Equine Glanders is one of the most serious and feared infectious diseases in horses, mules, and donkeys. Caused by the bacterium Burkholderia mallei, it is a highly contagious, often fatal disease that has been eradicated from most developed countries through decades of strict test-and-slaughter programmes. Glanders is also a zoonotic disease — it can infect humans, and human cases, whilst rare, carry a high mortality rate without aggressive treatment. In the UK and European Union, glanders is a notifiable disease; any suspected case must be reported to the relevant veterinary authority immediately.
Other Names
- Farcy (the chronic cutaneous form)
- Burkholderia mallei infection
- Malleus (archaic)
What Is Equine Glanders?
Glanders is a bacterial disease caused by Burkholderia mallei, an obligate mammalian pathogen that cannot survive for long periods outside a host. The disease primarily affects equids — horses, mules, and donkeys — but can cause severe, often fatal infection in humans and certain other mammals including lions, bears, and dogs. Cats are notably resistant.
The disease has two primary clinical forms: a pulmonary (lung) form and a cutaneous (skin) form, the latter historically called "farcy." In practice, these forms often overlap. Chronic carrier horses — animals that appear healthy but continuously shed the bacteria — pose the greatest epidemiological risk, as they are difficult to identify without specific testing and can silently infect entire herds.
Glanders was once widespread globally, decimating horse populations during 19th-century urbanisation and causing significant military losses during both World Wars. Systematic testing and culling programmes eliminated the disease from Western Europe and North America during the 20th century. It remains endemic in parts of the Middle East, Central Asia, Africa, and South America.
Causes
Glanders is caused by Burkholderia mallei, a Gram-negative aerobic bacterium. Transmission occurs primarily through:
- Direct contact: Nasal secretions, skin lesions, and respiratory discharge from infected horses are highly infectious. Shared water troughs, feed containers, and grooming equipment are common transmission vectors.
- Indirect contact: Contaminated bedding, tack, clothing, or stable fittings can harbour the bacterium for a limited period
- Aerosol inhalation: Inhalation of infected droplets — particularly relevant in enclosed stabling
- Skin abrasions: B. mallei can enter through skin wounds or mucous membranes
Risk factors for introduction into a previously clean herd include importing horses from endemic regions, attending international competitions or sales, and inadequate biosecurity at mixing points.
Symptoms and Signs
Glanders may present acutely, subacutely, or chronically. The incubation period ranges from a few days to several months in the chronic form. Clinical signs vary by form:
Pulmonary (lung) form — most common:
- High fever and depression
- Profuse, thick, purulent (pus-containing) nasal discharge — initially one-sided, then bilateral
- Cough
- Difficulty breathing
- Rapid weight loss
- Ulceration and nodules on the nasal septum
- Submandibular (under the jaw) lymph node enlargement and abscessation
Cutaneous form (Farcy):
- Nodules (farcy buds) along the course of superficial lymphatics — particularly on the inside of the hindlimbs
- Lymphatic cording — thickened, rope-like lymphatic vessels
- Ulceration of nodules, discharging a sticky, honey-like fluid
- Oedema of affected limbs
Chronic form:
- Gradual weight loss
- Intermittent nasal discharge
- Mild respiratory signs
- A horse may appear relatively healthy whilst actively shedding bacteria
Acute cases may result in death within days. Chronic cases can persist for years with periods of apparent recovery.
Diagnosis
Glanders can be clinically confused with several other conditions including strangles, chronic respiratory disease, and lymphangitis. Definitive diagnosis requires laboratory confirmation:
- Mallein test: The traditional and still widely used diagnostic test. Mallein (a purified protein derivative from B. mallei) is administered intradermally or into the conjunctival sac. A positive reaction (swelling and ocular discharge within 24–48 hours) is highly suggestive of exposure. This is the most widely used field test in endemic countries.
- Complement Fixation Test (CFT): A serological test that detects antibodies to B. mallei. Used for official testing in the EU for imported horses.
