- Overview of Hendra Virus Infection – Generalized Conditions
- Hendra virus: managing the risk in Western Australia
- Signs of Hendra virus infection
- How do horses catch Hendra virus?
- How can I reduce the risk of my horse catching Hendra virus?
- What should I do if my horse shows signs similar to Hendra virus?
- Should I vaccinate my horses?
- Is vaccinating horses mandatory?
- What is the risk of horses bringing in Hendra virus from other areas?
- How do people catch Hendra virus?
- How can I reduce the risk of catching Hendra virus from my horse?
- Where are flying foxes found in WA?
- Other diseases that flying foxes can transmit to horses
- Safety advice for veterinarians
- Hendra virus infection in a veterinarian
- Hendra virus
- What is the risk in Victoria?
- Why is Hendra virus considered low risk in Victoria?
- How is Hendra Virus transmitted?
- Is there a vaccine against Hendra available for horses?
- What to do if you suspect HeV in your horse?
- How do I reduce the risk of becoming infected?
- What happens if my horse is confirmed HeV positive?
- What happens to my HeV positive horse?
- Human exposure to HeV
- Possible complications
- Hendra Virus Infection
- Other names
- Affected animals
- Transmission to horses
- Transmission to humans
- Transmission to dogs
- Hendra virus case management
Overview of Hendra Virus Infection – Generalized Conditions
Naturally occurring disease caused by Hendra virus has been reported only in horses and people. Experimentally, disease has been produced in cats, hamsters, ferrets, monkeys, pigs, and guinea pigs, but not in mice, rats, rabbits, chickens, or dogs. The clinical response and pathologic findings in cats are very similar to those seen in horses.
Hendra virus infection and disease in horses has only been reported in Australia, and events are sporadic and infrequent, with 14 events recorded between 1994 and 2010. Most of these were single horse events. Thus, Hendra virus appears to have limited infectivity, and under field conditions, transmission between infected and noninfected horses occurs infrequently.
However, the frequency of Hendra virus infection in horses has increased since 2011, with 18 incidents in 2011, 8 in 2012, 8 in 2013, and 3 in 2014 (up to October), with extended geographic locations (between far north Queensland to north New South Wales, Australia).
In July 2011, a dog on a property with horses infected with Hendra virus (in Queensland) was identified as seropositive without any clinical signs. In July 2013, a dog on a property (in New South Wales) with Hendra virus infection in a horse was confirmed to be infected with the same virus.
Further research is underway to investigate whether these increased incidents in horses were because of greater public awareness in reporting the disease or whether environmental or ecologic factors triggered this increased number of cases and extended geographic occurrence.
Experimentally, attempted transmission from virus-infected horses to in-contact horses or cats has been unsuccessful. Nonetheless, the possibility of respiratory transmission cannot be excluded.
The frothy nasal discharge (originating from the lungs) sometimes observed terminally in naturally affected horses could plausibly provide a source of virus for aerosol transmission.
Hendra virus has been found in the urine, blood, and nasal and oral secretions of naturally infected horses and cats.
available field and laboratory data, infection of people or animals appears to require direct contact with virus-infective secretions (lung exudates), excretions (urine), body fluids, or tissues. Although Hendra virus appears to have limited infectivity, the case fatality rate in individuals that become infected is high: 75% in horses, 57% in people.
Available epidemiologic, serologic, and virologic evidence implicates fruit bats as the natural reservoir of Hendra virus. Serologic surveys have revealed a high prevalence of neutralizing antibodies in wild-caught fruit bats (Pteropus spp) in Australia and Papua New Guinea.
The geographic distribution of the virus in fruit bats appears to be limited to Australia and Papua New Guinea, although a transition of Hendra- to Nipah- viruses may occur beyond Australia. Infection in fruit bats (either natural or experimental) causes no evident disease.
There is field and experimental evidence of vertical transmission, with isolates recovered from the uterine fluid and fetal tissues of a grey-headed flying fox (P poliocephalus) and a black flying fox (P alecto). The infrequent occurrence and sporadic nature of equine cases suggest that exposure of horses to Hendra virus is, at least in part, a chance event.
