In a recent letter Oakeshott 1 cited the lack of data on the prevalence of Trichomonas vaginalis (TV) in young women in the UK. In their own pilot study of 183 stored self -taken vaginal samples from multi-ethnic London female students in age group of 16-27, 2 (1.1%, 95% CI 0.1%-3.9%) were positive by an in house multiplex real-time PCR test. We in Macclesfield, UK, recently conducted a prospective pilot study to gain female positivity data with the use of a Nucleic acid amplification test (NAAT), the Gen-Probe Aptima TV assay (ATV) in three different clinical settings - community clinics, genitourinary (GU) medicine clinic and its satellite prison GU medicine service2. All women at the three different settings were offered an ATV test on the residual portions of the Aptima transport medium from any vulvovaginal swabs or first catch urine samples that had been collected for a routine Aptima Combo 2 Chlamydia/Gonorrhoea test. Women below the age of 16 were excluded. Positivity rates at community clinics and GU medicine, were respectively 0/382 (0%) and 3/358 (0.8%, CI 0% - 1.7%). Positivity was significantly higher, 29/269 (10.8%, CI 7.1% - 14.5%) - Odds Ratio 14.3 (4.11 < OR < 59.55) - in those tested at the prison. This compares to overall chlamydia positivity rates of 4.6% in the community, 6.3% in GU medicine and 5.3% in the prison and overall gonorrhoea positivity rates of 0.09%, 0.2% and 0.2% respectively.

For the 32 ATV positive women, the mean age was 30.6 (range 19 to 48) years, 27 were White British/Irish, 2 Chinese and 3 were of Black African origin, 9 (28%) were symptomatic and 3/32 (9.4%) had concomitant chlamydia. No woman had concomitant gonorrhoea. We also conducted a questionnaire survey of English GU medicine clinics and obtained data from the United Kingdom Health Protection agency (HPA) for England. Both demonstrated the large variation in case rates by region and testing methods employed. Higher rates were seen in women, in prison GUM services and in London GUM clinics. Perry et al3 in a recent ongoing study in a London GUM clinic using the ATV assay on residual routine samples taken for CT /GC in women found a positivity rate of 11.8% (36/305, age range for both men and women 24-39 years ), 81% of whom were symptomatic. They concluded that ATV improved clinical detection by 33% over wet mount microscopy and did not reveal as many missed diagnoses as predicted. They speculated that this was because the majority were symptomatic and that the ATV assay may have more important role in community based screening of asymptomatic women or men.

Consideration of current standards of care may mean more tests should be offered to a wider population. Monitoring positivity in defined patient groups where the test might be introduced should lead to cost- effective application and also help to clarify the levels of asymptomatic carriage. Use of the new CE marked ATV assay in some populations is warranted so as to lead to proper detection and treatment of TV and also possibly the prevention of other co-transmitted infections, such as HIV. REFERENCES 1. Oakeshott P, Ahmed J, Hay PE et al. Trichomonas vaginalis among multi- ethnic female UK students. Sex Trans Infect 2011;doi:10.2236/sextrans-2011 -050061 2. Mahto M, Evans-Jones J, Zia S et al Finding cases of Trichomonas vaginalis infection in England. International Journal of STD and AIDS 2011;22:471-473 3. Perry M, Benzie A, Erasmus K et al Clinical utility of a nucleic acid amplification test for Trichomonas vaginalis in a targeted urban genitourinary medicine clinic population. Oral Presentation, British Association for Sexual Health and HIV (BASHH) Spring Meeting, Gateshead, 11th-13th May 2011.

Conflict of Interest:

None declared