key: cord-1004639-nu4hlm9y authors: Joshi, Madhuri S.; Lole, Kavita S.; Barve, Uday S.; Salve, Dawal S.; Ganorkar, Nital N.; Chavan, Nutan A.; Shinde, Manohar S.; Gopalkrishna, Varanasi title: Investigation of a large waterborne acute gastroenteritis outbreak caused by group B rotavirus in Maharashtra state, India date: 2019-07-05 journal: J Med Virol DOI: 10.1002/jmv.25523 sha: 7a57a2039925df8de385fd5d6f4d46a5945afffc doc_id: 1004639 cord_uid: nu4hlm9y An acute gastroenteritis outbreak at Devli Karad village, Maharashtra, India with an attack rate of 22.6% affected mainly adolescent and adult population. The viral investigations conducted on fecal specimens of patients hospitalized indicated the presence of rotavirus B (RVB) using RNA polyacrylamide gel electrophoresis and reverse transcription polymerase chain reaction. The samples collected from the source of drinking water also showed the presence of the only RVB. Absence of other viral agents and identification of RVB of genotype G2 as the etiological agent of the acute gastroenteritis outbreak highlights, the necessity of monitoring RVB, the viral agent known for its large outbreak potential. Diarrhea is the eighth leading cause of mortality and responsible for more than 1‧6 million deaths. 1 Among different diarrheal etiological agents, namely viruses, bacteria, and parasites, viral gastroenteritis continues to be an important cause of morbidity and mortality globally despite the improvements in sanitation and hygiene. The clinical manifestations of viral gastroenteritis include diarrhea, vomiting, fever, anorexia, headache, abdominal cramps, and myalgia . 2 The enteric viruses associated with acute gastroenteritis include rotavirus A (RVA), rotavirus B (RVB), rotavirus C (RVC), Caliciviruses (Norovirus and Sapovirus), enteric adenovirus, human astroviruses, aichiviruses, toroviruses, coronaviruses, picobirnaviruses, enteroviruses, and Sali/Klassi viruses. Globally, RVA is the main cause of sporadic cases of acute gastroenteritis in children less than 5 years of age and outbreak cases in infants hospitalized, day care centers, and old age individuals. 3 The circulation of RVC, in individuals of all age groups has been documented in sporadic and large outbreak cases from different parts of the world. 4 In contrast, RVB infections in sporadic and outbreak cases are mainly restricted to Asian countries namely China, India, Bangladesh, Myanmar, and Nepal and largely during gastroenteritis outbreaks in adults. [5] [6] [7] [8] [9] [10] [11] [12] [13] Among non-rota viral agents, Norovirus, Astrovirus, and Adenovirus infections have been reported to be predominant and known to be responsible for different gastroenteritis outbreaks globally. [14] [15] [16] The transmission of these viruses could be water-borne, food-borne, person-to-person, and a variety of less clearly identifiable modes. Tris-glycine buffer and gel was stained with silver nitrate as described earlier. 18 RT-PCR reaction for different viral agents was carried out by the methods as described earlier. 4, 5, [19] [20] [21] [22] [23] [24] The specimens positive for RVB using NSP2 gene-based RT-PCR were further subjected to genotyping analysis and nucleotide sequencing using previously reported VP7 gene-specific primers. 25 Nucleotide sequence identity was determined through BLAST (www.ncbi.nlm.nih.gov/blast) analysis. The phylogenetic tree was generated with the maximum likelihood method using MEGA 6 software. 26 Nucleotide sequences of the strains examined in the study have been deposited in GenBank under the accession numbers MK515128 to MK515139. Two water samples of 5 L each was collected from two wells on 18th November 2017, the only source of drinking water in the affected area before the emergence of the outbreak. Two water samples were also collected (5 L each) from both the sources after routine chlorination treatment on 28th December 2017. 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