state of Washington from January 1982 through December 1984 (29). During these 3 years the tuberculosis incidence in Washington was 7.1/ 100,000 in 1982, 5.6/100,000 in 1983, and 4.8/100,000 in 1984; national case rates for these years were 11.0/100,000 in 1982, 10.2/100,000 in 1983, and 9.4/100,000 in 1984 (1). In this survey 124,869 skin tests were completed and 110 skin test conversions were documented (excluding 19 additional converters identified by health department contact investigations). Overall, the conversion rate was 0.09 percent (calculated ARI = 0.03 percent/ year). For hospitals with no cases of tuberculosis admitted during the study interval the rate was 0.07 percent (calculated ARI = 0.02 percent/ year), and for hospitals to which cases of tuberculosis were admitted the rate was 0.091 percent (calculated ARI = 0.03 percent/year) in those hospitals with sputum smear-positive cases and 0.094 percent (calculated ARI = 0.03 percent/year) for those with smear-negative, culture-positive cases. In larger urban hospitals the rate was 0.11 percent (calculated ARI = 0.04 percent/year) and for small hospitals the rate was 0.08 percent (calculated ARI = 0.03 percent/year). There were no significant differences among these rates. The authors estimated that the tuberculin test conversion rate in the general population of Washington at that time was between 0.008 and 0.11 percent/year. They concluded that hospital employees were at no greater risk than the general public.

From these studies certain generalizations can be made about occupational tuberculosis in the 1970s and 1980s. First, it is evident that the risk of tuberculous infection was much greater in hospitals located in such cities as Baltimore than in those represented by Salt Lake City. This almost certainly reflected the tuberculosis incidence in those communities. Next, the evidence presented here indirectly, but not directly, implicates the communities in which health care workers resided as the major source of tuberculous infection. That does not mean that occupation-related infection did not occur; rather, it means that the risk in the community was often as great as or greater than the risk in the workplace. Finally, that risk related to employment was probably greatest for certain hazardous work activities, such as bronchoscopy and other aerosol-generating procedures.

Beginning in the mid-1980s and extending into the early to mid-1990s, the United States witnessed an unprecedented resurgence of tuberculosis. Borne on a tide of AIDS, homelessness, and immigration, tuberculosis rates increased in most major urban areas of the Northeast, southern Florida, and California, as well as along the Mexican-American border. In other areas of the country, notably the less densely populated central portions of the continental United States, tuberculosis case rates did not increase and continued to decline. In many of the areas of resurgence, this emerging epidemic was accompanied by increasing rates of drug resistance, including multidrug resistance. Public health agencies responded with a variety of measures, including well-reasoned guidelines intended



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