This is our Friday rubric: every week a new Science Page from the Bob Morrison’s Swine Health Monitoring Project. The previous editions of the science page are available on our website.
Doctors Guilherme Preis and Cesar Corzo from the University of Minnesota share with us preliminary data from a Senecavirus A (SVA) outbreak investigation in a sow herd. This research emphasizes the importance of understanding the within-herd epidemiology of this virus.
SVA is still present in the U.S. swine herds at lower levels.
SVA RNA has been consistently detected in processing fluids in the event of a disease outbreak in a sow herd.
Viral dynamics and shedding cessation in the breeding herds need to be better characterized.
PhD-candidate Guilherme Milanez Preis, working with Drs. Cesar Corzo and Fabio Vannucci on the epidemiology of Senecavirus A. In an article for the National Hog Farmer, Preis shares the latest results of his work on Senecavirus A prevalence in the USA.
Naturally-infected boars have been documented to shed Senecavirus A (SVA) RNA in semen for up to three months after exhibiting vesicular disease.
Experimentally-infected boars shed SVA RNA in semen for up to three weeks post-inoculation.
The majority of experimentally-infected boars did not exhibit clinical signs or develop apparent lesions.
“This update shows that SVA RNA is shed in semen from both naturally-infected and experimentally-inoculated boars. The prolonged shedding of viral RNA in semen and the presence of SVA RNA in the testes and tonsils of the naturally-infected boars for up to three months are concerning findings and raises the possibility of persistent infection in boars. While the duration of shedding in semen for the experimentally-infected boars was considerably shorter than for the naturally-infected boars, the fact that all contemporary-strain boars had PCR-positive semen on at least one collection indicate that shedding in semen is a repeatable phenomenon and shedding occurred in some boars which did not exhibit clinical signs or develop vesicular lesions. It is currently unknown whether semen from infected boars can serve as a source of infection if used to inseminate susceptible females.”