Epidemiology and clinical characteristics of tularemia in Oklahoma, 1979 to 1985

We studied the clinical and epidemiologic characteristics of tularemia in 165 Oklahomans from 1979 to 1985. The ulceroglandular form of the disease was most common (60%), followed by typhoidal (18%), glandular (15%), oropharyngeal (7%), and oculoglandular (1%) forms. The male-female ratio was 3.7:1, and the highest rates of disease were found in the age groups 5 to 14, 35 to 44, and 55 to 74. Ticks were most frequently implicated as the source of infection (84/154 [55%]), followed by rabbits, (58/154 [38%]). Seventy percent of the patients were hospitalized, and four (2.5%) died. The annual number of patients who reported that rabbits were their probable source of exposure to Francisella tularensis and the estimated number of rabbits harvested (ie, killed by hunters) for the year correlated closely with the total number of cases reported from year to year.