An epidemic of acute blastomycosis occurred during the Fall of 1972 in Bigfork, Minnesota. Eighteen of 21 people exposed to the site developed some evidence of blastomycosis. Of the 18 people judged to have been infected, 16 had a positive skin test to blastomycin. None of the patients were treated and all have recovered and remained entirely well during the three years of follow up observation. Eighteen months after the epidemic, only 11 of 16 patients continued to show a positive skin test to blastomycin and three years after the outbreak only five of 16 were still positive. In vitro blast transformation of blastomycin stimulated lymphocytes showed close correlation to the skin test. At 18 months, 12 of 16 were positive (stimulation index > 3) and after three years, only seven of 16 remained positive. The rapid decay of blastomycin skin test positivity may explain the high frequency of negative skin tests in patients with chronic blastomycosis.
|Number of pages
|American Review of Respiratory Disease
|Published - Jan 1 1976