Hendra viruses

Hendra viruses may cause a disease that can be fatal to people and horses. There are 2 variants:

  • Hendra virus (HeV)
  • Hendra virus genotype 2 (HeV-G2)

These are notifiable diseases, and any suspected cases must be reported immediately.

Horse symptoms

The signs of HeV can look similar to other diseases in horses, including:

  • acute onset illness
  • depression, not eating
  • discomfort, weight shifting between legs
  • increased body temperature and heart rate
  • rapid deterioration or death
  • neurological – muscle twitching, weakness, and loss of balance
  • respiratory – nasal discharge, coughing, and breathing difficulty.

Virus transmission

Flying-foxes (fruit bats) are the natural reservoir of HeV. Research is being conducted to understand the mode of transmission between flying-foxes, and the spillover to horses.

The virus can spread rapidly between horses, causing contagious excretions in nasal fluids, urine and faeces. HeV also transfers from horses to humans through close contact – veterinarians and their hospital staff are a high-risk group.

There is no evidence of HeV transmission between humans, from humans to horses, or from flying-foxes to humans.

Current advice regarding the original HeV should be considered valid for HeV-G2. Learn more about the transmission from Hendra viruses in flying-foxes.

High risk areas

All areas in Australia where flying-foxes and horses co-exist are at risk of HeV spreading.

There have been no cases of horses infected with HeV in South Australia. Outbreaks have only been detected in Queensland and northern New South Wales, which remain the highest risk areas for HeV.

The incubation period (time from infection to symptom development) for HeV is up to 16 days. A horse could therefore be infected interstate, then transported into SA before showing symptoms.

Given this presence of small flying-fox colonies in Adelaide and the southeast of SA, there is potential for HeV to occur in a local horse that has not travelled.

Resources for veterinarians

Prepare your veterinary practise for handling potential cases of HeV:

Information for horse owners

Prior to purchasing a horse, you should check:

  • its vaccination status
  • the current situation for HeV in the state the horse is coming from.

Read the below advice for responding to HeV and reducing the risks to your horses.

Handling sick horses

It is good practice to use protective equipment, including gloves and masks, while handling sick horses.

If your horse is showing signs consistent with HeV, avoid all contact, even if they are vaccinated. Arrange for urgent veterinary examination, especially if they:

  • are not vaccinated for HeV
  • have come from interstate within the last 21 days.

If necessary, veterinarians will carry out HeV exclusion testing, which is funded by PIRSA's Biosecurity division.

Find out how to reduce risks while awaiting HeV test results, including preparing for a potential property quarantine.

Biosecurity practices

  1. Wash your hands with soap and water between handling horses and afterwards.
  2. Isolate sick horses from people and other animals until you have a veterinary opinion.
  3. Do not allow visiting horse practitioners to work on sick horses.
  4. Handle healthy horses before handling any sick horses on your property.
  5. Talk to your vet about appropriate cleaning agents to use. Clean and disinfect all gear that has been exposed to horse bodily fluids, including halters, lead ropes, and twitches.
  6. Seek veterinary advice before bringing a sick horse back to your property.

Reducing risk from flying-foxes

  1. Discuss HeV vaccination with your private veterinarian. Expert opinion suggests the vaccine (Equivac HeV from Zoetis) provides immunity against both Hendra strains. Horses from 4 months of age can be vaccinated.
  2. Place feed and water under cover if possible. Do not place food and water containers under trees if flying-foxes are attracted to them.
  3. Avoid feeding your horses sweet foods, fruits and vegetables if you live in an area with flying-foxes.
  4. Remove horses from areas that have fruiting or flowering trees. Return the horses after the trees have stopped flowering.
  5. Remove horses from paddocks during times when flying-foxes are most active – dawn, dusk, and overnight.

Safety precautions

If you encounter a horse infected with HeV, follow these steps:

  1. Wash contaminated skin thoroughly with soap and water, ideally in a shower.
  2. Cleanse any cuts or abrasions. If available, use an antiseptic with viricidal action such as:
    • povidine-iodine
    • iodine tincture
    • aqueous iodine solution
    • alcohol (ethanol).
  3. Seek medical advice from your local doctor or contact SA Health: 1300 232 272.

Emergency Animal Disease Hotline

Suspected disease or pests in livestock, poultry or aquatic animals must be reported immediately.

Call us to help stop the spread of animal illness, even if you are unsure of the disease.

24 hours a day, 7 days a week

Freecall 1800 675 888
Page last reviewed: 07 Dec 2023

 


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