The plates were incubated at 37C for approximately 48 hours. among the stakeholders were done to be able to recognize patterns of behavior and communication in aLegionellarisk perspective. No substantial ramifications of the procedures againstL. pneumophilawere confirmed, aside from a placed membrane filtration system distally. No significant positive relationship between TPC andL. pneumophilaconcentrations had been discovered.L. pneumophilaserogroup 214 was confirmed in 21% from the 29 structures examined in the security pilot. Few cells ofL Relatively.pneumophilawere transferred from shower drinking water to aerosols. Anxiety appeared as the major driving force in the risk governance ofLegionella. In conclusion, the risk of acquiring MRX-2843 Legionnaires’ disease from municipal shower systems is evaluated as low and uncertain. By eliminating ineffective approaches, targetedLegionellarisk governance can be practiced. Risk management by surveillance is evaluated as appropriate. == Introduction == Extensive research has been done onLegionella pneumophilaand otherLegionellaspecies. In spite of this, the handling ofL. pneumophilain general, and in shower systems in particular, may be characterized by the word uncertainty[1],[2],[3]. This uncertainty concerns pathogenicity/virulence, host susceptibility, prevention methods, infection sources, and how to execute and analyze water samples. L. pneumophilawas named after being recognized as the causative agent of pneumonia among American legionnaires during a convention in 1976. The hotel’s air condition system was identified as the infection source. The genusLegionellais primarily associated with Legionnaires’ disease[4]. About 50 different species ofLegionellahave been identified [1, 5, 6 7, 8]. The speciesL. pneumophilais found to account for at least 90% of reported cases of Legionnaires’ disease[7],[9]. So far, at least 15 serogroups (sg) ofL. pneumophilahave been identified[5],[7],[10]. MRX-2843 Only a few of the approximately Smo 15 serogroups ofL. pneumophilahave been associated with disease[5],[9],[10],[11]. In Europe,L. pneumophilasg 1 has been attributed to more than 85% of the cases Legionnaires’ disease[9]. Sg 1 is further divided into types which seem to represent different levels of virulence[11],[12],[13]. In summary, a few subgroups ofL. pneumophilasg 1 appear to be the source of most cases of Legionnaires’ disease. L. pneumophilais an opportunistic pathogen concerning Legionnaires’ MRX-2843 disease[4],[14]. Statistics show that the most susceptible individuals are male smokers over 40 years of age who are also suffering from diseases like diabetes or chronic heart disease[1],[9]. It has been reported that less than 1% of the individuals exposed toLegionelladevelop Legionnaires’ disease[15]. Different degrees of mortality have been reported for individuals suffering from Legionnaires’ disease, i.e. from 0.1 to 30%[16],[17]. In Stavanger, Norway, the first, and so far the only known case of contracting Legionnaires’ disease from municipal showers, occurred in 2007 in an indoor swimming pool facility[3]. Prior to this event, there were no municipal procedures aimed at reducing the risk of being infected byL. pneumophilafrom showering. Based on the Norwegian guidelines for the prevention ofLegionellainfection[18],[19],[20], a routine of temperature control, quarterly chlorination of shower heads, and monthly hot water treatment of all municipal shower systems was implemented in Stavanger municipality. High total heterotrophic plate count (TPC) was used as an indication of the presence ofL. pneumophila.Initially, a high TPC was defined as a concentration MRX-2843 above 1000 colony forming units/ml (cfu/ml). At TPC exceeding 1000 cfu/ml, a second hot water treatment was initiated. The consequence was a comparatively high and demanding flushing frequency. A new limit of 10 000 cfu/ml was therefore introduced after half a year. The limit of 10 000 cfu/ml was in accordance the EWGLI Technical Guidelines for Investigation, Control and Prevention of Travel Associated Legionnaires’ Disease concerning cooling towers[21]. We are not acquainted with research data, however, that support that a TPC higher than 10 000 cfu/ml is a valid indicator of the presence ofL. pneumophila. The lack of knowledge mentioned above may be ascribed to a fragmentary research approach concerning the genusLegionella. By fragmentary we mean that only one or a few perspectives have been studied at a time. Additionally, evaluation of prevention measures is often case-oriented[1],[22],[23]which makes it difficult to MRX-2843 generalize the results. The conclusion from comprehensive literature studies in which different measures againstL. pneumophilahave been compared, is that no single method stands out as unambiguously effective[1],[24],[25],[26],[27]. The uncertainty about the risk associated withLegionellamay easily lead to formation of myths[2],[3]. Myths appear like truths and are thereby seldom questioned. One such myth seems to be that all kinds of man-made aerosol-producing water systems with temperatures in the range of 2545C have identical potential of inflicting Legionnaires’ disease. In Norway, this has resulted in implementation.