PAEP and infection: For instance, in the 50-oocyst groups which resulted in 100% infection rate for the four isolates, the peak OPG (log) of IIdA20G1-HB, IIdA20G1-HLJ, IIdA19G1-GD and IIdA19G1-HN were 6.49 ± 0.20, 7.26 ± 0.19, 6.22 ± 0.29 and 5.39 ± 0.40, respectively.