Fatal potomac horse fever (Ehrlichial colitis) in a foal: A case report from Connecticut

Summary A 4-month-old Quarter Horse filly died after only 3 hours of illness. An autopsy revealed transmural congestion and hyperemia of cecum and colon consistent with acute colitis. Histologic and electron microscopic studies demonstrated lesions of Potomac horse fever and an abundance of Ehrlichia organisms within diseased tissue.