- PCR: Real-time PCR on nasal swabs, blood, or tissue samples — highly sensitive and specific
- Culture: Isolation of B. mallei from nasal secretions or tissue — handled under strict biosafety Level 3 conditions due to the zoonotic risk
In the UK, laboratory testing must be conducted at an approved facility. Veterinarians are legally required to report any suspected case to the Animal and Plant Health Agency (APHA) before testing.
Treatment
In countries where glanders is eradicated or notifiable (including the UK), confirmed or strongly suspected cases are not treated — they are humanely euthanised and the carcass disposed of according to biosecurity protocols to prevent further spread. This is the policy required under UK and EU legislation.
In endemic regions where culling policies are not in place, experimental antibiotic protocols using combinations of trimethoprim-sulfamethoxazole, doxycycline, or imipenem have been trialled. B. mallei has intrinsic resistance to many common antibiotics, and treatment is difficult even under optimal conditions. Complete bacteriological cure is rarely confirmed.
Prevention
In glanders-free countries, prevention relies on maintaining disease-free status through vigilant biosecurity:
- Comply fully with import health certificate requirements for horses from non-EU/non-EEA countries — these include mandatory serological testing for glanders
- Apply strict quarantine for any horses arriving from endemic regions
- Report any horse with unexplained profuse nasal discharge, nasal ulceration, or lymphatic nodules to your vet immediately
- Do not share equipment, tack, or water sources between horses of unknown health status at events or sales involving international participants
- Maintain awareness of current global disease alerts issued by the World Organisation for Animal Health (WOAH) and BEVA
Prognosis
In affected horses in endemic regions, the prognosis is grave without treatment, and poor with treatment. The acute form is often rapidly fatal. Chronic carriers may survive for months to years but continually threaten other horses. In countries with eradication programmes, affected horses are humanely destroyed — the "prognosis" in the conventional sense does not apply as treatment is not permitted.
When to Call the Vet
In the UK, contact your vet immediately — and expect them to notify APHA — if a horse shows:
- Profuse, purulent nasal discharge — particularly if one-sided initially
- Ulceration or nodules on the nasal septum
- Nodular skin lesions with lymphatic involvement, particularly on the inner limbs
- Progressive weight loss with respiratory signs in a horse that has recently been imported or attended international events
Do not wait for laboratory confirmation before notifying your vet. Glanders is a legally notifiable disease in the UK — early notification protects other horses, other premises, and human health. For related conditions with similar presentations, see Equine Viral Arteritis (EVA) and Equine Mastitis. For general information on equine biosecurity, see our horse terminology guide on biosecurity.
Frequently Asked Questions
Is glanders still present in the UK?
Glanders has been officially eradicated from the UK and has not been confirmed in a UK horse since 1928. However, the risk of re-introduction via imported horses from endemic countries remains real. Import health certificate requirements and mandatory serological testing are the primary barriers against reintroduction.
Can I catch glanders from my horse?
Yes. Glanders is a serious zoonotic disease. Human infection can occur through contact with infected nasal secretions, skin lesions, or tissue — particularly through skin abrasions, mucous membranes, or inhalation. Human glanders is rare but carries a mortality rate of up to 95% without treatment, and even with antibiotic treatment outcomes are uncertain. This is why suspected cases in animals must be handled with strict biosafety precautions and reported immediately.
What countries still have glanders?
As of recent WOAH reports, glanders remains endemic or has been recently reported in parts of the Middle East (including Iran, Iraq, and Turkey), Central Asia, South Asia (India, Pakistan), parts of Africa, and South America. The disease situation changes, and current status should be verified through WOAH's disease information system before importing horses from any potentially endemic region.
Why is glanders treated differently from most equine diseases?
Glanders is treated as a public health emergency as well as an animal health issue because of its zoonotic potential and the severity of human disease. In glanders-free countries, the official policy of euthanasia and controlled disposal is designed to eliminate the pathogen completely and prevent it from re-establishing in the equine population. This is the same approach taken with other highly dangerous zoonotic diseases in livestock, such as foot-and-mouth disease and rabies.