MOLECULAR CHARACTERIZATION OF HEPATITIS A VIRUS FROM SPORADIC AND EPIDEMIC CASES OF JAUNDICE IN TAMIL NADU, INDIA

Abstract

Hepatitis A is an enterically transmitted viral disease, highly prevalent in India and mainly
occurs as a sporadic childhood disease. Focal outbreaks have also been reported among children
and adults in India. This study was initiated to find out the occurrence of sporadic and epidemic
cases of jaundice caused by HAV in Tamil Nadu. Both sporadic and epidemic cases of HAV were
subjected to molecular characterization to document the prevalent HAV genotype in Tamil Nadu.
A total of 584 sporadic cases and 23 cases from a jaundice outbreak in Perambalur District, Tamil
Nadu during Jan 2009 were included in the present study. Sera were tested for anti-HAV IgM by
ELISA. Twenty-two sporadic and 23 epidemic samples positive for HAV were subjected to RTPCR and RNA positive samples were further processed for sequencing and phylogenetic analysis.
Three hundred and seven (52.6%) sporadic cases and all the 23(100%) epidemic jaundice cases
were positive for HAV. Among the sporadic cases, 239(77.8%) were children less than 10 years of
age. However, RT-PCR was positive only in four sporadic and two epidemic cases. Sequencing and
phylogenetic analysis revealed that both sporadic and epidemic form of HAV infection was caused
by HAV genotype IIIA.
HAV was found to be the leading cause of jaundice especially among children in Tamil Nadu.
Genotype IIIA was the prevalent HAV genotype both in the epidemic and sporadic cases of
jaundice in the southern state in India, which has the potential to cause large scale epidemics in the
community. Environmental hygiene, sanitation and provision of safe and protected drinking water
have to be improved to avoid jaundice epidemics in Tamil Nadu. An effective control strategy
including new vaccination policies for the children need to be emphasized to reduce the HAV
related disease burden in the community.