Arbovirus circulation, epidemiology and spatiotemporal distribution in Uganda

Background: Arboviruses are endemic in Uganda; however, little is known about their epidemiology, seasonality and spatiotemporal distribution. Our study sought to provide information on arbovirus outbreaks from acute clinical presentations. Methods: Immunoglobulin M (IgM) and confirmatory Plaque Reduction Neutralisation Test (PRNT) results for arbovirus diagnosis of samples collected from patients attending sentinel sites from 2016−19 were analysed retrospectively. Demographic data were analysed with SaTScan and SPSS software to determine the epidemiology and spatiotemporal distribution of arboviruses. Results: Arbovirus activity peaked consistently during March−May rainy seasons. Overall, arbovirus seroprevalence was 9.5%. Of 137 IgM positives, 52.6% were confirmed by PRNT, of which 73.6% cases were observed in central Uganda with Yellow Fever Virus had the highest prevalence (27.8%). The 5−14 age group were four times more likely to be infected with an arbovirus p=0.003, 4.1 (95% CI 1.3−12.3). Significant arboviral activity was observed among outdoor workers(p=0.05). Spatiotemporal analysis indicated arboviral activity in 23 of the 85 districts analysed. Interpretation: Our study shows that arbovirus activity peaks during the March−May rainy season and highlights the need for YFV mass vaccination to reduce the clinical burden of arboviruses transmitted within the region.