Document Type
Article
Publication Title
American Journal of Tropical Medicine and Hygeine
Abstract
The seroprevalence and incidence of hepatitis A, B, C, and E virus infection were determined among North American missionaries (n = 328) serving in various geographic locations between 1967 and 1984. The mean age of subjects at entry into the study was 39.7 years (range 5-73 years); 65% were female; 89% had lived outside the United States before the study began. Seventy-eight percent of subjects served in sub-Saharan Africa during the study. At initial evaluation, 50.9% of the subjects had antibodies to hepatitis A virus (total anti-HAV), 8.5% to hepatitis B virus core antigen (total anti-HBc), 0.6% to hepatitis C virus (total anti-HCV by second-generation immunoblot assay), and 0% to hepatitis E virus (IgG anti-HEV). After an average period of service of 7.3 years (2,396 person-years total), 5.8% of the missionaries seroconverted to anti-HAV, 5.5% to anti-HBc, 0.6% to anti-HCV, and 0% to anti-HEV. This study indicates a relatively low risk of hepatitis C and E virus infection among missionaries while confirming the previously reported high risk of hepatitis A and B virus infection. Hepatitis A and B vaccination is recommended for long-term travelers to developing countries. Viral hepatitis A and B have long been recognized as a major risk for North American missionaries working in de veloping countries, with rates of infection more than three times that of Peace Corps volunteers.'~* This increased risk is believed to be related to missionaries' frequent exposure to unsafe water supplies, tendency to eat locally prepared foods, use of local health care facilities, and the lack of use of passive and active immunization.1-5 No study to date has examined the risk of other viral causes of hepatitis among missionaries, although the recent development of serologie tests for hepatitis C and E makes such investigations possi ble. Hepatitis C virus (HCV) primarily is transmitted by parenteral exposure; sexual transmission appears to be a less common cause of infection.6 Missionaries would most likely be exposed to HCV infection through blood transfusions or contaminated medical instruments. In contrast, hepatitis E virus (HEV) is enterically transmitted, like hepatitis A virus, and has been associated with large outbreaks from contam inated water supplies.7-8 Recent reports of travelers contract ing sporadic HEV infection after visiting developing coun tries indicate an increased risk of this viral infection among missionaries and other groups working for extended periods in endemic regions.9 The objective of this study was to de termine the risk of hepatitis A, B, C and E virus infection among North American missionaries serving in developing countries. MATERIALS AND METHODS The study was conducted using previously banked sera from missionaries who had blood drawn during medical ex aminations between 1967 and 1984.' Dr. J. D. Frame pro vided medical support and health evaluation services for many North American missions during this time period. He typically performed medical screening of missionary candi dates prior to their assignment overseas and on an interim basis between assignments. Blood samples were generally drawn on a routine basis at these examinations; however, approximately 5% of examinations were conducted for emergency medical purposes when missionaries returned home ill. Medical and demographic information, as well as countries of service, were updated at each examination. The clinical records for this cohort previously had been purged and only the demographic data were available for use in this study. Approximately 50% of the serum samples originally collected were depleted or damaged during the years of stor age; therefore, only sera from persons for whom at least two samples were available were evaluated. Laboratory methods. Serum was continuously stored at —30°Cbeginning in 1967, although freezer malfunctions were noted once in 1989 and once in 1992. Between two and five samples were available for each subject, providing a total of 742 samples. The following strategy was used for hepatitis A, B. and C testing. The most recent sample for each subject was test ed first. If this sample was reactive, then the oldest sample was tested. If the oldest sample was reactive, then no further testing was performed, but if the initial sample was negative, the other available samples were tested as well. For hepatitis E analysis, all sera, including the oldest and the most recent samples, were tested in an effort to document both seroconversions and possible loss of antibody to HEV. Serum samples were tested by enzyme immunoassay (EIA; Abbott Laboratories, Abbott Park, IL) for antibodies to hepatitis A virus (total anti-HAV), to hepatitis B core antigen (total anti-HBc), and to hepatitis C virus (total anti- HCV, second-generation EIA). Only samples that were re active twice in two separate assays were considered positive. Samples positive by EIA for anti-HCV were further tested with a second-generation immunoblot assay (RIBA®HCV Test System; Chiron, Emeryville, CA). Sera were tested at 1:20 and 1:100 dilutions for IgG an tibody to hepatitis E virus (anti-HEV) using enzyme-linked immunosorbent assay (ELISA) kits provided for research 233 Med. Hyg., 236 Copyright © 1995 by The American Society of Tropical Medicine and Hygiene THE RISK OF VIRAL HEPATITIS A, B, C, AND E AMONG NORTH AMERICAN MISSIONARIES ROGER D. SMALLIGAN, W. ROBERT LANGE, JOHN D. FRAME, PATRICE 0. YARBOUGH, DIANE L. FRANKENFIELD, AND KENNETH C. HYAMS Instituto de Lengua Espanola, San Jose, Costa Rica; Department of International Health, and Division of Public Health, The Johns Hopkins University School of Hygiene and Public Health, Baltimore, Maryland: College of Physicians and Surgeons, Columbia University, New York, New York: Genelabs Technology, San Antonio, Texas: Epidemiology Division, Naval Medical Research Institute, Bethesda, Maryland Abstract. North American missionaries (n = 328) serving in various geographic locations between 1967 and 1984. The mean age of subjects at entry into the study was 39.7 years (range 5-73 years); 65% were female; 89% had lived outside the United States before the study began. Seventy-eight percent of subjects served in sub-Saharan Africa during the study. At initial evaluation, 50.9% of the subjects had antibodies to hepatitis A virus (total anti-HAV), 8.5% to hepatitis B virus core antigen (total anti-HBc), 0.6% to hepatitis C virus (total anti-HCV by second-generation immunoblot assay), and 0% to hepatitis E virus (IgG anti-HEV). After an average period of service of 7.3 years (2,396 person-years total), 5.8% of the missionaries seroconverted to anti-HAY, 5.5% to anti-HBc, 0.6% to anti-HCV, and 0% to anti-HEY. This study indicates a relatively low risk of hepatitis C and E virus infection among missionaries A virus infection. Hepatitis and vaccination is recommended for long-term travelers to developing countries.
DOI
10.4269/ajtmh.1995.53.233
Publication Date
9-1-1995
Supplemental Associated Link
https://www.ajtmh.org/view/journals/tpmd/53/3/article-p233.xml
Recommended Citation
Smalligan, Roger D.; Lange, W Robert; Frame, John D.; Yarbough, Patrice O.; Frankenfield, Diane L.; and Hyams, Kenneth C., "The Risk of Viral Hepatitis A, B, C, and E Among North American Missionaries" (1995). UABH Articles. 9.
https://digitalcommons.library.uab.edu/uabh-articles/9
