FIG. 2.

Median hepatic histopathology ranks for mock-infected versus low- or high-passage A. phagocytophilum-infected mice at the time of infection through 21 days postinfection. Higher ranks correspond to higher degrees of severity. The error bars indicate the maximum and minimum ranks for replicate mice in each group at each time. An asterisk indicates that the P value is <0.05, as determined by a Wilcoxon signed-rank test comparing median ranks after reranking at each time. Ap, A. phagocytophilum.