The oocyst sporulation time of Eimeria species from the fowl.

Freshly isolated oocysts were sporulated at 29 degrees C with constant aeration. Minimum sporulation time was determined by dosing the developing oocysts at intervals of 1 h to successive groups of chickens to assess the first occurrence of infective forms. Microscopic analysis of the sporulating oocysts allowed calculation of the time required for 50% of the oocysts to complete the process. This was considered to be the most accurate determination and the most useful for comparative purposes. For 7 species of coccidia in the fowl, the 50% sporulation times were as follows: Eimeria acervulina 11.4 h; E. brunetti 38.3 h; E. maxima 38.1 h; E. mivati 19.0 h; E. necatrix 19.7 h; E. praecox 24.8 h; E. tenella 21.2 h.