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In June and July 2008, two office workers were admitted to a Dublin hospital with Legionnaires' disease. Investigations showed that cooling towers in the basement car park were the most likely source of infection. However, positive results from cooling tower samples by polymerase chain reaction (PCR) did not correlate with subsequent culture results. Also, many employees reported Pontiac fever-like morbidity following notification of the second case of Legionnaires' disease. In total, 54 employees attended their general practitioner or emergency department with symptoms of Legionnaires' disease or Pontiac fever. However, all laboratory tests for Legionnaires' disease or Pontiac fever were negative. In this investigation, email was used extensively for active case finding and provision of time information to employees and medical colleagues. We recommend clarification of the role of PCR in the diagnosis of legionellosis and also advocate for a specific laboratory test for the diagnosis of the milder form of legionellosis as in Pontiac fever.

Two cases of fulminant pulmonary legionellosis, complicated by prolonged intensive care unit stays and acute respiratory distress syndrome, and who were recently treated with infliximab for Crohn's disease, are described. A review of the literature revealed three additional cases in patients with inflammatory bowel disease, and a total of 22 cases of Legionella pneumophila pneumonia in the context of treatment with antitumour necrosis (TNF)-alpha medications. The median age of the patients was 49 years, and men and women were affected equally. The case fatality rate was 14% (three of 22). Early recognition and treatment of this anti-TNF-alpha-related complication would likely result in reduced mortality and morbidity. Physicians prescribing anti-TNF-alpha drugs should be aware of this association.

Legionnaires' disease (LD) is a major cause of severe community-acquired pneumonia but the source and mode of transmission are not always apparent, especially in sporadic cases. We hypothesized that LD can be acquired from the air-conditioning systems of motor cars. Swabs were taken from the evaporator compartments of the air-conditioning system of scrapped cars. Healthy subjects who were mainly employees of regional transportation companies were tested for antibody to Legionella pneumophila serogroups 1-6; they also completed a questionnaire. Legionella species were detected in 11/22 scrapped cars by the loop-mediated isothermal amplification method. The prevalence of microplate agglutination titres > or =1:32 was significantly higher in subjects who sometimes used car air-conditioning systems. Although we did not prove a direct link between Legionella spp. in the car evaporator and LD, our findings point to a potential risk of car air-conditioning systems in LD, which needs further investigation.

In May 2008, a report of two workers from the same construction equipment manufacturing plant who were admitted to hospital with Legionnaires disease confirmed by urine antigen prompted an outbreak investigation. Both cases were middle aged men, smokers, and with no travel, leisure or other common community exposure to Legionella sources. There were no wet cooling towers at the plant or in the surrounding area. No increase in respiratory disease or worker absenteeism occurred at the plant during the preceding month. Wider case ascertainment including alerts to hospitals and medical practitioners yielded no further cases. The environmental investigation (and sampling of water systems for Legionella) identified a Legionella pneumophila serogroup1 (Mab 2b) count of >3.0x10(4)cfu/l in water samples from an aqueous metal pre-treatment tunnel, which generates profuse water aerosol. Drainage, cleaning and biocide treatment using thiazalone eliminated Legionella from the system.

Background: Immunosuppressive therapy with anti-TNF-alpha antibodies is effective in patients with inflammatory bowel disease (IBD). However, there is an increased risk for infections associated with this therapy., Methods: Here, we report the case of a 58-year-old patient with Crohn's disease (CD) treated with steroids and azathioprine who developed severe Legionella pneumophila pneumonia after 3 infusions of infliximab. The patient presented at our IBD department with severe active CD complicated by inflammatory small bowel stenoses and entero-enteral fistulas despite long-term high-dose steroid therapy. To achieve steroid tapering and control of disease activity, immunosuppressive therapy with azathioprine was initiated. Due to persistent symptoms, infusion therapy with the anti-TNF-alpha antibody infliximab was started, subsequently leading to significant clinical improvement. However, after the third infliximab infusion the patient was hospitalized with fever, severe fatigue, and syncope., Results: Laboratory findings and chest X-ray revealed left-sided pneumonia; cultural analysis showed L. pneumophila serogroup 1 leading to respiratory insufficiency, which required mechanical ventilation for 2 weeks in the intensive care unit. After discontinuation of all immunosuppressive agents and immediate antibiotic therapy the patient recovered completely., Conclusions: To our knowledge, this is the third case of L. pneumophila pneumonia in an IBD patient treated with infliximab. Similar to other published cases, concomitant treatment of immunosuppressives and anti-TNF agents is a major risk factor for the development of L. pneumophila infection, which should be ruled out in all cases of pneumonia in patients with such a therapeutic regimen. Appropriate prevention strategies should be provided in these patients.

