Equine Morbillivirus Pneumonia (or Hendra Virus Infection): Disorders Affecting Multiple Body Systems of Horses: The Merck Manual for Pet Health


	Sections		Horse Disorders and Diseases

	Chapters		Disorders Affecting Multiple Body Systems of Horses

Equine Morbillivirus Pneumonia (or Hendra Virus Infection)

Equine morbillivirus pneumonia is a frequently fatal viral respiratory infection of horses caused by Hendra virus. Disease due to Hendra virus infection has only been reported in horses and people. The virus appears to be limited to Australia and Papua New Guinea.

Hendra virus does not appear to be highly contagious. Transmission between infected and uninfected horses occurs infrequently. Based on available field and laboratory data, infection of humans or animals appears to require direct contact with virus-infective secretions (lung discharges), urine, or tissues.

In infected horses, signs include fever (up to 106°F [41°C]), poor appetite, lethargy, elevated respiratory and heart rates, difficulty breathing, pneumonia, and frothy clear to blood-tinged nasal discharge. Additional signs seen in some affected horses include bluish-colored or jaundiced mucous membranes, tissue swelling, and neurologic signs. As many as 60 to 70% of infected horses die of the disease. The course of the disease is short; death may occur within 1 to 3 days.

There is no specific antiviral treatment and, as yet, no vaccine for this disease. Hendra virus is transmissible to humans. The infection has been fatal in a high percentage of the handful of cases recorded so far, either from severe pneumonia or from inflammation of the brain. Direct contact with infectious respiratory secretions, urine, or tissues appears to be necessary for viral transmission.

Last full review/revision July 2011 by Otto M. Radostits, CM, DVM, MSc, DACVIM (Deceased); Delores E. Hill, PhD; Barton W. Rohrbach, VMD, MPH, DACVPM; Charles J. Issel, DVM, PhD; Max J. Appel, DMV, PhD; David A. Ashford, DVM, MPH, DS; Daniela Bedenice, DrVetMed, DACVIM, DACVECC; Farouk M. Hamdy, DVM, MSc, PhD, MPA (Deceased); Kenneth R. Harkin, DVM, DACVIM; Johnny D. Hoskins, DVM, PhD; Eugene D. Janzen, DVM, MVS; Jodie Low Choy, BVMS; John E. Madigan, DVM, MS; Dale A. Moore, MS, DVM, MPVM, PhD; J. Glenn Songer, PhD; Joseph Taboada, DVM, DACVIM; Charles O. Thoen, DVM, PhD; John F. Timoney, MVB, PhD, Dsc, MRCVS; Ian Tizard, BVMS, PhD, DACVM; Brian J. McCluskey, DVM, MS, PhD, DACVPM; Bert E. Stromberg, PhD; Peter J. Timoney, MVB, MS, PhD, FRCVS