Seneca Valley Virus, RNA virus
University of California - San Diego
Seneca Valley Virus is a non-enveloped single-stranded RNA virus of the family Picronaviradae. Since it has similar symptoms as foot-and-mouth and swine vesicular disease, hog farmers finding lesions on the snout and coronary band/hoof lesions on sows, nursery pigs or finishing pigs should immediately consult their herd veterinarian.
Seneca Valley Virus has been found in pigs, cows and mice
Historical look into SVV
Historically, SVV has been reported in the United States, Canada, Australia, Italy and New Zealand. Over the past three decades less than 20 outbreaks on farms have been reported in the United States until now. The majority of those cases were reported in show pigs. However, an increasing number of outbreaks found in the last year in U.S. commercial herds are reasons for hog farmers to revisit the clinical signs of SVV.
Rapidly spreading in Brazil
Presently, the SVV is moving rapidly in Brazil. In the last 12 months, over 70% of Brazilian breeding herds have become positive for SVV.
Clinical signs in sows and gilts
American Association of Swine Veterinarians
Sows and gilts
Inspection of the sows of the affected litters may demonstrate any of the following lesions.
- Vesicles (intact or ruptured) on the snout or in the oral mucosa (Examples in Figures 1 and 2)
- Lesions on the feet around the coronary bands.
- May see ulcerative lesions on or around the hoof wall. (Figure 3)
- May see deep nail bed hemorrhages
- Breeding females which are not feeling well (anorexia, lethargy and/or febrile)
- Some sows will be off feed or not cleaning all of their feed up
- In the early course of the disease, fevers up to 105 degrees F have been reported
Clinical signs in neonatal pigs
- An acute increase in mortality in litters less than 7 days of age.
- Appear to be infected shortly after birth
- May or may not have diarrhea associated with it.
- May be confused with SECD (PEDV, TGE, PDCoV), PRRS, E.coli, Rota and/or Clostridium.
- Morbidity and mortality estimates are 30-70% for a short time period
- Clinical signs usually resolve quickly in four to seven days
- Most of the time, the pigs will be found to have milk in their stomach when necropsied.
Clinical signs in growing pigs
- Lameness is commonly observed
- Gross lesions include multifocal, round, discrete, erosive and/or ulcerative lesions on distal limbs, especially around the coronary bands
- Snout vesicles
- Submandibular edema
Method of SVV transmission unknown
Today, experts are unsure how SVV is spread from farm to farm. In Brazil, transportation has been a common thread.
Plan of action
Hog producers identifying any signs of vesicular disease must immediate reported to the state veterinarian or USDA APHIS assistant district director responsible for the state or region. They will determine if a foreign animal disease Investigation is warranted. Any movement from the farm is temporarily halted until directed by state and federal authorities. Hogs with lesions or any other listed clinical signs should not be taken to slaughter.
Charles Rudin and a team researchers found that SVV has an interesting property that it selectively infects and destroys cancer cells with neuroendocrine features but not other cells.