Two USA Ehrlichia spp. cause febrile illness in goats.

Ehrlichia spp. are not currently recognized as a cause of illness in goats in the USA, but three Ehrlichia are enzootic in lone star ticks (Amblyomma americanum) in the eastern USA, and related bacteria in other countries cause illness in goats. We exposed naïve goats to Ehrlichia-infected Amblyomma and demonstrated that infection and clinical illness can be caused by two USA species, E. ewingii and the recently discovered Panola Mountain Ehrlichia sp. Clinical features in all five goats are described; ehrlichioses were associated with pyrexia, serous nasal discharge, inappetance, lethargy, decreased alkaline phosphatase, and, in most cases, neutropenia. Goats remained chronically infected for several months following exposure to ehrlichiae and transmitted the pathogens to uninfected ticks. In the eastern USA, undifferentiated febrile illness in goats might be caused by previously unrecognized ehrlichial infections, and pastures housing-infected goats could become infested with a large number of infected ticks.