title: Epidemiology of Domestically Acquired Amebiasis in Japan, 2000-2013.
abstract: Notifications of amebiasis have been increasing in Japan. Using national surveillance data during 2000-2013, reported cases of amebiasis were analyzed. A case of amebiasis was defined as laboratory-confirmed Entamoeba histolytica infection, regardless of presence of symptoms. We described temporal trends and analyzed correlates of asymptomatic versus symptomatic cases based on odds ratios (ORs) and 95% confidence intervals (CIs) using logistic regression. Of 9,946 cases reported during 2000-2013, 7,403 were domestic cases. During this period, the proportion of domestic cases increased from 63% to 85%. Among male cases, majority were middle aged, and from 2008, the number of cases attributed to heterosexual contact surpassed that of homosexual contact. During 2010-2013, increase in notifications was associated with asymptomatic cases, colonoscopy diagnosis, and males with unknown or heterosexual route of infection. Among males, colonoscopy (OR = 31.5; 95% CI = 14.0-71.0) and cases with unknown route of infection, relative to homosexual contact (OR = 2.2; 95% CI = 1.3-3.9), were associated with asymptomatic infections in multivariate analysis. Although the recent rise may have been due to enhanced detection by colonoscopy or reporting, the large number of asymptomatic cases, with reportedly unknown or heterosexual route of infection, has led to a better understanding of amebiasis in Japan and highlights the potential public health concern.
authors.affiliation: Field Epidemiology Training Program, National Institute of Infectious Diseases, Tokyo, Japan; Division of Global Infectious Diseases, Department of Infection and Epidemiology, Graduate School of Medicine, Tohoku University, Miyagi, Japan; Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan; Department of Global Infectious Diseases and Tropical Medicine, National Defense Medical College, Saitama, Japan; Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Ishikane
authors.affiliation: Field Epidemiology Training Program, National Institute of Infectious Diseases, Tokyo, Japan; Division of Global Infectious Diseases, Department of Infection and Epidemiology, Graduate School of Medicine, Tohoku University, Miyagi, Japan; Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan; Department of Global Infectious Diseases and Tropical Medicine, National Defense Medical College, Saitama, Japan; Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan arima@niid.go.jp.
authors.forename: Yuzo
authors.initials: Y
authors.lastname: Arima
authors.affiliation: Field Epidemiology Training Program, National Institute of Infectious Diseases, Tokyo, Japan; Division of Global Infectious Diseases, Department of Infection and Epidemiology, Graduate School of Medicine, Tohoku University, Miyagi, Japan; Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan; Department of Global Infectious Diseases and Tropical Medicine, National Defense Medical College, Saitama, Japan; Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Atsuhiro
authors.initials: A
authors.lastname: Kanayama
authors.affiliation: Field Epidemiology Training Program, National Institute of Infectious Diseases, Tokyo, Japan; Division of Global Infectious Diseases, Department of Infection and Epidemiology, Graduate School of Medicine, Tohoku University, Miyagi, Japan; Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan; Department of Global Infectious Diseases and Tropical Medicine, National Defense Medical College, Saitama, Japan; Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Takuri
authors.initials: T
authors.lastname: Takahashi
authors.affiliation: Field Epidemiology Training Program, National Institute of Infectious Diseases, Tokyo, Japan; Division of Global Infectious Diseases, Department of Infection and Epidemiology, Graduate School of Medicine, Tohoku University, Miyagi, Japan; Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan; Department of Global Infectious Diseases and Tropical Medicine, National Defense Medical College, Saitama, Japan; Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Yamagishi
authors.affiliation: Field Epidemiology Training Program, National Institute of Infectious Diseases, Tokyo, Japan; Division of Global Infectious Diseases, Department of Infection and Epidemiology, Graduate School of Medicine, Tohoku University, Miyagi, Japan; Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan; Department of Global Infectious Diseases and Tropical Medicine, National Defense Medical College, Saitama, Japan; Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Yahata
authors.affiliation: Field Epidemiology Training Program, National Institute of Infectious Diseases, Tokyo, Japan; Division of Global Infectious Diseases, Department of Infection and Epidemiology, Graduate School of Medicine, Tohoku University, Miyagi, Japan; Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan; Department of Global Infectious Diseases and Tropical Medicine, National Defense Medical College, Saitama, Japan; Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Tamano
authors.initials: T
authors.lastname: Matsui
authors.affiliation: Field Epidemiology Training Program, National Institute of Infectious Diseases, Tokyo, Japan; Division of Global Infectious Diseases, Department of Infection and Epidemiology, Graduate School of Medicine, Tohoku University, Miyagi, Japan; Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan; Department of Global Infectious Diseases and Tropical Medicine, National Defense Medical College, Saitama, Japan; Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Tomimasa
authors.initials: T
authors.lastname: Sunagawa
authors.affiliation: Field Epidemiology Training Program, National Institute of Infectious Diseases, Tokyo, Japan; Division of Global Infectious Diseases, Department of Infection and Epidemiology, Graduate School of Medicine, Tohoku University, Miyagi, Japan; Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan; Department of Global Infectious Diseases and Tropical Medicine, National Defense Medical College, Saitama, Japan; Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Tomoyoshi
authors.initials: T
authors.lastname: Nozaki
authors.affiliation: Field Epidemiology Training Program, National Institute of Infectious Diseases, Tokyo, Japan; Division of Global Infectious Diseases, Department of Infection and Epidemiology, Graduate School of Medicine, Tohoku University, Miyagi, Japan; Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan; Department of Global Infectious Diseases and Tropical Medicine, National Defense Medical College, Saitama, Japan; Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Oishi
mesh_terms: D000562:Amebiasis / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D016017:Odds Ratio; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors