Sala M R, Arias C, Oliva J M, Pedrol A, Roura P, Domínguez A
Epidemiological Surveillance Unit of the Central Region, Health Department of the Generalitat de Catalunya, Terrassa, Spain.
Euro Surveill. 2007 Mar 1;12(3):223.
This paper reports the investigation of a community-acquired outbreak of Legionnaires' disease in the municipalities of Vic and Gurb (Central Region of Catalonia, Spain). There were 55 cases reported in October and November 2005. An epidemiological and environmental investigation was undertaken. Thirty-five case patients (64%) lived in Vic or Gurb, while 36% had visited or worked in Vic or Gurb during the 10 days before onset of symptoms, but no commonly frequented building could be identified. Water probes for culture were obtained from 30 cooling towers. In five cooling towers of two industrial settings in Gurb (plants A and B), Legionella pneumophila (Lp) serogroup 1 was present. Two Lp-1 strains were recovered from cooling towers in plants A and B. The Lp-1 strain from plant A showed a PGFE profile identical with those obtained from three patients. The exposure to Legionella pneumophila apparently occurred in a large area, since 43 of the 55 cases lived, visited or worked within a distance of 1,800 m from plant A, and six cases in a distance between 2,500 and 3,400 m. The inspections of cooling towers in plant A revealed inadequate disinfectant doses of biocide, non-existent maintenance records on weekends and wrong sample points for routine microbial check-ups. Weather conditions in October 2005 template temperature and high humidity (wind conditions are unappreciable) could have been favourable factors in this outbreak together with the flat terrain of Gurb and Vic area, explaining the extensive horizontal airborne dissemination of contaminated aerosols. The outbreak could have been prevented by proper and correct maintenance of the cooling tower at plant A.
本文报告了在西班牙加泰罗尼亚中部地区维克市和古尔布市发生的一起社区获得性军团病暴发调查。2005年10月和11月共报告了55例病例。开展了流行病学和环境调查。35例病例患者（64%）居住在维克市或古尔布市，而36%的患者在症状出现前10天内曾到访或工作于维克市或古尔布市，但未发现有共同频繁出入的建筑物。从30座冷却塔采集了用于培养的水样。在古尔布市两个工业场所（工厂A和工厂B）的5座冷却塔中检测到嗜肺军团菌（Lp）血清型1。从工厂A和工厂B的冷却塔中分离出2株Lp-1菌株。来自工厂A的Lp-1菌株的脉冲场凝胶电泳（PGFE）图谱与从3例患者身上获得的图谱相同。嗜肺军团菌的暴露显然发生在大片区域，因为55例病例中有43例居住、到访或工作在距离工厂A 1800米范围内，6例在2500至3400米之间。对工厂A冷却塔的检查发现，杀菌剂的消毒剂量不足，周末没有维护记录，且常规微生物检查的采样点错误。2005年10月的天气状况（气温较高且湿度较大，风力情况不明显）与古尔布市和维克市地区的平坦地形可能是此次暴发的有利因素，这解释了受污染气溶胶在水平方向上的广泛空气传播。通过对工厂A冷却塔进行妥善正确的维护，本可预防此次暴发。
