Characterization of Eimeria brunetti Isolated from a Poultry Farm in Japan

None of anticoccidial vaccines (Trivalent TAM (TM), monovalent Neca (TM) and imported pentavalent Paracox (R)-5) contain Eimeria brunetti in Japan, which has not been regarded as a cause of coccidiosis, because of its low prevalence. However, we have recently reported the evidence of a high nationwide prevalence of this species. In this report, we describe the characteristics of E. brunetti which have never been clearly defined in Japan. Mortality rates and other disease characteristics caused by our strain (Nb strain) were similar to those reported previously in other studies. Despite great reduction of body weight gains among groups infected with over 1 x 10(3) oocysts, the intestinal lesions in the infected chickens were rather mild compared to previous studies. Sulfa drugs and lasalocid were so effective that the E. brunetti infection was almost completely blocked. Consequently, it is suggested that the characteristics of E. brunetti are various among the strains, but the pathogenicity of the Japanese Nb strain is enough strong to cause clinical coccidiosis.