The modes of transmission between bats, and from bats to horses, are uncertain, as are factors that may facilitate spillover. Hendra virus has been identified in the birthing fluids, placental material, aborted pups, and urine of naturally infected fruit bats and in the urine of experimentally infected fruit bats.
The related Nipah virus has been detected in bat urine and on fruit partially eaten by bats. Horses are hypothesized to be infected through contact with food or water contaminated with material from infected fruit bats, but the definitive mechanism remains to be determined.
Hendra virus: managing the risk in Western Australia
- No horses or people in Western Australia have been diagnosed with Hendra virus infection.
- The lihood of Hendra virus infection occurring in WA is considered low, because of the low numbers of horses where flying foxes occur, and the relatively low concentrations of flying foxes.
- There needs to be close contact between flying foxes and horses for transmission of the virus.
- Flying foxes in northern WA (north of Shark Bay) can carry the Hendra virus.
- Horses in close contact with flying foxes have some risk of becoming infected with Hendra virus.
- Horses imported from Queensland or northern New South Wales, or which have had contact with horses from these areas, should be isolated for 20 days and monitored for signs of Hendra virus.
- People in close contact with infected horses have some risk of contracting Hendra virus.
Hendra virus is a disease carried by flying foxes (fruit bats) in Australia, Papua New Guinea and surrounding islands. While the virus does not visibly harm the flying foxes, it can occasionally spread from flying foxes to horses, and from infected horses to people.
Hendra virus was first diagnosed in Australia in 1994.
As of August 2019, there have been 62 confirmed incidents of Hendra virus in Australia, resulting in the death of 84 horses (statistics courtesy of the Business Queensland website).
Seven people have been infected with Hendra virus, and four of them have died. All of these cases have been in Queensland or northern New South Wales. No horses or people in WA have been diagnosed with Hendra virus infection.
Signs of Hendra virus infection
Hendra virus can cause a range of signs in horses, including:
- rapid onset illness
- increased body temperature (above 38.5°C) and heart rate
- rapid deterioration
- respiratory distress; laboured breathing, frothy and/or blood-stained nasal discharge
- neurological (nervous system) signs such as wobbly gait, lack of coordination, apparent loss of vision, aimless walking in a dazed state, head tilting and circling, muscle twitching, urinary incontinence, inability to rise.
If your horse shows any of these signs, and may have had exposure to flying foxes, or to other horses that have had exposure to flying foxes, call your veterinarian or the Emergency Animal Disease hotline on 1800 675 888 immediately. Minimise contact with the horse until you have received veterinary advice.
How do horses catch Hendra virus?
It is believed that horses catch the virus by having contact with feed, water or other items contaminated by the body fluids (urine, faeces) of flying foxes. In some cases infected horses have transmitted the virus to other horses via close contact with their body fluids.
How can I reduce the risk of my horse catching Hendra virus?
WA horse owners can reduce the risk of their horses becoming infected by taking the following steps:
- do not place feed and water containers under or near trees. If possible, place feed and water containers under a shelter.
- remove horses from paddocks where flowering or fruiting trees may be attracting flying foxes. Return horses only after the trees have stopped flowering or fruiting and the flying foxes have gone. If horses cannot be removed from the paddock, consider fencing (temporary or permanent) to restrict access to flowering or fruiting trees. Clean up any fruit debris underneath the trees before returning horses.
- if you cannot remove horses from paddocks where flowering or fruiting trees may be attracting flying foxes, try to temporarily remove them during times of peak flying fox activity (usually at dusk and during the night).
- vaccinate horses against Hendra virus.
What should I do if my horse shows signs similar to Hendra virus?
Hendra virus infection is a reportable disease — a disease that must be reported to government veterinary officers.
If your horse has signs suspicious of Hendra virus infection and may have had contact with flying foxes, has recently arrived from Queensland or NSW, or has had contact with horses from Queensland or northern NSW, contact your veterinarian or the Emergency Animal Disease hotline on 1800 675 888.
Should I vaccinate my horses?
Vaccination against Hendra virus in horses is available. Owners should consult their veterinarian about the option of vaccinating if their horses:
- have any risk of contact with flying foxes
- travel to Queensland or northern NSW, or
- have any risk of contact with horses from Queensland or northern NSW.
