Trichomonas vaginalis Virus: Current Insights and Emerging Perspectives

Abstract

Trichomonas vaginalis, a prevalent sexually transmitted protozoan parasite, is associated with adverse birth outcomes, increased risk of HIV and other sexually transmitted infections, infertility, and cervical cancer. Despite its widespread impact, trichomoniasis remains underdiagnosed and underreported globally. Trichomonas vaginalis virus (TVV), a double-stranded RNA (dsRNA) virus infecting T. vaginalis, could impact T. vaginalis pathogenicity. We provide an overview of TVV, including its genomic structure, transmission, impact on protein expression, role in 5-nitroimidazole drug susceptibility, and clinical significance. TVV is a ~5 kbp dsRNA virus enclosed within a viral capsid closely associated with the Golgi complex and plasma membrane of infected parasites. Hypothetical mechanisms of TVV transmission have been proposed. TVV affects protein expression in T. vaginalis, including cysteine proteases and surface antigens, thus impacting its virulence and ability to evade the immune system. Additionally, TVV may influence the sensitivity of T. vaginalis to treatment; clinical isolates of T. vaginalis not harboring TVV are more likely to be resistant to metronidazole. Clinically, TVV-positive T. vaginalis infections have been associated with a range in severity of genital signs and symptoms. Further research into interactions between T. vaginalis and TVV is essential in improving diagnosis, treatment, and the development of targeted interventions.

Keywords: TVV; Totiviridae; Trichomonas vaginalis virus; Trichomonasvirus; double-stranded RNA virus.

Figure 1

Trichomonas vaginalis virus (TVV) virion and genome. (A) TVV Virion: the dsRNA genome [pink] of TVV enclosed within a viral capsid [green]. (B) TVV Genome: the TVV genome consists of two overlapping open reading frames, GAG [green] and POL [orange], which encode the viral capsid and RdRp, respectively. Abbreviations: RdRp, RNA-dependent RNA polymerase; dsRNA, double-stranded RNA.