Seroprevalence of at a voluntary counselling and testing centre in Tokyo: a cross-sectional study.

Background: Amebiasis, which is caused by , is a re-emerging public health issue owing to sexually transmitted infection (STI) in Japan. However, epidemiological data are quite limited.

Methods: To reveal the relative prevalence of sexually transmitted infection to other STIs, we conducted a cross-sectional study at a voluntary counselling and testing (VCT) centre in Tokyo. Seroprevalence of was assessed according to positivity with an ELISA for -specific IgG in serum samples collected from anonymous VCT clients.

Results: Among 2083 samples, seropositive rate for was 2.64%, which was higher than that for HIV-1 (0.34%, p<0.001) and comparable to that for syphilis (rapid plasma reagin (RPR) 2.11%, p=0.31). Positivity for in urine by transcription-mediated amplification (TMA) was 4.59%. Seropositivity for was high among RPR/ hemagglutination (TPHA)-positive individuals and it was not different between clients with and without other STIs. Both seropositivity of and RPR were high among male clients. The seropositive rate for anti- antibody was positively correlated with age. TMA positivity for urine was high among female clients and negatively correlated with age. Regression analysis identified that male sex, older age and TPHA-positive results are independent risk factors of seropositivity.

Conclusions: Seroprevalence of was 7.9 times higher than that of HIV-1 at a VCT centre in Tokyo, with a tendency to be higher among people at risk for syphilis infection. There is a need for education and specific interventions against this parasite, as a potentially re-emerging pathogen.