Seroprevalence of Entamoeba histolytica infection in female outpatients at a sexually transmitted disease sentinel clinic in Tokyo, Japan.
From 2003 to 2006, we surveyed the seroprevalence of amoebic infection in female outpatients at a gynecologist's office, which was designated as a sexually transmitted disease sentinel clinic by the Tokyo Metropolitan Government, using an enzyme-linked immunosorbent assay (ELISA). The annual rate of anti-Entamoeba histolytica (HM-1:IMSScl6 strain; HM-1) antibody-positive cases as detected by ELISA increased during that period, and anti-Chlamydia trachomatis antibodies were detected in 60%, i.e., 24 of 40 anti-HM-1 antibody-positive individuals, suggesting sexual transmission of E. histolytica. We designed an ELISA with better sensitivity using the antigen extracted from the virulence-augmented E. histolytica strains (LHM-1 and LLA526 strains) by liver-passaging in hamsters. The average ratios of the S/N value (optical density [OD] of sample/OD of negative control) of ELISA with either the LHM-1 or LLA526 antigen and that of ELISA with the HM-1 antigen were significantly higher in intestinal amoebiasis cases with low S/N values than in amoebic liver abscess cases. In the present study of the seroprevalence of E. histolytica infection, the sera testing positive with low S/N values (<10) by ELISA with HM-1 antigen exhibited higher S/N values by ELISA using LHM-1 and LLA526 antigens. This modification of the antigen preparation for ELISA is expected to be effective in detecting anti-E. histolytica antibodies from such asymptomatic patients who have low antibody titers.
Suzuki
Jun
J
Department of Microbiology, Tokyo Metropolitan Institute of Public Health, Tokyo 169-0073, Japan. Jun_Suzuki@member.metro.tokyo.jp
Kobayashi
Seiki
S
Iku
Ise
I
Murata
Rie
R
Yanagawa
Yoshitoki
Y
Takeuchi
Tsutomu
T
D000328:Adult; D000554:Ambulatory Care Facilities; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D004748:Entamoeba histolytica / Q000276:immunology*; D004749:Entamoebiasis / Q000453:epidemiology* / Q000469:parasitology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008875:Middle Aged; D010045:Outpatients / Q000706:statistics & numerical data; D018571:Sentinel Surveillance; D016036:Seroepidemiologic Studies; D012749:Sexually Transmitted Diseases / Q000517:prevention & control
D000913:Antibodies, Protozoan