The family Totiviridae includes a number of viruses with monosegmented dsRNA genomes and isometric virions that infect either fungi or a number of medically important protozoan parasites such as Leishmania and Giardia. A new genus, Trichomonasvirus, was recently proposed for this family. Its name is based on the genus of its host organism, Trichomonas vaginalis, a protozoan parasite that colonizes the human genitourinary mucosa and is the most common non-viral sexually transmitted infection in the world. The type species of this new genus is Trichomonas vaginalis virus 1. Distinguishing characteristics of the new genus include infection of a human sexually transmitted parasite, stable mixed infection with more than one distinct Trichomonasvirus species, and sequence-based phylogenetic divergence that distinguishes it from all other family members.