[Seroprevalence of Legionella pneumophila infection in healthy, adults from Santiago, Chile].

In order to investigate the L pneumophila seroprevalence in healthy adult population of Santiago, Chile, a serologic survey of antibodies to serogroups 1 through G was performed. Sera of 100 blood donors were studied with the indirect fluorescent antibody method. Positive results (> or = 1.64) were obtained in five samples. Titres > or = 1:128 were not observed. We conclude that the seroprevalence of L pneumophila in Santiago is 5% and that a single titre > or = 1:256 suggests the diagnosis of legionellosis. The low seroprevalence in Santiago is in agreement with the few cases of legionellosis reported.