Potomac Horse Fever case diagnosed in Kentucky

The gelding, with an unknown vaccination history, began showing signs in late August.

A 6-year-old gelding in Kentucky has been diagnosed with Potomac Horse Fever (PHF), according to the Equine Disease Communication Center. The horse, whose vaccination history is not known, has been showing typical signs of the disease, including anorexia, lethargy and decreased gut sounds. PHF has the potential to be fatal by triggering devastating laminitis or severe diarrhea. 

If horses consume the bodies of infected aquatic insects while grazing or drinking, they may develop Potomac horse fever.

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PHF occurs when horses ingest the bacterium Neorickettsia risticii. N. risticii infects a parasitic fluke (a type of flatworm), which under-goes a complex life cycle in which at different stages it can be found in a number of aquatic species, including freshwater snails as well as aquatic insects, birds and bats, and it can even be free-swimming in water.

But the threat to horses comes from flying aquatic insects. N. risticii has been found in more than a dozen species, including dragonflies, damselflies and stoneflies, whose larvae consume infected free-swimming flukes then continue to carry the bacterium-containing fluke when they emerge as adults. If horses consume the bodies of infected aquatic insects while grazing or drinking, they may develop Potomac horse fever.

PHF is not contagious nor does it pass between horses via casual contact. When multiple cases appear together on the same farm, it means that more than one horse consumed infected insects.

A vaccine against PHF is available, and the American Association of Equine Practitioners recommends it for horses at greater risk of being exposed to N. risticii. Generally, this means horses who live on farms where PHF has appeared in the past as well as those who live in endemic areas within range of swarming aquatic insects.

Click here more information on PHF and how you can protect your horse. 

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