Whole-genome characterization of common rotavirus strains circulating in Vellore, India from 2002 to 2017: emergence of non-classical genomic constellations.

Rotaviruses (RVs) are the most common etiological agent of acute gastroenteritis among young children, even after vaccine introduction in low-income countries. A whole-genome classification representing the 11 RV genes, was introduced for surveillance and characterization of RVs. This study characterized the common circulating strains in Vellore, India from 2002 to 2017 to understand rotavirus strain diversity and evolution using Whole genome sequencing (WGS) carried out on Illumina MiSeq. The 89% (92% of Wa-like, 86% of DS-1-like) of strains had classical constellations, while reassortant constellations were seen in 11% (8% of Wa-like, 14% of DS-1-like) of the strains. The rare E6-NSP4 in combination with DS-1 like G1P[8] and the emergence of the OP-354 subtype of P[8] were identified. Phylogenetics of RV strains revealed multiple subtypes circulating in the past 15 years, with strong evidence of animal to human gene transmission among several strains.

Persistence of G10P[11] neonatal rotavirus infections in southern India.

BACKGROUND: Neonatal rotavirus infections are predominantly caused by distinct genotypes restricted to this age-group and are mostly asymptomatic. METHOD: Stool samples from neonates admitted for >48 h in neonatal intensive care units (NICUs) in Vellore (2014-2015) and Chennai (2015-2016) in southern India, and from neonates born at hospitals in Vellore but not admitted to NICUs (2015-2016) were tested for rotavirus by ELISA and genotyped by hemi-nested RT-PCR. RESULTS: Of 791 neonates, 150 and 336 were recruited from Vellore and Chennai NICUs, and 305 were born in five hospitals in Vellore. Positivity rates in the three settings were 49.3% (74/150), 29.5% (99/336) and 54% (164/305), respectively. G10P[11] was the commonly identified genotype in 87.8% (65/74), 94.9% (94/99) and 98.2% (161/164) of the neonates in Vellore and Chennai NICUs, and those born at Vellore hospitals, respectively. Neonates delivered by lower segment cesarian section (LSCS) at Vellore hospitals, not admitted to NICUs, had a significantly higher odds of acquiring rotavirus infection compared to those delivered vaginally [p = 0.002, OR = 2.4 (1.4-4.3)]. CONCLUSIONS: This report demonstrates the persistence of G10P[11] strain in Vellore and Chennai, indicating widespread neonatal G10P[11] strain in southern India and their persistence over two decades, leading to interesting questions about strain stability.

Diversity of rotavirus genotypes circulating in children < 5 years of age hospitalized for acute gastroenteritis in India from 2005 to 2016: analysis of temporal and regional genotype variation.

BACKGROUND: From 2016, the Government of India introduced the oral rotavirus vaccine into the national immunization schedule. Currently, two indigenously developed vaccines (ROTAVAC, Bharat Biotech; ROTASIIL, Serum Institute of India) are included in the Indian immunization program. We report the rotavirus disease burden and the diversity of rotavirus genotypes from 2005 to 2016 in a multi-centric surveillance study before the introduction of vaccines. METHODS: A total of 29,561 stool samples collected from 2005 to 2016 (7 sites during 2005-2009, 3 sites from 2009 to 2012, and 28 sites during 2012-2016) were included in the analysis. Stools were tested for rotavirus antigen using enzyme immunoassay (EIA). Genotyping was performed on 65.8% of the EIA positive samples using reverse transcription- polymerase chain reaction (RT-PCR) to identify the G (VP7) and P (VP4) types. Multinomial logistic regression was used to quantify the odds of detecting genotypes across the surveillance period and in particular age groups. RESULTS: Of the 29,561 samples tested, 10,959 (37.1%) were positive for rotavirus. There was a peak in rotavirus positivity during December to February across all sites. Of the 7215 genotyped samples, G1P[8] (38.7%) was the most common, followed by G2P[4] (12.3%), G9P[4] (5.8%), G12P[6] (4.2%), G9P[8] (4%), and G12P[8] (2.4%). Globally, G9P[4] and G12P[6] are less common genotypes, although these genotypes have been reported from India and few other countries. There was a variation in the geographic and temporal distribution of genotypes, and the emergence or re-emergence of new genotypes such as G3P[8] was seen. Over the surveillance period, there was a decline in the proportion of G2P[4], and an increase in the proportion of G9P[4]. A higher proportion of mixed and partially typed/untyped samples was also seen more in the age group 0-11 months. CONCLUSIONS: This 11 years surveillance highlights the high burden of severe rotavirus gastroenteritis in Indian children < 5 years of age before inclusion of rotavirus vaccines in the national programme. Regional variations in rotavirus epidemiology were seen, including the emergence of G3P[8] in the latter part of the surveillance. Having pre-introduction data is important to track changing epidemiology of rotaviruses, particularly following vaccine introduction.