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.

Full genomic analysis of G1P[8] rotavirus strains recovered from rotavirus vaccinated and non-vaccinated children hospitalized for acute gastroenteritis in Pune, western India.

G1P[8] rotaviruses are predominant in causing diarrheal infections in humans all over the world. This study reports the analysis of complete genomes of G1P[8] strains, two each recovered from Rotarix™ vaccine recipients and non-recipients hospitalized for acute gastroenteritis in Pune, western India. All four strains showed a genogroup-1 backbone with intra-genotypic diversity in the VP7 and VP4 gene segments and a homogeneous constellation of the internal gene segments. A divergence in the range of 1.4-17.3% from Rotarix™ vaccine strain was revealed by structural and non-structural genes of the strains at nucleotide and amino acid level. These data reflect ability of such G1P[8] strains to cause rotavirus infections in humans.

Genetic analysis of rotavirus G2P[4] strains in Pune, Western India: circulation of a novel reassortant bearing E6 NSP4 genotype.

In India, G2P[4] strains are known to be the second most predominant group A rotaviruses causing acute gastroenteritis among children. This study was performed to determine the diversity within VP7(G), VP4(P), VP6(I) and NSP4(E) genes of 16 G2P[4] rotavirus strains detected in children hospitalized for acute gastroenteritis in Pune, Western India during 2009-2013. Fourteen strains showed G2-P[4]-I2-E2 and two strains showed G2-P[4]-I2-E6 genotype constellation. Phylogenetic analysis showed their clustering into G2-IV-a3, P[4]-5bi/ii, I2-3ii and E2-4i/ii or E6 genotypes/lineages. These data reveal inter- and/or intra-genotypic variations in a genogroup-2 constellation of G2P[4] rotavirus strains circulating in Pune, Western India, providing evidence of a novel G2P[4] reassortant bearing a rare NSP4 genotype, E6 during 2009-2013.

Emerging OP354-Like P[8] Rotaviruses Have Rapidly Dispersed from Asia to Other Continents.

The majority of human group A rotaviruses possess the P[8] VP4 genotype. Recently, a genetically distinct subtype of the P[8] genotype, also known as OP354-like P[8] or lineage P[8]-4, emerged in several countries. However, it is unclear for how long the OP354-like P[8] gene has been circulating in humans and how it has spread. In a global collaborative effort 98 (near-)complete OP354-like P[8] VP4 sequences were obtained and used for phylogeographic analysis to determine the viral migration patterns. During the sampling period, 1988-2012, we found that South and East Asia acted as a source from which strains with the OP354-like P[8] gene were seeded to Africa, Europe, and North America. The time to the most recent common ancestor (TMRCA) of all OP354-like P[8] genes was estimated at 1987. However, most OP354-like P[8] strains were found in three main clusters with TMRCAs estimated between 1996 and 2001. The VP7 gene segment of OP354-like P[8] strains showed evidence of frequent reassortment, even in localized epidemics, suggesting that OP354-like P[8] genes behave in a similar manner on the evolutionary level as other P[8] subtypes. The results of this study suggest that OP354-like P[8] strains have been able to disperse globally in a relatively short time period. This, in combination with a relatively large genetic distance to other P[8] subtypes, might result in a lower vaccine effectiveness, underscoring the need for a continued surveillance of OP354-like P[8] strains, especially in countries where rotavirus vaccination programs are in place.

Genomic characterization of coxsackievirus type B3 strains associated with acute flaccid paralysis in south-western India.

