title: Eimeria maxima: a comparison of two laboratory strains with a fresh isolate.
abstract: Oocysts of the Weybridge and Houghton strains of Eimeria maxima and a fresh field isolate were similar and measured on average 30-9 X 22-4 mum. The Weybridge strain and the field isolate produced similar pathogenic effects in 6-week-old chickens, high doses causing 50-80% mortality and severe weight loss. The Houghton strain was slightly less pathogenic and few birds died but more oocysts were produced. With each strain, a single dose gave complete immunity to a light challenge with the homologous strain. Two or 3 immunizing doses gave complete immunity to a heavy homologous challenge but were not sufficient to protect against heterologous challenge.
mesh_terms: D000818:Animals; D001835:Body Weight; D002645:Chickens; D003048:Coccidiosis / Q000276:immunology / Q000469:parasitology / Q000662:veterinary*; D003429:Cross Reactions; D004539:Eimeria / Q000276:immunology / Q000472:pathogenicity / Q000502:physiology*; D005243:Feces / Q000469:parasitology; D011201:Poultry Diseases / Q000276:immunology / Q000469:parasitology; D014774:Virulence