Study explores how African swine fever spreads in backyard production systems

Researchers at the University of California, Davis’ Center for Animal Disease Modeling and Surveillance (CADMS) and FAO examined the pig trade structure of four pig-rearing regions of Georgia, a country with predominant backyard production systems, whose pig production was recently devastated as a consequence of African swine fever (ASF) epidemics. Their findings are reported in PLoS ONE.

Endemic to sub-Saharan Africa, ASF is re-emerging in new areas and is a major threat to pork production worldwide, both through direct losses and the effects of culling, trade sanctions and export restrictions imposed by countries to stop its spread. Georgia first reported ASF in 2007; from there the disease spread to the Caucasus region, Russian Federation and Eastern Europe, where it is still actively spreading today.

Esther Kukielka, graduate student at CADMS, UC Davis School of Veterinary Medicine, and first author of the study said that mathematical modelling and social-network analysis could shed light on how the virus might move through pig populations in Georgia and other countries where backyard pigs are predominant. These farmers typically raise a few animals for their own consumption and the economic impact for them is huge.

“We’re still investigating how African swine fever is moving in these regions, but pig trade and pig markets, in combination with wild boar movements, seem to play an important role,” said Kukielka.

“The disease is likely also spreading through the trade of contaminated pork products and the use of uncooked pork leftovers to feed pigs,” she said. “Results of our study can help to identify high-risk villages where target education and outreach activities should be conducted, mainly for pig producers and middlemen. We hope it will also help to inform the design of more cost-effective surveillance, prevention and control programmes.”

Kukielka said that preventive and control measures could include improving management, biosecurity and husbandry practices, conducting community workshops, providing better access to veterinarians, or encouraging governments to mitigate farmers’ losses by compensation or replacement of the dead or slaughtered pigs.

Article: Modeling the live-pig trade network in Georgia: Implications for disease prevention and control by Esther Andrea Kukielka, Beatriz Martínez-López and Daniel Beltrán-Alcrudo, published in PLoS ONE (2017) 12(6): e0178904, doi: 10.1371/journal.pone.0178904

[SOURCE: University of California, Davis]