Rabies Genetic Diversity and Reservoir Identification in Terrestrial Carnivores Throughout Ethiopia
[Thesis]
Binkley, Laura Elyse
Gebreyes, Wondwossen
The Ohio State University
2019
350
Ph.D.
The Ohio State University
2019
Ethiopia has long been among the most rabies-affected countries in the world with an annual incidence rate of 1.6/100,000 population. Domestic dogs serve as the principal reservoir for rabies transmission however, little information exists regarding the genetic diversity of RABVs circulating in dogs or the existence of cycles maintained by other mammalian species. Identifying all reservoirs of rabies plays a crucial role in effective disease control. Objectives include 1.) Investigation of the genetic diversity of rabies circulating in wild and domestic species throughout Ethiopia; 2.) Identification of intraspecies and interspecies contact rates at communal foraging sites; 3.) Application of contact rate estimates to mathematical expressions that will help determine maintenance potential. This work comprises the study of 230 partial and complete N-gene sequences obtained from both wild and domestic species collected throughout different regions of Ethiopia during the period 2010-2017. Camera traps were used to examine contact rates within and between terrestrial carnivore species at communal foraging sites. These contact rates were then applied to expressions of the basic reproductive number to determine the rabies maintenance potential of populations. Results identified the existence of a major dog rabies epizootic throughout Ethiopia involving a homogeneous RABV variant that has been spreading from an epicenter in the Oromia region. Additionally, a 3.3% divergent RABV variant circulating in side-stripped jackals was identified. Intraspecies contact rates and calculations of maintenance potential were highest in domestic dogs followed by spotted hyenas and domestic cats, respectively. Interspecies contact rates and calculations of maintenance potential were highest between domestic cats and spotted hyenas. This snapshot of rabies dynamics in Ethiopia provides important baseline data for prevention and control efforts and serves as the first steps in identifying wildlife reservoir hosts for rabies transmission throughout the country.