diseases

Peromyscus Diseases{3560}

Parasitic diseases

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Meadow Vole Diseases{3560}

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Rats

Respiratory tract

Consider using rnu rats as sentinels; they are more susceptible to Mycoplasma, Sendai virus and Tyzzer's disease.{4162}

©1999, Janet Becker Rodgers, DVM, MS, DipACLAM, MRCVS

All rights reserved.

Comments? Send an email to janet.rodgers@vet.ox.ac.uk