Detection and molecular characterization of porcine epidemic diarrhea virus in transportation and slaughterhouse-associated environments

Porcine epidemic diarrhea virus (PEDV) is a highly contagious and lethal pig coronavirus, particularly in neonatal piglets. The main route of PEDV transmission is the fecal-oral route via direct contact with infected pigs. As pigs are commonly transported to slaughterhouses in trucks, PEDV can infect farms through contact with contaminated trucks. In South Korea, there is insufficient understanding of pig transportation as a major source of virus transmission. Therefore, this study evaluated the presence of PEDV in transportation and slaughterhouses and investigated possible contamination sources. In total, 401 environmental samples were collected by swabbing surface areas with cotton gauze and classified into 4 categories based on their sampling location: vehicle interior, vehicle exterior, drivers, and slaughterhouses. The swab samples exhibited a relatively high PEDV detection rate of 19.2% (77/401). The detection rate was highest for the slaughterhouse (38.2%, 21/55) and lowest for the vehicle interior (13.0%, 12/92). Genetic and phylogenetic analysis revealed that all sequenced isolates belonged to the highly pathogenic genotype 2b currently circulating in South Korea. The high PEDV detection rates in transport vehicles and slaughterhouses suggest that transportation plays a major role in PEDV introduction into farms. Our findings emphasize the need to enforce biosecurity protocols, including adequate hygiene measures, to mitigate the risks associated with pig transportation.