A Barricarte, M García Cenoz, J Castilla (jcastilc@navarra.es), P Aldaz
 
 
Instituto de Salud Pública, Navarra, Spain
 
By 8 June 2006, 139 cases of legionellosis had been reported in an outbreak in Pamplona, north Spain. All cases presented with clinical signs of pneumonia, compatible radiography and positive urinary antigen test. The outbreak was recognised on 1 June, when 4 confirmed cases were reported to the Public Health Institute of Navarra. The number of cases diagnosed up to 8 June are presented in the figure, by date of diagnosis. Seventy six of the patients (55%) were admitted to hospital, and the other sixty three patients have been given treatment to take at home. A total of seven patients have required intensive care, and six patients remained in intensive care on 8 June, two of whom are seriously ill. No deaths have occurred. Men represent 47% of cases. The patients range in age between 21 and 97 years.

Figure. Numbers of legionellosis cases by date of diagnosis, Pamplona, May-June 2006

Most of the initial cases occurred in a neighbourhood close to the city centre, and the investigations began on 1 June with the inspection of 30 cooling towers in 11 buildings in this part of the city. Rapid tests for Legionella antigen were positive in four of the towers, located in three buildings, on 2 June, and these four towers were shut down immediately. Culture and PCR for Legionella have been positive in two of these cooling towers, but could not be confirmed in the other two.

The Public Health Institute in Navarra found Legionella with low bacterial load in two further cooling towers, which were shut down on 6 June. A helicopter inspection of the area was carried out on 2 June and identified eight structures that resembled undeclared cooling towers in the investigated area, but further investigation has found that none of these structures is a cooling tower.

Microbiological culture of respiratory samples from patients are in progress. Legionella isolates from the four positive cooling towers have been sent to the reference laboratory in the National Centre of Microbiology in Majadahonda, Madrid.
 
 
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