Litchi consumption and missed meals continue to be associated with acute encephalopathy syndrome among children: an investigation of the 2019 outbreak in Muzaffarpur district, Bihar, India

Background: Muzaffarpur district in Bihar State of India recorded a resurgence of acute encephalopathy syndrome (AES) cases in the summer of 2019 after no reported outbreak in 3 y. Earlier studies generated evidence that litchi consumption and missing the previous evening’s meal were associated with AES. We investigated the recent outbreak to understand the risk factors associated with AES. Methods: We conducted a matched case-control study by comparing AES cases with healthy controls from case-households and the neighborhood community for risk factors like missing evening meal and litchi consumption before onset of AES. Results: We recruited 61 cases and 239 controls. Compared with the community controls, case-patients were five times more likely to have reported eating litchi in the 7 d preceding the onset of illness (adjusted OR [AOR]=5.1; 95% CI 1.3 to 19) and skipping the previous evening’s meal (AOR=5.2; 95% CI 1.4 to 20). Compared with household controls, case-patients were five times more likely to be children aged <5 y (AOR=5.3; 95% CI 1.3 to 22) and seven times more likely to have skipped the previous evening’s meal (AOR=7.4; 95% CI 1.7 to 34). Conclusions: Skipping the previous evening’s meal and litchi consumption were significantly associated with AES among children in Muzaffarpur and adjoining districts of Bihar.