Imagine an infectious disease that creates ugly ulcerations on your horse inside and out, leading directly to death or the need for euthanasia. Consider a disease so bad that during World Wars I and II nations reportedly used it in germ warfare to dismount cavalry regimens and sicken human populations. It's like something out of an equine zombie apocalypse, only this disease--glanders--is very real and considered re-emerging in the Middle East.
Dr. habil. Ulrich Wernery, D.Med.Vet., scientific director at the Central Veterinary Research Laboratory (CVRL) in Dubai, United Arab Emirates (UAE), discussed his experience with the during the 2012 International Conference on Equine Infectious Diseases, held Oct. 22-26 in Lexington Ky.
While glanders has been eradicated from North American (last reported in the 1940s), Australia, and most of Europe, it's recently been reported in South America, Eastern Africa, Asia, and the Middle East. Wernery said 16 Middle East countries (60%) have confirmed cases of glanders but noted that not all countries are willing to report cases. "We do not know the situations in Egypt, Sudan, or Saudi Arabia," he said.
Even so, the evidence is enough to consider glanders a "re-emerging disease" in the Middle East, Wernery said. Animal health officials first detected it in the UAE in 2004 at a Dubai quarantine facility. The disease was then reported in Kuwait (2009), Bahrain (2010), and Lebanon (2011).
Due to reoccurrence of the disease during the past decade and the UAE's laboratory's experience diagnosing recent Middle Eastern outbreaks, the World Animal Health Organization (OIE) named the CVRL as an OIE reference laboratory for glanders in 2008.
Despite his expertise, Wernery noted that veterinarians and physicians in the early 20th century had much more experience recognizing and managing glanders than their contemporaries do today. "In 1945, they knew much more about glanders than I do now, because they were dealing with constant outbreaks," he told the audience.
Glanders is caused by Burkholderia mallei, a Gram-negative bacterium that is usually contracted through ingestion of contaminated water or feed. It's also communicable through direct contact or inhalation. Skin glanders is commonly referred to as "farcy" and mistaken as "African farcy," a fungal-derived disease that causes a similar clinical signs.
Clinical signs of acute glanders in equids include:
- High fever;
- Cough;
- Dyspnea (difficulty breathing);
- Thick nasal discharge (usually unilateral, or out of one nostril);
- Swollen and painful submaxillary lymph nodes (the "glands" in "glanders");
- Possible swelling of lymphatic vessels on legs (a condition also called "farcy pipe," Wernery noted);
- Rapidly spreading ulcers on the nasal mucosa, nodules, and chronic abscesses in stellate (starlike) or honeycomb patterns; and
- Multiple small abscesses in the lung and/or abscesses in the liver or spleen.
Clinical signs of chronic glanders in horses include:
- Coughing;
- Malaise;
- Weight loss;
- Intermittent fever;
- Possible thick nasal discharge, usually out of one nostril;
- Ulcers and nodules on the nasal mucosa;
- Enlarged submaxillary lymph nodes;
- Chronic enlargement and induration (hardening) of lymphatics and lymph nodes;
- Joint swelling and painful leg edema (fluid swelling); and
- Nodules, particularly on the legs, that rupture, release pus, and ulcerate
Donkeys tend to fair worse than horses, showing more severe clinical signs. Mules are also susceptible. Death usually follows within months of infection, and those that survive glanders become carriers of the pathogen.
Glanders is a zoonotic disease, meaning it can pass from animals to humans, which is why it's a concern for biologic germ warfare. According to the U.S. Center for Disease Control and Prevention, humans can develop four forms of disease, including septicemia, pulmonary infection, acute localized infection, or chronic infection.
The disease also infects animal species other than equids, including camelids, felines, dogs, and goats. Wernery presented photos of a zoo-kept white tiger diagnosed with glanders after eating the infected meat of a dead donkey. The tiger exhibited similar clinic signs as horses, including thick nasal discharge and farcy lesions.
Veterinarians diagnose glanders using serology (blood) or Mallein tests. With the Mallein test the practitioner injects a protein from the bacterium into the animal's skin or drops it in the eye; a positive horse will react with localized swelling within one to two days.
Wernery attributed the recent spread of glanders to a significant increase in horse movement between Middle Eastern countries, as well as a lack of veterinary services and quarantine facilities; lack of awareness among horse owners; lack of transparency; and poor control measures. The CVRL is working to better understand glanders and create recommendations for managing the spread of this devastating disease, he said.
Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.