Project description:Rotaviruses are the major etiological agents of diarrhea in children less than 5 years of age. The commonest G types in humans are G1-4 and G9. G12 is a rare human rotavirus (HRV) strain first reported in the Philippines. In this study, 13 G12 strains obtained from a community-based cohort and a hospital-based surveillance system in 2005 were characterized by phylogenetic analysis of partial nucleotide sequences of VP7, VP6, and NSP4 genes. Sequence and phylogenetic analysis of VP7 gene sequences showed that these southern Indian strains had the greatest homology with G12 strains recently reported from eastern India (97-99% identity both at the nucleotide level and deduced amino acid level) and less homology with the prototype G12 strain, L26 (89-90% identity at the nucleotide level and 90-94% at the deduced amino acid level). Phylogenetic analysis of the VP6 and the NSP4 genes revealed that the Vellore G12 strains belonged to VP6 subgroup II and NSP4 genotype B. The P types associated with these strains were P[6] and P[8]. A G12 type-specific primer was designed for inclusion in an established VP7 G-typing multiplex RT PCR, and tested against a panel of known G types and untyped samples and was found to detect G12 strains in the multiplex-PCR. Close homology of the South Indian G12 strains to those from Kolkata suggests that G12 HRV strains are emerging in India. Methods for characterization of rotaviruses in epidemiological studies need to be updated frequently, particularly in developing countries.
Project description:Background:Rotaviruses are a leading cause of gastroenteritis. Rotavirus vaccination has dramatically reduced rotavirus occurrence; however, we have noticed mild to moderate recurrences in the St. Louis area in alternate years. In 2013, we found rotavirus genotype G12 to be the dominant strain in the St. Louis region. In this study, we again determined the distribution of genotypes and ascertained vaccine history in patients infected with rotavirus G12 during the 2014-15 season. Methods:Samples submitted to the St. Louis Children's Hospital Microbiology Laboratory were tested for rotavirus using an antigen assay. We determined the VP7 genotype using amplicon sequence analysis. We determined genome sequences using high-throughput sequencing. We evaluated rotavirus immunization records when available. Results:Of 30 typed viruses from 2014-15, 29 were G12 (97%). Whole-genome sequencing revealed few changes from G12 viruses analyzed in 2012-13. VP4 and VP7 sequences were >99% identical to previously sequenced G12 strains from St. Louis, and immune epitopes were conserved. Vaccination histories were available from 17 patients. Of these, 4 had been vaccinated, 3 had received incomplete vaccination or had a vaccine history that could not be confirmed, and 10 had not been vaccinated. Conclusions:G12 re-emerged as the predominant rotavirus genotype in 2014-15, comprising a higher percentage of cases than in 2012-13. The majority of patients with G12 and available vaccination histories were unvaccinated. There was no genomic evidence to indicate that the G12 strains in St. Louis had evolved to escape vaccine protection. Our work emphasizes the need for continued surveillance.
Project description:Three rare human G12 strains were detected from diarrheic clinical samples of children (<8 months of age) in Calcutta during a routine surveillance study of rotaviral diarrhea in India. The VP7 genes of G12 strains and their products showed maximum homology (97 to 99% at the nucleotide level and 98% at the amino acid level, respectively) with those of two recently reported G12 strains (from the United States and Thailand) but lesser homology with those of prototype G12 strain L26.
Project description:The G and P type specificity of the human rotavirus strain T-152 (G12P[9]) isolated in Thailand was serologically confirmed with G12-specific monoclonal antibodies prepared in this study by using a reference G12 strain, L26, as an immunizing antigen and a P[9]-specific monoclonal antibody, respectively. The genomic relationship of strain T-152 with representative human rotavirus strains was examined by means of Northern blot analysis. The results showed that T152 is closely related to strain AU-1 (G3P[9]). Gene 5 (NSP1 gene) of T152, which did not hybridize with those of any other strains examined, was characterized by sequence determination. The T152 NSP1 gene is 1,652 nucleotides in length, encodes 493 amino acids, and exhibits low identity to those of representative human and animal rotaviruses.
