Sequential Clusters of Multidrug-resistant Cholera Cases in the Thai-Myanmar Border, 2015

A drug-resistant cholera outbreak occurred at the Thai-Myanmar border in April to May 2015. On 21 Oct 2015, the Bureau of Epidemiology was notified of a cholera outbreak in Mae Sot District, Tak Province. An investigation was conducted to confirm the outbreak, identify source of infection and provide control measures. Medical records were reviewed and all cases and contacts were interviewed. Active case finding was performed in the affected areas and nearby communities. Rectal swabs were collected and tested for Vibrio cholerae O1/O139. Water and food samples were tested for possible contamination. A series of three separate outbreaks of multidrug-resistant V. cholerae O1 El Tor Ogawa infection were identified in the same district. The first cluster occurred among Myanmar migrant workers in a garment factory. Poor hygiene was found among workers and food handlers. The second cluster occurred among persons from Myanmar in Mae Sot Subdistrict. The last cluster occurred among Thai while most of them joined a religious ceremony in Mae Pa Subdistrict. The outbreaks were confirmed as V. cholerae O1 Eltor Ogawa resistant to ampicillin, co-trimoxazole and tetracycline. Rapid response and improvement in hygiene were recommended.