BackgroundHuman papillomavirus (HPV), Epstein-Barr virus (EBV) and herpes simplex virus (HSV) cause sexually transmitted diseases (STDs) that are frequently found in men who have sex with men (MSM) with human immunodeficiency viral (HIV) infection.MethodsThis study investigated the prevalence of infection and anatomical site distribution of these viruses in asymptomatic MSM. DNA, extracted from cells collected from the anorectum, oropharynx and urethra of 346 participants, was investigated for the presence of EBV, HPV and HSV using real-time PCR. Demographic data from the participants were analyzed.ResultsAll three viruses were found in all sampled sites. EBV was the commonest virus, being detected in the anorectum (47.7% of participants), oropharynx (50.6%) and urethra (45.6%). HPV and HSV were found in 43.9% and 2.9% of anorectum samples, 13.8% and 3.8% of oropharynx samples and 25.7% and 2% of urethra samples, respectively. HPV infection of the anorectum was significantly associated with age groups 21–30 (odds = 3.043, 95% CI = 1.643–5.638 and P = 0.001) and 46–60 years (odds = 2.679, 95% CI = 1.406–5.101 and P = 0.03). EBV infection of the urethra was significantly correlated with age group 21–30 years (odds = 1.790, 95% CI = 1.010–3.173 and P = 0.046). EBV/HPV co-infection of the anorectum (odds = 3.211, 95% CI = 1.271–8.110, P = 0.014) and urethra (odds = 2.816, 95% CI = 1.024–7.740, P = 0.045) was also associated with this age group. Among HIV-positive MSM, there was a significant association between age-group (odds = 21.000, 95% CI = 1.777–248.103, P = 0.016) in HPV infection of the anorectum. A failure to use condoms was significantly associated with HPV infection of the anorectum (odds = 4.095, 95% CI = 1.404–11.943, P = 0.010) and urethra (odds = 7.187, 95% CI = 1.385–37.306, P = 0.019). Similarly, lack of condom use was significantly associated with EBV infection of the urethra (odds = 7.368, 95% CI = 1.580–34.371, P = 0.011).ConclusionThese results indicate that asymptomatic MSM in Northeast Thailand form a potential reservoir for transmission of STDs, and in particular for these viruses.Electronic supplementary materialThe online version of this article (10.1186/s12879-018-3406-0) contains supplementary material, which is available to authorized users.

Chlamydia trachomatis is a common agent of sexually transmitted infection, especially in asymptomatic extra-genital sites among men who have sex with men (MSM). This study aims to investigate anatomical site distribution and genotypes of C. trachomatis from asymptomatic MSM in northeast Thailand. Specimens were collected using swabs from anorectal, oropharyngeal, and urethral sites in 346 asymptomatic MSM. C. trachomatis infection was determined by real-time polymerase chain reaction and genotyping was based on sequences of the ompA gene. The results showed that infection by C. trachomatis was most common at the urethral site (29.1%, 101/346) followed by oropharyngeal (17.6%, 61/346) and anorectal site (17.0%, 59/346). In addition, C. trachomatis infection was significantly associated with absence of condom use (odds ratio = 1.909, 95%CI = 1.054-3.457, P = 0.033) at the urethral site. Overall 49.4% (171/346) of individuals were infected in at least one site. Infection at only the anorectum, oropharynx, or urethra was seen in 9.0, 9.3, and 18.5% of participants, respectively. Concurrent infections at anorectum/oropharynx, anorectum/urethra, oropharynx/urethra, and all three sites were 2.0, 4.3, 4.6, and 1.7%, respectively. Genotype D predominated at the anorectal and urethral sites among asymptomatic MSM in northeast Thailand. Concurrent infection in two or three anatomical sites occurred. C. trachomatis screening at all three sites in asymptomatic MSM is important and should be considered for proper treatment and prevention of transmission.