Project description:The prospect that rotavirus diarrhea in children may soon be prevented by vaccines has placed a new priority on understanding the diversity of rotavirus strains and the mechanism by which these strains evolve over time. We have characterized a total of 465 rotavirus strains collected in North India from 2000 to 2007 for G and P types by reverse transcription-PCR and sequencing. The novel G12 rotavirus strains recently detected in other countries were first detected in India in 2001 and have emerged as the predominant strains in Delhi, India, during 2005 to 2007. While the VP7 sequence was highly homologous among G12 strains isolated in Delhi, suggesting recent emergence from a common ancestor, the strains had a diverse constellation of other gene segments, demonstrating substantial reassortment. For the entire period, the common rotavirus G types G1 (26%), G2 (25%), and G9 (14%) comprised 65% of the strains, and common P types, P[4] (19%), P[6] (22%), and P[8] (35%), comprised 76% of the total P types. Of note, we detected a high percentage of unusual (17%) strains and fecal specimens with mixed (12% G and 15% P) rotavirus infections having a variety of genomic constellations. For the first time, we identified two novel rotavirus strains with unusual G/P combinations, G2P[11] and G3P[11], in patients with diarrhea. The study highlights the great diversity among rotaviruses isolated from Indian children, the opportunity for genetic reassortment between strains, and the emergence of a novel G12 strain in our country. Due to the demonstrated effect of antigenic diversity on rotavirus vaccines, it will be important to continue careful monitoring of these strains as rotavirus vaccine programs are implemented in India.
Project description:Rotavirus infections by G12 strains in several countries have recently been described. In this study, we report the emergence of G12 strains in south India. Fourteen cases of G12 infection were identified between June and September 2005. G12 was seen in combination with P[6], P[8], or nontypeable P type. Nine cases, including five symptomatic infections and four asymptomatic infections, were identified as part of routine surveillance for rotavirus infections in a birth cohort in the community between June and July 2005. Significant temporal and time-space clustering of eight of these cases represents a possible recent introduction of a new rotavirus VP7 genotype. Previous rotavirus infections had been documented for six of the nine children in the community. In the following 2 months, five cases of G12 infection were identified among children presenting to a referral hospital with diarrhea. This is the first description of symptomatic and asymptomatic G12 infections in children in the community. The detection of G12 strains from different parts of the world in recent years suggests the possibility of its emergence as an important global genotype. Monitoring of cocirculating rotavirus strains and detection of emerging strains is important in the context of the availability of rotavirus vaccines.
Project description:G12 rotavirus has not been detected anywhere in the world since the first detection of a human strain, L26 (G12, P1B[4]), in the Philippines in 1990. In this study, we isolated a human rotavirus (strain T152) with a VP7 of G12 specificity from the stool of an 11-month-old diarrheic patient in Thailand. The strain T152 exhibited a long RNA pattern and subgroup I specificity. In the comparison of the nucleotide and amino acid sequences of the VP7 gene of strain T152 with those of rotaviruses with different G type specificities, strain T152 showed the highest identity, 90.9 and 93.9%, respectively, to G12 prototype strain L26. In contrast, the VP4 gene of strain T152 showed the highest identity with P[9] specificity of human strains K8 and AU-1 and feline strains Cat2 and FRV-1, with homologies of 89.3 to 90.6% at the nucleotide level and 93.9 to 95.6% at the amino acid level. Thus, strain T152 was found to be a natural reassortant strain with G12 and P[9] specificities.
