Patients, needles, and healthcare workers: understanding the epidemiology, pathophysiology, and transmission of the human immunodeficiency virus, hepatitis B and C, and cytomegalovirus.

The risk of transmission of bloodborne pathogens in the healthcare environment is determined by three main factors: the nature and frequency of exposure to blood or body fluids; the risk of transmission of infection after a single exposure to the pathogen; and the prevalence of infected and susceptible patients and healthcare workers. This article will examine all three parts of the risk equation by addressing the risks and pathologic consequences of infection with four important bloodborne viruses: human immunodeficiency virus, hepatitis b, hepatitis C, and cytomegalovirus. Approaches to the management of occupational exposures to bloodborne pathogens and prospects for prevention also will be discussed.