Association of Trichomonas vaginalis and Cytological Abnormalities of the Cervix in Low Risk Women

Objective: Is Trichomonas vaginalis (TV) an inducing factor for the development of (pre-)cancerous lesions of the cervix? Design: Cross sectional study. Setting: Screening healthy Belgian women with low infection risk. Sample: 63,251 consecutive liquid based cervical samples. Methods: Real time quantitative PCR for presence of TV, 18 HPV types and Pap smear analysis of cytologic abnormalities. Main Outcome Measures: Association of TV and HPV with cervix dysplasia Results: The overall prevalence of TV DNA was 0.37%, of low risk HPV 2%, of high risk HPV 13.2%, and 8.8 % had cytological abnormalities. Both LR-HPV and HR-HPV were significantly associated with all cytological abnormalities. Presence of TV was associated with LR- and HR-HPV, ASC-US and HSIL, but not with other abnormalities. All women with TV and HSIL also had HR-HPV, while the latter was present in only 59% of women with TV and ASCUS. Amongst HPV negative women, TV was found in 1.3% of women with ASC-US, but only in 0.03% of women with normal cytology (OR 4.2, CL95% 2.1-8.6). In HR-HPV positive women, presence of TV increased the likelihood of cytological abnormalities somewhat (P=0.05), mainly due to an increase in ASC-US and LSIL, but not HSIL. Conclusions: We conclude that TV infection is associated with both LR and HR-HPV infection of the cervix, as well as with ASC-US and HSIL. TV is a concomitant STI, but is not thought to be a co-factor in the causation of HSIL and cervical cancer. However, TV may cause false positive diagnoses of ASC-US.