This summer, several cases of Potomac horse fever (PHF) were reported in central Virginia. Although the disease is not contagious, it can be fatal and the Virginia Department of Agriculture and Consumer Services made horse owners aware of the threat.

Megan Green, DVM, manager of Merial’s Large Animal Veterinary Services, advises horse owners, especially those in geographic areas where PHF is prevalent, to consult with their veterinarians.

“(Your veterinarian) will have the latest information about the cases in the surrounding community and help assess the situation,” Green says. “But since there have been cases reported, it’s very likely he or she will recommend vaccinating. It’s the only way to help protect horses against Potomac horse fever.”

PHF is most commonly found near creeks and rivers and likely caused when horses ingest infected aquatic insects such as damselflies, caddisflies, and mayflies. Named PHF because the initial 1979 outbreak occurred near the Potomac River in Maryland, the disease has since been identified in 43 states, three Canadian provinces, parts of South America, the Netherlands, and France