Consensus statement ularemia, a bacterial zoono

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and both sexes appear to be equally susceptible to tularemia. Certain ac- tivities, such as hunting, trapping, butchering, and farming, are most likely to expose adult men. Laboratory workers are especially vulnerable to in- fection, either by accidentally inocu- lating themselves or by inhaling aero- solized organisms.18,22,56-58 Ordinary exposures during examination of an open culture plate can cause infec- tion. Although F tularensis is highly in- fectious and pathogenic, its transmis- sion from person to person has not been documented.

Incidence

The worldwide incidence of tularemia is not known, and the disease is probably greatly underrecognized and underre- ported. In the United States, reported cases have dropped sharply from sev- eral thousand per year prior to 1950 to less than 200 per year in the 1990s.33-35 Between 1985 and 1992, 1409 cases and 20 deaths were reported in the United States, for a mean of 171 cases per year and a case-fatality rate of 1.4%.34 Per- sons in all age groups were affected, but most were children younger than 10 years and adults aged 50 years or older. Of 1298 cases for which information on sex was available, 942 (72.6%) oc- curred in males, and males outnum- bered females in all age groups. Most cases occur in June through September, when arthropod-borne transmission is most common.17,35,59 Cases in winter usually occur among hunters and trap- pers who handle infected animal car- casses.17,35,48 In the United States, cases are mostly sporadic or occur in small clusters34,35,49; in Eurasia, waterborne, ar- thropod-borne, and airborne outbreaks

involving hundreds of persons have been reported.40,43,44,51,53-55