Human spermatozoa were exposed to concentrations of live Trichomonas vaginalis varying from 10(4) to 10(7) organisms per ml. A striking decrease in spermatozoal motility ensued. The possible role of trichomoniasis in human reproductive failure is considered.
PIP: Trichomonas vaginalis is a flagellated parasite often found as an occult resident of the genital tract of sexually active women. A pure culture of T. vaginalis was isolated from urine and maintained at 37 degrees C by in vitro passage in Diamond's broth. Fresh semen specimens were incubated in .2 ml of serial dilutions of T. vaginalis culture. Spermatozoal motility was observed immediately on mixing and again after 2, 4, and 6 hours of incubation. Marked lessening of spermatozoal activity was observed but no agglutination. The motion of T. vaginalis continued normally. In control samples containing saline or Diamond's broth, only minor retardation of spermatozoal activity was noted during 6 hours of incubation. Filtered Diamond's broth, which prior to filtration had supported a dense concentration of protozoa, when added to equal volumes of fresh human ejaculate caused a similar retardation of spermatozoal activity. It was speculated that some metabolic metabolites of T. vaginalis decrease spermatozoal activity. T. vaginalis should be included among other factors that lead to infertility. In subfertile couples eradication of T. vaginalis may enhance fertility.