Why the fuss?
VS is a viral infection that can affect a range of animals species. In addition to horses, it can infect cattle, pigs and sheep (and a few others). It produces painful blisters in the mouth and other areas that can result in decreased eating and drinking, lameness, severe weight loss and secondary infections. In food animals, it can cause severe economic losses. Another issue is that in cattle and sheep, it looks like the dreaded food and mouth disease. Lab tests can distinguish the two, but there can be a lot of angst when sorting out what causes vesicular diseases in cattle.
VS is a reportable disease in Canada and was last identified in the country in 1949. Import restrictions are a routine measure in response to the periodic US cases that occur.
In this case, the following restrictions have been implemented:
- Horses cannot be imported from New Mexico.
- Canadian horses that are in New Mexico must either get an import permit and supplemental USDA health certificate, or must be moved to another state for at least 21 days prior to returning to Canada. The supplemental certification indicates they’ve been evaluated by a veterinarian, have not been on a farm where VS was present over the past 60 days, and have a negative VS blood test. Horses that are moved to another state require a USDA certificate indicating that they’ve lived in that state for at least 21 days. (This may be complicated by restrictions implemented by other states on accepting horses from New Mexico.)
- All other horses coming from the US must be certified by the USDA as not having been in New Mexico in the past 21 days.
Image: Ulcers on the tongue of a horse infected by vesicular stomatitis (VS) virus. Image source: Colorado State University Extension