6.5.4 Wild boar-habitat cycle
Wild boar is one of the most widespread group of mammals, which can be found on every continent expect Antarctica (He, 2014). The Indian crested wild-boar (Sus scrofa cristatus ) is seen in most of the wildlife-protection sanctuaries and is widely distributed in India, Sri Lanka, Nepal, Thailand and Myanmar (Naish, 2015).Wild boars exhibit a home range behaviour, in which the movements of these animals are generally restricted to a defined area over an extended period of time. However, depending upon ecological conditions, these animals may roam about widely in search of better forage conditions (Allwin et al., 2016). Presently, the wild boar population in India are fragmented and can be observed in isolated groups. Some of these isolated populations can become locally overabundant and depend upon agricultural crops especially in and around the protected areas and village interface areas for a major part of their food requirement (Chauhan et al., 2009). While utilizing the agro-ecosystem for food, resource and shelter, contaminated food waste originating from the infected domestic pigs can initiate an ASF epidemic which may accidentally be released into a wild boar habitat. Infections disseminated to a group of wild-boar will persist in the wild-boar habitat and their carcasses. This cycle will continue to infect healthy wild-boar and domestic habitat. Besides, as discussed earlier, in most of the Indian pig rearing states, carcasses or contaminated materials of infected domestic pigs are usually disposed in jungles or thrown in rivers. By doing so, it can not only be a source of infection to natural host and wildlife reservoirs, but also to pygmy hogs population (Porcula salvania ), an endangered species native to India and the only known population that lives in Assam which is estimated to be less than 250 in numbers (Meijaard et al., 2019). The susceptibility of pygmy hogs to ASFV is unclear , althoughClassical Swine Fever virus , an RNA virus that causes a disease with similar clinical signs to ASFV, can infect and kill pygmy hogs (Barman et al., 2012).
Based on the epidemiological cycles, the tick-pig, the domestic and the wild boar-habitat cycles are important in emergence of future outbreak of ASF and should be critically investigated to identify the transmission patterns and to implement control strategies.