Hendra virus primarily infects flying foxes. Occasionally it can spread from flying foxes to horses and then spread to humans who have had close contact with an infected horse. The disease can cause serious and life threatening infection in both horses and humans.
A registered vaccine is available to help prevent Hendra virus disease in horses—this is the most effective way to help manage the disease. Vaccination reduces the risk of Hendra virus transmission to humans and other susceptible animals.
There are no pathognomonic signs that define this disease in horses. Typically there is acute illness with rapid deterioration and respiratory and/or neurological signs.Some infected horses show variable and sometimes vague clinical signs, including an absence of fever.
Infected horses can shed the virus in naso-pharyngeal secretions before the onset of clinical disease. By the time the disease is apparent, the virus has spread throughout the horse's blood, body fluids and tissues. Horses infected with the virus are a transmission risk to humans from 72 hours before the onset of clinical signs up to and after the horse's death and until the safe disposal of the carcase. The transmission risk increases with disease progression and is highest at the point of the horse's death and during post-mortem contact.
Hendra virus infection has been reported in a small number of dogs with close contact with an infected horse. As a precautionary measure, care should be taken if coming into contact with dogs that have had close contact with an infected horse.
Hendra virus is a risk for veterinarians, veterinary practice workers, and others affected by veterinary work, such as the horse's owner. Human infection has occurred from veterinary procedures on infected horses, including procedures of the respiratory tract and necropsies. The virus requires careful risk management and stringent work health and safety and biosecurity measures to minimise human and animal health risks.