Trichomoniasis among men presenting to a sexual health clinic in Melbourne, Australia

Keywords: epidemiology, males, partner notification, prevalence, screening, sexual contacts, sexually transmitted infections, sexually transmitted diseases, testing, Trichomonas vaginalis, trichomoniasis.

Trichomoniasis is caused by the protozoan Trichomonas vaginalis (TV) and is one of the most common sexually transmitted infections (STI) globally, although the prevalence can vary with geographical location and age.^1,2 The positivity of TV in women in Australia ranges from 0.4% to 4.8% in urban sexual health clinics,^3–6 and up to 25% in rural Indigenous communities.⁷ Trichomoniasis is not a laboratory notifiable condition in Australia, except in Northern Territory and thus, there are limited surveillance data on trichomoniasis in Australia. The prevalence of trichomoniasis in men is estimated to be much lower, possibly due to the shorter duration of trichomoniasis in men.⁸ However, very few studies have investigated trichomoniasis in men. This study aimed to examine the positivity of trichomoniasis in men attending an urban Australian sexual health clinic to provide more up-to-date data on the epidemiology and positivity of trichomoniasis in men in urban Australia.

This was a retrospective analysis of routinely collected clinical data at the Melbourne Sexual Health Centre (MSHC) between 2 August 2018 and 31 May 2021. MSHC is a public HIV/STI clinic located in the city of Melbourne, Australia. Clients are invited to complete a questionnaire via computer-assisted self-interview (CASI) if they are new to MSHC or have not completed one in the past 3 months. This questionnaire collected demographic characteristics and sexual practices for routine clinical care and management.

In this study, we included cis-gender men aged 18 years and older who were tested for TV between 2 August 2018 and 31 May 2021. Men were generally only tested for TV if they had symptomatic urethritis and tested negative for other STIs such as chlamydia, gonorrhoea and Mycoplasma genitalium at a previous appointment, or if they reported sexual contact with a partner with trichomoniasis (hereafter ‘TV contacts’), as per the Australian STI Guidelines.⁹ Selective testing was also performed based on an individual’s risk profile. First pass urine samples or urethral swabs were collected from men for urethral trichomoniasis testing. All specimens were tested by nucleic acid amplification test (NAAT) using the Aptima Combo-2 (AC2) assay (Hologic Gen-Probe Panther system; Hologic, San Diego, CA, USA). Men who were TV contacts received presumptive treatment on the day of testing before the microbiological results were available, as per the Australian STI Guidelines.⁹ In Australia, the first-line treatment for trichomoniasis is a single dose of 2 g oral metronidazole or tinidazole.⁹

We divided the number of men who tested positive for TV by the total number of men who tested for TV to calculate the test positivity of TV. The 95% confidence intervals (CI) were calculated using the binomial exact method. Fisher’s exact test was used to compare the positivity between men who were TV contacts and men who were not contacts of trichomoniasis (i.e. hereafter ‘non-contacts’). All analyses were conducted in Stata (ver. 14.2; College Station, TX, USA).

Ethics approval was granted by Alfred Hospital Ethics Committee, Melbourne, Australia (341/21). Patient consent was not required for publication.

There were 893 men tested for TV between August 2018 and May 2021 who were included in this study. The median age was 31 years (interquartile range 26–39 years). Of these men, 43 (4.8%) were TV contacts, 386 (43.2%) had a clinical diagnosis of non-gonococcal urethritis on the day of attendance (i.e. individuals who had urethral symptoms but were tested negative for Neisseria gonorrhoeae), and 466 (52.2%) were considered to be at high risk for TV (i.e. men requiring a sex worker certificate, and men experiencing ongoing symptoms after treatment of another STI). There were 12 (1.3%) men who identified as Aboriginal or Torres Strait Islander. Of the 893 men who were tested for TV, 12 (1.3%; 95% CI: 0.7–2.3) tested positive for TV by NAAT. The test positivity of TV among TV contacts (8/43; 18.6%; 95% CI: 8.4–33.4) was significantly higher than non-contacts (4/850; 0.5%; 95% CI: 0.1–1.2) (P < 0.001) (Table 1). All 43 TV contacts reported sexual contact with a female with TV.

Table 1.  Test positivity of Trichomonas vaginalis in men by testing reasons.

A small proportion of men (67/893; 7.5%) reported having sex with both men and women in the past 12 months, no men reported having sex with men only, and none tested positive for TV.

