5. EPIDEMIOLOGICAL CYCLES OF ASF
The epidemiology of ASF was described as comprising four independent epidemiologic cycles (i) sylvatic (ii) tick-pig (iii) domestic and (iv) wild boar-habitat cycle (a newly discovered cycle in Europe) (Chenais et al., 2018). The sylvatic cycle, mostly restricted to African continent, is maintained between Ornithodoros ticks and natural reservoirs (warthogs and bush pigs) that are resistant to the ASFV and usually do not develop any clinical disease (Plowright et al., 1994; Guberti et al., 2018). In the tick-pig cycle, the virus is transmitted among domestic pigs through ticks serving as a reservoir and allowing the virus to persist locally in the environment (Wilkinson, 1984). In the domestic cycle, the virus is transmitted among domestic pigs or from pig products to domestic pigs without the involvement of natural reservoirs (Chenais et al., 2019).The wild boar-habitat cycle is a newly described cycle in Central and Eastern Europe while investigating the epidemiological pattern of ASF infections in wild and domestic pig population (Chenais et al., 2018).This newly evolved epidemiological cycle involves wild boar (Sus scrofa ), the wild boar habitat and their carcasses for the maintenance and transmission of ASFV to domestic pigs (Chenais et al., 2018). The wild boar-habitat cycle may describe the possibilities of new infections in areas with wild boar population and in the interspaces between wild and domesticated swine habitat such as a Wildlife Sanctuary or a National Park.