An outbreak of histoplasmosis in a prison

An investigation of three suspected cases of pulmonary histoplasmosis among 600 employees at a New York prison in a nonendemic area resulted in identification of 12 additional previously unrecognized cases. The 15 cases presented with diagnostic findings between February 1978 and October 1981; 10 were in prison employees, three in inmates and two in community persons. Unlike other outbreaks, cases presented over several years with chronic pulmonary lesions in the absence of an episode marked by acute respiratory illnesses. Of the 13 prison-associated cases, seven had undergone diagnostic thoracotomies for chest x-ray abnormalities. A skin test survey of a random sample of employees showed 53% to have positive histoplasmin skin tests compared with 11% in a community control population (chi 2 = 23.4, p less than 0.001). Over 63% of employees on the job for two or more years reacted positively compared with only 13% of those employed less than two years. Testing of some inmates showed 84% with residence of two years or more to be positive, compared with 20% for those with less than two years. A review of potential exposure sources revealed three sites where bird dropping accumulations had been cleared in 1978-1979. Four specimens from two of these areas were positive for Histoplasma capsulatum. The affected sites were treated with a 3% formalin solution and there have been no subsequent cases.