Hepatitis E seroconversion in United States travelers abroad

Sporadic cases of symptomatic hepatitis E virus (HEV) infection have been reported in United States travelers to developing countries, including Mexico and Pakistan. To evaluate the risk of exposure in United States travelers, 356 patients seen in our Travel Clinics were tested for antibodies to HEV before and 6 weeks after traveling. Samples obtained 6 months after traveling were available for 211 travelers. IgG and IgM antibodies to HEV were assayed with HEV ELISA diagnostic kits containing 3 recombinant antigens expressed in Escherichia coli representing immunodominant epitopes within open reading frames 2 and 3 of HEV. Nine patients were IgG seropositive in specimens obtained before travel. Four individuals seroconverted. In all 4 patients, IgG seroconversion was demonstrated in samples obtained at least 6 months after return. Samples obtained 6 weeks after return were seronegative for HEV in all 3 patients for whom such samples were available. Travel destinations were diverse: Thailand, China, Russia, and Peru. These data are consistent with an infection acquired while traveling. None of the seropositive subjects reported any symptoms of hepatitis before or after travel. In the absence of overt disease, these results imply that exposure to HEV resulted in subclinical infections.