No vaccine is 100% effective, so veterinarians and owners should still maintain good biosecurity when handling vaccinated horses and be vigilant for signs of Hendra virus.
At this stage the vaccine does not provide lifelong immunity and boosters will be required.
Information about the vaccine is available at health4horses.com.au and apvma.gov.au/node/12871
Is vaccinating horses mandatory?
The Department of Primary Industries and Regional Development does not require horses to be vaccinated against Hendra virus and there are no import restrictions on unvaccinated horses into WA.
Some veterinarians who work with high-risk horses may only accept clients whose horses are vaccinated in order to reduce the risk to their health and safety.
What is the risk of horses bringing in Hendra virus from other areas?
Wherever flying foxes and horses have contact, there is a risk that horses could develop Hendra virus. Therefore, recently arrived horses from Queensland or northern NSW could be incubating Hendra virus.
Horses travelling to and from northern WA may also have a risk of contracting Hendra virus if exposed to flying foxes.
Horses at shows or events may also be exposed to horses from Queensland or northern NSW, which may be incubating Hendra virus.
It is advisable to isolate horses that have been in areas where there are flying foxes or in contact with horses that have been exposed to flying foxes for 20 days and to monitor for signs of Hendra virus during that time.
How do people catch Hendra virus?
People have also been infected with Hendra virus after very close contact with infected or dead horses. To date, seven people have been infected with the virus, and four of them have died.
To date, there is no evidence that people have caught the virus from other people or from flying foxes.
How can I reduce the risk of catching Hendra virus from my horse?
As infected horses can transmit Hendra virus to people, it is advisable that you do not have close contact with any horse with:
- signs suspicious of Hendra virus, and which
- may have had contact with flying foxes, or
- has recently arrived from Queensland or northern NSW.
Immediately isolate the horse from other horses, people and animals, and contact your veterinarian or the Emergency Animal Disease hotline on 1800 675 888.
Guidelines for handling horses suspected of Hendra virus and for personal protective equipment are available on the Queensland Department of Agriculture, Fisheries and Forestry website.
Where are flying foxes found in WA?
Only the black and little red flying foxes are found in WA. The risk area for horses having contact with flying foxes is north of Shark Bay.
Although small numbers of red flying foxes may occasionally be sighted south of Shark Bay, these are not in high enough numbers to present a high risk of transmitting Hendra virus to horses.
A map of the distribution of the main flying fox species shows the distribution of the two species found in the north of WA.
Other diseases that flying foxes can transmit to horses
In May 2013, two horses in Queensland died as a result of being infected with Australian bat lyssavirus. These are the first recorded cases of Australian bat lyssavirus in horses.
Three people in Queensland have also contracted Australian bat lyssavirus from contact with infected bats and died.
Although Australian bat lyssavirus is very rare, horse owners are reminded to minimise contact between any species of bat and their horses’ feed and water.
Safety advice for veterinarians
As Hendra virus signs vary considerably, veterinarians should always consider their safety first. Always assess the risk of Hendra virus before examining a horse and wear appropriate personal protective equipment (PPE).
If veterinarians see signs suspicious of Hendra virus, they should immediately ring the Department's Diagnostics and Laboratory Services – Animal pathology unit on +61 (0)8 9368 3351 or the Emergency Animal Disease hotline on 1800 675 888 for advice on correct PPE.
The most recent ‘Guidelines for veterinarians handling potential Hendra virus infections in horses’ is available on the Queensland Department of Agriculture, Fisheries and Forestry website. The Australian Veterinary Association also has a video describing the use of PPE.
Hendra virus infection in a veterinarian
Med J Aust 2006; 185 (10): 562-564. || doi: 10.5694/j.1326-5377.2006.tb00692.x
Published online: 20 November 2006
A veterinarian became infected with Hendra virus (HeV) after managing a terminally ill horse and performing a limited autopsy with inadequate precautions.
Although she was initially only mildly ill, serological tests suggested latent HeV infection. Nevertheless, she remains well 2 years after her initial illness.
Recently emerged zoonotic viruses, such as HeV, necessitate appropriate working procedures and personal protective equipment in veterinary practice.
Hendra virus (HeV) and Nipah virus together comprise the genus Henipavirus within the family Paramyxoviridae (Box 1).
