Molecular characterization of double-stranded RNA virus in Trichomonas vaginalis Egyptian isolates and its association with pathogenicity

Abstract

Trichomoniasis is a common human sexually transmitted infection caused by Trichomonas vaginalis. The parasite can be infected with double-stranded RNA viruses (TVV). This viral infection may have important implications on trichomonal virulence and disease pathogenesis. This study aimed to determine the prevalence of T. vaginalis virus among isolates obtained from infected (symptomatic and asymptomatic) women in Ismailia City, Egypt, and to correlate the virus-infected isolates with the clinical manifestations of patients. In addition, the pathogenicity of TVV infected isolates on mice was also evaluated. T. vaginalis isolates were obtained from symptomatic and asymptomatic female patients followed by axenic cultivation in Diamond's TYM medium. The presence of T. vaginalis virus was determined from total extraction of nucleic acids (DNA-RNA) followed by reverse transcriptase-PCR. Representative samples were inoculated intraperitoneally in female albino/BALB mice to assess the pathogenicity of different isolates. A total of 110 women were examined; 40 (36.3 %) samples were positive for T. vaginalis infection. Of these 40 isolates, 8 (20 %) were infected by TVV. Five isolates contained TVV-2 virus species, and the remaining three isolates were infected withTVV-4 variant. A significant association was found between the presence of TVV and particular clinical manifestations of trichomoniasis. Experimental mice infection showed varying degrees of pathogenicity. This is the first report on T. vaginalis infection by TVV in Egypt. The strong association detected between TVV and particular clinical features of trichomoniasis and also the degree of pathogenicity in experimentally infected mice may indicate a possible clinical significance of TVV infection of T. vaginalis isolates.

Trichomonas vaginalis Virus Among Women With Trichomoniasis and Associations With Demographics, Clinical Outcomes, and Metronidazole Resistance

“…Only 1 study had a larger sample size than this study, with 500 TV isolates, of which 250 (50%) were TVV+ [16]. Unlike other STIs, TV infection rates are higher among women 25 years or older [27], compared to other age groups [3]. In this study, we found that TVV positivity was also associated with older age.…”

“…The authors suggested that TVV may have a role in the pathogenesis of trichomoniasis. El-Gayar et al [27] also found a significant association between TVV positivity and clinical manifestations of trichomoniasis among 40 TV-infected women in Egypt. However, the sample sizes of these studies were small and the associations between genital symptoms and TVV+ isolates have not been seen in larger studies, including our present study [28,30,31].…”

The First Detection of Co-Infection of Double-Stranded RNA Virus 1, 2 and 3 in Iranian Isolates of Trichomonas vaginalis

“…PCR was performed using specific primers described before ( 1 , 17 ) in a 25 μL mixture containing the template (3 μL of RT reaction), 2.5 U Taq DNA polymerase, 2.5 μL of 1 x PCR buffer, 20 pmol of each primer, 100 μmol dNTPs and 1.5 mmol MgCl 2 .Amplification was performed as follows: initial denaturing for 5 min at 95°C; 40 cycles of 94°C for 30 s, 51°C for 1 min and 72 °C for 40 s; extension at 72°C for 5 min and finally the PCR products were electrophoresed. Expected bands were found for TVV1 at 569 bp, TVV2 at 625 bp, TVV3 at 438 bp, and TVV4 at 514 bp.…”

Viruses of protozoan parasites and viral therapy: Is the time now right?

“…A correlation between TVV symbiosis with T. vaginalis isolates and the severity of clinical symptoms of trichomoniasis in humans is emerging; while different papers report a positive association between TVV infection and the exacerbation of trichomoniasis symptoms, other authors have shown the absence of any correlation [53]. However, T. vaginalis and its virus appear to have a clear role in the subversion of the innate immune response and inflammation in the human host [54,55]. Although TVV is unable to infect and replicate in human cells [56], its presence can modulate the pro-inflammatory response in the human host, amplifying the innate response, and thus exacerbating clinical symptoms and the severity of disease.…”

“…Problems associated with human (or animal) immune response to the viral administration must of course be evaluated in advance. It is evident that TVV and LRV might be disadvantaged in this specific issue due to their adverse impact on the human immune system [54,55,95].…”