Equine glanders - Symptoms and Prevention

Author: Laura McKinney
Date Of Creation: 4 August 2021
Update Date: 1 November 2024
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Glanders| Equine Farcy | Aetiology | Pathogenesis | Symptoms & Diagnosis
Video: Glanders| Equine Farcy | Aetiology | Pathogenesis | Symptoms & Diagnosis

Content

glanders are a very serious bacterial disease that mainly affects horses, although felines fall just behind in susceptibility and other animals can also be infected. People can also get this infection, so it's a mandatory notification zoonosis. Fortunately, it is now eradicated in most countries, but there are still cases in Brazil.

glanders can manifest acute forms with nodules and ulcers in the respiratory system, chronic or asymptomatic forms, in which horses remain carriers and transmitters of the bacteria throughout life. Continue reading this PeritoAnimal article to learn more about equine glanders - symptoms and diagnosis.


What is equine glanders?

The equine glander is a infectious disease of very serious bacterial origin that affects horses, mules and donkeys, and has zoonotic potential, that is, can be transmitted to human. Without treatment, 95% of horses can die from the disease, and other horses become chronically infected and continue to spread the bacteria until the end of their lives.

In addition to horses, mules and donkeys, members of the felidae family (such as lions, tigers or cats) and sometimes even other animals such as dogs, goats, sheep and camels can be affected by the disease. On the other hand, cows, pigs and poultry are resistant to glanders.

This disease is endemic in parts of the South America, Africa, Asia and the Middle East. It was eradicated in most countries in the middle of the last century and its outbreaks are rare today, however, there are recent records, including in 2021, in different states of Brazil.[1]


The bacteria that cause glanders was used as a biological weapon during World Wars I and II against people, animals and horses belonging to the army.

If you are a horse owner, we also recommend reading this article on the most common diseases in horses.

Cause of equine glanders

glanders are caused by a bacterium, more specifically a Gram negative bacillus calledburkholderia mallei, belonging to the Burkholderiaceae family. This microorganism was formerly known as Pseudomonas mallei, and is closely related to Burkholderia pseudomallei, which causes melioidosis.

How is equine glanders transmitted?

The transmission of this bacteria occurs by direct contact or with the respiratory secretions and skin of the infected, and horses and cats are infected by ingesting contaminated food or water by bacteria, as well as aerosols or through skin and mucosal lesions.


On the other hand, the most dangerous are horses with latent or chronic infection, which carry the glanders bacteria but do not show symptoms of the disease, as they remain contagious throughout their lives.

In this other article you can find out which plants are toxic to horses.

What are the symptoms of equine glanders?

glanders in horses can develop acutely, chronically or asymptomatically. Among the forms that cause symptoms, we find three: nasal, pulmonary and cutaneous. Although the first two are more related to acute disease, cutaneous glanders are usually a chronic process. The incubation period usually lasts. between 2 and 6 weeks.

Equine nasal gland symptoms

Within the nasal passages, the following lesions or symptoms can occur:

  • Deep nasal nodules.
  • Ulcers in the nasal mucosa, and sometimes in the larynx and trachea.
  • Uni or bilateral secretion, purulent, thick and yellowish.
  • Sometimes a bloody discharge.
  • Nasal perforation.
  • Enlarged submaxillary lymph nodes, which sometimes occlude and drain pus.
  • Star-shaped scars.
  • Fever.
  • Cough.
  • Breathing difficulty.
  • Anorexia.

Equine pulmonary glanders symptoms

In this clinical form, the following occur:

  • Abscesses and nodules in the lungs.
  • Secretions disseminated to the upper respiratory tract.
  • Mild or severe breathing difficulty.
  • Cough.
  • Fever.
  • Breath sounds.
  • Slimming.
  • Progressive debilitation.
  • Diarrhea.
  • Polyuria.
  • Nodules in other organs such as the spleen, liver and kidneys.

Equine cutaneous glanders symptoms

In cutaneous glanders, the following symptoms occur:

  • Superficial or deep nodules on the skin.
  • Skin ulcers.
  • Fatty, purulent and yellowish secretions.
  • Enlarged and swollen nearby lymph nodes.
  • Lymphatic system vessels filled with pus and hardened, usually at the ends or sides of the trunk; rarely in the head or neck.
  • Arthritis with edema.
  • Pain in the paws.
  • Testicular inflammation or orchitis.
  • High fever (donkeys and mules).
  • Respiratory symptoms (especially donkeys and mules).
  • Death in a few days (donkeys and mules).

the cases asymptomatic or subclinical they are the real danger as they are a major source of infection. In people, the disease is often fatal without treatment.

