Investigation of Diphtheria Outbreak in Chatuchak District, Bangkok, August - September 2013

Abstract

Background: Bangkok had been free from diphtheria for 6 years before this outbreak was notified in August 2013.
Methodology: An investigation was conducted during 27^th August - 18^th September, 2013 with the objectives to confirm a diagnosis and outbreak, to conduct active cases findings to assess the scope of the outbreak, and implement control measures. The investigations included epidemiological descriptive study, laboratory testing, environmental surveys at a patient’s house, community and schools. To identify other cases and close contacts, medical records review, data from interviews were recorded in the investigation forms.
Results: Investigation results revealed a fatal diphtheria case of 2 years and 4 months old girl with lab confirmation of toxin-produced Corynebacterium diphtheriae. Seven carriers were identified and they were children aged between 4 and 10 years. The index case patient and 3 carriers were siblings in the same household. Another carrier was her relative who lived nearby and contacted her in the same community. Of those 4 carriers, only one received full course of immunization as recommended in the Expanded Program on Immunization. The remaining 3 carriers were close contacts of the carriers in the community and they had completely received vaccines. Rapid survey of vaccine coverage in 83 children in the outbreak area found that 23 children did not receive one or more doses of DPT vaccine, accounted for the coverage at 72.29%.
Conclusion and discussion: The key success control measures were health educations provided to school teachers, students and guardians together with administering DPT/dT vaccines to 1,430 students within 2 weeks following a detection of the index case. The outbreak was curtailed and no second generation was observed in the outbreak affected area.