Potomac Horse Fever (PHF) is a potentially-fatal febrile illness affecting horses caused by the intracellular bacterium Neorickettsia risticii. PHF is also known as Shasta River Crud and Equine Monocytic Ehrlichiosis.
A severe, febrile condition in horses, Potomac Horse Fever (PHF) is triggered by the Neorickettsia risticii bacterium residing within the horse's cells. This disease also goes by the names Shasta River Crud and Equine Monocytic Ehrlichiosis.