Hepatitis E virus infection commonly presents as an acute self-limiting hepatitis in the developing world. However there have been reports that chronic hepatitis E may develop in immunocompromised subjects such as renal and liver transplant recipients. Progression to cirrhosis has also been reported in patients with chronic hepatitis E infection. We hypothesize that immunosuppression post-organ transplantation predisposes individuals to increased susceptibility to hepatitis E infection. Therefore, in this study, we wish to determine the seroprevalence of antibody to hepatitis E IgG in organ transplant recipients (an immunosuppressed population) and compare it to patients who are on organ transplant waitlist (not immunosuppressed). We plan to study samples and date from 300 organ transplant recipients and 300 patients on waitlist for liver, kidney or intestinal transplantation and control for age, gender, organ and transplant center. Three transplant centers (2 in the mid-Atlantic area and one in the Mid-West) will each enroll 100 cases and controls. A minimum of 50 cases at each site will be liver transplant recipients. Cases will be stratified based on number of years post transplant one, two or greater than or equal to three years. Consecutive patients who are eligible and agree to participate in the study will be enrolled. A brief questionnaire to assess risk factors for acquisition of hepatitis E will be administered and 8mls of blood will be drawn in a serum separator tube for anti HEV IgG, anti HEV IgM and HEV RNA testing analysis at the NIH. Subjects who are confirmed to have acute or chronic HEV infection will be managed according to standard of care at each respective transplant centers.