Etiology:  Clostridium piliforme is a Gram-negative, spore-forming, obligate intracellular bacterium.

Incidence:  The incidence of disease is rare and occurs in young or recently weaned guinea pigs as a result of an abrupt change in diet, antibiotic therapy, immunosuppressive therapy or environmental stressors.

Transmission:  The disease is spread by spore ingestion (fecal-oral route).

Clinical Signs:  In acute clinical disease, profuse watery brown diarrhea, dehydration and death within 12 to 48 hours after onset of diarrhea are typical.  The mortality rate is high.  Subclinical infections have also been noted to occur [2].

Pathology:  In acute disease, the cecum contains fluid brown contents with occasional serosal edema and hemorrhages.  Multifocal to segmental necrotizing enteritis extends from the ileum to the proximal colon.  Organisms are present in enterocytes and the tunica muscularis, which can be demonstrated using silver stains.  Pinpoint white foci on and within the liver may or may not be present and correspond histologically to coagulative necrosis with peripheral neutrophilic infiltrates.  There may be white myocardial streaks which histologically correspond to necrosis with a pyogranulomatous inflammatory response.  Histologically, there is granulomatous typhlitis with the presence of bacteria in enterocytes.  Liver granulomas may also be present.

Diagnosis:  PCR of feces, intestinal tissue or liver can be used to document the presence of the bacterium.  Serologic tests can be used for diagnosis but are best used for health monitoring purposes.  Histopathologic examination of liver or cecum stained with silver stain can be used to confirm diagnosis; however, organisms are often difficult to demonstrate.

2.            The Laboratory Rabbit, Guinea Pig, Hamster, And Other Rodents. 1 ed2012, 225 Wyman Street, Waltham, MA 02451: Elsevier.