Glanders
is an infection of equine species and rarely of humans.
The cause is
Burkholderia mallei , a small, gram-negative, nonmotile
bacillus.
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It may be acute and severe or
protracted and wasting.
The causative agent of glanders, Burkholderia (B.) mallei, is highly
contagious and leads to chronic disease in horses whereas in donkeys
and mules the disease is acute and often fatal. Occurrence of the
disease leads to international trading restrictions and infected
animals immediately should be culled and safely disposed off.
In
humans B. mallei infection results in a severe clinical course, and is
fatal without appropriate therapy.
Its pathogenicity makes B. mallei a
potential biological agent that may be used in bioterroristic attacks.
Although uncommon, glanders remain endemic in South
America, Asia, and Africa. In addition there have been rare infections of
laboratory workers in the United States and Canada.
The natural
reservoir is equines and transmission to human is by contact through
broken skin or by inhalation of contaminated aerosols. Glanders may
also be transmitted from person to person.
The acute disease is characterized by papule at the
site of inoculation, followed by bacteremia with severe prostration,
fever, vomiting, and generalized pain.
The bacilli drain from the
primary papule through lymphatics to regional lymph nodes and then to
the blood stream.
Abscesses may form along the draining lymphatics, in
the regional nodes and in many organs throughout the body, including
the lung, liver, spleen, muscle, joints, and especially the
subcutaneous tissues.
The abscesses are composed of a central zone of neutrophils surrounded by a granulomatous perimeter.
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Patients with the
chronic form of glanders show a low-grade fever, draining abscesses of
skin, lymphadenopathy, and hepatospenomegaly.
The lesions begin as abscesses and evolve to granulomas,
mimicking tuberculosis.
In its acute form, glanders is
almost always fatal, and in the chronic form mortality is more than
50%.
Some success in treatment has been
achieved with sulfonamides.
The lesions
are not pathognomonic, and the diagnosis depends on the isolation of
B.
mallei or the detection of compliment-fixing antibodies.
Although B. mallei may be cultured from blood, sputum
or pus, its high potential for causing laboratory-acquired infection
requires strict containment.
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