Hendra virus

Hendra virus is in the genus Henipavirus. Other members in this genus include Nipah virus and Cedar virus.

Hendra virus is in the Paramyxovirus family.

Pteropid bats (flying foxes)

Hendra virus is a fragile RNA virus which does not survive for very long (hours or days) outside the animal host.

Hendra virus can cause a broad range of signs in horses. Hendra virus infection should be considered in any sick horse when the cause of illness is unknown and particularly where signs progress quickly with rapid deterioration.

The following signs have all been associated with Hendra virus cases in horses, but not necessarily all signs will be found in any one infected horse:

• rapid onset of illness
• fever
• increased heart rate
• discomfort or weight shifting between legs
• depression
• rapid deterioration with either respiratory and/or nervous signs.

Respiratory signs include:

• difficulty breathing
• rapid breathing
• nasal discharge at death - can be initially clear, progressing to stable white froth or stable blood-stained froth.

Nervous signs include:

• wobbly gait
• apparent loss of vision in one or both eyes
• aimless walking in a dazed state
• head tilting and circling
• muscle twitching
• urinary incontinence
• inability to rise.

The small number of dogs infected both naturally and in a research setting have not shown any clinical signs.

Flying foxes infected with Hendra virus do not show any signs of illness.

Hendra virus infection in horses and humans has a high mortality rate. Approximately 80% of horses and 70% of people infected with Hendra virus die.

Properties with confirmed infected animals are jointly managed by Biosecurity Queensland, and the animal owner and their veterinarian until it can be determined there is no further transmission risk. Occasionally, neighbouring properties are also involved.

During a Hendra virus incident, there are no movement restrictions for the general horse population. Movement restrictions may be in place for properties with confirmed infected animals and those in close contact with them.

There is no evidence of Hendra virus spreading from flying fox to human, or from human to human.

Hendra virus is not a highly contagious disease. Close contact with the virus is required for infection to occur.

Transmission to horses

Transmission to horses is believed to take place by horses coming into contact with material contaminated with infected flying fox body fluids and/or excretions. Hendra virus can also potentially spread from horse to horse through direct contact with infectious body fluids, or indirect contact via equipment contaminated with infectious body fluids.

Transmission to humans

The few cases of Hendra virus infection in people have resulted from very close contact with respiratory secretions (e.g. mucus) and/or blood from an infected horse.

Transmission to dogs

Transmission to dogs is believed to occur by dogs coming into contact with infected horses, including infectious body fluids.

Infection in horses has occurred throughout the year and precautions should be taken year round.

Contact your veterinarian immediately if you suspect your animal may have Hendra virus infection. Veterinarians that suspect Hendra virus infection in a patient should follow standard procedures to investigate the situation.

As a horse owner or person who deals with horses, you have a general biosecurity obligation to take all reasonable and practical measures to prevent or minimise the effects of a biosecurity risk. Hendra virus poses a serious biosecurity risk. This means you are legally required to reduce the risk of Hendra virus infection and limit the spread of Hendra virus when dealing with horses and other possible carriers. Read more about:

• reducing the risk of Hendra virus infection
• what to do if you suspect your horse has Hendra virus.

If you become aware of Hendra virus infection in any species of animal, you must report it to Biosecurity Queensland by phoning:

• 13 25 23 during business hours.
• 1800 675 888 (the Emergency Animal Disease Hotline), 24 hours a day.

Clearly explain that you are calling to report a case of Hendra virus infection.

Contact your general practitioner, local hospital emergency department or local public health unit if you are concerned that a person has been exposed to a horse infected with Hendra virus.

Current understanding of the virus suggests a number of measures horse owners can take to reduce the risk of horses becoming infected with Hendra virus.

Read about the options to reduce the risks of Hendra virus infection.

Vaccination

A registered vaccine is available to help prevent Hendra virus disease in horses. Vaccination of horses is the most effective way to help manage Hendra virus disease.

Vaccination of horses provides a public health and workplace health and safety benefit by reducing the risk of Hendra virus transmission to humans and other susceptible animals. Whenever Hendra virus infection is suspected, even in vaccinated horses, appropriate biosecurity precautions including personal protective equipment (PPE) should be used as no vaccine can provide 100% guaranteed protection.

Talk to your veterinarian about vaccinating your horse.

Hendra virus case management

If Hendra virus infection is confirmed in an animal, Biosecurity Queensland will work with the animal owner and their veterinarian to manage the situation. Measures will be taken to ensure that infectious animals or items don’t leave the property or potentially spread Hendra virus. The actions that need to take place on the property aim to limit the spread of Hendra virus and prevent disease transmission to humans and other animals. Read more about what happens when Hendra virus infection is suspected.