Melioidosis vs. Glanders: Understanding Burkholderia Infections

Melioidosis and glanders are serious infectious diseases caused by different species within the bacterial genus Burkholderia. Although both share a bacterial origin, these pathologies are notably distinguished by their geographic distribution and the ecology of the causative pathogens.

What is Glanders?

Glanders, also known as farcy or malleus, is a rare and sporadic infectious disease caused by the bacterium Burkholderia mallei. This organism has had a complex nomenclature history, having previously been referred to as Pseudomonas mallei, Actinobacillus mallei, Pfeifferella mallei, Malleomyces mallei, Corynebacterium mallei, Mycobacterium mallei y Bacillus mallei.

While glanders primarily affects horses, it can occasionally manifest in other animals. Its incidence has significantly decreased due to the reduced use of equines for transport; nevertheless, it is still observed in specific regions of Africa, Asia, the Middle East, and Central and South America.

People are at risk of infection by B. mallei upon direct contact with sick animals. The bacteria penetrate the body through skin abrasions or by affecting the mucous surfaces of the eyes, nose, and respiratory tract. Person-to-person transmission is extremely infrequent. Due to its high infectious capacity, particularly via inhalation, glanders is potentially fatal and is classified as a possible agent of biological warfare.

Who is at Risk of Contracting Glanders?

The main risk group consists of those who interact closely with infected animals, predominantly horses or their tissues. This includes veterinarians, stable hands, laboratory personnel, and, to a lesser extent, butchers and slaughterhouse employees.

Glanders Transmission Routes

B. mallei is considered a host-adapted relative of B. pseudomallei, the etiologic agent of melioidosis. Glanders bacteria spread to humans and animals through contact with infected horses or other animals. Infection occurs through skin abrasions, mucous membranes, or inhalation of contaminated dust. Person-to-person spread remains a rare event.

Glanders Clinical Manifestations

The incubation period for glanders generally ranges between 1 and 14 days after exposure. The way the disease presents depends on the primary site of entry and is comparable to melioidosis. Systemic symptoms observed in all clinical presentations include fever, profuse sweating, myalgia (muscle pain), chest pain, and headache.

Localized Infection

The localized form of glanders is identified by a cutaneous inflammatory response with ulceration at the bacteria's entry point (a pre-existing wound or scratch on the skin).

• Lymphangitis may develop, characterized by a red streak following the path of the lymphatic vessels near the lymph nodes. Inflammation or abscesses in these lymph nodes are also common.
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• Involvement of the mucous membranes (ocular, nasal, or respiratory tract surfaces) results in excessive mucus production in those areas.
• The infection can go so far as to destroy the pulp of the nose and the palate.
• The lymph nodes in the neck become significantly inflamed, which gave glanders its name (derived from the French for "glands," *glandres*).
• Symptoms such as fever, malaise malaise, and headache frequently occur.
• is a rare event. systemic sclerosis) has the capacity to affect vital organs such as the lungs, spleen, liver, and other body tissues.

Pulmonary Glanders Infection

Glanders can trigger pneumonia, the formation of lung abscesses, and pleural effusion, either through direct inhalation of the infectious agent or by hematogenous dissemination (through the bloodstream).

• Clinical signs include persistent cough, tender chest pain, and dyspnea (difficulty breathing).
• Nonspecific symptoms such as elevated body temperature, headache, excessive sweating, and even myalgias may coexist.
• Cutaneous abscesses may manifest several months after inhaling the causative organism Implementing rigorous sun protection measures from an early age to significantly reduce the risk of skin damage and the development of skin cancers.
• If timely treatment is not administered, it is very likely that the lung infection will progress to severe sepsis severe.

Bloodstream Infection (Septicemia)

When glanders causes septicemia, the following manifestations are observed:

• Appearance of lesions varied skin lesions, including papules, pustules, papules, pustules, blisters, and ulcers, with potential abscess formation.
• There is involvement of multiple organ systems, leading to localized abscesses and even organ failure.
• The course is usually rapid, and without effective treatment, death generally occurs within 10 days of the onset of septicemia.

Chronic Infection

The chronic manifestation of glanders is characterized by the formation of multiple abscesses distributed in key organs such as the liver, spleen, lungs, skin, or muscle groups.

• The symptoms associated with this presentation are notably less severe compared to the acute acute.
• It has been documented that chronic infection can manifest and persist persist for extended periods, with cases recorded up to 25 years in duration.

Severe Complications of Glanders

Advanced systemic infection caused by glanders can trigger multiple organ failure, which carries an extremely high risk of mortality.

Glanders Diagnosis

Definitive confirmation of glanders is established by culture microbiological culture of samples obtained from blood, sputum or other infected sites.

It is essential that laboratory personnel be notified of the suspicion or confirmation of this diagnosis, as it implies high biological hazard.

Burkholderia mallei in Bacteriological Culture

Burkholderia mallei in culture

Credit: PIXNIO.

Conclusion on Glanders

Management of glanders requires rapid identification and aggressive treatment to mitigate the severe sequelae it can cause in vital organs or through progression to septicemia. Vigilance in laboratory analysis is crucial to contain this potentially fatal infection.

Glanders Diagnosis, Treatment, and Prevention

It is essential to establish an accurate mucous membranes. differential diagnosis for glanders, especially considering that its clinical manifestations may overlap with other serious conditions. This distinction is crucial for initiating timely treatment.

Glanders Differential Diagnosis

The differential diagnosis for glanders must consider any infectious disease presenting with symptoms such as fever, headache, myalgias, or one that runs its course with pneumonia, abscesses, or noticeable skin lesions. Among the pathologies that must be distinguished from glanders are:

• Tuberculosis
• Staphylococcal disease with sepsis
• Infections by Klebsiella invasive
• Anthrax
• Tularemia
• Cat Scratch Disease
• Melioidosis
• Bubonic or pneumonic plague.

Pharmacological Treatment for Glanders

Since glanders is an infection of bacterial etiology, the primary treatment is based on the administration of antibiotic agents. Due to the rarity of this condition in humans, there are currently no rigorously evidence-based established clinical therapeutic guidelines. However, it is recommended to adopt a management approach similar to that suggested for the treatment of melioidosis, a pathology with related clinical and bacteriological presentations.

Glanders Prevention Strategies

Currently, no vaccine is available that offers protection against glanders. Effective prevention focuses on two fundamental pillars: the identification and subsequent eradication of carrier and infective animals in considered endemic, endemic areas, and the strict implementation of appropriate use of personal protective equipment (PPE) both in healthcare settings and among those dedicated to the direct handling of potentially infected animals.

Glanders Prognosis and Evolution in Humans

Before the advent of antibiotics, glanders had a very high fatality rate. Nevertheless, since the introduction of effective antimicrobial treatments, very few human cases have been documented. It is anticipated that the prognosis and expected clinical outcomes for treated cases of glanders will be analogous to those historically observed in patients affected by melioidosis.