Rotaviruses cause an estimated 140 million cases of
gastroenteritis and 800,000 deaths in
children between the ages of 6 months to 2 yr in
developing countries. In
India, one of every 250
children or about 100-150,000
children die of
rotavirus diarrhoea each year. The
prevalence of
rotavirus diarrhoea in
India has been found to vary from 5-71 per cent in
hospitalized children <5 yr of age with acute
gastroenteritis. The
seasonal variation of
rotavirus diarrhoea in
India varies in different geographical regions with high
incidence in winter months at low relative
humidity in north
India. The distinctive features of
rotavirus infection in
India include the occurrence of severe
disease at an early age and common neonatal
rotavirus infections which are often asymptomatic.
Rotavirus shows genetic and
antigenic diversity in terms of subgroup, electropherotypes and G and P
serotypes/
genotypes. There are a few studies in terms of
prevalence of different antigenic and genetic variants from various regions of
India. In most studies on subgroup distribution from
India a higher
prevalence of subgroup II was reported compared to subgroup I. Electropherotyping has also demonstrated that a number of multiple electropherotypes co-circulate at one
time in a particular
community leading to extensive genomic variation and the appearance of new
strains which may become the predominant electropherotype during the peak
season. The most common G types reported from
India are G1 and G2 and P types are P[4] and P[8]. A significant number of
children also have mixed
rotavirus infections. G9
strains are also quite commonly seen in Indian
children. In addition P6
strains of probable bovine origin have been reported from
India. A novel neonatal
strain P type 11
human rotavirus (116 E) was isolated from
neonates in Delhi, the VP4 of which was closely related to the bovine
serotype G10P[11]
strain B223 and VP7 was closely related to the
human serotype G9
strain. Another neonatal
strain G10P[11] was reported from Bangalore. G10P[11]
strains also have a high
prevalence in calves with diarrhoea, in
India. The occurrence of these unusual
rotavirus strains which are natural reassortants of
human and bovine
rotaviruses, suggests that reassortment may be an important mechanism for generation of
rotavirus strains of
newborns. This is catalyzed by the age old traditions of calves and
humans living in the same
household and socio-
economic conditions in
India. The diversity of
rotavirus strains and the high
prevalence of
mixed infections in
India are unique features of
rotavirus epidemiology in
India and emphasizes that
vaccines should be formulated against a broad range of
strains. Another important aspect is that
vaccines in
India should also target G9
strains. Since
neonates acquiring
rotavirus infection are protected against severe diarrhoea, neonatal
rotavirus strains can be effective potential
vaccine candidates and
vaccines based on these neonatal
strains are being indigenously developed in
India.