Characteristics.
Brucellosis is a systemic zoonotic
disease caused by one of four species of
bacteria: Bucella melitensis, B.
abortus, B suis, and B.
canis; virulence for humans
decreases somewhat in the order given.
These bacteria are small gram-negative,
aerobic, non-motile coccobacilli that
grow within monocytes and macrophages.
They reside quiescently in tissue and
bone-marrow, and are extremely difficult
to eradicate even with antibiotic
therapy. Their natural reservoir is
domestic animals, such as goats, sheep,
and camels (B. melitensis);
cattle (B. abortus); and pigs (B.
suis). B. canis is
primarily a pathogen of dogs, and only
occasionally causes disease in humans.
When used as a biological weapon,
brucellae would most likely be delivered
by the aerosol route; the resulting
infection would be expected to mimic
natural disease. Terrorist and partisans
would most likely spread Brucellosis
through contamination of dairy products.
Clinical
Features. Brucellosis presents
after an incubation period normally
ranging from 3-4 weeks, but may be as
short as 1 week or as long as several
months. Clinical disease presents
typically as an acute, non-specific
febrile illness with chills, sweats,
headache, fatigue, mylagia, arthralgia,
and anorexia. Cough occurs in 15-25% of
patients, but chest radiographs are
usually normal. Complications include:
sacroiliitis, arthritis, vertebral
osteomyelitis, epididymo-orchitis, and
rarely, endocarditis. B. melitensis
may result in a 30-40% patient fatality
rate.
Vaccine.
Live animal vaccines are widely used.
Killed and live attenuated human vaccines
have been available in many countries but
are of unproven efficacy. No approved
human vaccine is available at this time.
Back to Top
Medical
Management of Biological Agent Patients