Incidence of chicken coccidia from broiler houses in Japan, 1973-1977.

A survey was made on the incidence of coccidial oocysts in 11,365 fecal samples from Japanese broiler houses during five years from 1973 to 1977. The Eimerian species were identified by a combination of two methods, examination of oocyst morphology and chicken passage test. Oocysts were detected from 7,526 (66.2%) of the samples tested during five years. Annual variation was statistically significant at the 5% level. Coccidial incidence during July to September (corresponding to summer season) was found to be higher than that of other seasons. With regard to regional variation, incidence found in the north-eastern half of Japan was lower than that in the south-western half. Oocyst detection rate increased up to 40 days of age in chickens and kept plateau thereafter. Eimeria acervulina predominated throughout the years, seasons, regions and age of chickens. Other species of Eimeria were subjected to wide fluctuation while the survey was carried out.