Project description:Group A rotavirus (RVA) genotype G12 has spread globally and has become one of the most prevalent genotypes of rotavirus in Africa. To understand the drivers for its genetic diversity and rapid spread we investigated the Bayesian phylogeography, viral evolution and population demography of Rotavirus G12 in Africa. We downloaded and aligned VP7 gene sequences of Rotavirus genotype G12, from thirteen African countries (n = 96). Phylogenetic analysis, Evolutionary analysis and Bayesian Phylogeography was carried out, using MEGA Vs 6, BEAST, and SPREAD3. Phylogenetic analysis revealed that all the African sequences fell into lineage III diversifying into two major clades. The evolutionary rate of the African rotavirus G12 sequences was 1.678×10-3, (95% HPD, 1.201×10-3 - 2.198×10-3) substitutions/site/year, with TMRC of 16.8 years. The Maximum clade credibility (MCC) tree clustered into three lineages (II, III, IV), African strains fell within lineage III, and diversified into three clusters. Phylogeography suggested that South Africa seemed to be the epicentre of dispersal of the genotype. The demographic history of the G12 viruses revealed a steady increase between the years1998-2007, followed by a sharp decrease in effective population size between the years 2008-2011. We have shown the potential for genetic diversification of Rotavirus genotype G12 in Africa. We recommend the adoption of Molecular surveillance across Africa to further control spread and diversification of Rotavirus.
Project description:Rotaviruses are a major etiologic agent of gastroenteritis in infants and young children worldwide. To learn the shift of genotypes and genetic characteristics of Rotavirus A (RVA) causing diarrhea in children and adults, a hospital-based surveillance of rotavirus was conducted in Wuhan, China from June 2011 through May 2019, and representative virus strains were phylogenetically analyzed. Among a total of 6733 stool specimens collected from both children and adults with acute gastroenteritis, RVA was detected in 25.5% (1125/4409) and 12.3% (285/2324) of specimens, respectively. G9P[8] was the most common genotype (74.5%), followed by G1P[8] (8.7%), G2P[4] (8.4%), and G3P[8] (7.3%), with G9P[8] increasing rapidly during the study period. The predominant genotype shifted from G1P[8] to G9P[8] in 2012-2013 epidemic season. G12P[6] strain RVA/Human-wt/CHN/Z2761/2019/G12P[6] was detected in April 2019 and assigned to G12-P[6]-I1-R1-C1-M1-A1-N1-T2-E1-H1 genotypes. Phylogenetic analysis revealed that VP7, VP4, VP6, VP3, NSP1, NSP2, and NSP5 genes of Z2761 clustered closely with those of Korean G12P[6] strain CAU_214, showing high nucleotide identities (98.0-98.8%). The NSP3 gene of Z2761 was closely related to those of G2P[4] and G12P[6] rotaviruses in Asia. All the eleven gene segments of Z2761 kept distance from those of cocirculating G9P[8], G1P[8], and G3P[8] strains detected in Wuhan during this study period. This is the first identification of G12 rotavirus in China. It is deduced that Z2761 is a reassortant having DS-1-like NSP3 gene in the background of G12P[6] rotavirus genetically close to CAU_214.
Project description:In anticipation of rotavirus vaccine introduction in Saudi Arabia, this study was undertaken to determine the distribution of the G and P genotypes of rotaviruses in order to examine whether there was any emerging serotype or unusual strain circulating in children in Saudi Arabia. Of 984 stool specimens collected between 17 April 2004 and 16 April 2005, rotavirus was detected by an enzyme-linked immunosorbent assay in 187 (19%) diarrheal children less than 5 years of age. Of these, 160 (86%) were classified into G and P genotypes as follows: G1P[8] (44%), G2P[4] (20%), G9P[8] (11%), G12P[8] (4%), and G3P[8] (4%). RNA polyacrylamide gel electrophoresis identified 94 (50%) specimens as long RNA patterns, 30 (16%) specimens as short RNA patterns, and 1 mixed infection. Only a single long RNA electropherotype was identified for seven specimens containing G12P[8] rotavirus. RNA-RNA hybridization demonstrated that the G12P[8] strains were similar in their genomic constellation to locally cocirculating strains and to a Nepalese G12P[8] strain. The Saudi Arabian G12 VP7 gene had a 99% nucleotide sequence identity with Nepalese and Indian G12 VP7 genes and belonged to the third lineage. This study is the first to describe the distribution of rotavirus G and P types and also the first to identify G9P[8] and G12P[8] strains in the country.