OUTBREAK OF HISTOPLASMOSIS AMONG EMPLOYEES IN A PAPER FACTORY - MICHIGAN, 1993

In December 1993, four reported cases of histoplasmosis among employee s in a Michigan pulp paper factory prompted an investigation, A cohort of employees was surveyed to identify additional cases, A case of acu te histoplasmosis was defined as an influenza-like illness in a plant employee with the onset of illness during October or November 1993 and laboratory evidence of recent infection with Histoplasma capsulatum. Among the 96 employees surveyed, 18 persons met the case definition; a ll of these had illness onset during the last week of October in 1993, The attack rate among maintenance employees (16 of 53 [30%]) was much greater than that among nonmaintenance employees (2 of 43 [5%]) (rela tive risk = 6.5; 95% confidence interval = 1.6 to 26.7; P = 0.003), On October 22, a dry, windy day, one maintenance worker swept bird guano , approximately 10 cm deep, from an adjacent roof <20 m from the maint enance building, The disturbance of the bird guano was the likely even t which caused this outbreak, H. capsulatum remains an important patho gen among immunocompetent hosts, We recommended that the plant authori ties (i) discourage birds from roosting at the facility and (ii) use s afe procedures for the cleanup and disposal of soil contaminated with bird droppings.