Acute flaccid paralysis (AFP) associated with coxsackievirus type B3 (CV-B3) of the species Enterovirus B is an emerging concern worldwide. Although CV-B3-associated AFP in India has been demonstrated previously, the genomic characterization of these strains is unreported. Here, CV-B3 strains detected on the basis of the partial VP1 gene in 10 AFP cases and five asymptomatic contacts identified from different regions of south-western India during 2009-2010 through the Polio Surveillance Project were considered for complete genome sequencing and characterization. Phylogenetic analysis of complete VP1 gene sequences of global CV-B3 strains classified Indian CV-B3 strains into genogroup GVI, along with strains from Uzbekistan and Bangladesh, and into a new genogroup, GVII. Genomic divergence between genogroups of the study strains was 14.4 % with significantly lower divergence (1.8 %) within GVI (n = 12) than that within GVII (8.5 %) (n = 3). The strains from both AFP cases and asymptomatic contacts, identified mainly in coastal Karnataka and Kerala, belonged to the dominant genogroup GVI, while the GVII strains were recovered from AFP cases in north interior Karnataka. All study strains carried inter-genotypic recombination with the structural region similar to reference CV-B3 strains, and 5' non-coding regions and non-structural regions closer to other enterovirus B types. Domain II structures of 5' non-coding regions, described to modulate virus replication, were predicted to have varied structural folds in the two genogroups and were attributed to differing recombination patterns. The results indicate two distinct genomic compositions of CV-B3 strains circulating in India and suggest the need for concurrent analysis of viral and host factors to further understand the varied manifestations of their infections.

Molecular characterization of emerging G9P[4] rotavirus strains possessing a rare E6 NSP4 or T1 NSP3 genotype on a genogroup-2 backbone using a refined classification framework.

Rotavirus infections associated with unusual strains are an emerging concern in rotavirus vaccination programmes. Recently, an increase in circulation of unusual G9P[4] strains was reported from different regions of India, placing this genotype in third position, after G1P[8] and G2P[4], of the most common rotavirus strains. The aim of the present study was to analyse the complete genomic constellation of three G9P[4] strains (RV09, RV10 and RV11), determine their genetic relatedness to other genogroup-2 strains and understand the evolution of a rare E6 and other NSP4 genotypes. All strains revealed the presence of a genogroup-2 backbone, with RV09 constituting the NSP3 T1 genotype and RV10 and RV11 bearing the NSP4 E6 genotype. A refined criterion adopted to classify the nine internal gene segments of G2P[4] and non-G2P[4] strains with the genogroup-2 backbone into lineages and sub-lineages indicated divergence of >8 % (except NSP1: >5.5 %) for lineages and >3 % for sub-lineages. The VP1 and/or VP3 genes of study strains showed close relationships with animal-like human rotaviruses. The estimated evolutionary rate for the NSP4 E6 genotype was marginally higher (3.78×10-3 substitutions per site per year) than that of genotypes E1 (2.6×10-3 substitutions per site per year) and E2 (3.06×10-3 substitutions per site per year), suggesting a step towards adaptation of E6 on a genogroup-2 backbone. The time and origin of the most recent common ancestor of E6 genotype were estimated to be 1981 and South Asia, respectively. Full-genome and evolutionary analyses performed in this study for G9P[4] strains will help better understand the extent of gene reassortment and origin in unusual rotavirus strains that may remain viable and cause infections in humans.

Seroprevalence of antibodies against GII.4 norovirus among children in Pune, India.

This study reports the seroprevalence of antibodies against GII.4 norovirus among children (≤5 years) in Pune, India. Of 191 serum specimens, 98 (51.3%) tested positive with 61, 34 and 3 having IgG, IgG-IgA and IgG-IgA-IgM, respectively. Histoblood group antigen (HBGA)-blocking antibodies were detected in 33 of the 54 tested positive specimens. IgG and blocking antibody prevalence and titer varied with age and was lowest among children aged 6-23 months. Antibody-positive children, suggesting past norovirus exposure, showed significantly lower faecal norovirus RNA detection rate than antibody-negative children. Further investigation of the seroepidemiology of norovirus infections in India is warranted. J. Med. Virol. 88:1636-1640, 2016. © 2016 Wiley Periodicals, Inc.

Molecular surveillance of non-polio enterovirus infections in patients with acute gastroenteritis in Western India: 2004-2009.