All 12 men who tested positive for TV were men who have sex with women only, and four presented with symptoms. Of men who tested positive for TV, none had concurrent STIs (i.e. gonorrhoea, chlamydia and syphilis). There were eight TV contacts, and they were all asymptomatic upon presentation. Of the four symptomatic men, three men had urethral discharge with the duration of symptoms ranging from 2 weeks to 3 months. One man with urethral discharge also had mild erythema of the meatus. One man reported scrotal discomfort only.

The present study shows that the positivity of TV among men attending an urban sexual health clinic in Melbourne who were selectively tested for TV was low (1%). One-fifth of men who were TV contacts tested positive. Given only 1% of our sample were positive and men were tested because they were considered to be at higher risk of TV, it is likely that the true prevalence of infection among men in Melbourne is very low.

There have been very few studies estimating the positivity of TV in men in urban Australian cities. Bygott and Robson tested samples that sent to a pathology service in south-east Queensland, and they found that the positivity was 0.7% in 7242 men.¹⁰ However, the samples in Bygott and Robson’s study were provided by several clinics, and the reason for testing was not available.¹⁰ A Dutch STI clinic in Amsterdam also reported a low positivity of TV in men (0.5%) in 2004, and the positivity of TV in heterosexual men (6/526; 1.1%) was similar to our study.¹¹ A 2018 US study analysed samples collected from STI clinics in Alabama reported a positivity of 6.1% by NAAT in 12 604 men.¹² The higher positivity could be due to the large proportion of samples (72.6%) collected from African American men, who are at a higher risk of TV.¹³ The positivity of TV was 6.7% in Indigenous men living in remote Australian communities.¹⁴ This confirms previous findings that trichomoniasis disproportionately affects disadvantaged populations in high income countries. These populations may have limited access to sexual health services; and therefore, interventions such as targeted outreach programs, online STI test request, online pathology request forms in these communities may increase access to testing and treatment.^15,16

The positivity among TV contacts was substantially higher than non-contacts. A US prospective study reported that the positivity of TV among male partners of women with trichomoniasis presenting to STI clinics was 72%.¹⁷ The higher positivity in the US study was presumably because the women of all male contacts were confirmed with laboratory results but the male contacts in our study were self-reported. This highlights the importance of partner notification. An online partner notification service named ‘Let Them Know’ was introduced in 2008 in Australia.¹⁸ Individuals who are diagnosed with an STI can contact their partners anonymously via text message or email. The number of text messages sent for TV has increased from 173 in 2011 to 629 in 2019 (a 264% increase) and 64% of the individuals with TV expressed they would like to use this online service to let their partner know.¹⁹

Historically, wet mount microscopy was used for TV diagnosis and this method is still widely used in many resource-limited settings.²⁰ Wet mount microscopy has a high specificity, but it has a poor sensitivity of 23–60% when compared with NAAT.^10,20–22 Although NAAT is a highly sensitive diagnostic method for TV, the equipment is expensive, and it may only be limited to high-resource settings.

This study has several limitations. First, this study was conducted at an urban sexual health clinic. It is possible that individuals with symptoms and reporting sexual contact with partners with an STI are more likely to attend a sexual health service; thus, our findings may not be generalisable to the wider Australian population, particularly in locations with a higher prevalence of trichomoniasis. Second, we were unable to examine the risk factors associated with trichomoniasis in men due to the small number of cases (n = 12).

To conclude, the positivity of TV in men attending a sexual health clinic in Australia was low. However, one fifth of men who were TV contacts tested positive. The high positivity among male TV contacts highlights the importance of partner notification, testing and management.

All data relevant to the study are included in the article.

CKF is the Editor-in-Chief of Sexual Health and EPFC is a Joint Editor of Sexual Health, but they were blinded from the peer review process for this paper. All other authors declared no conflicts of interest.

EPFC is supported by an Australian National Health and Medical Research Council (NHMRC) Emerging Leadership Investigator Grant (GNT1172873). CKF is supported by an Australian NHMRC Leadership Investigator Grant (GNT1172900).

EA, TRP and EPFC conceived and designed the study. EA performed chart review, data analyses and wrote the first draft of the manuscript. CKF, ETA, CSB, MYC, TRP and EPFC assisted with data interpretation. All authors revised the manuscript for intellectual content and approved the final version of the manuscript. The corresponding author had full access to all the data in the study and had final responsibility for the decision to submit for publication.