Hendra virus - Frequently Asked Questions
Last updated: 6 June 2012
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.
- 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.
- Clean up any fruit debris under the trees before horses are returned to the paddock.
What is the current situation in NSW?
See the Hendra home page for the latest situation.
What movement restrictions are imposed when a case of Hendra virus is detected?
The property where an infected horse is found is quarantined and horse movements on and off the property are prohibited.
Hendra virus is not highly infectious and has only ever been transmitted from one horse to another when they are in very close contact (e.g. nose to nose). This is a totally different situation from Equine Influenza, which is highly infectious.
The NSW horse industry is not subject to general movement restrictions for Hendra virus - except for the properties under quarantine.
Horse owners should practice good biosecurity, and not travel, work on or take unwell horses to other properties or equestrian events.
All owners or managers of properties with horses should develop a property biosecurity plan. Contact your veterinarian for advice and/or refer to the Horse Venue Biosecurity Workbook (www.farmbiosecurity.com.au) available from Animal Health Australia.
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 Livestock Health and Pest Authority 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.
All veterinary staff assessing or managing a sick horse should do so in accordance with the Biosecurity guidelines and other veterinary advice, which can be found in the 'For Veterinarians' section of the Queensland DPI website: www.dpi.qld.gov.au (includes 'Guidelines' and 'Veterinary practice pack'). This information was written for Queensland vets but the principles are applicable wherever there is a risk of Hendra virus infection.
NSW vets should also read Hendra virus- information for vets for state specific requirements
What are the symptoms?
Hendra virus should be suspected whenever a horse’s health deteriorates rapidly.
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:
- laboured breathing
- 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%.
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 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 Livestock Health and Pest Authority, 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.
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. Follow the procedures outlined in the 'For Veterinarians' section of the Queensland DPI website.
Personal protective equipment (PPE)
Everyone handling a sick horse or a horse on which any invasive work is being performed must wear full PPE. PPE must be fitted correctly.
When using PPE:
- Cover cuts and abrasions with a water-resistant dressing.
- Put on PPE before approaching the horse.
- After handling the horse, remove and dispose of PPE carefully into waste bags, making sure there is no contact with your face, particularly your eyes, mouth and nose.
- Carefully remove any clothing contaminated with the horse’s body fluids.
- Wash your hands thoroughly after removing PPE.
Horse owners should always have a PPE kit on hand. Items for a PPE kit can be purchased from most hardware stores.
Your PPE kit should contain:
- hand cleansers/soap
- waste disposal bags
- disposable gloves
- rubber boots
- facial shields or safety glasses
- P2 particulate respirators (Note surgical masks do not provide respiratory protection, and P2 respirators are only effective for clean shaven people).
Remind your veterinarian to bring and wear their own PPE. They can also help you obtain PPE.
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 seven 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 flowering or fruiting trees may attract flying foxes?
Flying foxes are attracted to a wide range of flowering and fruiting trees and vegetation as a food source. Some examples of the trees and vegetation on NSW properties where Hendra virus in horses has occurred include:
- a range of fig trees (including the Moreton Bay fig tree)
- melaleucas (including paperbarks)
- palms (including date plams)
- citrus trees.
Other trees that may attract flying foxes include flowering or soft fruiting trees e.g. mangoes, pawpaws, cherries, bananas, apricots, peaches, palms, lilly-pillies and grevilleas.
Please note this is not an exhaustive list of trees that are attractive to flying foxes. This will vary with the geographical area and the season. Check your property (including the boundary fence) regularly to identify what trees are about to fruit or flower and make sure your horse is not accessing the area under these trees.
What signs may indicate that flying foxes are visiting or feeding?
Signs that flying foxes are feeding include:
- tooth marks on fruit on or under the tree
- large compressed pieces of fruit skin and flesh on the ground under the tree (spats)
- broken twigs or shoots
- debris under the tree including: leaves, broken branches and partly eaten fruit or flowers
- fruit distributed up to 100 metres from the tree.
What types of trees are less attractive to flying foxes?
You can reduce the risk by taking care with both the type of trees you plant and how you set the trees out.
Trees that are safer include:
- casuarinas (she oaks)
- conifer or cypress
- Brachychitons e.g. Flame trees, bottle trees and Kurrajongs
- Jacarandas, Olives, Fiddlewoods, Tipuanas, and
- other deciduous or evergreen trees that don’t flower or produce soft fruits.
Horses should not be placed in paddocks with dense tree planting that may attract roosting bats. Safer plantings for horse paddocks are single line plantings or shade trees spaced at least fifty metres apart.
Is a vaccine for horses available?
CSIRO scientists are testing a new vaccine that shows promise of preventing infection by Hendra virus. The vaccine has been shown to protect horses from experimental infection in the laboratory, but further testing is required to ensure its safety and effectiveness in the field.
The earliest it is likely to be released is 2013.
Humans will be protected indirectly by vaccination of horses, but there are no immediate plans for development of a vaccine for humans.
For more information on progress with vaccine development see www.csiro.au/multimedia/Hendra-virus-vaccine.html
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.
Why are there so many more cases of Hendra virus now than in the past?
The reason for this is not entirely clear, but it is possible that the destruction of bat habitat and food sources by cyclone Yasi and the widespread flooding in northern Queensland has driven northern bats south. These hungry bats may have been carrying Hendra virus, and stressed animals tend to shed more virus.
The northern bats have exposed bats further south to the virus that have not been previously exposed, and animals usually shed higher levels of virus when they are first infected.
If this theory is accurate, then as the newly exposed bats become immune, the level of viral shedding is likely to decrease.
What about dogs, cats and other domestic animals?
A Domestic Animals Q&A page has been set up to answer these questions
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.