Acute gastroenteritis is a major cause of childhood morbidity and mortality worldwide. Rotavirus (RV) and Norovirus (NoV) are the leading cause of the disease. Despite the use of improved diagnostic methods a significant proportion of gastroenteritis cases remained undiagnosed. Though nonpolio enteroviruses (NPEVs) have been reported frequently in children with acute gastroenteritis, their etiologic role has not been established. To investigate the epidemiology of NPEVs in gastroenteritis cases which remained negative for leading causative agents, 955 RV and NoV negative stool specimens from children hospitalized for acute gastroenteritis were included in the study. A case control study was conducted which includes stool specimens from 450 children with gastroenteritis and 162 asymptomatic control subjects to determine the association of NPEVs with the disease. NPEV detection and typing was carried out by RT-PCR and sequencing. Presence of RV, NoV, Adenovirus, and Astrovirus was confirmed by ELISA or PCR/RT-PCR. Overall 14% NPEV prevalence was noted. The percentage of children with NPEV infection differed significantly between gastroenteritis and non-gastroenteritis patients (13.7% vs. 4.9%). NPEV was more prevalent among patients with gastroenteritis of undetectable etiology as compared to those detected positive for other viruses (17.9% vs. 7%) (P < 0.01). Genotyping of NPEV identified predominance of EV-B species (56.5%) followed by EV-C (16.7%), EV-A (13.8%) species and mixed NPEV infections (13%). These data support the association of NPEVs with acute gastroenteritis and highlights the clinical and epidemiological features of NPEV infections in patients with acute gastroenteritis from western India.

Genomic characterization of coxsackievirus type A24 strains associated with acute flaccid paralysis and rarely identified Hopkins syndrome.

The full-length genome sequence analysis of four coxsackievirus A24 (CV-A24) strains, detected in three paralytic and one post-asthmatic paralytic (Hopkins syndrome) cases, is reported here for the first time. A phylogenetic tree constructed on the basis of entire genomes displayed topology similar to that of the full-VP1 tree, classifying the study strains in genogroup CV-A24vGIV along with their temporal counterparts in strains from non-paralytic cases. The strains of the study formed a single genetic cluster C4 within CV-A24vGIV and showed 3.5-19.4 % nucleotide sequence divergence, with 2-4 novel nucleotide mutations in the 5'NCR and 3-8 unique amino acid substitutions in the polyprotein, with respect to the CV-A24 strains associated with non-paralytic cases. Among the nucleotide mutations, A299U was identified in the 5'NCRs of all of the study strains. CV-A24v strains of the same genogroup with few genomic variations but different disease manifestations need to be explored to investigate the molecular basis of evolution of neurovirulence.

Full genome analysis of group B rotaviruses from western India: genetic relatedness and evolution.

To date, full-genome sequences of only seven human group B rotavirus (RVBs) strains have been described. Such data on more RVBs are necessary to establish the evolutionary relationship and ecological features of RVBs from different geographical regions. The present study was aimed at determining the full-length sequences of all 11 genes of 13 human RVB strains detected during 1995-2010 in sporadic and outbreak cases of acute gastroenteritis from four different cities of western India. This study also included estimation of evolutionary rates and site-specific selection pressure analysis for all gene segments. Nucleotide/deduced amino acid sequence analyses of structural and non-structural genes showed 95.1-99.8/94.1-100 % identity with the counterparts of RVB strains isolated in India, Bangladesh and Myanmar. Phylogenetic analyses of all gene segments revealed formation of a monophyletic clade of the western Indian RVB strains, reflecting their highly conserved nature. All gene segments were also found to be under negative/purifying selection pressure. These data suggest that RVB is circulating in the natural host as a series of stable viral clones. Estimates of rates of nucleotide substitution in all RVBs ranged from 1.36-4.78×10(-3) substitutions per site per year. The rate for human RVB VP7 and NSP2 genes were comparable, respectively, with the evolution kinetics of genotype G9/G12 and N1 group A rotavirus strains. The time of the most recent common ancestor of the extant human RVBs was estimated to be during 1915-1974. Evolutionary and genetic analyses carried out in this study provide data that is useful for the elucidation of evolutionary relationship/timescale, stasis or dynamics existing in the RVB population.

Diversity in the VP7 encoding genes of rotavirus strains isolated from adolescent and adult cases of acute gastroenteritis.

