Hepatitis E seroprevalence and seroconversion among US military service members deployed to Afghanistan.

Background. Hepatitis E virus (HEV) has been recognized as a threat to military forces since its discovery. Although HEV seroprevalence in Afghanistan is not known, HEV infection is thought to be highly endemic in that country. This study determined the incidence of HEV seroconversion among United States (US) service members who were deployed to Afghanistan, as well as the prevalence of antibodies to HEV prior to the deployment. Methods. A random sample of 1500 subjects was selected from the cohort of service members who were deployed to Afghanistan between 2002 and 2006. Predeployment and postdeployment serum samples from these subjects were tested by enzyme immunoassay for total antibodies to HEV. Results. The seroprevalence of antibodies to HEV in US service members prior to deployment was 1.1%. The seroconversion rate among service members deployed to Afghanistan was 0.13%. Conclusions. Although subpopulations may be at higher risk for HEV exposure during deployment, the risk among US service members deployed to Afghanistan in this study was low. Previously implemented and current preventive measures in theater appear to have been adequate. With future deployments to new areas or changes in military operations in areas of risk, continued surveillance for HEV infection in the military will be warranted.