Pathogenicity of Seneca Valley Virus in Pigs and Detection in Culicoides from an Infected Pig Farm

Background: Porcine vesicular disease is caused by the Seneca Valley virus (SVV), it is a novel Picornaviridae, which is prevalent in several countries. However, the pathogenicity of SVV on 5-6 week old pigs and the transmission routes of SVV remain unknown. 

Methods: This research mainly focuses on the pathogenicity of the CH-GX-01-2019 strain and the possible vector of SVV. In this study, 5-6 week old pigs infected with SVV (CH-GX-01-2019) and its clinical symptoms (including rectal temperatures and other clinical symptoms) were monitored, qRT-PCR were used to detect the viremia and virus distribution. Neutralization antibody assay was set up during this research. Mosquitoes and Culicoides were collected from pigsties after pigs challenge with SVV, and SVV detection within mosquitoes and Culicoides was done via RT-PCR. 

Results: The challenged pigs presented with low fevers and mild lethargy on 5-8 days post infection. The viremia lasted more than 14 days. SVV was detected in almost all tissues on the 14th day following the challenge, and it was significantly higher in the hoofs (vesicles) and lymph nodes in comparison with other tissues. Neutralizing antibodies were also detected and could persist for more than 28 days, in addition neutralizing antibody titers ranged from 1:128 to 1:512. Mosquitoes and Culicoides were collected from the pigsty environments following SVV infection.