ABSTRACT
background & objectives: Recent influenza antiviral resistance studies in South East Asia, Europe and the United States reveal adamantane and neuraminidase inhibitor (NAIs) resistance. This study was undertaken to evaluate antiviral resistance in influenza viruses isolated from various parts of India, during 2004 to 2011. methods: Influenza viruses were analyzed genetically for known resistance markers by M2 and NA gene sequencing. Influenza A/H1N1 (n=206), A/H3N2 (n=371) viruses for amantadine resistance and A/H1N1 (n=206), A/H3N2 (n=272) and type B (n=326) for oseltamivir resistance were sequenced. Pandemic (H1N1) (n= 493) isolates were tested for H274Y mutation by real time reverse transcription (rRT)-PCR. Randomly selected resistant and sensitive influenza A/H1N1 and A/H3N2 viruses were confirmed by phenotypic assay. results: Serine to asparagine (S3IN) mutation was detected in six isolates of 2007-2008.One dual-resistant A/H1N1 was detected for the first time in India with leucine to phenylalanine (L26F) mutation in Mm2 gene and H274Y mutation in NA gene. A/H3N2 viruses showed an increase in resistance to amantadine from 22.5 per cent in 2005 to 100 per cent in 2008 onwards with S3IN mutation. Fifty of the 61 (82%) A/H1N1 viruses tested in 2008-2009 were oseltamivir resistant with H274Y mutation, while all A/H3N2, pandemic A/H1N1 and type B isolates remained sensitive. Genetic results were also confirmed by phenotypic analysis of randomly selected 50 resistant A/H1N1 and 40 sensitive A/H3N2 isolates. Interpretation & conclusions: Emergence of influenza viruses resistant to amantadine and oseltamivir in spite of negligible usage of antivirals emphasizes the need for continuous monitoring of antiviral resistance.
ABSTRACT
Context: With rotavirus vaccines now available globally, it will be useful to assemble the available evidence on the epidemiology and burden of rotavirus gastroenteritis in India, in order to weigh the urgency of introducing a vaccine to help control rotavirus disease. Evidence Acquisition: We reviewed published studies on rotavirus infection and genotype distribution in India, as well as safety and immunogenicity studies of currently available vaccines. PubMed was searched for papers published after 1990, and several authors who are experts in the field recommended papers of known significance. Results: Rotavirus accounts for close to 40% of hospitalizations for diarrhea in India, with more recent studies showing an increased proportion compared with older studies. There is substantial serotype diversity in India, although there is less intra-country variation than previously thought. Two genotypes, G1P[8] and G2P[4], account for roughly 50% of symptomatic infections in non-neonates. Currently licensed vaccines are safe, and although the efficacy appears lower in developing countries, given the extremely high incidence of diarrhea these could still be cost-effective interventions. Conclusions: The epidemiology and burden of rotavirus diarrhea is fairly well characterized in India. Introducing rotavirus vaccine into the UIP, along with adequate surveillance, should be an important part of efforts to reduce diarrhea mortality, the third leading cause of death among Indian children, and achieve the country’s MDG goals.