Changing pattern of human group A rotaviruses: Emergence of G12 as an important pathogen among children in eastern India

Distribution of rotavirus VP7 and VP4 genotypes circulating in Tunisia from 2009 to 2014: Emergence of the genotype G12

“…Samples that remained untypeable after this first VP7-typing assay were further tested with a second PCR assay aiming to detect G12 VP7 specificity. Indeed, to detect the G12 genotype, we optimized a second semi-nested reaction using a G12 specific primer (Samajdar et al, 2006) and, as a positive control, a Tunisian G12 RVA strain which was previously confirmed by sequencing (Ben Hadj Fredj et al, 2013a). The size of the resultant amplicon allows determination of the VP7 genotype.…”

Rotavirus Infection: A Perspective on Epidemiology, Genomic Diversity and Vaccine Strategies

“…The VP7 genes of the serotype G12 strains and their deduced amino acid products showed maximum homology (97-99% at the nucleotide level and 98% at the amino acid level, respectively) with those of two recently reported serotype G12 strains from the United States and Thailand, but lesser homology with those of the prototype G12 strain, L26 [30]. Thereafter this serotype maintained a steady rate of occurrence between 8 and 17% between the year 2001-2008 [58,80].…”

“…Two G9 strains (RMC321 and ISO-3) were identified with P [19] and P [8] specificities after sequence analysis and revealed that they have much lower homology to the G9 strains (116E, INL1, and G16) isolated earlier from Indian subcontinent, but have much higher homology to isolates from Argentina, Brazil, Malawi, Taiwan, and USA suggesting a separate progenitor for these strains [31]. The genotypic distribution in eastern India, varied remarkably from the earlier study period (1998-2001) with G1 being the most predominant strain followed by G2, G12, G9 and not a single G3 or G4 isolate was detected separately during a surveillance (2003)(2004)(2005) where G12 strains emerged as an important pathogen among children in eastern India [80]. In the year 2006, it was also reported that the G9 strains are increasing as an important VP7 genotype among children in eastern India and phylogenetic analysis of these G9 strains revealed clustering within G9 lineage III [81].…”

“…In recent years, studies from India, Bangladesh, Nepal, Argentina and other parts of the world have reported increasing incidence of another potentially emerging strain G12, with a variety of P types such as P [6], P [8] and P [9] [6,8,19,35,58,67,68,70,71,73,80,82,89]. During routine surveillance of diarrhea caused by rotavirus in Calcutta, India, the emergence of a novel type of human rotavirus, serotype G12, was reported [80]. Three rare human serotype G12 strains were detected from diarrheic samples from children aged less than 8 months.…”

“…The epidemiological characteristics of the introduction of serotype G9 and G12 strains worldwide may suggest that pre-existing immunity towards other rotavirus serotypes was not sufficient in preventing infection and proliferation of these strains [26,30,44,80]. Though the current vaccines seem to provide heterologous protection, long term studies after vaccination in highly endemic areas with lots of strain variations will shed light whether the formulation of rotavirus vaccines used in different parts of world will need regular updating to adapt their composition to that of locally or regionally circulating prevalent strains.…”