The Virginia Department of Agriculture and Consumer Services today announced that the Virginia-Maryland Regional College of Veterinary Medicine and the Marion DuPont Equine Medical Center have been contacted about several confirmed cases of Potomac Horse Fever in central Virginia.
The Leesburg equine center is one of three campuses of the regional veterinary medical center and Interim Director Dr. Michael Erskine confirmed that the EMC had treated a couple of cases recently. “But the hospital population has not been indundated,” he said.
The disease is not contagious although it can be fatal. Cases are not required to be reported to the state veterinarian’s office,. VDACS Director of Communications Elaine Lidholm said the alert was issued to ensure horse owners in Virginia are aware of the potential for disease.
The disease is caused by multiple strains of the organism Neorickettsia risticii. It lives in a developmental stage of a freshwater fluke, or worm, which infects aquatic snails and insects. Horses become infected by ingesting infected snails, snail slime and/or aquatic insects as they grave and drink, most likely through ingesting infect adult flies as they can travel some distance from the water source where they originated and then contaminate water or food sources on the farm.
Erskine confirmed that the recent heavy rainfalls may have increased the number of aquatic insects and snails, thus exposing horses on area farms to the disease.
Erskine said the Blacksburg campus of the regional medical college issued the initial alert and asked EMC to pass the word—which it did via its website and Facebook page.
Potomac Horse Fever is treatable, particularly if the disease is detected early on. “Unvaccinated horses tend to get more sick,” he said.
The first symptoms for horse owners to look for include fever, loss of appetite and, sometimes, diarrhea—which can cause a horse to lose fluids and electrolytes. Monitoring body temperature regularly as well as a horse’s food consumption is important, Erskin advised. Unless the horse becomes seriously ill, the disease can be successfully treated on the farm through antibiotics, fluids and electrolytes and fever management.
Horses that are sicker are the ones that come to EMC, in need of intravenous fluids and more specific treatment. “Much of it has to do with severity of the disease. If the horse has been vaccinated, it has some immunity, and therefore more likely to be able to be treated at the farm,” Erskine said.
An important consideration for horse owners, according to Erskine, is not to be complacent about PHF. Vaccination is not very effective at preventing infection, but it may reduce the severity of the illness. “Don’t think vaccination alone will do,” he said, noting that booster shots are recommended in areas where the disease has been reported. Three further steps are also important, he said:
1. Reducing the horse’s exposure to aquatic insects and cleaning water buckets and troughs frequently while keeping night lights off to discourage insects;
2. Restricting horses from access to flowing streams or ponds, standing water or low-lying pasture areas; and
3. Contacting a veterinarian if the horse develops a fever or becomes depressed. Monitoring the horse’s temperature daily helps with early detection of fever.
Early treatment increases survivability rates and reduces the severity of the clinical signs.
If a horse does get sick, it can recover with treatment within several days, if there are no complications, the most common of which is laminitis or foundering.
Erskine has been in the interim directorship position since May. He is a referring veterinarian and equine practitioner in Maryland. He was appointed to the job after Nathaniel White, DVM, stepped down after nine years as director but remains on staff at the center.
For more information on Potomac Horse Fever go to the American Association of Equine Practitioners’ website: aaep.org/Potomac_fever.htm.