Infertility associated with sub clinical salmonellosis.

Subclinical infection of guinea pigs with isogenic wild type and aroA, htrA and aroA-htrA mutants of Salmonella enterica subspecies enterica serovar Abortusequi (S. Abortusequi) induced infertility, while mutants had little or no effect on conception rate in guinea pigs. Conception rate was significantly lower in guinea pigs inoculated with wild type (S-787) and aroA mutant of S. Abortusequi than those inoculated with intracellular survival deficient htrA or aroA-htrA mutants of S. Abortusequi. Chi-test analysis revealed that none of the three mutants could be attributed to low conception rate, but wild type Salmonella inoculation and chronic carriage of the pathogen were significant cause of low conception rate in guinea pigs. Role of S. Abortusequi in causation of infertility was proven from the experiment for the first time.

Evaluation of guinea pig model for experimental Salmonella serovar Abortusequi infection in reference to infertility.

The present study conclusively revealed the role for Salmonella enterica subspecies enterica serovar Abortusequi in conception failure. None of the 12 guinea pigs conceived when orally exposed to sublethal dose of the pathogen during breeding, while 66.67% of animals in control group were found pregnant during same period of observation under similar conditions. Salmonella carrier animals also had drastic reduction in conception rate (16.67%). During mid pregnancy, S. Abortusequi exposure to guinea pigs through intravaginal, intramuscular and subcutaneous routes induced fetal death followed by resorption. While 2 out of 6 orally inoculated and 3 out of 6 intraperitonially inoculated guinea pigs aborted, in rest of the animals fetal death was followed by meceration and resorption. It was interesting to note that S. Abortusequi could not persist longer than a week in males while in pregnant females it could be detected for >10 weeks after inoculation. In late pregnancy, most of the exposed animals aborted and non aborting animals though had normal parturition, survival rate of their babies was nearly zero in comparison to the control group. The study revealed role for S. Abortusequi in impairing conception, abortion, early fetal deaths, fetal meceration and resorption. Further studies are required to identify factors responsible for increased susceptibility of females particularly during pregnancy.