Eimerian life cycles: the patency of eimeria vermiformis, but not Eimeria pragensis, is subject to host (Mus musculus) influence.

The ability of Eimeria vermiformis and Eimeria pragensis to produce oocysts in primary infections is influenced by host factors. Oocyst production and the duration of patency were determined for each species in: NIH mice, normal or immunosuppressed (by X-irradiation or injection of cortisone acetate), and strains of mice: nu/+, nu/nu; BALB/c, C57BL/6 known (E. vermiformis), or suspected (E. pragensis), to be of contrasting susceptibility to infection. The effect of induced or genetic susceptibility on the reproduction of E. vermiformis resulted in increases in both oocyst production and the duration of patency. Eimeria pragensis was less affected, with smaller increases in the numbers of oocysts produced and no significant prolongation of patency. The implications of these findings with respect to eimerian life cycles are discussed.