ECO-EPIDEMIOLOGY OF EBOLA AND MARBURG VIRUSES UNDER A CHANGING CLIMATE IN WESTERN UGANDA

Abstract

Despite the fact that the Ebola Virus (EBOV) and Marburg Virus diseases (MARV) are well known zoonotic diseases, most of the existing studies focus on secondary infection (humanhuman transmission) and clinical treatment of the viruses often ignoring the primary source of infection. However, improving our understanding upon the interactions that promote contact among host species and identifying risky areas are important in determining EBOV and MARV transmission and subsequent control measures at a wildlife-livestock-human interface. The purpose of the study was to identify and evaluate environmental factors linked to Marburg and Ebola virus transmission and develop a risk map for the emergence and spread of the viruses to human populations. The study applied a cross sectional two-stage sampling with ‘region’ as the highest stage followed by ‘district’ as lowest sampling stages. Questionnaires were used to collect data on risk factors linked to Marburg and Ebola virus transmission. MaxEnt was used to predict habitat suitability of fruit bats, the hypothesized reservoir of filoviruses and QGIS was used to develop filovirus risk maps. Results show that unprotected water source (p=0.024) and contact with bats and nonhuman primates (p= 0.017) were the significant risk factors for exposure of the study population to filoviruses at 95% CI. MaxEnt results demonstrated that 30.3% of Uganda is suitable for fruit bats. In addition, models indicated that 60% of Uganda is at risk of filovirus outbreak. Land cover and precipitation driest quarter were the most critical factors for distribution of fruit bats. The study infers that research into the epidemiology of filoviruses is still an urgent call in the Albertine region of Africa. However, refocusing efforts towards the ecological interactions of the disease causing agents, reservoirs and hosts at wildlife-livestock-human interaction may lend a window into understanding the mechanism of spillover of viruses into the human population. The study, however, recommends that future climatic scenarios and variables related to population size, human settlement patterns, habitat alterations and cave distribution points should be included in the future studies in order to get a more realistic impression of the risk areas