Infections acquired in the fields and forests of the United States.

Sportsmen, backpackers, and outdoor workers may present with unusual infections acquired in the fields and forests of the United States. Infections to be considered in such persons with a febrile illness include Rocky Mountain spotted fever, Colorado spotted tick fever, babesiosis, borreliosis, and Lyme disease. The differential diagnoses for clinical presentations of pulmonary and gastrointestinal disease are also discussed.