A small outbreak of Legionnaires' disease in a cargo ship under repair

It was reported that two mechanics working on a cargo ship under repair in the port of Barcelona had died after having fever. An investigation was made into the possibility of any additional cases and the presence of Legionella pneumophila in the ship they were repairing and in their hotel. The contaminated water system was treated with sodium hypoc hlorite. Both patients died after hating been repeatedly diagnosed as having influen za. The two cases occurred among those who had been working with the pump o f the ship's water system, while no cases were observed among the other wor kers (p = 0.02). Various serogroups of L. pneumophila were isolated from th e ship's water pump and distribution system. However, organism of serogroup 1, subgroup Pontiac (Knoxville) were identified with identical deoxyribonu cleic acid (DNA) patterns in the lung tissue of one patient and in the cool ing water circuit valve of the ship's water pump. The first postinterventio n control water samples showed no further growth of legionella, but serogru ps 4 and 8 were identified 8 months later. This legionellosis outbreak, although small, was highly lethal, probably du e to the high levels of bacteria to which the patients were exposed and als o because of the failure of correct diagnosis. International recommendation s on prevention and control of legionellosis, which include ships under rep air, are required.