Risk factors associated with yellow fever epidemic, Luanda, 2016

Abstract

Introduction : on 22 January 2016, the Minister of Health of Angola declared an outbreak of yellow fever in Luanda province; after 30 years without any confirmed cases. This study aimed to identify factors associated with the yellow fever infection in patients residing in Luanda province. Methods : we conducted a 1:1 case-control study, with 120 cases and 120 controls. A case was defined as a person with positive laboratory confirmation for yellow fever. A control was a neighbor of case with negative laboratory test for yellow fever. A structured questionnaire was applied to those who gave informed consent to participate. Multivariate logistic regression models were used to identify associated factors with yellow fever infection. Significance level was set at p Results : 63.3% of the cases and controls were male, 48.3% of the cases belonged to the 11-20 age group, whereas only 47.5% of controls belonged to that age-group, and 34.2% lived in viana district. In 6.9% of cases co-infection with Malaria was detected. Factors associated with yellow fever infection were: not being vaccinated against yellow fever [OR = 24.9 (95% CI 9.8-62.8)]; presence of water containers without cover at home [OR = 13.7 (95% CI 4.6-40.8)]; existence of gutters in the house [OR = 3.5 (95% CI 1.1-12.1)]; and having bottles around the house [OR = 2.7 (95% CI 1.1-7.2)]. Conclusion : these results show the need for increasing public awareness about vector control communitarian strategies and personal protection from mosquito bites, as well as, the need to improve yellow fever vaccination coverage throughout the province of Luanda, mainly in the district of Viana, which was the most affected.