Two horses in Blount County, Tennessee, have tested positive for Potomac horse fever (PHF), and one horse is suspected to be positive. Unfortunately, all three horses have had to be euthanized due to the severity of the disease.
EDCC Health Watch is an Equine Network marketing program that utilizes information from the Equine Disease Communication Center (EDCC) to create and disseminate verified equine disease reports. The EDCC is an independent nonprofit organization that is supported by industry donations in order to provide open access to infectious disease information.
About Potomac Horse Fever
Potomac horse fever is caused by Neorickettsia risticii, an organism found in parasites, called flukes (flatworms), that infect aquatic snails and insects. Horses can contract Potomac horse fever by ingesting insects carrying the organism or by drinking water contaminated with N. risticii. In addition, horses may become infected by inadvertently consuming infected insects or parasites in their feed, water, or on pasture.
The incubation period for Potomac horse fever is typically between one and three weeks, with a mortality rate of up to 30%. While vaccines against Potomac horse fever are not foolproof, vaccinated horses often exhibit milder clinical signs and have a lower incidence of the disease.
Most cases of Potomac horse fever are reported during the months of July through September, and outbreaks tend to be seasonal.
Horse owners and caretakers, especially those with horses near bodies of water, should be vigilant for symptoms such as:
- Diarrhea
- Colic
- Loss of appetite
- Lethargy
- Toxic shock
- Dehydration
- Abortion in pregnant mares
- Laminitis
- Mild to severe fever.