Unusual Indian asymptomatic neonatal human rotaviruses: Potential candidates for development of live reassortant rotavirus vaccines

Abstract

We have isolated a large number of unusual rotavirus strains from asytnptomatically infected new-born children from hospitals in Bangalore during a 3-year period from 1988 to 1991. About 36 per cent of the neonates in the age group 2 to 60 days showed asymptomatic infection, exclusively by these novel strains. All the isolates, without exception, showed 'long' RNA pattern but for subgroup I specificity which is characteristic of animal rotaviruses. Serotypic analysis revealed that these viruses did not belong to any known human serotypes. instead, were related to bovine serotype 10 viruses. Genogroup analysis showed a high level of relatedness to serotype 10 bovine rotavims and a low level of homology to human serotype 1 virus. Some of these strains have been adapted to tissue culture. Because of their attenuated nature and their ability to grow to high titres in cell culture and to effectively infect humans, these asymptomatic neonatal Indian strains represent ideal candidates towards development of reassortant live rotavins vaccines as an alternative to recombinant vaccines. 1321 and related neonatal vimses represent ideal candidates to study not only the molecular evolution of human rotaviruses but also the mechanism of virulence and host range restriction.