Hendra virus is a newly identified virus seen so far only in Australia and Papua New Guinea. The viral agent is commonly found in specific species of fruit bats (also called flying foxes), and close contact among horses and these bats is suspected to have caused transfer of the virus to horses. The disease, called equine morbillivirus pneumonia, develops in horses that are infected by direct contact with the virus particles in urine, saliva, and respiratory secretions. Humans in very close contact with infected horses can become infected as well and develop flu-like symptoms.

Infected horses develop severe and often fatal respiratory disease, characterized by labored breathing and fluid and swelling in the lungs. Damage to the heart and blood vessels may occur. Depression, loss of appetite, fever, respiratory difficulty, poor coordination, increased heart rate, and frothy nasal discharge are other common signs (see Disorders Affecting Multiple Body Systems of Horses: Equine Morbillivirus Pneumonia (or Hendra Virus Infection)).

Last full review/revision July 2011 by Bonnie R. Rush, DVM, MS, DACVIM; Neil W. Dyer, DVM, MS, DACVP; Joe Hauptman, DVM, MS, DACVS; Ned F. Kuehn, DVM, MS, DACVIM; Stuart M. Taylor, PhD, BVMS, MRCVS, DECVP; Wendy E. Vaala, VMD, DACVIM; Maureen H. Milne, BVMS, MVM, DCHP, MRCVS