Outbreak investigation of acute diarrhea disease associated with the Songkran festival in Mueang Suphan Buri district, Suphan Buri province, Thailand, 22–26 April 2024

Abstract

Background: On 19 April 2024, the Division of Epidemiology (DOE), Department of Disease Control (DDC), Thailand, was notified by the Event-based Surveillance WATCH Team of a cluster of acute diarrhea illness in Suphan Buri Province involving 54 cases. Preliminary investigation revealed that all laboratory-confirmed cases had attended the Songkran water festival in Mueang Suphan Buri District, Suphan Buri Province. A joint outbreak investigation was conducted by the DOE, the Office of Disease Prevention and Control Region 5, Ratchaburi, and the Suphan Buri Provincial Public Health Office from 22 to 26 April 2024. The objectives of the investigation were to verify the diagnosis and confirm the outbreak, describe the epidemiological characteristics of the outbreak by person, place, and time, identify the source and mode of transmission, determine risk factors associated with illness, and recommend appropriate prevention and control measures.

Methods: A descriptive epidemiological study. Data were collected through medical record reviews, patient interviews, and active case finding in the community. A suspected case was defined as any individual presenting with at least two symptoms (vomiting, fever, diarrhea, abdominal pain, watery stool, nausea, dizziness, headache, or bloating) between April 13 and 23, 2024. A probable case was a suspected case with a positive rapid diagnostic test for Rotavirus, while a confirmed case was a suspected case with Rotavirus detected via Multiplex or Real-time PCR. Environmental surveys were conducted at the event site. Stool samples and water samples were collected for laboratory analysis. Data were analyzed using descriptive statistics; categorical variables were presented as frequencies and percentages, while continuous variables were reported as medians.

Results: The investigation identified 327 suspected cases, 13 probable cases, and 19 confirmed cases. The male-to-female ratio was 1 : 1.16, with a median age of 10 years. Predominant clinical manifestations included vomiting, fever, and watery diarrhea. Most patients were treated as outpatients and reported attending "Songkran" Specifically, many guardians reported that their children had intentionally ingested water from the water tunnel. Environmental assessment revealed that the water used for the tunnel was diverted from a source located near public restrooms. Laboratory results confirmed Rotavirus in 19 clinical specimens and in water samples taken from both the source and the discharge pipes of the water tunnel.

Conclusion and Recommendations: This outbreak of Rotavirus diarrhea was definitively linked to exposure to contaminated water during Songkran. It is recommended that local public health authorities enhance public awareness regarding diarrheal diseases. Furthermore, event organizers for water-related festivals must ensure that water sources meet safety and sanitation standards to prevent contamination and protect public health in future events.