The coccidian parasite Eimeria is among the most common pathogens infecting pet rabbits. Fifteen separate species infect rabbits: Eimeria stiedai, which resides in the liver and biliary tract, and 14 intestinal species. Concurrent infection with multiple intestinal species can occur in rabbits and probably exacerbates clinical signs such as diarrhea, dehydration, anorexia, and malnutrition. The current study aims to describe the relationship between oocyst shedding and fecal occult blood (FOB) in rabbits infected with 1 of 6 intestinal Eimeria species. Three rabbits each were infected with oocysts of E media, E magna, E perforans, E coecicola, E piriformis, or E exigua. Fecal samples were collected daily, and infected rabbits were monitored for oocyst shedding and FOB. Light diarrhea was observed from several infected animals. Of the 6 Eimeria species identified, only E perforans had a positive result on the FOB test in infected animals. These results were seen on days 11 to 12 after infection and coincided with the peak oocyst shedding (> 2.2 × 105 oocysts/g feces). Two rabbits with concurrent natural infections of E perforans and either E media or E magna were also examined; they showed a positive FOB result even with lower levels of oocyst shedding (1.6–1.75 × 105 oocysts/g).

COMMENTARY:
This report appears to be the first documented case of intestinal hemorrhage in rabbits due to Eimeria infection. The data suggest that E perforans is the most virulent intestinal Eimeria species infecting rabbits. This report also shows that the FOB test can be used to monitor intestinal pathology in Eimeria-infected rabbits. However, further research is needed to determine the extent of intestinal hemorrhage occurring with E perforans and the reliability of the FOB test in rabbits.—Carly Jordan, PhD candidate (parasitology/cellular biology)

Fecal occult blood manifestation of intestinal Eimeria spp infection in rabbit. Li MH, Ooi HK. VET PARASITOL 161:327-329, 2009.