Cell invasion of haplogroup C3.3 T. gondii isolates. (A) Propagation of tachyzoites in HFFs with Wright-Giemsa staining: a, b, c, d, and e represent the growth of tachyzoites in host cells after 2 h, 8 h, 16 h, 24 h and 48 h p.i., respectively. (B) The growth rate of tachyzoites in infected cells. Ba: the cell infection rate at different post infection time points. There was no significant difference in each time point (P > 0.05); Bb: the mean of T. gondii tachyzoites in each infected cell. From the diagram, Wh6 isolate showed a lower growth rate in host cells. *P < 0.01.