Organisms which cause osteoarticular problems
• Brucellosis: Gram-negative, intracellular coccobacillus transmitted to humans mainly through ingestion of nonpasteurized dairy products (cheese). The febrile illness can have an acute or insidious onset with 33% developing musculoskeletal manifestations. Sacroiliitis (50%) is the most common presentation followed by peripheral arthritis (35%), spondylitis (25%), and osteomyelitis (5%). Peripheral joint involvement is usually a monarthritis involving the hip or knee. Treatment is a combination of doxycycline and rifampin for 6 weeks.
• Parasitic infection: Protozoan, cestode, nematode, or trematode infection should be considered in patients who present with an oligoarthritis, myositis, or vasculitis after visiting an endemic area. Eosinophilia and lack of response to antirheumatic treatment should prompt consideration of a parasitic infection causing the musculoskeletal problems.