Key result
Continuous APPV circulation in swine shows purifying selection and no substantial amino acid variation.
Why the study?
The molecular evolution and persistence of atypical porcine pestivirus within affected swine herds over time were not well characterized.
Observational
No
APPV can circulate in swine farms for years with limited immune pressure, and massive testing and removal of infected animals are insufficient to clear the virus.
Suggests current testing and removal may fail to clear APPV; leaves open need for alternative control strategies in swine.
Atypical porcine pestivirus (APPV) is a single-stranded RNA virus from the family Flaviviridae, which is linked to congenital tremor (CT) type A-II in newborn piglets. Here, we retrospectively investigated the molecular evolution of APPV on an affected herd between 2013 and 2019. Monitoring was done at regular intervals, and the same genotype of APPV was found during the entire study period, suggesting no introductions from outside the farm. The nucleotide substitutions over time did not show substantial amino acid variation in the structural glycoproteins. Furthermore, the evolution of the virus showed mainly purifying selection, and no positive selection. The limited pressure on the virus to change at immune-dominant regions suggested that the immune pressure at the farm might be low. In conclusion, farms can have circulation of APPV for years, and massive testing and removal of infected animals are not sufficient to clear the virus from affected farms.
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Folgueiras-González et al. (2020) conducted an observational in Atypical porcine pestivirus (APPV). Atypical porcine pestivirus (APPV) circulation was evaluated on Molecular evolution of APPV. Continuous circulation of the same APPV genotype was observed in an affected swine herd from 2013 to 2019, showing mainly purifying selection and no substantial amino acid variation.
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