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Background: Two suspected shellfish poisoning events were reported in Cuddalore District in Tamil Nadu, India, between January and April 2015. Objectives: The study was conducted to confirm the outbreaks and to identify the source and risk factors. Methods: For both outbreaks, a case was defined as a person with nausea, vomiting, or dizziness. Sociodemographic details and symptoms were noted down. Data were also collected in a standard 3-day food frequency questionnaire, along with a collection of clam samples. A case–control study was initiated in the April outbreak. Stool samples were collected from cases, and clam vendors were interviewed. Results: In an outbreak that happened in January, all the twenty people reported to be consumed clams were diagnosed as cases (100% attack rate, 100% exposure rate). In the April outbreak, we identified 199 cases (95% attack rate). In both outbreaks, the clams were identified as genus Meretrix meretrix. The most common reported symptoms were dizziness and vomiting. The clams heated and consumed within 30–60 min. No heavy metals or chemicals were detected in the clams, but assays for testing shellfish toxins were unavailable. All 64 selected cases reported clam consumption (100% exposure rate) as did 11 controls (17% exposure rate). Illness was associated with a history of eating of clams (odds ratio = 314, 95% confidence interval = 39–512). Of the six stool samples tested, all were culture negative for Salmonella, Shigella, and Vibrio cholerae. The water at both sites was contaminated with garbage and sewage. Conclusion: Coordinated and timely efforts by a multidisciplinary team of epidemiologists, marine biologists, and food safety officers led to the outbreaks' containment.

Background: A suspected food-poisoning outbreak occurred in a residential school in Mirzapur, India, in February, 2017. Objective: We investigated the outbreak to find out the epidemiology and to identify the risk factors. Methods: A descriptive study followed by retrospective-cohort study was done to investigate the outbreak. Cases (defined as ≥3 or more loose stools in 24 h, abdominal pain, or vomiting with onset between February 1 and 4, 2017) were searched by reviewing sick/patient registers from school and nearby health facilities. Cases were also searched through active surveillance by visiting school hostels. Stool samples were sent for microbiological testing. Food sources and food handlers were also assessed. Results: Among 468 students, 204 cases were identified (44% attack rate) without any mortality. The median age was found to be 14 years (range: 10–18 years) and 59% were male. Relative risk with consumption of curd, apple, and panjiri (sweetened wheat flour) was found to be 15.4, 2.5, and 3.7, respectively. All these three food items were served as prasad, a religious offering. Only consumption of sweetened curd (adjusted odds ratio = 36.1, 95% confidence interval = 12.1–107.8) was significantly associated with gastroenteritis. No microorganism was isolated from two tested stool samples. Curd from the vendor was prepared from nonpasteurized milk. There were no illnesses among food-handlers. Conclusions: This outbreak of acute gastroenteritis in a residential school was associated with consumption of curd, likely contaminated with preformed toxins. We recommend implementation of the food safety and standards authority of India regulations.

Background: In December 2018, an acute gastroenteritis outbreak was reported from Faridpur-Gujjran village, Patiala district, Punjab, India. Objective: The objective of this study was to describe the epidemiology and risk factors of the outbreak and recommend prevention measures. Methods: We conducted a descriptive study and a retrospective cohort study in the village. We defined a case as vomiting or ≥3 loose feces in 24 h plus abdominal pain and/or fever in a resident of the village during December 23–28, 2018. To find cases, we conducted a house-to-house survey; to identify risk factors, we conducted a retrospective cohort study. Fecal specimens were tested for enteric pathogens; water samples were tested for fecal contamination. We also interviewed food handlers. We compared attack rates by level of exposure. From the cohort study, we calculated risk ratios with 95% confidence intervals. Results: From the 261 residents of the village, we identified 116 cases (attack rate 44%) and no deaths. The median age of affected persons was 27.5 years (range 0.5–80 years). The illness was associated with eating in a community kitchen of a temple during December 23–24, 2018. Eating mixed vegetables was associated with illness. We found no pathogens in fecal specimens. All three water samples showed coliform contamination. Cooked food had been left at room temperature before serving. Conclusion: Improper storage practices might have led to microbial proliferation of the food served. Our findings will help guide the enforcement of food safety policies for community kitchens.

