Transboundary spread of pig diseases: the role of international trade and travel

Beltran-Alcrudo, Daniel; Falco, John R.; Raizman, Eran; Dietze, Klaas

Live imported infected pigs may lead to outbreaks by infecting directly additional animals at their destination site (e.g. receiving farm, live animal market), or once slaughtered and processed when the resulting meat or slaughter leftovers are improperly disposed or swill fed. Home-slaughtering is a particularly risky practice, since blood and other leftovers will likely contaminate the farm, hence easily infecting other susceptible animals on the premises. In Africa, it has been reported that whenever there are ASF outbreaks, in the absence of a compensation policy, farmers hurriedly sell the dying and in contacts pigs and their meat to salvage some income, for example in Uganda [72, 76, 92] . The same practice is suspected in China following the 2018 introduction [128] . This enhances disease spread across large geographical areas within or even across countries. Alternatively, when pigs die their carcasses may be then improperly disposed by the owners, unwilling to report the disease, which is a practice described as early as the 1910s [14] . Such behaviour was in fact responsible for some CSF cases in wild boar due to farmers who buried or dumped dead piglets in a nearby wood in 1951 in Germany [25] , which has also been reported as a common practice in Georgia and Uganda [11, 72] .