Eurosurveillance - Volume 9, Issue 2, 01 February 2004

Disease acquired in one country but diagnosed and reported in another, necessitates international cooperation if it is to be controlled, investigated and further cases prevented. The European surveillance scheme for travel associated legionnaires' disease (EWGLINET) was established in 1987 to operate in this type of context and has been highly active in sharing information and coordinating its actions since then. In July 2002 European guidelines were introduced by EWGLINET that have standardised the response to clusters across most countries in Europe. Three papers presented in this special issue show how the guidelines have been successfully adopted in France (1), Italy (1) and Spain (2), despite the additional workload associated with their implementation. The paper from the coordinating centre in London provides an overview of EWGLINET results in 2002.

Twenty countries reported 676 cases of travel associated legionnaires' disease to the EWGLINET surveillance scheme, and 94 clusters were detected. 80.5% of all cases were diagnosed by the urinary antigen test. On average there were 20.5 days between onset and report of cases, compared with 51.5 days in 1993. Between the introduction of the EWGLI investigation guidelines (on 1st July 2002) and the end of 2002, 37 six-week investigation reports were accepted as satisfactory and on time by the coordinating centre. 274 sites were investigated in total in 2002. The travel patterns of the main reporters in EWGLINET influenced the months of peak activity, and helped to determine which countries bore the greatest investigation burden.

In Italy, 35 clusters of travel associated Legionnaires' disease were identified from July 2002, when the European Guidelines for Control and Prevention of Travel Associated Legionnaires' Disease have been adopted by the EWGLINET network, to October 2003. Eight per cent (28.6%) would not have been identified without the network. The clusters detected were small, ranging from 2 cases to a maximum of 6. All clusters involved 5 camping sites and 30 hotels/residences, and an overall of 87 patients. The diagnosis was confirmed in 92.0% of the cases and mainly performed by urinary antigen detection (84.7%). A clinical isolate was available only in one case. Following environmental investigations, samples were collected for all the 35 clusters from the water system, and Legionella pneumophila was found in 23 occasions (65.7%). In 15 resorts out of 35, investigations were already in progress at the time of EWGLI cluster notification, since in Italy full environmental investigation is performed even after notification of a single case. Control measures were implemented in all accommodation sites at risk and one hotel only was closed. In all the 35 clusters, reports were completed and sent on time, highlighting that it is possible to comply with the procedures requested by the European Guidelines.

Clusters of travel associated legionnaires' disease warrant urgent attention, and are detected by the French national surveillance system and the European network EWGLINET. Between September 2001 and August 2003, 37 clusters were identified in French tourist accommodation: 27 hotels and 10 campsites. The number of clinical cases per cluster was as follows: 30 clusters of 2 cases (81%), 6 clusters of 3 cases (16%) and one cluster of 4 cases (3%), a total of 82 cases. The local health authorities performed environmental investigations for 36 of the 37 clusters. Among the 36 clusters investigated, water samples were collected for 35. At 16 (46%) sites, Legionella pneumophila was found at a level of more than 103 cfu/litre. In all of the accommodation where risk assessment was found to be inadequate- control measures were implemented immediately. Six hotels were closed immediately following cluster alerts. Comparison of clinical and environmental isolates by pulsed field gel electrophoresis (PFGE) was possible in 3 clusters and identical genomic profiles of the isolates were found in all. During this two year period of surveillance, we found that on many sites there has been a risk of exposure to Legionella. This reinforces the importance of the European surveillance network and the timely notifications of all the cases to EWGLINET.

Epidemiological surveillance and control of travel associated cases of legionnaires´ disease are necessary tasks for public health and collaboration between countries is necessary to do this. Within the framework of the European Surveillance Scheme for Travel Associated Legionnaires' Disease (EWGLINET), European Guidelines for Control and Prevention of Travel Associated Legionnaires' Disease have been produced . This has established the reporting and response criteria when cases or clusters appear. In this paper the analysis of the information corresponding to the 46 reported clusters related to Spain is presented. Data corresponds to the period January 2001 to July 2003.