A study was conducted to examine the diversity in the VP7 genes of rotavirus strains circulating in adolescent and adult cases of acute gastroenteritis during two different time periods, 1993-1996 and 2004-2007. The multiplex RT-PCR carried out on 131 rotavirus positive fecal specimens detected 65 (49.6%) single and 48 (36.6%) mixed infections of VP7 genotypes that included 43G1 (38.1%), 37G2 (32.7%), 8G3 (7.1%), 15G4 (13.3%), and 10G9 (8.8%) specificities. Sequencing and phylogenetic analysis of the VP7 gene amplicons revealed the presence of G1-IA (4.7%), G1-IB (69.8%), and G1-IC (25.5%) lineages within the G1 strains, G2-IIb1 (70.3%) and G2-IIb2 (29.7%) lineages within G2 strains, G3-3S1 (12.5%) and G3-3S4 (87.5%) lineages within G3 strains, G4-Ia (6.7%) and G4-Ib (93.3%) lineages within G4 strains, and G9-III lineage within G9 strains. The variability within VP7 genotypes was evident by 1.4-8.0% and 1.3-3.9% amino acid divergence respectively from the prototype strains and between the groups of strains at the two time points. This is the first report describing the phylogenetic analysis of VP7 genes of rotaviruses from adolescent and adult cases of acute gastroenteritis in India. Since adults infected with rotavirus could act as a source of infection and affect the epidemiology of rotaviruses in children, genetic analysis of the rotavirus strains circulating in adults is required. The intragenotypic diversity within VP7 genes demonstrated by the present study highlights the need for constant surveillance of rotavirus infections to understand better the evolution and transmission of group A rotaviruses in the community.

Direct costs of hospitalization for rotavirus gastroenteritis in different health facilities in India.

BACKGROUND & OBJECTIVES: Diarrhoeal disease is the fifth leading cause of all mortality globally. To this burden, rotavirus contributes over half a million deaths annually. This pilot study was conducted to determine the economic burden of diarrhoeal episodes on families from different geographical regions accessing medical facilities in India. METHODS: Participants were enrolled from four study sites with eight reporting hospitals, categorized as non-profit and low cost, private and government facilities between November 2008 and February 2009. Questionnaires detailing healthcare utilization, medical and non-medical expenditure and lost income were completed by families of children < 5 yr of age hospitalized for gastroenteritis. All available faecal samples were tested for rotavirus. RESULTS: A total of 211 patients were enrolled. The mean total cost of a hospitalized diarrhoeal episode was ` 3633 (US$ 66.05) for all facilities, with a marked difference in direct costs between governmental and non-governmental facilities. Costs for rotavirus positive hospitalizations were slightly lower, at ` 2956 (US$ 53.75). The median cost of a diarrhoeal episode based on annual household expenditure was 6.4 per cent for all-cause diarrhoea and 7.6 per cent for rotavirus diarrhoea. Of the 124 samples collected, 66 (53%) were positive for rotavirus. INTERPRETATION & CONCLUSIONS: Data on direct costs alone from multiple facilities show that diarrhoeal disease constitutes a large economic burden on Indian families. Affordable, effective vaccines would greatly reduce the economic burden of severe gastroenteritis on patients, families and the government.

Longer duration of viremia and unique amino acid substitutions in a hepatitis A virus strain [corrected] associated with Guillain-Barré syndrome (GBS).

The molecular characteristics of hepatitis A virus (HAV) have been studied widely though there is a paucity of data on the correlation with virological and serological findings. In the present study, the whole genome of an Indian HAV strain associated with Guillain-Barré syndrome (GBS) was characterized vis-à-vis two other Indian HAV genotype IIIA strains, associated with a self-limiting disease. The percentage nucleotide divergence displayed by the Indian strains (CP-IND, PN-IND, and GBS-IND) varied from 3 to 6, whereas the percentage amino acid divergence varied from 0.1 to 0.7 as compared to the other HAV IIIA strains (n = 5) available in the GenBank. The GBS-IND strain showed an increased rate of nonsynonymous substitutions as well as a larger number of unique and heterologous amino acid substitutions compared to the HAV IIIA GenBank strains. These amino acid substitutions in the GBS-IND strain were detected in a nonstructural protein (2C-251F) and the B-cell epitope regions of structural proteins (VP1-29E, VP1-91S, VP3-50Y, and VP4-5S). In a comparative analysis of HAV strains, homology-based models of the capsid proteins indicated a localized alteration in the surface charge distribution on the VP1 protein of GBS-IND strain and involvement of its unique amino acid substitutions in the predicted antigenic determinants. Overall, the study suggests that the unique amino acid substitutions in the GBS-IND strain may have contributed to neutralization escape of the virus leading to a longer duration of viremia.

