Outbreaks of hepatitis A among children in western India.

Hepatitis A in most developing countries is a sporadic childhood disease, but lately focal outbreaks have been observed among children in India. During 2004, we investigated a large-scale outbreak of hepatitis among children living in a residential colony in Daund Taluka of District Pune in the western region of India. In total, 123 overt and 56 sub-clinical cases were detected. All the patients were reactive for IgM antibodies against hepatitis A virus (IgM anti-HAV) and were negative for IgM anti-hepatitis E virus, confirming HAV to be the etiological agent of the outbreak. Serum samples, feces and sewage samples were tested for HAV RNA and molecular characterization of the positives showed the presence of genotype IIIA. Further, IgM anti-HAV-positive sera from eight focal outbreaks were analyzed. The causative HAV in all these small-scale outbreaks also belonged to genotype IIIA, indicating the predominance of genotype IIIA in this region. This report of a large-scale, explosive outbreak of hepatitis A in Indian children once again emphasizes the need to evolve proper public health strategies, especially for vaccination, in countries in the transitional phase from hyperendemicity to intermediate endemicity.