Rat enteric coccidia

Etiology: Eimeria nieschlzi and E. seperata are coccidia infecting rats.

Incidence:  Incidence of infection is rare in laboratory rats.

Transmission:  Fecal-oral transmission occurs via ingestion of sporulated oocysts.  Oocysts require 1-3 days in an oxygenated atmosphere to sporulate.


E. nieschlzi – small intestine

E. seperata – cecum, colon

Clinical Signs:  Clinical signs range from none to enteritis which results in anorexia, diarrhea and sometimes death.  Eimeria are often part of a multifactorial disease and primarily affect young animals.

Relative pathogenicity:

E. nieschulzi > E. seperata

Diagnosis:  Diagnosis is made by performing fecal flotation.  Oocysts must be sporulated to speciate. Induce sporulation with time in a moist, oxygenated atmosphere or with 2.5% potassium dichromate solution.

Diagnostic Morphology:

E. nieschlzi: 16-26 x 13-21µm, tapered, with 1 polar granule. No residuum or micropyle.

E. seperata: 10-19 x 10-17 µm with 1-3 polar granules. No residuum or micropyle.

Rat enteric coccidia