Genetic characterization and evolutionary analysis of norovirus genotypes circulating among children in eastern India during 2018-2019.

Noroviruses are significant etiological agents of acute gastroenteritis (AGE) across all age groups, especially in children under 5 years of age. Although the prevalence of norovirus infection is known to have increased in various countries, in India there are few reports pertaining to the norovirus disease burden. We investigated the epidemiology and molecular characteristics of noroviruses in children seeking health care at two hospitals in Kolkata, Eastern India. Faecal specimens were collected between January 2018 and December 2019 from 2812 children under 5 years of age with acute gastroenteritis. Noroviruses were detected in 6.04% (170/2812) of the samples, and 12.9% (22/170) of these were cases of coinfection with rotavirus. Among children (≤5 years), a higher infection rate (8.2%, n = 94/1152) was observed in the 6 to 12 month age group. GII.4 Sydney 2012 was the dominant norovirus capsid genotype (n = 75/90, 83.3%), followed by GII.3 (n = 10/90, 11.1%). Other capsid types GII.13 (n = 4/90, 4.4%) and GII.17 (n = 1/90; 1.1%) were also detected at low frequency. Phylogenetic analysis showed that the GII.P16 polymerase of strains in this region clustered with those of the phylogenetically distinct monophyletic clade of GII.P16 strains, whose members have been circulating worldwide since 2014. Inter-genotypic norovirus recombinants such as GII.P16-GII.3 (n = 10) and GII.P16-GII.13 (n = 4) were also observed among the circulating strains. In comparison to previous studies from eastern India, the present study shows a higher detection rate of norovirus infection in the paediatric population suffering from acute gastroenteritis. Continuous surveillance is required for predicting the emergence of novel genotypes and recombinant strains and for future vaccine development.

Genetic characterization and phylogenetic variations of human adenovirus-F strains circulating in eastern India during 2017-2020.

Human adenovirus-F (HAdV-F) (genotype 40/41) is the second-most leading cause of pediatric gastroenteritis after rotavirus, worldwide, accounting for 2.8%-11.8% of infantile diarrheal cases. Earlier studies across eastern India revealed a shift in the predominance of genotypes from HAdV41 in 2007-09 to HAdV40 in 2013-14. Thus, the surveillance for HAdV-F genotypes in this geographical setting was undertaken over 2017-2020 to analyze the viral evolutionary dynamics. A total of 3882 stool samples collected from children (≤5 years) were screened for HAdV-F positivity by conventional PCR. The hypervariable regions of the hexon and the partial shaft region of long fiber genes were amplified, sequenced, and phylogenetically analyzed with respect to the prototype strains. A marginal decrease in enteric HAdV prevalence was observed (9.04%, n = 351/3882) compared to the previous report (11.8%) in this endemic setting. Children <2 years were found most vulnerable to enteric HAdV infection. Reduction in adenovirus-rotavirus co-infection was evident compared to the sole adenovirus infection. HAdV-F genotypes 40 and 41 were found to co-circulate, but HAdV41 was predominant. HAdV40 strains were genetically conserved, whereas HAdV41 strains accumulated new mutations. On the basis of a different set of mutations in their genome, HAdV41 strains segregated into 2 genome type clusters (GTCs). Circulating HAdV41 strains clustered with GTC1 of the fiber gene, for the first time during this study period. This study will provide much-needed baseline data on the emergence and circulation of HAdV40/41 strains for future vaccine development.

Genotypes of glycoprotein B gene among the Indian symptomatic neonates with congenital CMV infection.

BACKGROUND: Cytomegalovirus [CMV] is a causative agent of congenital infection worldwide and often leads to neurological deficits and hearing loss in newborns. Infants born with symptomatic congenital Cytomegalovirus infection [cCMV] are at significant high risk for developing adverse long-term outcomes. In this study, we look into the sequence variability of surface glycoprotein B [gB] encoding region in newborns with symptomatic CMV infection for the first time in Eastern region of India. METHODS: 576 suspected newborns from seropositive mothers were subjected to the study and ELISA was used to confirm CMV infection. Different genotypes and their subtypes were determined using multiplex nested-PCR. Viral load of different glycoprotein B [gB] genotypes was measured using RT-PCR. Sequencing and phylogenetic analysis was then performed using Bayesian interference. RESULTS: The overall frequency of cCMV infection was 18.4%, where 16.0% neonates were symptomatic. Among the different gB genotypes, gB1 had the highest frequency [23.5%] and gB4 showed the lowest occurrence [5.8%]. 23.5% of symptomatic neonates had mixed genotypes of gB, probably indicating matrenal reinfection with CMV strains in Indian population. Significant genotypic clades [gB1-gB2-gB3-gB5] were grouped closely based on gene sequences, but the gB4 sequence was in the outlier region of the phylogenetic tree indicating the genetic polymorphism. CONCLUSION: This is the first study on cCMV genotyping and its phylogenetic analysis from Eastern Indian neonatal population. The study holds importance in the assessment of cCMV seroprevalence in global perspective. gB protein can be used as a potential therapeutic target against CMV infection.

Clinical profile of dengue during 2005 outbreak in Kolkata and predictive markers of dengue haemorrhagic fever.

Epidemics of dengue outbreak are frequent in south-east Asian countries. Dengue is a major cause of morbidity and mortality in this region. This prospective observational study was done at Dr BC Roy Memorial for Children during the outbreak in 2005 in Kolkata to know the clinical pattern of dengue cases and to find the possible markers of development of dengue hemorrhagic fever. Two hundred and eighty seropositive cases of dengue were included in the study. Among paediatric population, 5 to 10 years age group was most commonly affected. One-sixth of the cases were from villages indicating the extension of the epidemic in rural areas. Abrupt onset of high fever, non-purulent conjunctival injection, erythematous lips, flushed appearance, myalgia, arthralgia, headache and thrombocytopenia were the predominant features. Rhinitis and pharyngitis were rarely found. Prolonged fever more than 7 days, flushed appearance, pharyngeal congestion, shock evidence, serous effusion, bleeding manifestations, thrombocytopenia, elevated liver enzymes and elevated PCV were associated with development of dengue haemorrhagic fever and dengue shock syndrome.