Equine glanders diagnosis

The diagnosis of glanders in horses will be based on clinical and laboratory tests.

Diagnosisóclunkeríonly equine glander

The appearance of the clinical symptoms we describe should lead to suspicion of this disease, but each case must be differentiated from other processes in horses that cause similar symptoms, like:

  • Equine adenitis.
  • Sporotrichosis.
  • Ulcerative lymphangitis.
  • Epizootic lymphangitis.
  • Pseudotuberculosis.

at necropsy, it is possible to highlight the following organ damage of the horses:

  • Ulceration and lymphadenitis in the nasal cavity.
  • Nodules, consolidation, and diffuse lung pneumonia.
  • Pyogranulomatous nodules in the liver, spleen and kidneys.
  • Lymphangitis.
  • Orchitis.

Laboratory diagnosis of equine glanders

The samples collected for the diagnosis of the disease are from blood, exudates and pus from lesions, nodules, airways and affected skin. The tests available to detect the bacteria are:

  • Culture and coloring: samples are from respiratory lesions or exudates. Bacteria are seeded on blood agar medium for 48 hours, in which it is possible to observe white, almost transparent and viscous colonies, which later turn yellow, or on glycerin agar, where after a few days a creamy, viscous, soft and moist layer will be seen it can become thick, hard and dark brown. The bacteria in the culture are identified with biochemical tests. B. mallei it can be stained and viewed under a microscope with methylene blue, Giemsa, Wright or Gram.
  • real-time PCR: to differentiate between B. mallei and B. pseudomallei.
  • malein test: useful in endemic areas. It is a hypersensitivity reaction that allows the identification of infected horses. It consists of inoculating a fraction of the bacterial protein by intrapalpebral injection. If the animal is positive, inflammation of the eyelids will occur 24 or 48 hours after inoculation. If inoculated subcutaneously in other areas, it will cause an inflammation with raised edges that will not cause pain the next day. The most common form is inoculation using eye drops, causing conjunctivitis and purulent secretion 5 to 6 hours after its administration, with a maximum duration of 48 hours. These reactions, if positive, are accompanied by fever. It can give inconclusive results when the disease is acute or in the late stages of the chronic phase.
  • Agglutination with Rose Bengal: Used especially in Russia, but not reliable on horses with chronic glanders.

On the other hand, the exams with greater reliability to diagnose glanders in horses are:

  • Attachment of the add-on: is considered the official test in the international horse trade and is capable of detecting antibodies from the first week after infection.
  • ELISA.

How to cure equine glanders

Because it's such a dangerous disease, your treatment is discouraged. It is only used in endemic areas, but it results in animals that carry the bacteria and act as spreaders of the disease, so it is better not to treat it, and there are no vaccines either.

glanders prevention

The glander is in the list of mandatory reporting diseases for horses by the World Organization for Animal Health (OIE), therefore, the authorities must be notified, and the requirements and actions can be consulted in the OIE Terrestrial Animal Health Code. It is established that animals that obtain positive results in diagnostic tests in an area that does not have the disease (non-endemic area) are sacrificed because of the danger they pose to public health and the severity of the disease. Corpses must be burned because of the danger they carry.

In case of an outbreak of equine glanders, establish a quarantine of establishments where horses are found, with thorough cleaning and disinfection of places and objects, horses and other fomites. Animals susceptible to infection must be kept far enough away from these establishments for months, as the morbidity or contagion of the disease is very high, so places where animals congregate represent a great danger.

In areas free of glanders, it is prohibited to import horses, their meat or derived products from countries with the disease. In the case of importing horses, negative tests are required (malein test and complement fixation) before boarding the animals, which are repeated during the quarantine performed on arrival.

This article is for information purposes only, at PeritoAnimal.com.br we are not able to prescribe veterinary treatments or perform any type of diagnosis. We suggest that you take your pet to the veterinarian in case it has any type of condition or discomfort.

If you want to read more articles similar to Equine glanders - Symptoms and Prevention, we recommend that you enter our Bacterial Diseases section.