The first acute febrile illness investigation associated with dengue fever in Ethiopia, 2013: A descriptive analysis

Background: Dengue fever (DF) is a febrile illness caused by any one of four serotypes of the dengue flavivirus. Approximately 50 to 270 million DF infections occur every year globally. Dire-Dawa town of Ethiopia reported unidentified febrile cases in September 2013. Methodology: We investigated the case to identify the etiology and source of the outbreak. Medical records were reviewed and descriptive data analysis was performed. Serum-samples were tested for arbovirus by Enzyme-linked Immunosorbent Assay (ELISA) and Real Time Polymerase Chain Reaction (RT-PCR) techniques. Vector surveillance was carried out in the affected area. Results: A total of 11,409 suspected DF cases were identified from 12/9/2013 to 31/12/2013. The Attack Rate (AR) was 3.6%. Age groups consisted of 15-44 year-olds who were mostly affected (AR: 5.5%). Laboratory investigation showed that 50/88 (56.8%) samples were positive for DF infection, DEN-2 serotype. Aedes aegypti was identified both at indoor and outdoor levels. Breteau and container indices ranged from [19.3 - 36.4] and [8.1 - 25.2] respectively. Conclusion: This is the first investigation that revealed DF in Ethiopia. We found artificial breeding sites were the primary source of the vector. Vector control should be in placed to interrupt the ongoing outbreak and ensure future prevention. DF needs to be included in the existing routine surveillance.