Background: On May 23, 2017, the health authorities in Longding district, Arunachal Pradesh, India, reported four suspected measles-related deaths in Konsa village, a remote village on the Indo-Myanmar border. Objective: We investigated to describe the epidemiology of the outbreak and identify associated risk factors. Methods: We defined a measles case as fever and maculopapular rash with cough, coryza, or conjunctivitis in a village of Longding district resident from March 1 to June 18, 2017. In Konsa village, we conducted a retrospective cohort study of children ≤5 years. We calculated attack rate (AR), case fatality rate (CFR), measles-containing vaccine first dose (MCV1) and Vitamin A coverage, risk ratio (RR), and vaccine efficacy. We collected samples for laboratory confirmation. We conducted a routine immunization system evaluation at multiple levels of Longding district. Results: We identified 75 suspected cases (56% females) for a Konsa village-specific AR of 86% (75/87) among children ≤5 years; the median age was 36 months; CFR was 7% (5/75); all deaths unvaccinated; none received Vitamin A. Coverage for MCV1 was 9.2% (6/65) and Vitamin A 4.6% (3/65). No MCV1 (RR = 7.3, 95% confidence interval [CI] = 1.3–53) and participation in a recent local festival (RR = 5.3, 95% CI = 1.5–18.5) were associated with illness. MCV vaccine efficacy was 100%. Of 17 cases, 13 tested positive for measles. The local health facility had neither staff nor immunization microplans. Conclusions: This outbreak was likely due to low MCV1 and Vitamin A coverage due to poor health-care access. The investigation led to a district measles catch-up campaign and resumption of regular immunization.

In July 2015, we investigated a foodborne illness outbreak in Sithalikuppam and Verupachi villages, Cuddalore district, Tamil Nadu, among the political rally attendees to determine the risk factors for illness. We conducted a retrospective cohort study, calculated risk ratio for the food exposures, and cultured stool specimens. Of 55 rally attendees, we identified 36 (65%) case patients; 32 (89%) had diarrhea and 20 (56%) had vomiting. Median incubation period was 14 h. Eighty-nine percent (32/36) of those who ate lemon rice at dinner had illness compared to 21% (4/19) of those who did not (RR 4.2). Of the six nonattendees who ate leftovers on July 25, all ate only lemon rice and became ill. Stool cultures were negative for Salmonella, Shigella, and Vibrio species. Lemon rice was probably contaminated with enterotoxins such as from Bacillus cereus. Our findings highlighted need for community food safety education and importance of thorough outbreak investigations.

Background: A foodborne disease outbreak among wedding attendees from Makunsar village, Palghar district, Maharashtra state, India, was reported on February 18, 2018. Objectives: The outbreak investigation was conducted to find out the epidemiology of the outbreak and to identify the etiologic agent and risk factors. Methods: A case–control study was carried out, where cases (patients), controls, and food handlers were interviewed and leftover foods were collected for culture. A case was defined as a person having vomiting or diarrhea (i.e., ≥3 loose stools within 24 h) who attended the wedding ceremony at Makunsar village, Palghar district, Maharashtra, on February 18, 2018. Attack rate and odds ratio (OR) were calculated with 95% confidence intervals (CIs). Results: Out of 75 cases, 63% were female. Altogether, forty-two (56%) cases were hospitalized, and later on, all of them were discharged from hospital without any mortality. About 93%, 68%, 43%, and 41% of the cases reported with vomiting, nausea, abdominal pain, and diarrhea, respectively. The median incubation period was found to be 4 h (range: 2–8 h). Eating gaajar halwa (carrot pudding) was significantly associated with illness (OR: 12.8; 95% CI: 3.5–46). Gaajar halwa is prepared with khoa, a perishable milk product. The gaajar halwa culture yielded no growth. Conclusion: The case-patients' clinical presentation and incubation period were consistent with enterotoxin-producing Staphylococcus aureus as the probable etiologic agent. The epidemiologic investigation identified the probable etiologic agent and food source in a low-resource community setting. Community food handlers were educated on food preparation hygiene and safe storage measures to prevent future outbreaks.