Trichomonas vaginalis: Pathogenesis, Symbiont Interactions, and Host Cell Immune Responses

The parasite Trichomonas vaginalis(Tv) causes a highly prevalent sexually transmitted infection. As an extracellular pathogen, the parasitemediates adherence to epithelial cells to colonize the human host. In addition, the parasiteinterfaces with the host immune system and the vaginalmicrobiota. Modes of Tv pathogenesis include damage to host tissue mediated by parasitekilling of host cells, disruptionof steady-state vaginal microbial ecology, and eliciting inflammation by activating the host immune response. Recent Tv research has uncovered new players that contribute to multifactorial mechanisms of host– parasiteadherence and killing, and has examined the relationship between Tv and vaginalbacteria. Mechanisms that may lead to parasiterecognition and killing, or the evasion of host immune cells, have also been revealed.