Abstract

In order to study the genetic relationships and epidemiological links between strains circulating in the Vellore region of India, 70 wild type poliovirus strains isolated from paralytic poliomyelitis cases were sequenced at the VP1-2A junction region of the viral genome. This showed that three genotypes of types 1 and 2 and four genotypes of type 3 poliovirus were circulating in India at least since 1985. Different clusters were identified within wild genotypes. This study demonstrates the endemic circulation and wide genetic variation of all three serotypes in Southern India. Knowledge of wild poliovirus distribution before NIDs beginning could be helpful for a critical monitoring of poliomyelitis control and further evaluation of the NIDs impact on wild poliovirus transmission in India.

Key words: Poliovirus, poliomyelitis, genotype, molecular epidemiology, eradication, surveillance.