Risk Factors for Chikungunya Outbreak in Kebridhar City, Somali Ethiopia, 2019. Unmatched Case-Control Study

Background: Chikungunya Virus is a Ribose Nucleic Acid (RNA) virus transmitted by a mosquito bite. Aedes Aegypti and Aedes Albopictus are responsible vectors for Chikungunya Virus transmission. CHIKV outbreaks are characterized by rapid spread and infection rates as high as 75%. A combination of health system efforts and healthy behavior practices by the community is essential for effective control. Methods: Unmatched case control study was done to identify risk factors of this outbreak. One case to two controls ratios was calculated. All cases during the study period (74 cases) and 148 controls were included in the study. Bivariate and multivariable analysis were implemented. Serum samples were tested by Real Time Polymerase Chain Reaction at Ethiopian Public Health Institute laboratory. Results: A total of 74 chikungunya fever cases were reported starting from 19 th May 2019 to 8 th June 2019. Not using bed net at day time sleeping (P- value < 0.001, AOR 20.8, 95CI 6.4 – 66.7), presence of open water holding container (P- value 0.023, AOR 4, 95CI 1.2 – 13.5), presence of larvae in water holding container (P- value 0.015, AOR 4.8, 95CI 1.4 – 16.8), ill person with similar sign and symptoms in the family or neighbors (P- value <0.001, AOR 27.9, 95CI 6.5 – 120.4) and wearing not full body cover clothes (P- value 0.002, AOR 8.1, 95CI 2.2 – 30.1) were significant risk factors. Conclusion: Using bed nets at day time sleeping, cover the water holding containers, wearing full body cover cloths are protective factors.