Incidence of Legionella pneumophila infection in tourists: Italy.

Legionella pneumophila has frequently been recognised as a cause of infection in tourists. From 1973 to 1987, 117 cases of legionellosis were reported in tourists who spent one or more weeks in Italian summer resorts. 6 (5.1%) patients died. 42 (35.9%) were sporadic cases, and 75 (64.1%) were related to clusters or outbreaks. Among the 117 cases, 63 were reported to the Istituto Superiore di Sanità by the health authorities of other countries. Some travellers became ill while in Italy, others soon after they returned home. All tourists but two had stayed in hotels. L. pneumophila was isolated from the water system of 10 hotels, and in another hotel the same Legionella species was detected by direct immunofluorescence. Persistent and/or recurrent sources of infection seem to be present in some summer resorts on the Adriatic Coast and in the Lake Garda area in northern Italy. Some groups of cases were associated with particular hotels over a period of several months and sometimes years. Investigations have implicated potable water as the likely vehicle and the source of infection for tourists. The need of a greater awareness amongst clinicians that travel is a risk factor for legionellosis, and for better international surveillance and cooperation, is stressed.