Seroprevalence ofEntamoeba histolyticaat a voluntary counselling and testing centre in Tokyo: a cross-sectional study

Abstract

BackgroundAmebiasis, which is caused byEntamoeba histolytica, is a re-emerging public health issue owing to sexually transmitted infection (STI) in Japan. However, epidemiological data are quite limited.MethodsTo reveal the relative prevalence of sexually transmittedE. histolyticainfection to other STIs, we conducted a cross-sectional study at a voluntary counselling and testing (VCT) centre in Tokyo. Seroprevalence ofE. histolyticawas assessed according to positivity with an ELISA forE. histolytica-specific IgG in serum samples collected from anonymous VCT clients.ResultsAmong 2083 samples, seropositive rate forE. histolyticawas 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 forChlamydia trachomatisin urine by transcription-mediated amplification (TMA) was 4.59%. Seropositivity forE. histolyticawas high among RPR/Treponema pallidumhemagglutination (TPHA)-positive individuals and it was not different between clients with and without other STIs. Both seropositivity ofE. histolyticaand RPR were high among male clients. The seropositive rate for anti-E. histolyticaantibody was positively correlated with age. TMA positivity for urineC. trachomatiswas 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 ofE. histolyticaseropositivity.ConclusionsSeroprevalence ofE. histolyticawas 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.

Identification of asymptomatic Entamoeba histolytica infection by a serological screening test: A cross-sectional study of an HIV-negative men who have sex with men cohort in Japan

“…histolytica infection was performed for HIV-negative MSM individuals. The overall seropositivity (6.7%) was between that found in HIV-positive individuals (21.3%) [ 12 ] and that at a voluntary counselling and testing centre in Tokyo (2.6%) [ 13 ], even though no participants had a previous treatment history of E . histolytica infection at inclusion.…”

“…histolytica are asymptomatic [ 11 ]. Indeed, seroprevalence data has shown that asymptomatic infection occurs among sexually active individuals [ 12 , 13 ] who act as a reservoir for sexual transmission. Polymerase chain reaction (PCR) using stool samples is the best method for detecting E .…”

British Association of Sexual Health and HIV (BASHH) United Kingdom national guideline for the management of sexually transmitted enteric infections 2023

“…S. flexneri, S. sonnei, C. jejuni, C. coli , STEC and S. Typhi can be sexually transmitted 1,80–82 The protozoan infection, E. histolytica can cause proctocolitis and is sexually transmissible. 29,32,51,83–87 Most cases of sexually transmitted proctocolitis are self-limiting but some may develop severe dysentery, and sepsis. 88…”

“…E. histolytica can be sexually transmitted in MSM (particularly in MSM living with HIV), and in heterosexual men and women. 27,29,31,32,51,83–87,143–146 E. histolytica causes a procto-colitis (and rarely distal ileitis) and can be complicated by liver abscess formation. 26,147,148…”

Multiple colon ulcers in a patient with HIV: Do not forget amoebiasis

“…Polymerase chain reaction tests were positive for Entamoeba histolytica in stool, and for CMV in colon tissue.Compared with CMV colitis, invasive amoebic colitis is rare, and was detected in only 1.3% of patients with HIV with CD4 + T cell counts <50/mL (Blanshard et al, 1996). Recent studies from Japan have shown the seropositivity rate for E. histolytica to be low among volunteers (2.64%), but much higher among patients with HIV (28.3%) (Yanagawa et al, 2016(Yanagawa et al, , 2020. As gastroenteritis in patients with HIV typically results from multiple pathogens,…”