Legionella in the veterans healthcare system: report of an eight-year survey.

The Veterans Health Administration (VHA) of the Department of Veterans Affairs tracks legionella disease in the system of 172 medical centres and additional outpatient clinics using an annual census for reporting. In fiscal year 1999, 3.62 million persons were served by the VHA. From fiscal year 1989-1999, multiple intense interventions were carried out to decrease the number of cases and case rates for legionella disease. From fiscal year 1992-1999, the number of community-acquired and healthcare-associated cases decreased in the VHA by 77 and 95.5% respectively (P=0.005 and 0.01). Case rates also decreased significantly for community and healthcare-associated cases (P=0.02 and 0.001, respectively), with the VHA healthcare-associated case rates decreasing at a greater rate than VHA community-acquired case rates (P=0.02). Over the time of the review, the VHA case rates demonstrated a greater decrease compared to the case rates for the United States as a whole (P=0.02). Continued surveillance, centrally defined strategies, and local implementation can have a positive outcome for prevention of disease in a large, decentralized healthcare system.