Trichomonas vaginalis, Genetic Variation, and Pathogenicity: a Systematic Review

Patricia Abreu Pinheiro de Lemos, Waldemar Naves do Amaral

Trichomoniasis is a sexually transmitted infection that has been associated with acquired immunodeficiency syndrome and cervical cancer. The objective of the present study was to conduct a systematic review of the literature to identify the genetic variations of Trichomonas vaginalis and their correlations with the vaginal environment in the human host. Two electronic databases, PubMed and the Virtual Health Library (Biblioteca Virtual de Saúde), were searched using Medical Subject Headings (MeSH) and Health Sciences Descriptors (DeCS), respectively. The terms “T. vaginalis and genetic variation” and “T. vaginalis and oxidative stress” were searched to identify relevant original articles. The inclusion and exclusion criteria established took into consideration the specific characteristics of each article, thus guaranteeing the quality of the papers selected (the first and second tests of relevance). Two principal types of population structure of T. vaginalis were reported in the papers: type 1 and type 2. Type 1 parasites were associated with pathogenicity, as shown by findings of increased viral loads in human immunodeficiency virus (HIV)-positive women.