Outbreak of cholera due to contaminated pond water utilisation in a rural area of West Bengal, India, 2021.

BACKGROUND: On March 31, 2021, an outbreak of diarrhoeal disease was reported in Dangapara village of Purba Bardhaman district, West Bengal, India. The outbreak was investigated to estimate the magnitude, identify aetiological agents and source of infection, and guide prevention control measures. METHODS: We did an active search for case patients at Dangapara village. We excluded children under five years of age from the epidemiological analysis. We described the outbreak by time, place, and person. We conducted a case control study with 133 controls and 65 cases. Water samples from different sources and rectal swabs from case patients were collected and sent for laboratory investigations. RESULTS: We identified 95 case patients among 330 residents of Dangapara village (attack rate 29 %). Three stool samples were positive for Vibrio cholerae, and two pond water samples were contaminated with coliform organisms. Washing utensils [adjusted odds ratio (AOR): 69.8, (95% confidence interval (CI) 6.5-749.5)] and taking a bath in pond water [AOR: 3.4, (95% CI 1.2-9)] were associated with increased risk of illness. About 97% of cases were attributed to washing utensils in pond water. Washing hands before taking food was associated with a lower risk of developing disease with AOR: 0.1 (95% CI 0.03-0.33). CONCLUSION: A cholera outbreak occurred among residents of Dangapara village due to theuse of contaminated pond water for washing utensils and bathing. Prompt management of cases and immediate discontinuation of pond water use stopped the outbreak.

Upsurge and spread of G3 rotaviruses in Eastern India (2014-2016): Full genome analyses reveals heterogeneity within Wa-like genomic constellation.

Advent of new strains and shift in predominantly circulating genotypes are characteristics of group- A rotavirus (RVA), one of the major causes of childhood gastroenteritis. During diarrheal disease surveillance at Kolkata, India (2014-2016), a shift in circulating RVA strains from G1P[8] to G3P[8] was seen. Stool samples from children (n = 3048) with acute gastroenteritis were tested of which 38.7% were RVA positive. G1 was the predominant strain (65.3%) in 2014-2015 whereas in late 2015 and 2016, G3 became the preponderant strain (44.6%). In the past decade G3 strains were not observed in this region, we conducted whole genome sequencing of representative strains to gain insight into the phenomenon of emergence and genetic constellation of these circulating human G3 strains. The analyses revealed intergenogroup reassortment in G3P[4] strains (among Wa and DS-1-like genogroup) whereas G3P[8] strains were authentic Wa-like. Phylogenetic analysis revealed Kolkata G3 strains as polymorphic and thus they formed two sub-clusters due to antigenic differences in their VP7 protein. One of the sub-clusters had the wild-type threonine at 87 amino acid position while another sub-cluster had an isoleucine mutation. Presence of additional N-linked glycosylation site at amino acid 283 of VP7 glycoprotein suggests that the major neutralizing epitope on the VP7 (G3) of RotaTeq vaccine differs from the currently circulating G3 strains. The study is important as efficiency of rotavirus vaccine depends on the circulating heterogeneous genotype constellations. Continuous monitoring of circulating RVA strains in endemic settings like India is therefore important in pre- and post-vaccination period to monitor the emergence of new reassortant genotypes in addition to assessing vaccine efficacy.

Reporting measles case fatality due to complications from a tertiary care hospital of Kolkata, West Bengal 2011-2013.

INTRODUCTION: Measles is affecting millions of people in the developing countries particularly in India with significant morbidity and responsible for thousands of death in spite of having a safe, effective, and cheap vaccine. Pulmonary complications account for 90% measles-related death. The objectives of this study were to describe age distribution, clinical features, complications, and clinical outcomes of measles cases in a referral infectious disease hospital of West Bengal. METHODS: We conducted a retrospective descriptive study including 584 patients and collected information from record section on demographics, clinical features, complications, and clinical outcomes using data abstraction form. RESULTS: The mean age of 584 measles cases was 3.7 years (±1.2 years). The most common complication was pneumonia (149 cases) followed by diarrhea and encephalopathy. Very severe pneumonia occurred in 34 cases requiring intensive care out of which 13 patients died. The average duration of stay in the hospital was 5.7 days (±3.2 days). Surprisingly, 45 cases admitted to this hospital were <9 months of age with subsequent death in 5 cases. CONCLUSION: Substantial number of measles cases was seen in zero to <9 months of age group and fatality due to complication was more among them.