Hendra virus is a serious zoonotic infectious disease (ie able to spread to humans) transmitted by flying foxes. The virus was first discovered in Brisbane in 1994 by CSIRO and Queensland researchers (in fact, it was a new virus that had not been reported anywhere else in the world). A vaccine, Equivac HeV, has since been developed and released for use in November 2012 – CVH vets are accredited to administer the vaccine.
The disease can be fatal to both humans and horses – since discovery, it has been responsible for the death of 4 people and 81 horses.
Horses are thought to contract Hendra virus by eating feed or water contaminated with the virus, possibly from the saliva, urine, aborted foetuses and/or reproductive fluids of flying foxes. The disease can spread from flying fox to horse, horse to horse, and horse to human. There is no evidence to suggest it can spread from human to human.
The disease has been primarily diagnosed in Queensland, but horse owners need to be aware that Hendra virus has recently been reported further south and west of the Great Dividing Range.
Symptoms in horses
Symptoms in horses include fever, nasal discharge, increased respiration rate and breathing difficulties, muscle twitching, head tilt, difficulty walking and lack of appetite. Sudden death after brief illness
Symptoms in humans
Humans are thought to become infected by coming into close contact with bodily secretions and/or blood of an infected horse. Signs become apparent within 5-21 days of contact with an infected horse. Symptoms in humans include fever, a cough and sore throat, drowsiness, headache
Vaccination
There is no known cure for Hendra virus and vaccination is the most effective defence against the virus. Vaccination is crucial to breaking the cycle of Hendra virus transmission from flying foxes to horses and then to people.
The Equivac® HeV vaccine (developed by Pfizer Animal Health in collaboration with CSIRO’s Australian Animal Health Laboratory and US researchers) is available for use by accredited veterinarians only.
Should your horses be vaccinated?
CVH vets are accredited to administer Equivac® HeV vaccine. We can help you assess the vulnerability of your horse(s) to Hendra virus and whether vaccination is recommended in your particular situation. Do your horses travel and compete? Will they be travelling to known Hendra areas, or mixing closely with other horses?
Vaccination schedule
Equivac HeV Hendra virus vaccine is a 1mL intramuscular vaccine. Horses can be vaccinated from 4 months of age, and require 2 vaccinations three weeks apart. The vaccine is not live and cannot cause infection in horses – live virus is not used at any stage in the manufacture of the vaccine.
Annual boosters are recommended after the initial course.
Note that Hendra vaccine has not yet been tested in pregnant or breeding horses.
Other protection
Regardless of vaccination, it is still important for anyone who works with horses to take precautions to protect themselves against the disease. Anyone handling a sick horse should use infection control measures including:
- wearing personal protection equipment
- quarantining sick horses
- following good hygiene practices as a matter of routine.
It should also be noted that July 2011 saw the first reported case of a dog testing positive for Hendra virus outside laboratory conditions. Keeping companion animals such as dogs and cats away from sick horses is advisable to reduce the risk of an infection.
More information on Hendra virus is available in the AVA's Hendra Virus Fact Sheet.