Investigating an Outbreak of Hepatitis A in an Urban Area of Madurai, Tamil Nadu, 2023.

In July 2023, we investigated a cluster of jaundice cases in Madurai district, Tamil Nadu, to identify outbreaks, etiology, and source and to propose control measures. A door-to-door survey identified 119 cases, with an attack rate of 8.3 per 1000. An environmental investigation and matched case-control study confirmed that the outbreak was linked to contaminated urban local body (ULB) water. Consuming ULB piped water caused 33% of cases (odds ratio [OR] 9.9, 95% confidence interval [CI]: 2.5-38.6), whereas drinking unboiled water caused 81% (OR 15.1, 95% CI: 5.4-42.3). The outbreak highlighted the need for improved water and sewage management in the district.