Outbreak investigation of pulmonary tuberculosis in rubber wood processing factories, Natamnue sub district, Muang Trang district, Trang, 30 August–7 September 2015

Abstract

Background: On 31^st August 2015, the investigation team of Muang Trang District had received a notification from TB clinic at Trang Hospital about 3 pulmonary tuberculosis patients who working in two rubber wood processing factories. Both factories are located in nearby area. Case investigation and close contacts tracing performed during 31^st August – 7^th September 2015 with aims to confirm diagnosis and outbreak, describe epidemiologic linkage, describe the disease burden and implement control and prevention measures.
Methods: Descriptive study was conducted. All patients were interviewed for their clinical presentations, history of exposure to active tuberculosis patient and their close contacts person. Active case finding was done by chest radiographs and sputum examination in all employees who worked or lived with patients. Interferongamma release assay technique was also used to support the diagnosis.
Results: During 2013-2014, six cases of pulmonary TB were detected in both factories. Both factories had above average rate of TB. All patients are foreign migrant workers (Myanmar), worked in different categorical job and lived in different factory dormitories. Two cases had been epidemiological linkage. Three new abnormal chest radiographs were found in asymptomatic close contacts of factory B. Interferon Gamma Release Assay (IGRA) specific for M. tuberculosis was used to confirm diagnosis and two new smear-negative pulmonary TB cases were positive. Both serological confirmed workers had history of pulmonary tuberculosis in family.
Conclusions: We confirmed outbreak of pulmonary TB in migrant workers and under detected for such a long time. It needs intensive active case finding procedures for control and prevention. Pre-employment and periodic chest radiograph for all workers and family members should be performed for early detection of new active pulmonary tuberculosis case.