Community Based Case-Control Study of Rotavirus Gastroenteritis among Young Children during 2008-2010 Reveals Vast Genetic Diversity and Increased Prevalence of G9 Strains in Kolkata |
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| Authors: | Satarupa Mullick Anupam Mukherjee Santanu Ghosh Gururaja P Pazhani Dipika Sur Byomkesh Manna James P Nataro Myron M Levine Thandavarayan Ramamurthy Mamta Chawla-Sarkar |
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| Institution: | 1. National Institute of Cholera and Enteric Diseases, Kolkata, India.; 2. Department of Paediatrics, University of Virginia, School of Medicine, Charlottesville, Virginia, United States of America.; 3. Center for Vaccine Development, University of Maryland, School of Medicine, Baltimore, Maryland, United States of America.; Instituto de Higiene e Medicina Tropical, Portugal, |
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| Abstract: | BackgroundGroup A Rotaviruses are a major etiologic agent of gastroenteritis in infants and young children (<5 years) worldwide. Although rotavirus vaccines have been successfully administered in many countries, in India the introduction of rotavirus vaccine in national immunization program was approved in 2014. Since high disease burden and large number of genetic variants have been reported from low income countries including India, monitoring of rotavirus was initiated prior to implementation of the vaccine in the region.MethodsA total number of 3,582 stool samples were collected from an urban slum community in Kolkata, among which 1,568 samples were obtained from children of ≤5 years of age, with moderate to severe diarrhoea and 2,014 samples were collected from age-sex matched healthy neighbourhood controls. Rotavirus positive samples were typed by multiplex semi-nested PCR and nucleotide sequencing. Circulating strains were phylogenetically analyzed.ResultsAmong 1,568 children with diarrhoea, 395 (25.2%), and among 2,014 asymptomatic children, 42 (2%) were rotavirus positive. G1P8] was identified as the most common strain (32%) followed by G9P8] (16.9%), G2P4] (13.5%) and G9P4] (10.75%). G12 strains with combinations of P4], P6] and P8] comprised 11.9% of total positive strains. The rest (<10%) were rare and uncommon strains like G1P4], G1P6], G2P8] and animal-like strains G4P6], G6P14] and G11P25]. The 42 rotavirus positive samples from asymptomatic children revealed common genotypes like G1, G2 and G9.ConclusionThis community based case-control study showed increased predominance of genotype G9 in Kolkata. It also confirmed co-circulation of a large number of genetic variants in the community. Asymptomatic rotavirus positive children though low in number can also be a source of dispersal of infection in the community. This study provides background information to the policy makers for implementation of rotavirus vaccines in this region. |
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