[Legionella epidemic in the Netherlands]

In March 1999 an epidemic of Legionella pneumonia developed in the province of Noord Holland, the Netherlands: by the end of April 233 patients had become ill after a visit to a flower show, in 106 of whom the diagnosis of Legionella pneumonia was established, while in 48 the disease was probable and in 4 it was possible; 23 patients died, in 16 of whom the diagnosis of legionnaires' disease was established. In 37 patients Legionella pneumophila was isolated. There was a significant association with stands on the show that displayed anticondense fluids to clean glasses, steam ironing machines and whirlpools and bubble baths, making a relation to aerosol transmission of the causative agent very probable. Legionella (the same serotype) was indeed isolated from a whirlpool. As Legionella can readily be isolated from the human environment, a limited number of species can cause disease and laboratory tests are expensive and time consuming, an effective primary preventive programme is an illusion. Prevention should be aimed at monitoring the environment of susceptible hosts and tracing sources of infection of index cases. Patients with severe pneumonia requiring intensive care must be treated with antibiotics that cover Legionella, until this cause is excluded.