Glanders
Glanders is a highly infectious and potentially life-threatening disease caused by the bacterium Burkholderia mallei, which primarily affects horses but can also infect humans. Although eradicated in many parts of the world, glanders remains endemic in regions of Africa, Asia, the Middle East, Central America, and South America. Human infections can occur through direct contact with infected animal tissues or bodily fluids, inhalation of aerosolized bacteria, or through minor cuts. Symptoms vary based on the infection route and can include localized skin infections, respiratory issues, and severe systemic complications leading to sepsis.
Diagnosis of glanders requires specific laboratory tests, including sputum cultures and radiography, due to its sporadic occurrence in humans. Effective treatment typically involves antibiotics such as ceftazidime, doxycycline, and imipenem, but the disease has a high mortality rate if not treated promptly. Preventive measures focus on biosafety practices and the elimination of infected animals, as there is currently no vaccine available for humans. Individuals at higher risk include veterinarians and those working in laboratories with the bacterium.
Glanders
- ANATOMY OR SYSTEM AFFECTED: Blood, lungs, skin, upper respiratory tract
Definition
Glanders is a highly infectious, life-threatening, disease caused by Burkholderia mallei, a potential biological warfare agent. It has been eradicated from most regions except parts of Africa, Asia, the Middle East, Central America, and South America. Human infection occurs through the skin, lungs, or bloodstream.
Causes
B. mallei, classified as a category B priority pathogen by the National Institutes of Health (NIH) and the Centers for Disease Control and Prevention (CDC), is highly infectious when aerosolized and is often antibiotic-resistant. Some antibiotics, such as ceftazidime, doxycycline, and imipenem, have shown effectiveness against glanders. It is a zoonotic agent because of its transmission between animals and humans. The bacteria exist in animal hosts (often horses, donkeys, and mules). Transmission of the disease in humans occurs through direct contact with tissue or bodily fluids of infected animals. The bacteria enter the body through minor cuts, ingestion, or inhaling infected aerosols and then release toxins that interrupt cellular processes. Person-to-person transmission of the disease can occur.
Risk Factors
The disease can affect people of all ages. However, people in close contact with animals, such as veterinarians and laboratory personnel working with B. mallei, are at greater risk of exposure. Additional risk factors include living and working in areas where glanders is endemic, poor hygiene and sanitation, consuming infected meat, having a weakened immune system, and exposure to it as a bioweapon.
Symptoms
Clinical symptoms of glanders vary depending on the route of infection. A localized skin infection is characterized by rashes, bumps, and ulcerated lesions. Swollen lymph nodes, pain at the infection site, and general malaise are also symptoms of a localized infection. An upper respiratory tract infection occurs when bacteria enter through mucous membranes (nose, eyes) and cause an increased nasal discharge and inflammation. Symptoms of pulmonary infection include cough, fever, chest pain, fluid in the lungs, difficulty breathing, and lung abscesses. Infection can disseminate to other areas and into the bloodstream (sepsis), causing fever, chills, muscle aches, chest pain, skin rash, diarrhea, liver and spleen enlargement, and multiple organ failure, followed by death. A chronic and progressive infection involves abscesses throughout the body.
Screening and Diagnosis
Glanders is a sporadic disease in humans, and any suspected cases should be reported to local health officials. Primary care physicians should consult with an infectious disease specialist and the CDC for diagnosis and treatment to prevent misdiagnosis. Diagnostic tests include sputum culture, chest X-ray, radiography, and polymerase chain reaction assays. Definitive diagnosis of glanders requires isolating and confirming the presence of B. mallei from infected specimens.
Treatment and Therapy
Persons with glanders are treated with antibiotics based on the extent of the disease. The few human cases and clinical studies have limited information about effective antibiotic treatment. Some antibiotics, including ceftazidime, doxycycline, and imipenem, have proven effective against glanders; however, extended multidrug therapy may be necessary. Glanders has a high mortality rate and is quickly fatal if left untreated.
Prevention and Outcomes
Because there is no vaccine for glanders, preventive measures must be employed. In endemic areas, identifying and eliminating infected animals is essential in preventing human transmission. One should follow biosafety containment practices in healthcare, laboratory, and animal care settings.
Bibliography
Currie, Bart J. "Burkholderia pseudomallei and Burkholderia mallei: Melioidosis and Glanders." Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases, edited by Gerald L. Mandell, John F. Bennett, and Raphael Dolin. 7th ed., New York: Churchill Livingstone/Elsevier, 2010.
"Glanders Fact Sheet." New York State Department of Health, July 2017, www.health.ny.gov/diseases/communicable/glanders/fact‗sheet.htm. Accessed 30 Sept. 2024.
Larsen, Joseph C., and Nathan H. Johnson. "Pathogenesis of Burkholderia pseudomallei and Burkholderia mallei." Military Medicine, vol. 174, 2009, pp. 647-651.
Smith, Matthew E. "Glanders and Melioidosis - StatPearls." NCBI, 14 Aug. 2023, www.ncbi.nlm.nih.gov/books/NBK448110. Accessed 30 Sept. 2024.