Wildlife as Potential Vectors of African Swine Fever Virus

The African swine fever virus (ASFV) remains contagious for a long time, not only in the carcass, but also in the bone marrow of an infected animal. The scavenging activity of various animals on ASFV-infected carcasses is a likely risk factor for ASFV transmission. Thus, we conducted this study to determine whether scavengers are potential vectors for ASFV. In nonprotected wild boar carcasses on the forest floor, we investigated the seasonal patterns of carcass decomposition and scavenger visits for feeding on them. The duration from fresh to early skeletonization (only bones and leather remaining) of adult carcasses was 37.6±23.1 days (n=3, range=11-51 days) in winter. The duration from fresh to later skeletonization (only bones and some fur remaining) of all carcasses, including subadult carcasses, was 8.3±2.5 days (n=4, range=7-12 days) in summer. At all three study sites, leopard cats (30.3%), large-billed crows (21.6%), and golden eagles (18.1%) were the frequently visiting species, representing more than 10% of the total visits (343 visits) in winter, whereas raccoons (21.9%), grey-backed thrushes (39.4%), and eyebrowed thrushes (14.7%) were the most frequent visitors in summer. In winter, crows or cinereous vultures were the first animals to arrive at a carcass; in summer, raccoons or crows arrived first. Our results showed that wild boars, raccoons, and leopard cats relatively frequently visited wild boar carcasses and stayed there for a long time. Wild rodents chewing on or staying near carcasses were photographed during winter. In addition to wild boars, thus, mammals, such as raccoons, leopard cats and rodents, and birds, such as accipitrids and thrushes, may be spreaders of ASFV in South Korea.