1 HeV, formerly called equine morbillivirus, was first described after an outbreak of severe respiratory disease in horses, leading to the deaths of 14 horses and a horse trainer in Brisbane in September 1994.
2,3 The trainer had had very close manual contact with frothy nasal and oral secretions, some of which were blood-tinged, from several of the very ill horses, as did a stable-hand; he developed an influenza- illness but made a full recovery. The horses and both people were infected with HeV.2,3
An earlier outbreak of HeV disease was not recognised until the death, in 1995, of a farmer in Mackay. He had assisted his veterinarian wife with the autopsies of two horses that died suddenly from unknown cause in August 1994.
He was hospitalised about 2 weeks later with an aseptic meningitis, from which he apparently made a full recovery.3,4 However, about a year later he became acutely unwell again, and died from a severe encephalitis caused by HeV.
3,4 The two horses were (retrospectively) shown to have also been infected with HeV.5
After these two outbreaks, extensive investigations identified fruit bats (Pteropus spp.), commonly known as flying foxes, as the ly natural reservoir of HeV; the infection is probably subclinical in most infected flying foxes.
6,7 Although it is not certain how HeV could be transmitted from flying foxes to horses, the isolation of the virus from uterine fluid and aborted fetal tissue of flying foxes suggests that horses could ingest the virus on feed or pasture recently contaminated by birth products (Box 2).
6,7 The available evidence indicates that transmission of the virus from horses to people, albeit rare, occurs through physical contact with nasal and oral secretions emanating from very ill, dying or dead horses.8
The third recognised outbreak of HeV disease occurred in January 1999, when a horse in a northern suburb of Cairns died from pneumonia.9 No human infection associated with this equine HeV case was detected.
We report here the fourth known outbreak of HeV infection and discuss the implications of this recently emerged virus for veterinary practice.
In early November 2004, a veterinarian notified the Tropical Population Health Unit (TPHU) in Cairns that one of his colleagues had become unwell a week after performing an autopsy on a horse.
Two other people who had assisted with the autopsy, both members of the family who owned the horse, had apparently also become unwell, and the notifying veterinarian asked about the possibility of HeV infection in the three individuals.
The horse: The horse was a 10-year-old gelding located on a property about 25 km south of Cairns. It had been acutely unwell for 1 day, with restlessness, increased respiratory effort and profuse sweating.
On examination, the horse was febrile (41°C per rectum), tachycardic (120 beats/min), markedly dyspnoeic and very weak; it lay in a lateral recumbent position and could not raise its head. It was very dehydrated, and had injected mucous membranes and large amounts of blood-stained frothy secretions issuing from its nose.
A decision was made to euthanase the horse, but it had a convulsion and expired before this could be performed. Blood-stained froth emanated from its nose and mouth as it died.
Autopsy on the horse: Because the diagnosis was uncertain, the treating veterinarian performed a limited autopsy on the horse in the paddock where it died.
She initially wore gloves, but quickly abandoned these as they were not of an appropriate design and soon became contaminated inside. No other personal protective equipment was used.
For the procedure she had to reach deep into the carcass to examine some internal organs.
The autopsy resulted in the veterinarian becoming heavily contaminated with the horse’s body fluids, especially those from the abdominal cavity. Contamination from the thoracic cavity was less, as this was opened only through a relatively small “window” over the heart. The veterinarian had a thorough shower immediately on returning home after completing the autopsy.
The main gross findings at autopsy were massive fluid congestion of the lungs, cardiomegaly with marked thickening of the ventricular walls, and a grossly enlarged liver.
The veterinarian concluded that the horse had died from acute heart failure and pulmonary oedema of unknown aetiology; no tissue samples were collected for further laboratory studies.
At the completion of the autopsy, the horse was deep-buried using a back hoe.
The veterinarian: Seven days after performing the autopsy, the veterinarian developed a dry cough and sore throat, associated with cervical lymphadenopathy and a fever lasting 4 days. She had generalised body aches and was very tired. The illness continued for about 8 days, during which time she was unable to work.
She was seen 2 days after the onset of symptoms by a medical practitioner who had been informed (by the TPHU) of the possibility of HeV infection. However, the practitioner considered that her illness was consistent with a tonsillar infection and prescribed an antibiotic; blood was collected for HeV laboratory studies only.
