Ingestion of unpasteurized dairy products and contaminated meat. Inoculation of abraded skin or mucosal surfaces. Following introduction into the body, Brucella organisms are phagocytized by polymorphonuclear or mononuclear cells and are transported to regional lymph nodes. However, Brucella organisms can survive intracellularly. Illness persists as a systemic illness, with or without localizing signs and symptoms.
Fever can be intermittent.
Physical examinations may be unrevealing or may disclose fever, mild lymphadenopathy, and hepatosplenomegaly. Disease localization can occur, usually in tissues high in reticuloendothelial content. Bone and joint disease is the most common localizing complications, occurring in up to 40 percent of cases. These include bursitis, sacroiliitis, spondylitis, peripheral joint arthritis, and osteomyelitis. Vertebral osteomyelitis can result in epidural abscess resulting in spinal cord compression, and psoas abscess.