Why must you report an emergency animal disease?
An emergency animal disease has severe consequences for:
- livestock production and/or
- exports of livestock and livestock products and/or
- human health and/or
- national or industry revenue.
When should I suspect an emergency animal disease?
You should suspect an emergency animal disease if you see:
- unusual signs in stock (new or more severe signs or more stock affected than expected)
- large numbers of stock deaths
- a big drop in expected production and growth rates.
What should I do if I see unusual signs of disease in my animals?
- Call a vet — your private vet or a DPIRD vet.
- Call your local DPIRD office.
- Call the emergency animal disease hotline, which operates seven days a week, on 1800 675 888.
Equine influenza
Equine influenza occurs sporadically in Europe, Japan, North America and South America with recent outbreaks in the United Kingdom.
Australia had a significant outbreak of equine influenza in August 2007, which was successfully eradicated.
Horses, donkeys and mules are the natural host of the virus that causes equine influenza.
How equine influenza spreads
Contact between horses is the main way the disease spreads. However, contaminated equipment (such as horse transport equipment) can spread the infection as the virus can survive in the environment for up to 36 hours or longer. People can also spread the infection because the virus can contaminate clothing and skin.
If an outbreak occurs, a high number of exposed horses will usually get sick because the virus is highly contagious.
Signs of equine influenza
These include:
- fever (up to 41°C) after an incubation period of 1–5 days
- frequent dry hacking cough during the first few days
- then less frequent and more moist coughing which stops after 1–3 weeks if horses are well and rested
- nasal discharge, changing from clear to a thick mucous
- fatigue, lethargy and loss of appetite
- foals die from pneumonia if they have not had adequate colostrum
- death of older or weak horses, more susceptible to secondary bacterial bronchitis.
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. To date, over 100 horses have been infected with Hendra virus and have died or been euthanased. Seven people have been infected with Hendra virus, and four of them have died. All of these cases have been in either Queensland or northern New South Wales. No horses or people in WA have been diagnosed with Hendra virus infection.
Safety precautions
Hendra virus can be fatal in humans. Report suspicious cases and ensure you use appropriate personal protective equipment if you have to handle suspect horses. An effective vaccine for Hendra virus is available and a decision to use the vaccine should be made in consultation with your veterinarian.
Human infection is thought to occur through contact with body fluids, including the mucous secretions of infected horses. Persons in close contact with horses that have Hendra virus-like signs should wear protective face masks, goggles and gloves while taking care with personal disinfection.
Signs of Hendra virus
Hendra virus can cause a broad range of clinical signs in horses, and should be considered whenever horses have had exposure to fruit bats (flying foxes) or to horses from areas known to have had cases of Hendra virus, and suffer acute onset fever and rapid progression to death associated with respiratory or neurological signs.
These include:
- rapid onset illness
- increased body temperature (above 38.5°C) and heart rate
- dullness
- rapid deterioration
- respiratory distress, laboured breathing, frothy and/or blood-stained nasal discharge
- neurological (nervous system) signs such as wobbly gait, lack of coordination.
Other respiratory signs include:
- respiratory distress — increased respiratory rates
- terminal nasal discharge — can be initially clear progressing to stable white froth and/or stable blood-stained froth
- terminal weakness, loss of control of muscle movement and collapse.
Other neurological signs include:
- ‘wobbly gait', progressing to loss of control of muscle movement
- apparent colic signs
- altered consciousness — apparent loss of vision in one or both eyes, aimless walking in a dazed state
- head tilting, circling
- muscle twitching
- urinary incontinence
- lying down with an inability to get up.
For more information about Hendra virus, see the DPIRD Hendra virus webpage.
African horse sickness
Australia has not recorded any outbreaks of African horse sickness, which is caused by an insect-transmitted virus.
African horse sickness (AHS) is endemic or occurs in all parts of Africa south of the Sahara but epidemics have spread further north to Egypt, the Middle East and Spain. Thailand is currently experiencing an outbreak of AHS thought to have entered the country via imported zebra, which do not show clinical signs. The outbreak is being contained by vaccination and by excluding insects from stables.
Horses and mules are highly susceptible and often die following infection. Dogs show severe disease if infected.
There are several forms of the disease. The specific signs of AHS reflect the effects of the virus on the lungs, or on the heart and circulatory system, or a combination of both.
Signs of African horse sickness
Lung form signs include:
- sudden fever with temperature to 41°C, panting, copious amounts of frothy nasal discharge
- standing with forelegs apart, ears drooping, nostrils dilated, head extended and very sweaty
- death within 4–24 hours.
Similar signs are seen in dogs.
Heart and circulatory form signs include:
- less acute with fever 39–41°C persisting for 3–4 days before swelling above and behind the eyes (the swelling may cause the eyes to close and bulge)
- later pinpoint haemorrhages of the membrane over the white of the eye and the inside of the eyelid (conjunctiva)
- swelling of the lips, cheeks, tongue and throat area
- swelling of the neck, brisket, lower chest and abdomen.
Swelling gradually subsides over a week or so in horses that recover.
