Fecal occult blood manifestation of intestinal Eimeria spp. infection in rabbit.

The relationship between oocysts production and fecal occult blood manifestation was studied in rabbits experimentally infected with a single species of Eimeria. Pure single Eimeria species infection in non-infected rabbits for 6 species of Eimeria, namely: Eimeria media, Eimeria magna, Eimeria perforans, Eimeria coecicola, Eimeria piriformis, and Eimeria exigua were produced using a single oocyst. Fecal samples from these single Eimeria species infected rabbits were collected daily from day 1 through day 23 post-infection (DPI) to observe for oocysts shedding and also to test for presence of fecal occult blood (FOB). Rabbits infected with E. perforans were positive for FOB test (FOBT) reaction when their OPG exceeded 2.2x105 at 11 and 12 DPI. FOBT positive reactions were also seen in naturally infected rabbits with concurrent infections, of E. perforans and E. media as well as of E. perforans and E. magna. Thus, E. perforans was observed to cause intestinal hemorrhage during the period of massive oocyst shedding. This phenomenon was not seen in the other Eimeria species that we had examined. This is also the first report on the association of E. perforans infection with intestinal hemorrhage in rabbit.