Abstract

August 2005

Section 7 Infectious Disease

This chapter reviews the epidemiology, pathology, clinical features, laboratory findings, and treatment for Lyme disease, leptospirosis, relapsing fever, and rat-bite fever. Lyme disease is a tick-borne illness caused by the spirochete Borrelia burgdorferi. Lyme disease is a progressive infectious disease with a wide array of clinical manifestations. In most persons, the initial sign of infection is the development of erythema migrans. In general, three stages of the illness can be distinguished: early localized disease, early disseminated disease, and persisting late disease. A photograph shows an erythema migrans lesion, and an algorithm for diagnosis of Lyme disease is provided. A table lists the antibiotic regimens used for the different stages and manifestations of Lyme disease. Leptospirosis is a worldwide zoonosis caused by spirochetes from the genus Leptospira; these spirochetes are shown in a photomicrograph. The disease is acquired by contact with infected animals or exposure to contaminated soil or freshwater and can cause illness ranging from asymptomatic infection to severe multisystem disease with a significant mortality. Relapsing fever is an acute louse-borne or tick-borne infection caused by spirochetes of the genus Borrelia and is characterized by recurrent febrile episodes separated by asymptomatic intervals. Rat-bite fever is infection caused by Streptobacillus moniliformis in the United States and Europe or by Spirillum minus in Asia. A table details the differing characteristics of rat-bite fever from these two organisms. This chapter contains 111 references.

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