The Legionellae are Gram-negative bacteria able to survive and replicate in a wide range of protozoan hosts in natural environments, but they also occur in man-made aquatic systems, which are the major source of infection. After transmission to humans via aerosols, Legionella spp. can cause pneumonia (Legionnaires' disease) or influenza-like respiratory infections (Pontiac fever). In children, Legionnaires' disease is uncommon and is mainly diagnosed in children with immunosuppression. The clinical picture of Legionella pneumonia does not allow differentiation from pneumonia caused by others pathogens. The key to diagnosis is performing appropriate microbiological testing. The clinical presentation and the natural course of Legionnaires' disease in children are not clear due to an insufficient number of samples, but morbidity and mortality caused by this infection are extremely high. The mortality rate for legionellosis depends on the promptness of an appropriate antibiotic therapy. Fluoroquinolones are the most efficacious drugs against Legionella. A combination of these drugs with macrolides seems to be promising in the treatment of immunosuppressed patients and individuals with severe legionellosis. Although all Legionella species are considered potentially pathogenic for humans, Legionella pneumophila is the etiological agent responsible for most reported cases of community-acquired and nosocomial legionellosis.

Legionella spp. are pathogens that can cause Legionnaires' disease in humans through inhalation of contaminated aerosols. The principal reservoir for these microorganisms is water, but Legionella spp. have been isolated from composted vegetable and plant material, and from many potting mixes as well. In Australia, there have been several cases of Legionnaires' disease in which Legionella longbeachae has been isolated from potting soils. In Switzerland, the source of infection cannot always be identified as water or cooling towers: therefore, we have investigated 46 commercially available potting soils in Switzerland to determine the presence of Legionella spp. We were able to detect Legionella spp. in 45.7% (21/46) of the potting soil samples analysed by culture. Legionella pneumophila was present in 19.6% (9/46) of the samples and L. pneumophila serogroup 1 in 6.5% (3/46). Quantification by both culture and quantitative real-time PCR revealed high concentrations of legionellae in potting soils, ranging between 10(3) CFU/g and 10(5) CFU/g and 10(4) genomic units (GU)/g and 10(6) GU/g, respectively. Thus, potting soils may represent an alternative reservoir for Legionella spp. in Switzerland.

A 60-year-old-man with diabetes mellitus was admitted to our hospital because of pyrexia of up to 40 degrees and dyspnea. Chest radiograph revealed ground glass infiltrates in both lung fields. Legionella pneumonia was diagnosed as a consequence of the urinary examination performed for Legionella antigen detection; further, we initiated intravenous pazufloxacin administration. Despite an antibiotic, sivelestat sodium, and mechanical ventilation, the condition of the patient worsened and he died of respiratory failure 5 days following admission. Pulse-field gel electrophoresis (PFGE) was performed to investigate the route of infection: this technique was applied to patient sputum samples and water from the humidifier in the room of the patient. The same DNA pattern as Legionella pneumophilla serogroup 1 was identified via analysis with PFGE.

We report the investigation of a community-acquired outbreak of Legionnaires' disease. An epidemiological, environmental, and meteorological investigation was undertaken. Fifty-five cases were reported in October and November 2005. The exposure occurred in a large area, with 12 cases (21.8%) located between 1,800 and 3,400 metres from the source. Water sample cultures showed that Legionella pneumophila serogroup 1 (Lp-1) was present in five cooling towers in two industrial locations in Gurb (plants A and B). Two Lp-1 strains were recovered from plants A and B, but only Lp-1 strains from plant A showed a pulsed-field gel electrophoresis (PFGE) profile identical to those obtained from three of the cases. Inspection of the cooling towers in plant A revealed inadequate maintenance. Weather conditions in October 2005, with mostly high temperatures and high humidity, together with the flat terrain could have been favouring factors. This study showed a community outbreak from a cooling tower as a common source in a large area. Climate and terrain could explain the dissemination of contaminated aerosols.

Therapy with tumour necrosis factor-alfa inhibitors is widely used in various inflammatory disorders, but adverse events from severe infections with intracellular pathogens may occur. We describe two cases of severe pulmonary legionellosis in patients treated with infliximab for Crohn's disease and psoriasis, respectively. We conclude that legionella infections are probably more frequent in patients receiving immunosuppressive therapy with tumour necrosis factor-alfa inhibitors than in the background population.

Legionella species are increasingly recognized as a cause of both healthcare- and community-acquired pneumonia (so-called "Legionnaire's disease"). These pathogens are ubiquitous in the environment, but environmental factors in the occurrence of sporadic legionellosis remain poorly understood. We analyzed all legionellosis cases identified in the Greater Toronto Area of Ontario from 1978 to 2006, and evaluated seasonal and environmental patterns in legionellosis case occurrence by using both negative binomial models and case-crossover analysis. A total of 837 cases were reported during the study period. After adjusting for seasonal effects, changes in the local watershed, rather than weather, were the strongest contributors to legionellosis risk. A 3.6-fold increase (95% confidence interval (CI), 2.4-5.3) in odds of disease was identified with decreasing watershed levels approximately 4 weeks before case-occurrence. We also found a 33% increase (95% CI, 8-64%) in odds of disease with decreasing lake temperature during the same period and a 34% increase (95% CI, 14-57%) with increasing humidity 5 weeks before case-occurrence. We conclude that local watershed ecology influences the risk of legionellosis, notwithstanding the availability of advanced water treatment capacity in Toronto. Enhancement of risk might occur through direct contamination of water sources or via introduction of micronutrients or commensal organisms into residential and hospital water supplies. These observations suggest testable hypotheses for future empiric studies.

