AbstractsBiology & Animal Science

By the term coccidiosis we imply an infection with one or more of the several species belonging to the order Coccidia, a subdivision of the class Sporozoa whose members are parasitic forms reproducing typically by schizogony and which give rise to sporozoites enclosed in a resistant oocyst after syngamy has occurred. The seven species of coccidia occurring in the domestic chicken are all members of the genus Eimeria, a genus characterized by the formation of four sporoblasts within the oocyst and by the ultimate development of two sporozoites within each sporoblast in the infective stage. While the oocysts of each species differ in respect to shape, size and sporulation time it is most difficult, as pointed out by Becker (1934), to distinguish the species on the basis of oocyst characteristics alone. One should also take into consideration the location of the parasite in the intestine, the position of the parasite in the intestinal mucosa, the prepatent period and the macroscopic lesions. The problem of identifying species is further complicated by the possibility, of the occurrence of multiple species in a single host species. [...] Various experiments have, therefore, been conducted with the hope that the results obtained will contribute towards the solution of this controversial problem regarding the pathogenicity of Eimeria acervulina.