Is there a seasonal difference in the detection of Trichomonas vaginalis by cervical cytology?

This objective of our study was to determine the prevalence of a Trichomonas vaginalis diagnosis in routine Papanicolaou smears and whether it is seasonal. We reviewed the diagnosis rendered for 93,681 Papanicolaou smears evaluated at a medical school hospital laboratory between 1992 and 1997. The occurrence of a diagnosis of T. vaginalis was analyzed by year, by quarter, and by month using a generalized linear regression model. The prevalence of a T. vaginalis diagnosis during the 6-year study period was 3.1%. The between-month and between-quarter comparisons of prevalence were not statistically different. In the population reported here, the prevalence of a Papanicolaou smear diagnosis of T. vaginalis was low and no seasonal difference in making this diagnosis was identified.