Characterization of group A rotavirus infections in adolescents and adults from Pune, India: 1993-1996 and 2004-2007.

A total of 1,591 fecal specimens were collected in 1993-1996 and 2004-2007 from adolescents and adults with acute gastroenteritis in Pune, India for detection and characterization of rotavirus. At the two time points, group A rotavirus was detected in 8.6% and 16.2% of the adolescents and 5.2% and 17.2% of the adults, respectively. Reverse transcription-PCR with consensus primers followed by multiplex genotyping PCR detected common strains G1P[8], G2P[4], G3P[8], and G4P[8] in a total of 53.1% of the samples from 1993 to 1996, while the only prevalent strain identified in 2004-2007 was G2P[4] (23.5% of total). Uncommon rotavirus strains (G1P[4], G2P[8] G9P[6]/P[4]) increased from 7.8% (1993-1996) to 41.2% (2004-2007), while the prevalence of mixed rotavirus infections was high (39%/35%) at both time points. Mixed infections detected by multiplex PCR were confirmed by sequencing two or more individual genotype-specific PCR products of the VP7 and VP4 genes from the same sample. Phylogenetic analysis of the sequences showed circulation of a heterogeneous rotavirus strain population comprising genotypes G1 (lineages I and IIb), G2 (lineages I and IIb), G4 (lineage Ia), P[4] (lineages P[4]-5 and P[4]-1), P[8] (lineages P[8]-II and P[8]-III), and P[6] (M37-like lineage). The VP6 gene sequences of the nontypeable strains were most homologous to animal strains. This study documents the molecular epidemiology of rotavirus strains in adolescents and adults in India, and suggests that it may be important to monitor these strains over time for the potential impact on rotavirus vaccines under development for use in the Indian population. J. Med. Virol. 82:519-527, 2010. (c) 2010 Wiley-Liss, Inc.

Multicenter, hospital-based surveillance of rotavirus disease and strains among indian children aged <5 years.

BACKGROUND: Current, nationally representative data on rotavirus disease burden and rotavirus strains in India are needed to understand the potential health benefits of rotavirus vaccination. METHODS: The Indian Rotavirus Strain Surveillance Network was established with 4 laboratories and 10 hospitals in 7 different regions of India. At each hospital, children aged <5 years who presented with acute gastroenteritis and required hospitalization with rehydration for at least 6 h were enrolled. A fecal specimen was obtained and was tested for rotavirus with use of a commercial enzyme immunoassay, and strains were characterized using reverse-transcription polymerase chain reaction. RESULTS: From December 2005 through November 2007, rotavirus was found in approximately 39% of 4243 enrolled patients. Rotavirus was markedly seasonal in northern temperate locations but was less seasonal in southern locations with a tropical climate. Rotavirus detection rates were greatest among children aged 6-23 months, and 13.3% of rotavirus infections involved children aged <6 months. The most common types of strains were G2P[4] (25.7% of strains), G1P[8] (22.1%), and G9P[8] (8.5%); G12 strains were seen in combination with types P[4], P[6], and P[8] and together comprised 6.5% of strains. CONCLUSIONS: These data highlight the need for development and implementation of effective prophylactic measures, such as vaccines, to prevent the large burden of rotavirus disease among Indian children.

Epidemiology of rotavirus diarrhea among children less than 5 years hospitalized with acute gastroenteritis prior to rotavirus vaccine introduction in India.

BACKGROUND: Rotavirus is an important cause of severe diarrhea requiring hospitalization, accounting for approximately 78,000 deaths annually in Indian children below 5 years of age. We present epidemiological data on severe rotavirus disease collected during hospital-based surveillance in India before the introduction of the oral rotavirus vaccine into the national immunization schedule. METHODS: The National Rotavirus Surveillance Network was created involving 28 hospital sites and 11 laboratories across the four geographical regions of India. From September 2012 to August 2016 children less than 5 years of age hospitalized for diarrhea for at least 6 h, were enrolled. After recording clinical details, a stool sample was collected from each enrolled child, which was tested for rotavirus antigen using enzyme immunoassay (EIA). Nearly 2/3rd of EIA positive samples were genotyped using reverse transcription polymerase chain reaction to identify the G and P types. RESULTS: Of the 21,421 children enrolled during the 4 years surveillance, 36.3% were positive for rotavirus. The eastern region had the highest proportion of rotavirus associated diarrhea (39.8%), while the southern region had the lowest (33.8%). Rotavirus detection rates were the highest in children aged 6-23 months (41.8%), and 24.7% in children aged < 6 months. Although rotavirus associated diarrhea was seen throughout the year, the highest positivity was documented between December and February across all the regions. The most common rotavirus genotype was G1P[8] (52.9%), followed by G9P4 (8.7%) and G2P4 (8.4%). CONCLUSIONS: There is high burden of rotavirus gastroenteritis among Indian children below 5 years of age hospitalized for acute diarrhea thereby highlighting the need for introduction of rotavirus vaccine into the national immunization program and also for monitoring circulating genotypes.

