Legionnaires' disease in Vermont, May to October 1977

Abstract

Thirty-two confirmed and 24 highly probable cases of Legionnaires'' disease occurred in Vermont, USA between May 1 and Oct. 15, 1977. Confirmed cases had positive results for direct fluorescent antibody testing of lung tissue or 4-fold rise in antibody titer. Highly probable cases had 1 elevated titer (.gtoreq. 1:256) and a compatible illness. Forty-eight (86%) had underlying chronic disease, and 22 (39%) were immunocompromised. Prominent early symptoms were fever, cough, chills and malaise. All but 1 patient had verified pneumonia. Courses ranged from a pneumonia not requiring hospitalization to respiratory failure necessitating support with mechanical ventilation. Seventeen patients died. Although the clinical presentation was variable, rapid development of high fever and leukocytosis together with negative cultures of lower respiratory tract secretions strongly suggested the diagnosis in an epidemic setting.