Hendra Virus in Horses

Update: "...Scientists at Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO) have reached the final stages of developing a vaccine designed to protect horses against the deadly zoonotic Hendra virus (HeV). The announcement came last week during the 2011 Australian Veterinary Conference...." Hendra Virus Vaccine Nearing Completion in Australia

Equine morbillivirus pneumonia, Acute equine respiratory syndrome - Merck Veterinary Manual

"Equine morbillivirus pneumonia is an acute viral respiratory infection of horses caused by Hendra virus. Characteristic clinical signs include fever, anorexia, depression, increased respiratory and heart rates, respiratory distress, and death in a high percentage of affected animals. Facial edema, frothy nasal discharge, cyanotic/jaundiced mucous membranes and mild neurologic signs have been less frequently observed in field and/or experimental cases of the disease.

Etiology and Pathogenesis: Hendra virus is a large, pleomorphic enveloped RNA virus, and the prototype virus of the genus Henipavirus. Although initially considered to be more closely related to members of the genus Morbillivirus than to other genera in the family Paramyxoviridae, studies have shown only low-level sequence homology with respiroviruses, morbilliviruses, and rubuloviruses and negligible immunologic cross-reactivity with other paramyxoviruses, reacting very weakly by immunofluorescence and protein immunoblot analysis with antiserum to rinderpest virus. Hendra virus is antigenically related to Nipah virus (Nipah Virus Infection: Introduction), with which it shares ~90% amino acid homology. Both viruses have been classified in a new genus, Henipavirus, in the subfamily Paramyxovirinae, family Paramyxoviridae. Hendra and Nipah viruses vary with regard to the species they infect and mode(s) and ease with which each can be transmitted..."

Following the above link to learn all about this virus. It is also important to note that it is a zoonotic.

Hendra virus is transmissible to humans. The infection has been fatal in a high percentage of the cases recorded so far, either from a fulminant interstitial pneumonia or from a nonsuppurative encephalitis. Direct contact with infectious respiratory secretions, urine, or tissues appears to be necessary for viral transmission. Special precautions should be taken when conducting a clinical examination or necropsy on a horse suspected of having the disease."