6.4 Availability of wildlife reservoirs and their habitat
AFSV is maintained in a stable equilibrium with its wildlife hosts, warthogs and soft ticks of Ornithodoros species, in a unique ecological niche (Netherton et al., 2019). Though the sylvatic cycle of ASFV in warthogs contrasts with the domestic cycle in swine, yet, in both instances, soft ticks of the genus Ornithodoros   in warthog burrows and domestic pigpens serve as biological hosts and vectors (Calisher and Fenner, 2000). The wildlife reservoirs, warthogs are native to Africa and often found in abundance (de Jong et al., 2017).The Common warthog (Phacochoerus africanus ) is widely distributed over sub-Saharan Africa, and expanded its geographic range to West Africa eastwards to Eritrea and Ethiopia, southward through eastern Africa, and over much of southern Africa to southern Angola, Botswana, and Mozambique to northeast South Africa (de Jong et al., 2017). The Desert warthog (Phacochoerus aethiopicus ) is presently known only from south-eastern Ethiopia, western Somalia, and in central and eastern Kenya (d’Huart et al., 2011). Since warthogs are confined mostly to Africa, outbreaks of ASF recorded outside the continent (recent outbreaks in Europe and Asia including India) raises questions about the involvement of sylvatic cycles, but might have arises through other means of disease dissemination such as infected pig-derived products and circulation of Ornithodoros  species across the borders. However, distribution of warthogs (desert warthogs in particular), is largely unstudied for which further field surveys are needed to better determine geographic limits, area of occupancy, abundance and the impacts of various human/livestock-raising activities on distribution and abundance (d’Huart et al., 2011). There are also limited investigations on bushpigs to understand their contribution in the epidemiology of ASF and the interactions between these natural hosts and domestic pigs (Ravaomanana et al., 2011).