Combination of lung and heart form signs include:
- temperature may be above 40°C for a day or two
- inflammation of the conjunctivae (whites of the eyes and inside of eyelid), breathing difficulty and increased pulse rate before a rapid recovery.
Contagious equine metritis
Contagious equine metritis (CEM) was first diagnosed in 1977 in the UK and spread to many countries, initially in thoroughbreds. It was also identified in Australia in 1977, but since eradication in 1980, Australia has been free of the disease. Contagious equine metritis currently occurs in parts of Western Europe and South Africa.
Contagious equine metritis is caused by the bacteria Taylorella equigenitalis. Horses are the only hosts. The disease was originally detected in thoroughbreds but is now rare. Cases still occur in warmblood and Arabian horses. Transmission is venereal by both mares and stallions. Transmission may also occur with poor hygiene when examining genital tracts of mares and stallions.
Signs of contagious equine metritis
Signs include:
- mares develop an inflamed vagina and thick, odourless discharge from their genital tract 1–3 days after mating, or sometimes later
- there may be a lot of discharge or only an accumulation of grey or grey-white fluid in the vagina
- discharge usually disappears after 3–4 weeks
- mares may return to heat a few days after infection.
Stallions show no clinical signs and some infected mares show no signs. Test for CEM if mares show chronic infertility.
Japanese encephalitis
Japanese encephalitis (JE) occurs throughout most of Asia, including India, China and Japan. In 1995, the virus was found in dogs, pigs, horses and people in the Torres Strait islands. The virus was detected at the top of Cape York Peninsula in 1998 and it now appears widespread in the Torres Strait.
In temperate areas, infection usually occurs in late summer and autumn, when mosquitoes are more active. Infection builds up in water birds and then spreads by mosquitoes to pigs during late spring and early summer and finally to humans and horses.
Cases in humans and horses tend to be sporadic or occur in small clusters, but serious outbreaks could occur in a large, susceptible population exposed to infected mosquitoes. Infected horses are dead-end hosts as there is not enough of the virus in their blood to infect mosquitoes.
Japanese encephalitis is caused by a virus related to West Nile virus and Murray Valley encephalitis virus. The virus cycles naturally between water birds (herons and egrets) and mosquitoes. Pigs can also be infected and spread disease causing abortions in pregnant sows and neurological signs in piglets.
Humans and horses may suffer severe disease from the virus, but they do not spread the disease. Infections without recognisable signs occur in other livestock and animals.
The disease has an incubation period of 8–10 days.
Signs of Japanese encephalitis
These include:
- vary from a passing fever through to violent neurological signs and death
- mild cases: off feed, sluggish and reddened or jaundiced (yellow) mucous membranes (gums)
- more serious cases: lethargic with a fluctuating fever, difficulty swallowing, jaundice (yellow), pinpoint haemorrhages in mucous membranes (gums)
- nervous signs such as lack of coordination, staggering, falling, aimless wandering and unpredictable behaviour may occur in serious cases
- severe cases: blindness with profuse sweating and muscle trembling before collapsing and dying.
Other less common but significant horse diseases
Surra
Surra is caused by a blood parasite, Trypanosoma evansi, which is spread by biting flies. Surra is most severe in horses, donkeys, mules, deer, camels, llamas, dogs and cats. The only Australian case of surra was found in imported camels at Port Hedland in 1907. Surra occurs in South America, and from Northern Africa, through the Middle East and Asia to Indonesia.
Anthrax
Anthrax is present in many countries, including Australia. Most cases in Australia occur in cattle and sheep, and occasionally pigs.
Now, outbreaks are largely sporadic, especially in the central western plains of New South Wales.
Rabies
Rabies is present in most countries but does not occur in Australia, the UK, Japan, Singapore, New Zealand, Papua New Guinea or the Pacific Islands. Many species, including horses, are ‘dead-end’ hosts (that is, they cannot transmit the virus to other animals). Horses always die from rabies.
Equine piroplasmosis (equine babesiosis)
Equine piroplasmosis (or equine babesiosis) is a tick-borne protozoal disease caused by Babesia equi or B. caballi. B. caballi has not been identified in Australia. Australia is free from equine piroplasmosis, although an outbreak due to B. equi was diagnosed in 1976 in the Moss Vale region of New South Wales. The disease was very mild, and most infections were subclinical.
Vesicular stomatitis
Vesicular stomatitis is confined to North and South America, with recent outbreaks having occurred in North and Central America. It is a viral disease of horses, cattle and pigs.
Particular significance is placed on the recognition of clinical signs in cattle and pigs because they are virtually indistinguishable from the lesions seen in foot-and-mouth disease. Horses are not affected by foot-and-mouth disease.
Glanders
The bacteria Burkholderia mallei causes glanders, and affects all equids with donkeys being the most susceptible before mules. Australia is free of glanders. The disease is endemic in areas of the Middle East, Asia, Africa and South America and continues to be reported in Brazil, China, India, Iran, Iraq, Mongolia, Pakistan, Turkey and the United Arab Emirates. The most recent outbreaks have occurred in South America and the Middle East.
Horse biosecurity
For information about keeping your horses healthy through good biosecurity practices, see the DPIRD horse biosecurity webpage.