An investigation of dengue outbreak in a village number 6, Jompratad sub district, Watphleng district, Ratchaburi province, 18-26 August 2015

Abstract

Background: On 17 August 2015, the epidemiology unit of Watphleng Hospital received the notification of cluster dengue fever from outpatient department. They lived in the same village. The surveillance rapid response team conducted outbreak investigation in the village during 18-26 August 2015. The objectives aimed to confirmed diagnosis and outbreak, to describe the epidemiological characteristics, to identify the disease burden and to implement control and prevention measure.
Methods: The descriptive epidemiological study was carried out. Active case finding was done by passive search in the hospital and active search in the community with case definition. Environmental survey in case households and the community was done and mosquito larva survey also done in the affected commune. Dengue antigen and antibody confirmation was done by immunochromatography assay.
Results: Totally eleven cases were met case definition of dengue. Nine cases were dengue fever and two cases were dengue hemorrhagic fever. There were three cases occurred in two weeks of index cases detection. And the outbreak was ongoing for two weeks with six cases detected. The most common clinical presentation was high grade fever followed by myalgia. The most common gender was female and the female to male ratio was 4.5 : 1. The case’s ages were 4 to 62 years old with the average of 28.7 years old. Most of them were student (45.5%). The cases were detected from the end of July to early August 2015. High HI index was also observed (50%) on 18 August 2015. There were three cases with laboratory confirmation. First case was positive Dengue NS1, second case was positive both Dengue IgM with IgG and last one was positive only Dengue IgG by immunochromatography assay.
Discussions: The delay detection of first case in the village was a crucial factor for wide spreading of outbreak in the village. Improvement of early detection was done by event base notification. The success of outbreak control was well cooperation between health sector and local administration.