Introduction

• Cause: infection with Encephalitozoon cuniculi, a eukaryotic organism belonging to the phylum microsporidia, in the kingdom Fungi. It is an obligate intracellular parasite. This is not a common disease entity in guinea pigs.
• Signs: in spontaneous cases, there may be neurologic or nephritis as occurs in other species. Literature reports often finding it only at necropsy.
• Diagnosis: usually at necropsy with histopathology. Unknown if antemortem testing like in rabbits with protein electrophoresis, serology effective. PCR testing of tissues may be possible.
• Treatment: no reports in the literature; base on rabbit protocol.
• Prognosis: grave.

Pathogenesis

Etiology

• Infection with Encephalitozoon cuniculi, a microsporidian fungi.

Predisposing factors

General

• Possible exposure to shedding rabbits: pet stores frequently will house baby bunnies and baby guinea pigs in the same enclosure.

Specific

• Likely pups are infected at a young age.

Pathophysiology

• Spontaneous infection has been reported.
• The parasite can cause a multifocal granulomatous encephalitis and multifocal lymphocytic interstitial nephritis; this is similar to lesions seen in other species.

Timecourse

• Slow: lesions, signs may not show up until aged, or immunosuppressed.

Epidemiology

• Likely transmitted by ingestion of food or water contaminated with spores, although possibly transplacentally.
• Has been found in a wide variety of mammals: dogs, cats, hamsters, rabbits, guinea pigs, rats, mice, nonhuman primates and humans.
• Baby rabbits and guinea pigs should not be housed in the same enclosure (done at many pet stores).

Diagnosis

Treatment

Prevention

Outcomes