REMEMBER: A 6 monthly booster is required to maintain immunity against the Hendra virus.
This vaccination needs to be given within a 5 week period, 6 months after the two initial vaccinations. Horses that are not vaccinated within this time frame may not be protected against Hendra Virus and cannot be entered onto the Hendra Vaccination Registry. For horses to be reinstated on this registry the vaccination protocol must be restarted with the 2 initial doses 3-6 weeks apart.
Zoetis, the company who produce the vaccination, have new information that indicates horses will be adequately protected for 12 months after receiving 2 initial doses and one 6 month booster. Therefore it is likely that in the future Zoetis will make amendments to the vaccination protocol with annual boosters required following one 6 month booster.
The risk of HeV in horses has to date been managed through increased hygiene and cleaning practices and various recommendations around paddock management. Unfortunately, HeV has still claimed the lives of horses despite these sound management practices being adopted. Vaccination is the single most effective way of reducing the risk of Hendra virus infection in horses. Human infection and death have occurred following high-level exposure to body fluids from an infected horse. Vaccinating horses is an important measure to prevent this occurring and provides a public health and workplace health and safety benefit.
What is Hendra virus?
Hendra virus is a virus that mainly infects large flying foxes (fruit bats) which can be passed on to horses.
The infection may occasionally be passed onto people or animals that have been in close contact with an infected horse.
The virus can be deadly to both humans and horses.
How do I reduce the chances of my horses becoming infected?
NSW DPI advises horse owners to take precautions in areas with flying foxes - to reduce the risk of their horses becoming infected:
- Do not place feed and water under trees.
- Cover feed and water containers with a shelter so they cannot be contaminated from above.
- Do not leave food lying about that could attract flying foxes, such as apples, carrots, or molasses.
- Inspect paddocks regularly and identify trees that are flowering or fruiting,
- Remove horses from paddocks where fruiting or flowering trees have temporarily attracted flying foxes.
- If the horse(s) cannot be removed from the paddock, erect temporary or permanent fencing to keep horses from grazing under trees.
- Clean up any fruit debris under the trees before horses are returned to the paddock.
If these measures are not practical, consider stabling horses, or removing them from the paddock before dusk and overnight, when flying foxes are most active.
Hendra virus symptoms in horses
Hendra virus can cause a range of symptoms in horses. Usually there is a sudden fever and either respiratory or neurological illness and rapid death. In some cases the onset of illness is gradual.
Other symptoms can include:
frothy and/or blood stained nasal discharge a
a temperature (usually but not always higher than 40°C)
Neurological changes, including tilting of the head, loss of vision, abnormal muscle twitching, weakness and loss of balance
Colic like discomfort.
Most cases in horses are fatal but occasionally a horse will survive the infection. The reported mortality rate in infected horses is greater than 70%.
What should I do if I suspect Hendra virus in a horse?
If you notice symptoms of Hendra virus including fever, nervous and respiratory symptoms, abnormal behaviour or unexpected deaths keep everyone away from the horse and call your private veterinarian immediately. The vet will notify the Local Land Services or an inspector with DPI, if they consider the case highly suspect for Hendra. If they are unavailable, and the illness is progressing rapidly, call the Emergency Animal Disease Watch Hotline on 1800 675 888.
Hendra virus infection is notifiable in NSW and all suspected cases in horses must be reported. It is not an exotic disease in NSW.
If a horse is suspected to have a Hendra virus infection it is important to keep it away from all animals on the property. If possible, leave the sick horse where it is and move other animals away, rather than move the sick horse. This will minimise the area that is potentially contaminated.
Exercise extreme caution and limit contact with suspected cases. In particular, avoid contact with any body fluids such as nasal secretions or saliva.
Only experienced veterinary staff who are using appropriate personal protective equipment should have contact with the horses until the diagnosis is known.
How is it controlled?
Where Hendra virus has been confirmed as the cause of illness or death in horses, NSW DPI in conjunction with the Local Land Services, and NSW Health will manage the situation.
Urgent measures including quarantine of infected horse/s will be taken to minimise the risk to people and other horses, and to track the likely cause and extent of the infection.
NSW DPI will contact NSW Health whenever Hendra virus is confirmed or strongly suspected. NSW Health will then work with the horse owner, handlers and attending veterinarians to assess their risk from exposure to the infected animal.
Hendra virus symptoms in people
If you have been in contact with an infected horse please seek medical attention immediately.
Symptoms typically develop between 5 and 21 days after contact with an infectious horse.
Fever, cough, sore throat, headache and tiredness are common initial symptoms. Meningitis or encephalitis (inflammation of the brain) can then develop, causing headache, high fever, and drowsiness, convulsions and coma.
Hendra virus infection can be fatal.
For more information on Hendra virus infection in humans, refer to the NSW Health website.
How do people get the disease?
A small number of people are known to have been infected with Hendra.
These infections resulted from very close contact with infected horses (either sick horses or during autopsies).
There is no evidence of bat-to-human, human-to-human or human-to-horse spread of Hendra virus.
Keys to preventing the disease in people
Horses can shed Hendra virus before they show any sign of illness. All horse handlers should protect themselves by routinely using good hygiene practices whenever handling horses.
Always cover any cuts or abrasions on exposed skin before handling your horse. Always wash your hands with soap and water, particularly after handling your horse’s mouth or nose. Do not smoke, eat or touch your eyes, nose or mouth until you have washed your hands.
Remember that every time you put a bridle on or take it off you are likely to contact the horse’s saliva.
Take care with hygiene and personal protection when handling sick horses. In particular, avoid contact with blood, other body fluids (especially respiratory and nasal secretions, saliva and urine) and tissues.
Ideally you should avoid all contact with suspect horses until a veterinarian has investigated and provided advice on the safe handling of affected horses.
Everyone handling or investigating a suspect case of Hendra virus should wear full protective clothing. The minimum standard is overalls, boots, gloves, respirator mask and eye protection.
How can I avoid the risk of being infected by Hendra virus, if I need to visit a property where there are horses?
Hendra virus infection in horses and humans is a very rare disease. All confirmed human cases to date became infected following close contact with the body fluids of an infectious horse. Any properties on which Hendra is identified are quarantined and movement restrictions are imposed on susceptible animals. However if people wish to reduce the risk even further they should avoid close contact (preferably more than five metres if not protected with PPE) with horses, particularly any horses that may look ill or appear to be acting strangely.
What control measures for flying foxes are in place to prevent the spread of the Hendra virus?
It is not practicable to kill flying foxes because of the risk of Hendra virus infection to horses. Increasing stress levels in flying foxes by attempting to scare them off or eradicate them may increase shedding of the virus.
Flying foxes are protected native fauna in NSW. To enable better management of the risk of infection, research is underway to understand how the infection is maintained in flying fox populations and what factors are associated with the spread of the virus to horses.
How long does Hendra virus survive in the environment?
Hendra virus is very fragile. It is easily killed by heat, soap or detergents and by desiccation (drying out). It may survive in the environment from several hours to several days depending on environmental conditions. Survival is longer in cool moist conditions where the pH is close to neutral.