Managing Malaria outbreak in a village nested in tea garden of Jalpaiguri district, West Bengal, India 2023-2024.

BACKGROUND OBJECTIVES: In November 2023, the district health authority notified a malaria outbreak from a village nested in tea garden area of Jalpaiguri district. We investigated the outbreak with the objectives to characterize the agent, describe the persons affected and identify the risk factors. METHODS: A malaria case was defined as fever and laboratory confirmed malaria in Bamandanga village from October 2023-January 2024. Cases were identified by house-to-house visit and cases interviewed for demographic, clinical and exposure history using a semi-structured questionnaire. To test the main hypothesis of potential risk factor, a 1:1 unmatched case-control study was conducted. Controls included asymptomatic neighbours or those tested negative during the same period. Odds ratios (OR) with 95% confidence intervals (CI) was calculated using Epi Info software. RESULTS: One hundred eighteen P. vivax malaria cases (50% female) were identified from population of 4262 (attack rate=2.7%). The median age was 23 years (range: 2-70 years), 53% between 15-45 years. All patients were treated as per protocol, 44% were tribal, four with travel history). Bivariate analysis showed education ≤primary (OR=2.8, CI=1.62-4.76), kutcha housing (OR=9.3, CI=1.15-74.41), no animal shelter in house (OR=2.2, CI-1.2-3.88) animal shelter locating inside house (OR=3.3, CI-1.54-6.70), engaging in evening outdoor activity (OR=3.3, CI-1.92-5.74) and irregular pattern of mosquito net usage (OR=4.6, CI-2.62-7.93) linked with illness. Reactive surveillance through survey with vector control management was conducted as public health response. Three subspecies of Anopheles: hyrcanus , jamesii , gigas were identified during entomological surveillance. INTERPRETATION CONCLUSION: We investigated a P. vivax outbreak in a village nested in tea garden linked with behavioural factors. Interpersonal communication of risk factors to the villagers, early diagnosis through active case search, complete treatment and integrated vector management help controlled the outbreak. The outbreak was managed with reactive surveillance, case management, vector control measures along with interpersonal risk factor communication with villagers.