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.”
More than 230 Senecavirus outbreaks have been confirmed after July 2015 in the United States and this is why it is important:
“The clinical signs in pigs infected with vesicular disease caused by SVA are variable and can range from no outward signs, to nonspecific signs such as decreased appetite or fever, or pigs may develop vesicles, or blisters, on the skin or in the mouth.[..]
While SVA continues to plague U.S. and global pork producers, it is important to be reminded of and understand some basic characteristics and behavior of this virus. SVA causes vesicular lesions affecting the skin, mouth and feet of pigs of all ages and has been associated with increased neonatal mortality which may be accompanied by neonatal diarrhea. If vesicular disease is present, your state animal health official must be notified in order to rule out other foreign animal diseases, such as FMD. The virus can be detected in multiple sample types but there is variability in the amount of time for which each sample type can be used for detection. Finally, SVA is extremely stable and contaminated facilities, transport vehicles and fomites are concerns for possible virus transmission but several disinfectants have been shown to be effective at neutralizing the virus.”