Hendra Virus Infection
Learn what the condition is, how it may be detected early, how it is treated or managed, and which breeds or species are linked to it.
Condition snapshot
A concise guide to the condition’s pattern, detection, management and urgency.
Emergency presentation is possibleSuspected disease requires immediate veterinary and government coordination; the horse should remain where it is, isolated from people and…
Human-health precautions may applyFollow veterinary and public-health hygiene advice, especially for higher-risk household members.
This snapshot is a general guide, not a diagnosis or treatment plan. New, severe or worsening signs require veterinary assessment.
About the condition
Hendra virus infection is a rare, usually fatal zoonotic disease of horses caused by a henipavirus maintained in Australian flying-fox populations. Spillover is thought to occur when horse feed, water or the environment is contaminated with flying-fox secretions or excretions. Infected horses can then transmit virus through close contact with body fluids to people, other horses and susceptible animals.
Clinical presentation is variable and can resemble many common illnesses. A horse may develop sudden fever, depression, rapid heart and respiratory rates, breathing difficulty and clear nasal discharge that progresses to froth. Neurological signs can include an unsteady gait, altered awareness, circling, apparent blindness, muscle twitching, urinary incontinence and inability to rise. Rapid deterioration is an important warning, but no single sign is diagnostic.
Hendra must be considered in an unexplained sick horse wherever flying-foxes and horses coexist, not only in areas of historic cases. A second recognised viral genotype has widened awareness of geographic risk. The disease has major human-health implications, and examining or treating a suspect horse without appropriate precautions can expose owners, veterinary personnel and others.
Vaccination is the most effective way to reduce disease risk in horses and consequently human exposure. Vaccination does not justify unsafe handling of an acutely ill horse, and an unvaccinated status does not confirm infection. Hendra virus is nationally notifiable in Australia. Suspected disease requires immediate veterinary and government coordination; the horse should remain where it is, isolated from people and animals, rather than being transported to a clinic without prior arrangements.
Fruit bats are the natural reservoir and transmission to horses is associated with contamination of feed or water, followed by possible horse-to-horse and horse-to-human spread. Disease can be respiratory, neurological or rapidly fatal with nonspecific early signs. Any compatible illness in an endemic region is also a human-safety event, so unprotected examination and necropsy are dangerous.
Screening & Early Detection
There is no routine owner-administered screening test. Prevention records should include current Hendra vaccination dates and property risk factors such as feed or water positioned beneath trees used by flying-foxes. Any rapidly progressive unexplained illness, particularly with respiratory or neurological signs, should prompt a phone call to a veterinarian before close examination or movement.
The sick horse is isolated at its location, and unnecessary contact stops. People keep away from nasal fluid, saliva, blood, urine and other secretions. The veterinarian performs a structured risk assessment and consults the state or territory biosecurity authority before sampling. Appropriate personal protective equipment and controlled specimen handling are essential. In Australia, suspect cases are reported through the Emergency Animal Disease Hotline or relevant authority.
Approved laboratories use PCR and other official tests on veterinarian-collected samples. Testing procedures are designed to detect recognised variants. Differential diagnoses are investigated only within a safety plan because routine invasive work can expose staff. Contact tracing records people, horses, dogs and equipment that may have encountered the animal. A negative result and release of restrictions are determined through official veterinary processes, not an on-property rapid-test interpretation.
Treatment & Management
There is no proven curative treatment for Hendra virus infection in horses. Suspect animals must not receive routine hands-on treatment until veterinary authorities establish a safe response. Confirmed cases are managed under emergency animal-disease arrangements, with humane euthanasia generally required because of the grave prognosis and risk of transmission. Carcass handling, environmental cleaning and disposal are directed by the responsible authority.
People who may have been exposed should avoid further contact, wash contaminated skin as directed and seek prompt advice from public-health professionals. Other horses and companion animals on the property are managed and tested according to the official incident plan. Owners should not attempt to collect samples, open the mouth, clear nasal secretions or transport the horse themselves.
Long-term prevention centres on maintaining vaccination according to the registered schedule and veterinary advice. Feed bins and water troughs should be moved away from trees attracting flying-foxes, and horses can be excluded from paddocks beneath flowering or fruiting trees during high activity. Fallen fruit and contaminated feed are not handled casually. Routine hand hygiene, covered cuts and appropriate protection around every sick horse reduce broader zoonotic risk. These measures complement vaccination; none supports delaying a report when Hendra is clinically plausible.
Breeds or species affected
Akhal-Teke
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Anglo-Arabian
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Arabian
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Barb
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Caspian
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Kathiawari
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Marwari
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Shagya Arabian
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Thoroughbred
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American Quarter Horse
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American Paint Horse
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Appaloosa
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Australian Stock Horse
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Brumby
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Waler
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Morgan
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Standardbred
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American Saddlebred
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Tennessee Walking Horse
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Missouri Fox Trotter
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Rocky Mountain Horse
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Peruvian Paso
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Criollo
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Mustang
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Canadian Horse
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Andalusian
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Lusitano
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Lipizzaner
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Friesian
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Dutch Warmblood
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Hanoverian
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Holsteiner
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Oldenburg
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Westphalian
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Trakehner
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Selle Français
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Belgian Warmblood
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Danish Warmblood
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Swedish Warmblood
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Swiss Warmblood
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Australian Warmblood
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Irish Sport Horse
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Cleveland Bay
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Württemberger
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Zangersheide
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Knabstrupper
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Orlov Trotter
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Camargue
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Icelandic Horse
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Pony of the Americas
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Quarter Pony
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Miniature Horse
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Clydesdale
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Shire
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Percheron
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Belgian Draft
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Suffolk Punch
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American Cream Draft
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Ardennes
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Breton
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Boulonnais
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Comtois
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Dutch Draft
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North Swedish Horse
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Norwegian Fjord
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Haflinger
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Gypsy Cob
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Irish Draught
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Welsh Pony and Cob
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Connemara Pony
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New Forest Pony
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Dartmoor Pony
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Exmoor Pony
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Shetland Pony
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Highland Pony
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Fell Pony
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Dales Pony
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Australian Pony
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Finnhorse
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Black Forest Horse
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