Comparison of hepatitis A and E virus infections among healthy children in Mongolia: Evidence for infection with a subgenotype IA HAV in children

To compare the epidemiologic profiles of hepatitis A virus (HAV) and hepatitis E virus (HEV) infections in children in Mongolia, the prevalence of HAV and HEV infections was investigated serologically and molecularly among 717 apparently healthy individuals of 0–20 years of age (mean ± standard deviation, 8.6 ± 4.9 years) using serum samples obtained between October 2005 and January 2006. Total antibody against HAV (anti‐HAV [total]) was detected in 494 (68.9%) of the 717 subjects, while IgG antibody against HEV (anti‐HEV IgG) was detected in only five subjects (0.7%) ( P  < 0.0001). All five subjects who had anti‐HEV IgG, were negative for anti‐HEV IgM and HEV RNA. Anti‐HAV was detectable in 24 (75.0%) of the 32 infants aged 7 days to 6 months, but not in any of the 8 infants aged 7 to <12 months. The prevalence of anti‐HAV was 19.5% (17/87) in the age group of 1–3 years, and it increased to 50.0% (69/138) in the age group of 4–6 years, and further to 81.4% (105/129) in the age group of 7–9 years. Of note, 97.2% of the subjects in the age group of 16–20 years had anti‐HAV. The presence of HAV RNA was tested in all 717 subjects, and three children of 1, 4, or 8 years of age were found to have detectable HAV RNA (subgenotype IA). No subject had a history of hepatitis or jaundice. In conclusion, HEV infection was uncommon, but HAV infection lacking overt clinical features was prevalent among children in Mongolia. J. Med. Virol. 79:18–25, 2007. © 2006 Wiley‐Liss, Inc.