Enteroviruses in patients with acute encephalitis, uttar pradesh, India.

An outbreak of viral encephalitis occurred in northern India in 2006. Attempts to identify an etiologic agent in cerebrospinal fluid by using reverse transcription-PCR showed positivity to enterovirus (EV) in 66 (21.6%) of 306 patients. Sequencing and phylogenetic analyses of PCR products from 59 (89.3%) of 66 specimens showed similarity with EV-89 and EV-76 sequences.

Identification and characterization of enteric adenoviruses in infants and children hospitalized for acute gastroenteritis.

Enteric adenoviruses are important etiological agents associated with sporadic infections and outbreaks of acute gastroenteritis in infants and children. Fecal samples were collected from 439 hospitalized patients in the years 2005-2007 from Pune, Aurangabad, and Nagpur cities of western India to identify the most prevalent strains of enteric adenoviruses. The viruses were detected by PCR and characterized by sequencing and phylogenetic analysis. The prevalence of enteric adenoviruses in patients from Pune, Aurangabad and Nagpur was found to be 9% (10/111), 7% (7/100), and 7.5% (17/228), respectively. Sequence based analysis of the partial hexon and/or fiber genes showed the presence of adenovirus serotypes 40, 41, and 31 and variations at the subgenus and strain level. Phylogenetic analysis of the adenovirus strains indicated 98-100% homology with adenovirus 40 of the UK, 96-99% with adenovirus 41 of the USA and 94-100% with adenovirus 31 of Austria. The study indicates circulation of enteric adenovirus serotypes 40 and 41 with an unreported serotype 31 in sporadic cases of gastroenteritis. This is the first report from India on the association of enteric adenoviruses with acute gastroenteritis.

Epidemiological, clinical, and molecular features of norovirus infections in western India.

The study was conducted to investigate the molecular epidemiology of noroviruses (NoVs) from western India. A total of 830 fecal specimens were collected during July 2005-June 2007 from children, < or =7 years of age suffering from acute gastroenteritis in Pune, Nagpur, and Aurangabad cities. All the specimens were subjected to RT-PCR, sequencing and phylogenetic analysis for detection and characterization of Genogroup I (GI) and GII NoVs. NoV positivity varied between 6.3% and 12.6% in different cities with the predominance of GII (96.6%). NoV infections were very common in the patients < or =2 years of age. A majority (55%) of the patients suffered from severe disease, however, vomiting was not experienced in 35%. Coinfections with rotaviruses were found in 10% cases. Summer month seasonality supported NoV infections in western India. The phylogenetic analysis of partial RNA polymerase and VP1 (capsid) genes identified 2 GI (GI. 2 and GI.6) and 5 GII (GII.4, GII.6, GII.7, GII.8, and GII.14) genetic clusters with possible occurrence of "2007 new-variant" of GII.4. Six different combinations of RdRp and capsid genes (GII.b/GII.3, GII.b/GII.4, GII.d/GII.3, GII.b/GII.18, GII.1/GII.12 and GII.3/GII.13) were also identified. GII.4 (52%) prevailed in 2005-2006 while the predominance of probable recombinant NoV strains (58%) was noted in 2006-2007 with the contribution of GII.b/GII.3 at 79% level. GII.b/GII.18 type identified in 37% infections in 2005-2006 was completely replaced by GII.b/GII.3 type in 2006-2007. This is the first report that highlights the norovirus epidemiology and strain diversity demonstrating possible circulation of new variants in patients with acute gastroenteritis from western India.