Follow-up serum samples were collected for further HeV studies at 14, 30, 50, 363, 470 and 559 days after the onset of symptoms.
Laboratory studies: HeV RNA was not detected by a reverse transcriptase polymerase chain reaction (RT-PCR) (TaqMan) assay10 on the initial serum sample. Similarly, HeV IgM and IgG antibodies were not detected by either immunofluorescence assay (IFA) or enzyme-linked immunoassay (EIA).11 However, the subsequent samples demonstrated clear HeV IgM and IgG seroconversions by both IFA and EIA.
A serum sample taken nearly a year later was initially reported as having a very high antibody titre on IgG IFA (>1024), but on repeat testing this was revised to a level of 512 (Box 3). Subsequent antibody levels have fallen by one dilution. A plaque reduction neutralisation test11 showed that the serum collected 14 days after the onset of illness neutralised HeV at a dilution of 1 : 5.
Autopsy assistants: An adult member of the family who owned the horse held the dying animal’s head; two others assisted with the autopsy. All three were exposed to the frothy nasal secretions to varying degrees.
Although the two who assisted were reported as having become unwell after the procedure, further investigation revealed that neither had a febrile illness. Rather, both seemed to have had symptoms of pre-existing conditions.
HeV serological studies on samples collected from all three adults 3–4 weeks after the autopsy did not show any evidence of HeV infection.
Site visit: A site visit took place on the day of the notification to TPHU, which was about 2 weeks before laboratory confirmation of HeV infection was obtained. The paddock was in a semi-rural area and held seven other horses, all of which appeared in good health. It was surrounded by other paddocks, some of which held horses.
There was no obvious flying fox colony nearby; the owner of the property voluntarily quarantined the property (not allowing any horse movement in or out). Once the HeV infection in the veterinarian was confirmed, the other seven horses in the paddock were tested for serological evidence of HeV infection (38 days after the horse died); all were negative.
The quarantine was subsequently lifted.
All four reported outbreaks of HeV infection have occurred in Queensland, and three have occurred in the northern part of the state.
Although no samples were collected from the horse, with hindsight it clearly had an illness consistent with previous clinical reports of HeV disease in horses.
The disease is usually fulminant in nature, with fever, tachycardia, respiratory distress and a frothy nasal discharge being the typical reported features in horses.
8,12 Facial oedema, physical distress and unease (suggestive of colic), and the close proximity of flying foxes add further support to the clinical suggestion of HeV disease in horses.12 The most obvious gross pathology is marked fluid congestion in the lungs, with a thick, foamy haemorrhagic exudate in the airways.8
Although there was no obvious flying fox colony nearby, large numbers of flying foxes are usually obvious in the evening sky in the latter part of the year in and around Cairns.
The timing of the horse’s illness is not only the flying foxes’ birthing season,13 but also the season for many domestic and rainforest fruits in Far North Queensland; flying foxes travel considerable distances on nocturnal forays from their colonies in search of these foods.
The owner of the horse reported frequently seeing flying foxes in the vicinity of the property.
We assume that the veterinarian’s symptoms were caused by HeV, occurring after an apparent incubation of 7 days. Unfortunately, haematological and biochemical investigations were not requested after her initial medical consultation. The illness was mild, despite her being heavily contaminated with blood and body fluids during the autopsy.
This veterinarian is the fourth person known to have been infected with HeV. All four had direct exposure to secretions and tissues from very ill, dying or dead horses; two were directly involved in autopsies of these horses. Two of the four died, whereas the other two had relatively mild illnesses.2-4
The veterinarian has remained clinically well for 2 years since her initial illness.
A rise in the antibody titre 1 year after the initial illness was of concern in view of the observed late neurological relapse (13 months after acute illness), associated with increasing antibody levels, in one of the other cases of HeV infection.
4 The closely related Nipah virus has also been associated with late neurological relapse in 7.5% of cases, occurring up to 22 months after initial infection.14 In one case, late-onset Nipah virus encephalitis coincided with rising antibody titres.15
The veterinarian undertook a high-risk procedure, taking less than optimal precautions. She was a relatively recent graduate, and her training may not have adequately impressed upon her the need to undertake such procedures with due care.
