Potomac Horse Fever Outbreak: What You Can Do

By Patch editor Susan Larson 

Six cases of Potomac Horse Fever have been confirmed in the Hanover area of Virginia, which is just north of Richmond.  Equine veterinarians in the Commonwealth are recommending horse owners have their animals vaccinated and booster the vaccine for those already vaccinated.

Rappahannock Equine Veterinary Clinic released the following information:

"Potomac horse fever (PHF) is caused by an organism called Neorickettsia risticii (formerly called Ehrlichia risticii) and can affect any breed, age, or sex of horse. The disease has a seasonal pattern, occurring between late spring and early fall.  The organism that causes PHF is found within aquatic insects and infection in horses is believed to occur when the insects are accidentally ingested. Clinically ill horses are not contagious to other horses.

"Clinical signs are variable but typically include depression and anorexia (not eating), fever (102-107°F), mild colic, decreased abdominal sounds, diarrhea (60% of cases), and laminitis (40% of cases). If you see any of these signs in your horse, please call our office immediately. The antibiotic oxytetracycline can successfully treat the disease if given early in the course of illness. However, if the clinical signs are severe, the horse may need to have more supportive care such as fluids and anti-inflammatories.        

"There is a vaccine against Potomac Horse Fever. The vaccine may not be 100% effective against preventing the disease because multiple strains of the organism exist, however it often decreases the severity of illness if contracted.

"We are strongly recommending that you have your horses vaccinated against Potomac Horse Fever if they have never been vaccinated. They will then need a booster in 30 days. If your horses have been vaccinated but not within the last 30 days, we are also strongly recommending that you booster their vaccine." 

Horse owners should contact their veterinarian with any questions and to schedule a vaccine appointment.

• Regularly empty ponds, bird baths, fountains, plant pots, buckets, barrels, tarps, kids' toys, pet water dishes or anything else that holds water.
• Walk through the yard after every rain and empty any containers or areas where water has collected. Also, watch for puddles where condensation gathers from the AC unit.
• Clean out gutters to avoid standing water –- examine them for clots and damage that would cause water to collect.
• Make sure there are no low spots under decks where water can hide. For example, Dogs love to make low spots where they rest under decks because it’s cool.
• Drill holes in the bottom of tire swings to prevent rainwater from accumulating. Do the same for garbage or recycling bins that reside outdoors.
• Use soil to fill in low areas in lawns and landscaped areas where rainwater may collect and stand for more than seven days.
• Keep swimming pools clean, properly circulated and filtered. Empty "kiddie pools" regularly. 
  
• Make sure you have good drainage around hot tub areas.
• Repair leaky outdoor faucets.
• Don't be afraid to educate neighbors. They may not realize they have a wheelbarrow full of water behind their shed. Politely offer to turn it over for them.
• Cut grass and shrubs short, as adult mosquitoes gather to rest in shady, cool areas. Keep the yard weed-free and avoid overgrown vegetation.
• Remove yard clippings, leaves, etc. from your yard.

Mosquitoes can only travel about 20 feet before they land, so professionally applied barrier sprays mean mosquitoes have no where to go.

"With any body of water, it is important to use an all-organic spray that protects fish while simultaneously removing mosquitoes," Deiters said. "We’ve discovered the first spray removes about 85 percent of mosquitoes, and usually the second spray sets the property."