Clinical Isolates of Trichomonas vaginalis Concurrently Infected by Strains of Up to Four Trichomonasvirus Species (Family Totiviridae)

Abstract

Trichomonas vaginalis, which causes the most common nonviral sexually transmitted disease worldwide, is itself commonly infected by nonsegmented double-stranded RNA (dsRNA) viruses from the genus Trichomonasvirus, family Totiviridae. To date, cDNA sequences of one or more strains of each of three trichomonasvirus species have been reported, and gel electrophoresis showing several different dsRNA molecules obtained from a few T. vaginalis isolates has suggested that more than one virus strain might concurrently infect the same parasite cell. Here, we report the complete cDNA sequences of 3 trichomonasvirus strains, one from each of the 3 known species, infecting a single, agar-cloned clinical isolate of T. vaginalis, confirming the natural capacity for concurrent (in this case, triple) infections in this system. We furthermore report the complete cDNA sequences of 11 additional trichomonasvirus strains, from 4 other clinical isolates of T. vaginalis. These additional strains represent the three known trichomonasvirus species, as well as a newly identified fourth species. Moreover, 2 of these other T. vaginalis isolates are concurrently infected by strains of all 4 trichomonasvirus species (i.e., quadruple infections). In sum, the full-length cDNA sequences of these 14 new trichomonasviruses greatly expand the existing data set for members of this genus and substantiate our understanding of their genome organizations, protein-coding and replication signals, diversity, and phylogenetics. The complexity of this virus-host system is greater than has been previously well recognized and suggests a number of important questions relating to the pathogenesis and disease outcomes of T. vaginalis infections of the human genital mucosa.

Genetic diversity studies of Papaya meleira virus

“…The identity values among PMeV isolates are close to those observed in a similar study comprising RdRp from nineteen isolates belonging to four possible species of Trichomonas vaginalis virus (TvV-1 to 4), which determined that the level of identity ranged from 82 to 94%, depending on the virus specie (Goodman et al, 2011). In another study with TvV isolates from Cuba, it was found that the conservation in the aa sequence of RdRp was of 81 to 85% (Fraga et al, 2012).…”

Do persistent RNA viruses fit the trade-off hypothesis of virulence evolution?

“…Up to four different species of viruses (TVVs) can infect T. vaginalis simultaneously [17], and this raises questions regarding competition, recombination and packaging of virus particles that still need to be investigated. TVVs induce phenotypic plasticity in the surface immunogen P270, which could lead to evasion of the mammalian immune response (reviewed in [18]).…”

Unexplained Infertility Caused by a Latent but Serious Intruder: Trichomonas vaginalis?

“…Also, T. vaginalis carries viruses and other parasites, such as mycoplasma and gardenella, causing chronic mucosal damage and an inflammatory reaction which gives rise to severe consequences in reproductive outcomes [21][22][23][24]. Goodman et al [24] reported the presence of a Totiviridae viral family, which is a virus with a doubled stranded RNA that concurrently, is infecting the T. vaginalis parasite [24][25][26]. Infection of T. vaginalis by such a virus increases severely the immunological genesis of trichomona virulent factors by changes in its genome organization, protein coding, and replication signals.…”

“…Infection of T. vaginalis by such a virus increases severely the immunological genesis of trichomona virulent factors by changes in its genome organization, protein coding, and replication signals. Trichomona virus increases the recurrence of the parasite infection and resistance to the metronidazole treatment [7,24,[27][28][29]. Several reports punctuate the serious and detrimental outcome of trichomoniasis in pregnancy but exists a gap of knowledge in the correlation of T. vaginalis infection with unexplained infertility in humans.…”