undulant fever
Summary
Undulant fever is the characteristic relapsing, rising-and-falling fever pattern of brucellosis. It is acquired from unpasteurized dairy products or contact with infected livestock and is accompanied by drenching sweats, myalgia, and arthralgia.
Detail
Brucella species are small, aerobic, facultative intracellular gram-negative coccobacilli that survive within macrophages of the reticuloendothelial system; this intracellular niche produces the undulating fever curve, the tendency to relapse, and the requirement for prolonged combination therapy. Species map to animal hosts: B. melitensis from goats and sheep is the most virulent, B. abortus from cattle, B. suis from pigs, and B. canis from dogs. Transmission is by ingestion of unpasteurized milk or soft cheese, direct contact with placental or abattoir material, or inhalation, making it an occupational disease of farmers, veterinarians, and abattoir and laboratory workers, and one of the commonest laboratory-acquired infections; it is also a potential bioterrorism agent. Findings include hepatosplenomegaly, lymphadenopathy, sacroiliitis and vertebral osteomyelitis of the lumbar spine, orchitis, and non-caseating granulomas in liver and marrow. Treatment is doxycycline plus rifampin, or doxycycline plus streptomycin or gentamicin, for at least six weeks.
Sources
- Levinson Medical Microbiology and Immunology
- Harrison's Principles of Internal Medicine
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