Identifications of polyphyletic variants in acute hepatitis suggest an underdiagnosed circulation of hepatitis E virus in Argentina.

Background: In recent years, an increasing number of infections with genotype 3 hepatitis E virus (HEV) have been reported in western countries. Data in South America, however, are still scarce. Swine and human variants previously described in Argentina are closely related to a human Austrian one.

Objective: To identify whether HEV is still circulating in Argentina.

Study Design: Sera and stool samples from adults and children with unexplained acute liver disease referred to our center during the last six years were prospectively studied. Dual infection with hepatitis A was retrospectively studied in a group of children with fulminant hepatic failure.

Results: Fifteen new cases (13 adults and 2 children), seven of whom required hospitalization, were diagnosed. Nine had detectable HEV RNA, and one had imported genotype 1. Subgenotype 3i HEV-related variants are still circulating. Five autochthonous sequences, related to European, American and Japanese ones, grouped in subgenotype 3a. One case had a subgenotype 3b variant.

Discussion: The polyphyletic variants widespread in Argentina suggest multiple sources of infection. Whether or not their reservoir is swine merits further investigation. Since hepatitis E is still considered rare, differential laboratory testing in unexplained acute liver disease is not routinely performed in Argentina. Broadening awareness of this disease is important in light of the decrease in hepatitis A incidence since universal vaccination was implemented in 2005. The diagnosis of hepatitis E with a combination of serological and molecular tools is needed to better understand its epidemiology and impact on the clinical management of patients with unexplained increased transaminases.