Clinical Manifestations
Leptospira interrogans causes leptospirosis, a usually mild febrile illness that may result in liver or kidney failure.
Structure, Classification, and Antigenic Types
Leptospira is a flexible, spiral-shaped, Gram-negative spirochete with internal flagella. Leptospira interrogans has many serovars based on cell surface antigens.
Pathogenesis
Leptospira enters the host through mucosa and broken skin, resulting in bacteremia. The spirochetes multiply in organs, most commonly the central nervous system, kidneys, and liver. They are cleared by the immune response from the blood and most tissues but persist and multiply for some time in the kidney tubules. Infective bacteria are shed in the urine. The mechanism of tissue damage is not known.
Host Defenses; Serum antibodies are responsible for host resistance.
Epidemiology
Leptospirosis is a worldwide zoonosis affecting many wild and domestic animals. Humans acquire the infection by contact with the urine of infected animals. Human-to-human transmission is extremely rare.
Diagnosis
Clinical diagnosis is usually confirmed by serology. Isolation of spirochetes is possible, but it is time-consuming and requires special media.
Control
Animal vaccination and eradication of rodents are important. Treatment with tetracycline and penicillin G is effective. No human vaccine is available.
Borrelia - Clinical Manifestations
Borrelia recurrentis (louse borne) and B hermsii and B turicatae (tick borne) cause relapsing fevers: influenza-like febrile diseases that follow a relapsing and remitting course. Myocarditis is a rare sequela. BorreliaCopyright © 1996
The University of Texas Medical Branch at Galveston