influence of toxoplasma gondii infection on male fertility: a pilot study on immunocompetent human volunteers

background: this study was conducted to investigate the influence of toxoplasma gondii infection on spermatic and hormonal parameters in a pilot sample of immunocompe­tent human male subjects. methods: this cross sectional, observational pilot study on 60 immunocompetent hu­man male subjects aged between 18 and 60 yr old was conducted between 2012 -2013. blind evaluation of serological markers of past t. gondii infection (tox-igg, tox-igm) was performed, along with individual spermiograms and determinations of folli­cle-stimulating hormone (fsh) and testosterone serum levels. results: the overall prevalence of past t. gondii infection in the investigated immunocom­petent male subjects was 25%. no statistically significant influence of t. gondii infection on sperm characteristics (ejaculate quantity, sperm count, motility, morphol­ogy) and serum levels of fsh or testosterone were found. among possible predictors of a modified spermiogram studied by multiple logistic regression along with the t. gondii infection (age, smoking, alcohol consumption, fertility influencing malfor­mations, infections, trauma or medication), only the presence of varicocele in the medi­cal history of the studied subjects was found to significantly participate in the predic­tion of a modified spermiogram (p=0.0154). a necessary sample size of 994 subjects was computed in order to achieve a test power of 0.8 (80%) to discriminate an effect size of 8.89% estimated by our pilot study. conclusions: although our investigation did not demonstrate an influence of latent t. gondii infection on spermatic and hormonal parameters of immunocompetent male hu­mans, the absence of such an influence cannot be affirmed, due to the limited sample size of our pilot study.