Development of long-lasting hydrosalpinx in CBA/J but not A/J mice following C. muridarum infection. Both CBA/J (n = 10) and A/J (n = 10) mice were intravaginally infected with 2 × 105 IFUs of C. muridarum, and 60 days after infection all mice were sacrificed for observing hydrosalpinx. (A) Images of whole genital tracts from all 20 mice are presented in the left columns (a to j for CBA/J, k to t for A/J) with vagina on the left and oviduct/ovary on the right sides. The images for areas covering the oviduct/ovary portions were magnified and are shown to the right of the corresponding whole-genital-tract images, with hydrosalpinx marked with red arrows and hydrosalpinx severity scores indicated in white numbers. (B) The hydrosalpinx severity scores and incidence rates (data not shown) are listed along the y axis. Mice with hydrosalpinx in either or both oviducts were considered positive for hydrosalpinx. The severity of both hydrosalpinges from a given mouse was scored separately and added together as the severity score assigned to the particular mouse. Note that A/J mice failed to develop any significant hydrosalpinx, with both hydrosalpinx incidence (a, Fisher's exact test) and severity (b, Wilcoxon rank-sum test) significantly lower than those of CBA/J mice (**, P < 0.01 for both).