Case investigation of Pertussis in Ban Aoe Arthon community, Bangkok, 23 May–7 June 2017

Abstract

Background: On 23rd May 2017, Public Health Center 50 was notified by Communicable Diseases Control Division, Department of Health, Bangkok Metropolitan Administration (BMA) that a pertussis patient was admitted at a BMA hospital. An investigation was conducted from 23rd May to 7th June 2017 in order to confirm diagnosis, determine the extent of the outbreak and recommend control measures.
Methods: We reviewed treatment records and conducted active case finding in Ban Aoe Arthon community. A suspected case was defined as a person who lived in Ban Aoe Arthon community and developed at least two of the following symptoms: fever, cough and inspiratory whooping cough between April 24th and June 7th, 2017. A probable case was defined as a person who had upper respiratory tract symptoms with epidemiologic linkage with confirmed case. A confirmed case was a suspected case with a positive Reverse transcription polymerase chain reaction (RT-PCR) for B. pertussis from a nasopharyngeal swab. A coverage of vaccines under EPI (Expanded Program for Immunization) was surveyed in the community.
Results: An index case with a laboratory confirmation was a Thai female infant aged 28 days. She developed symptoms on 15th May 2017 and had been admitted in a hospital during 21st May–5th June 2017 with paroxysmal cough, vomiting and inspiratory whoop. Laboratory investigation showed leukocytosis with lymphocytosis (lymphocyte 56%) and a nasopharyngeal swab was yield positive Bordetella pertussis by PCR on 24th May 2017. Four household contacts, all members had upper respiratory infection symptoms but their nasopharyngeal swabs were tested negative for B. pertussis. All household members and 30 health care professionals who had exposure to the case received post-exposure prophylaxis with oral azithromycin for 5 days. After monitoring for 21 days, no secondary case of pertussis was found in this outbreak.
Conclusions and discussions: An outbreak of pertussis in Ban Aoe Arthon community was confirmed. This disease was probably transmitted from caretakers in the family to the index case. In order to prevent and control pertussis in the community, we educated people about pertussis, gave post-exposure prophylaxis to all contact persons, and increased DTP vaccine coverage in the community.