Just as human health workers have had to accept that several recently emerged viruses (eg, blood-borne viruses and the SARS coronavirus) have changed working procedures, those working in animal health also must accept that recently emerged zoonotic viruses (eg, HeV and Australian bat lyssavirus) necessitate appropriate working procedures and personal protective equipment in veterinary practice.
After this HeV incident, the Queensland Department of Primary Industries and Fisheries published revised guidelines for veterinarians handling horses suspected of being infected with HeV.
12 These guidelines provide clinical case definitions and the recommended response measures, including the personal protective equipment that should be used when managing a suspected case, and the necessary reporting procedures.
12 We suggest that these guidelines should be widely disseminated throughout the Australian veterinary community.
In early December 2004, a horse on a property just south of Townsville died of laboratory-confirmed HeV disease; there were no human infections associated with this fifth recognised outbreak of HeV disease.
In mid June 2006, a horse on a property near Peachester on the Sunshine Coast hinterland died of laboratory-confirmed HeV disease; to date there have been no apparent human infections associated with the sixth outbreak of HeV disease.
1 Electron micrograph of the Hendra virus
|Courtesy, Mr Howard Prior, Senior Technician, Queensland Department of Primary Industries and Fisheries.|
2 Possible mode of transmission of Hendra virus (HeV) infection
3 Hendra virus (HeV) laboratory studies in serum collected from the veterinarian at various intervals after the onset of symptoms. The onset occurred 7 days after the autopsy of the horse
|Laboratory studies||Days after symptom onset|
|HeV RNA||Not detected|
|HeV IgM (IFA)|
The natural host for Hendra Virus is the flying fox (fruit bat). On rare occasions, Hendra Virus can pass from flying foxes to horses, causing severe illness, usually resulting in death.
Hendra Virus is a zoonotic disease; that is the disease can be transmitted from horses to humans during close contact with an infected horse.
Hendra Virus is a notifiable disease in Australia. It is a rare disease and has only been detected in Queensland and Northern NSW. However, the death rate related to infection is very high – about 50% in humans and more than 70% in horses.
What is the risk in Victoria?
Hendra Virus is a low risk disease for Victoria, but precautions should always be taken in areas where there are large flying fox populations in close proximity with horses, and/or with horses arriving in Victoria from Queensland or Northern NSW.
Protecting horse feed and water from contamination by flying foxes, early isolation of a sick horse while awaiting veterinary attention, and good hygiene and cleaning practices are all important.
Why is Hendra virus considered low risk in Victoria?
Hendra virus disease has never been identified in Victoria, despite our best efforts to detect it since its first occurrence in Queensland in 1994.
Regular monitoring and testing aimed at finding the disease in horses showing Hendra- signs has continually been negative Other routine monitoring activities (e.g. testing horses for export) and targeted activities (e.g.
knackery surveillance) have also provided supporting evidence of the ongoing absence of Hendra virus in the Victorian horse population.
In addition, the virus has not been isolated from samples obtained from flying foxes in Victoria, although serological evidence indicates that a percentage of the flying fox population has been exposed to the virus.
There are clear differences in epidemiological conditions between Victoria (where the disease has not occurred) and coastal Queensland/ northern NSW (where occurrence has been sporadic).
Flying fox populations in Victoria are smaller and less numerous, and the opportunities for transmission are fewer.
The apparent high level of exposure required for transmission from bats to horses does not occur in Victoria.
The normal range of the flying fox species most closely associated with Hendra virus outbreaks, the black flying fox, does not extend to Victoria.
Notably, all confirmed cases of Hendra infection in horses and people, to date, have occurred in the typical range of the black flying fox (see map).
Cases have only occurred within a small part of the range of the grey headed flying fox (the prevalent flying fox species in Victoria): that part in Queensland/northern NSW which it shares with the black flying fox.
Monitoring and testing strongly suggest that Victoria is free from endemic Hendra virus disease in horses, and transmission from local flying fox populations to horses is considered highly unly. However, it would be a mistake to assume that the disease will never be diagnosed here.
