The outbreak investigation of Tuberculosis in group villages, Yang Kham Subdistrict, Nong Ruea District, Khon Kaen Province, Thailand, August 2024–June 2025

Abstract

Background: A preliminary disease investigation conducted by the Tuberculosis Clinic at Nong Ruea Hospital on 28 February 2025 identified two tuberculosis (TB) patients residing in the same household within a three-month period. Consequently, the Nong Ruea District Surveillance and Rapid Response Team (SRRT), in collaboration with relevant agencies, carried out an investigation and implemented disease control measures in the area on 7 March 2025 to confirm the outbreak, assess disease distribution, identify prevention and control measures, and develop recommendations.

Methods: This study employed a descriptive epidemiological design comprising three components. 1. Epidemiological data review: General area information and the TB situation in Nong Ruea District and Yang Kham Subdistrict were analyzed using data from the National Tuberculosis Information Program (NTIP) of Thailand for the period 2020–2024 and 2025 (1 January–30 June 2025). Disease distribution was examined by person, place, and time. 2. Environmental investigation: Environmental conditions of the index case household, the surrounding community in villages 1, 2, 13, and 14 of Yang Kham Subdistrict, and locations regularly visited by the patients were assessed. 3. Laboratory investigation: This included presumptive diagnosis through routine laboratory tests, chest radiography (CXR), and specific diagnostic laboratory testing.

Results: An outbreak of tuberculosis was identified in villages 1, 2, 13, and 14 of Yang Kham Subdistrict, Nong Ruea District, during August 2024–June 2025. Four confirmed TB cases (20.0%) and four presumptive TB cases were identified among 33 suspected cases (12.12%). Among 25 household and close contacts of the index case and her husband, one confirmed TB case (4.0%) and three cases of latent tuberculosis infection (LTBI) (12.0%) were detected. The likely source of infection was transmission from the husband, who had been diagnosed with TB approximately one month earlier, to the index case. The husband was presumed to have acquired TB from a fellow participant in religious practice at a temple who had been diagnosed with TB approximately five months prior.

Recommendations: Nong Ruea Hospital, in collaboration with the public health network, should ensure comprehensive screening of all household and close contacts of confirmed TB cases in accordance with the guidelines of the Division of Tuberculosis. Local public health agencies in each subdistrict should survey community settings at risk for TB transmission, particularly venues where people regularly congregate, and collaborate with site managers to improve environmental conditions to prevent disease transmission.