Although infectious diseases were once considered a diminishing threat, new pathogens are constantly challenging the health care system. This article reviews the clinical presentation, diagnosis, and treatment of seven emerging infections that primary care physicians are likely to encounter.KEY POINTS
Parvovirus B19 attacks erythrocyte precursors; infection is usually benign and self-limiting but can cause aplastic crises in patients with chronic hemolytic disorders. Hemorrhagic colitis due to Escherichia coli O157:H7 infection can lead to the hemolytic-uremic syndrome, especially in children; it also can cause thrombotic thrombocytopenia purpura. Chlamydia pneumoniae causes a mild pneumonia that resembles mycoplasmal pneumonia. Bacillary angiomatosis primarily affects immunocompromised patients, especially those infected with human immunodeficiency virus (HIV). At least two organisms can cause bacillary angiomatosis: Bartonella henselae and Bartonella quintana. Hantavirus pulmonary syndrome is spread by exposure to the droppings of infected rodents. Contrary to previous thought, HIV continues to replicate throughout the course of the illness and does not have a latency phase. Ehrlichiosis is a tick-borne disease that resembles Rocky Mountain spotted fever.