The horse population in Australia is highly mobile, and it is not impossible that a horse that is incubating Hendra virus disease could be transported from Queensland or northern New South Wales to Victoria. In addition, the typical range of the black flying fox appears to be have been slowly expanding southwards over past several decades.
It is, therefore, important that vigilance be maintained.
Horse owners and veterinary practitioners need to be familiar with the signs of Hendra, and instigate an investigation when the disease is suspected.
How is Hendra Virus transmitted?
The transmission of Hendra Virus from flying foxes to horses is not yet fully understood. However, there is no evidence of bat-to-human, human-to-human or human-to-horse transmission of Hendra Virus.
Hendra Virus has not been shown to be highly contagious; however, human cases of infection have been linked directly with exposure to the virus during autopsy of an infected horse or from close contact with an infected horse.
Is there a vaccine against Hendra available for horses?
There is a vaccine against Hendra virus available that is fully registered with the Australian Pesticides and Veterinary Medicines Authority, through specially accredited veterinarians.
Horse owners moving horses to Queensland or northern New South Wales should consider vaccination, as well as horses from these areas that are to be introduced to Victoria.
More information on the vaccine is available from the manufacturer at Health4horses and the APVMA.
What to do if you suspect HeV in your horse?
If you notice a sudden onset of illness in your horse or your horse has died suddenly, and you live in an area where there is a population of flying foxes that could come in contact with your horse, and/or your horse has traveled from Queensland or Northern NSW in the past 2-3 weeks you should contact your veterinary practitioner or the Emergency Animal Disease Hotline on 1800 675 888.
How do I reduce the risk of becoming infected?
Hendra virus is a public health concern and can create substantial workplace health and safety issues. It requires careful management.
There are several steps you should take while you are waiting for veterinary confirmation of Hendra virus:
- Avoid close contact with suspect infected horse/s and other horses that have been in contact with them
- Isolate the suspected horse where possible—preferably by relocating other animals
- Observe suspect horse from a distance and notify your veterinarian if you notice changes in their condition
- Where possible, provide feed and water for the suspect horse/s from a distance
- If close contact with the suspect horse is necessary ensure you take the following precautions:
- If you have any cuts or abrasions, ensure they are covered with a water-resistant dressing
- Use personal protective equipment (PPE), covering hands with gloves, feet with boots, and clothing with overalls
- Wear a P2 mask (particulate respirator) and safety glasses. This should help to protect your face from potential contact with the suspect horse's bodily fluids (saliva, nasal secretions, blood and urine)
- Remove and dispose of PPE carefully
- Wash your hands carefully with soap/disinfectant after all activities
Ask your veterinarian for help with putting on, taking off and safe disposal of PPE. Ensure P2 masks are fitted correctly to reduce your risk of infection.
What happens if my horse is confirmed HeV positive?
If your horse tests positive to HeV your local veterinarian will work with the Department of Economic Development, Jobs, Transport and Resources (DEDJTR) to manage the situation.
The property where the horse is located will be placed under quarantine by DEDJTR until all other horses on the property and that have visited or traveled off/on the property within the last few weeks can be cleared of infection.
Once DEDJTR has sufficient evidence to suggest that no other horses have been infected with HeV, the quarantine will be lifted.
What happens to my HeV positive horse?
It is Australian national policy that all horses confirmed positive, by laboratory testing, for HeV are humanely destroyed. This aims to prevent the spread of infection to humans and other animals. For further information on Hendra Virus please contact your local DEDJTR Animal Health Staff on 136 186.
Human exposure to HeV
DEDJTR will work with the Department of Health whenever HeV is confirmed or strongly suspected and there is reason to believe humans are at risk of exposure to the virus.
Hendra Virus is not particularly infectious, which means that exposure doesn't always lead to infection. If infection does occur, the incubation period usually ranges from about five to 15 days. Evidence suggests that the virus cannot be passed from one person to another.
The symptoms of infection in a person can include fever, headache, dry cough, sore throat breathing difficulties, dizziness, unusual sleepiness and confusion.
People at increased risk of infection include veterinarians, farriers, equine dentists, strappers, feed delivery merchants, horse owners and stud workers.
