Brucellosis (Brucella melitensis, abortus, suis, and canis)


Clinical Features In the acute form (<8 weeks from illness onset), nonspecific and "flu-like" symptoms including fever, sweats, malaise, anorexia, headache, myalgia, and back pain. In the undulant form (<1 year from illness onset), symptoms include undulant fevers, arthritis, and epididymo-orchitis in males. Neurologic symptoms may occur acutely in up to 5% of cases. In the chronic form (>1 year from onset), symptoms may include chronic fatigue syndrome, depression, and arthritis.
Etiologic Agent Brucella species, usually B. abortus (cattle), B. melitensis, B.ovis (sheep, and goats), B. suis (pigs), and rarely B. canis (dogs).

Incidence In the United States, < 0.5 cases per 100,000 population, primarily B. melitensis. . Most cases are reported from California, Florida, Texas, and Virginia.

Sequelae Variable, including granulomatous hepatitis, peripheral arthritis, spondylitis, anemia, leukopenia, thrombocytopenia, meningitis, uveitis, optic neuritis, papilledema, and endocarditis.

Transmission Zoonotic. Commonly transmitted through abrasions of the skin from handling infected mammals. In the United States, occurs more frequently by ingesting unpasteurized milk or dairy products. Highly infectious in the laboratory via aerosolization; handling cultures warrants biosafety level-3 precautions.

Risk Groups Abattoir workers, meat inspectors, animal handlers, veterinarians, and laboratorians.
Surveillance Brucellosis is a nationally notifiable disease and reportable to the local health authority.
Trends For previous 10 years, approximately 100 cases per year have been reported.
Challenges Elimination of domestic and feral animal reservoirs. In 2001, the National Brucellosis Eradication Program reported only 3 newly affected cattle herds, compared to 14 herds identified in 2000. Establish and validate methods for isolation and detection of Brucella spp. in foods.

Opportunities Validation of rapid diagnostic technologies developed for identification of Brucella spp. in natural or bioterrorism-associated outbreaks.