First detection and genetic characterization of atypical Porcine pestivirus in pigs, Thailand

Atypical Porcine Pestivirus (APPV) is an emerging pathogen in pigs. The virus causes diseases associated with neurological disorders, such as congenital tremors (CT) Type A-II in piglets, leading to economic losses in the swine industry. This study investigated an outbreak of Atypical Porcine Pestivirus (APPV) on a commercial pig farm in eastern of Thailand from November 2023 to July 2024. Our results showed APPV positive in 14.18% (39/275). APPV was highly detected in nursery pigs at 40.00% (12/30) with a statistically significant (P < 0.05) association between age and APPV infection. Thai-APPVs (n = 9) were characterized by complete genome sequencing. Phylogenetic analysis of the whole genome of APPVs showed that Thai-APPVs belonged to APPV-Clade I. Moreover, the Thai-APPVs were clustered into a distinct subclade of APPV-Clade I, namely the Thai subclade, suggesting potential geographical adaptation. In conclusion, this study is the first to report the detection and genetic characterization of APPVs in a pig farm in Thailand, enhancing the understanding of its epidemiology and genetic diversity. Our findings highlight the need for APPV surveillance, particularly in young pigs, to facilitate early interventions and control measures.