Hendra Virus tends to attack either the respiratory system or the nervous system. In Australia, the fatal complications have included:
Septic pneumonia – severe lung infection involving pus, abscesses and destruction of lung tissue
Encephalitis – severe brain inflammation and swelling which can lead to convulsion or coma
Currently there is no cure or specific treatment for infection with Hendra virus. Treatment aims to ease symptoms and reduce the risk of complications while the person recovers. There are experimental treatments available for people at high risk for exposure to the virus to prevent infection.
For further information on human health and Hendra Virus please contact Department of Health Communicable Diseases Section on 1300 651 160.
Hendra Virus Infection
Preventing horse infection
A vaccine to prevent Hendra virus infection in horses has been available since November 2012. The Hendra virus vaccine was registered by the Australian Pesticide and Veterinary Medicines Authority (APVMA) on 4 August 2015.
Further information can be found on the APVMA website and in product information accompanying the vaccine.
While the vaccine has been shown to be safe and to provide high levels of protection in horses, continued efforts to reduce exposure of horses to Hendra virus are essential.
It is important to
- protect horse food and water from contamination by flying fox fluids,
- isolate sick horses early while awaiting test results, and
- pay attention to standard hygiene and cleaning practices.
More information is available from Biosecurity Queensland or call 13 25 23 and Workplace Health & Safety Queensland or call 1300 369 915.
Preventing human infection
As a horse may be infectious with Hendra virus before becoming noticeably unwell, it is important to pay attention to standard hygiene practices when interacting with any horse. Horses should never be kissed on the muzzle.
Hands must be washed with soap and water regularly after touching horses, particularly before eating, smoking or touching your eyes, nose or mouth. Wounds should be covered with a waterproof dressing.
The use of personal protective equipment is recommended when it is ly that a person will come into contact with body fluids from any horse.
See Biosecurity Queensland and Workplace Health & Safety Queensland for more information.
If a horse’s body fluids or manure comes into contact with unprotected skin the area should be washed with soap and water as soon as possible. If the exposure involves a cut or puncture wound, gently encourage bleeding and then wash the area with soap and water.
Where water is not available, wipe the area clean, then use a waterless cleanser such as alcohol based gel. If eyes are contaminated, gently but thoroughly rinse open eyes with clean water or normal saline for at least 30 seconds.
If body fluids get in the mouth, spit the fluid out and then rinse the mouth with clean water several times.
If a horse becomes unwell and Hendra virus infection may be a possibility, as few people as possible should care for the horse until the infection is ruled out.
Children should be kept away from the horse.
Appropriate personal protective equipment which prevents contamination of the skin, eyes, nose or mouth from the horse's body fluids should be worn when in close contact with the sick horse.
Although there is no evidence of human to human transmission, close contact with the body fluids of a person who is unwell with possible Hendra virus infection should be avoided.
In hospitals, healthcare workers will take routine precautions which include the use of personal protective equipment.
In home settings, pay particular attention to standard hygiene measures such as regular hand washing.
People exposed to Hendra virus should not donate blood or other tissue until they are cleared of infection. Confirmed cases should never donate blood or any other tissue, even if they fully recover.
Suspected cases of Hendra virus infection in horses should be notified urgently to Biosecurity Queensland on 13 25 23 (during business hours) or 1800 675 888 (24-hour Emergency Animal Disease Watch Hotline).
Pathology laboratories are required to urgently notify all requests for Hendra virus testing in humans to the appropriate public health unit.
Public health response
When a horse is strongly suspected or confirmed to be infected with Hendra virus, Biosecurity Queensland will notify Queensland Health and take urgent measures to minimise risk to other people and other animals (horses, dogs and cats).
Public health staff will seek to identify all people who may have been exposed to an infectious horse and conduct a detailed assessment of their level of exposure.
People at risk of infection will be provided with information about Hendra virus and advised of appropriate ongoing monitoring and management.
If you have had recent exposure to an infected horse and have not been contacted by public health staff, please telephone your nearest public health unit or 13 HEALTH (13 43 25 84).
- Called equine morbillivirus when first discovered
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.
- Horses, flying foxes, dogs and humans have been infected in a natural setting
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
- increased heart rate
- discomfort or weight shifting between legs
- 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:
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 Watch 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.
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.
- Last reviewed: 24 Jul 2018
- Last updated: 08 Aug 2018