A fatal nosocomial infection with Legionella pneumophila serogroup 5 occurred in a patient with leukemia. Isolates recovered from both the potable water supply and the patient showed an identical genomic profile. With no other exposure identified, the water from the washbasin was evidently the source of infection.

Problem/condition: Since 1971, CDC, the U.S. Environmental Protection Agency (EPA), and the Council of State and Territorial Epidemiologists have maintained a collaborative Waterborne Disease and Outbreak Surveillance System (WBDOSS) for collecting and reporting data related to occurrences and causes of waterborne-disease outbreaks (WBDOs) and cases of waterborne disease. This surveillance system is the primary source of data concerning the scope and effects of waterborne disease in the United States., Reporting Period: Data presented summarize 28 WBDOs that occurred during January 2005--December 2006 and four previously unreported WBDOs that occurred during 1979--2002., Description of System: The surveillance system includes data on WBDOs associated with recreational water, drinking water, water not intended for drinking (WNID) (excluding recreational water), and water use of unknown intent. Public health departments in the states, territories, localities, and Freely Associated States (FAS) (i.e., the Republic of the Marshall Islands, the Federated States of Micronesia, and the Republic of Palau, formerly parts of the U.S.-administered Trust Territory of the Pacific Islands) are primarily responsible for detecting and investigating WBDOs and voluntarily reporting them to CDC by a standard form. Only cases and outbreaks associated with drinking water, WNID (excluding recreational water), and water of unknown intent (WUI) are summarized in this report. Cases and outbreaks associated with recreational water are reported in a separate Surveillance Summary., Results: Fourteen states reported 28 WBDOs that occurred during 2005--2006: a total of 20 were associated with drinking water, six were associated with WNID, and two were associated with WUI. The 20 drinking water-associated WBDOs caused illness among an estimated 612 persons and were linked to four deaths. Etiologic agents were identified in 18 (90.0%) of the drinking water-associated WBDOs. Among the 18 WBDOs with identified pathogens, 12 (66.7%) were associated with bacteria, three (16.7%) with viruses, two (11.1%) with parasites, and one (5.6%) mixed WBDO with both bacteria and viruses. In both WBDOs where the etiology was not determined, norovirus was the suspected etiology. Of the 20 drinking water WBDOs, 10 (50) were outbreaks of acute respiratory illness (ARI), nine (45%) were outbreaks of acute gastrointestinal illness (AGI), and one (5.0%) was an outbreak of hepatitis. All WBDOs of ARI were caused by Legionella, and this is the first reporting period in which the proportion of ARI WBDOs has surpassed that of AGI WBDOs since the reporting of Legionella WBDOs was initiated in 2001. A total of 23 deficiencies were cited in the 20 WBDOs associated with drinking water: 12 (52.2%) deficiencies fell under the classification NWU/POU (deficiencies occurred at points not under the jurisdiction of a water utility or at the point-of-use), 10 (43.5%) deficiencies fell under the classification SWTDs (contamination at or in the source water, treatment facility, or distribution system), and for one (4.3%) deficiency, classification was unknown. Among the 12 NWU/POU deficiencies, 10 (83.3%) involved Legionella spp. in the drinking water system. The most frequently cited SWTD deficiencies were associated with a treatment deficiency (n = four [40.0%]) and untreated ground water (n = four [40.0%]). Three of the four WBDOs with treatment deficiencies used ground water sources., Interpretation: Approximately half (52.2%) of the drinking water deficiencies occurred outside the jurisdiction of a water utility. The majority of these WBDOs were associated with Legionella spp, which suggests that increased attention should be targeted towards reducing illness risks associated with Legionella spp. Nearly all of WBDOs associated with SWTD deficiencies occurred in systems using ground water. EPA's new Ground Water Rule might prevent similar outbreaks in the future in public water systems., Public Health Actions: CDC and EPA use surveillance data to identify the types of water systems, deficiencies, and etiologic agents associated with WBDOs and to evaluate the adequacy of current technologies and practices for providing safe drinking water. Surveillance data also are used to establish research priorities, which can lead to improved water-quality regulation development. The majority of drinking water deficiencies are now associated with contamination at points outside the jurisdiction of public water systems (e.g., regrowth of Legionella spp. in hot water systems) and water contamination that might not be regulated by EPA (e.g., contamination of tap water at the POU). Improved education of consumers and plumbers might help address these risk factors.

To estimate incidence and completeness of notification of Legionnaires' disease (LD) in The Netherlands in 2000 and 2001, we performed a capture-recapture analysis using three registers: Notifications, Laboratory results and Hospital admissions. After record-linkage, 373 of the 780 LD patients identified were notified. Ascertained under-notification was 52.2%. Because of expected and observed regional differences in the incidence rate of LD, alternatively to conventional log-linear capture-recapture models, a covariate (region) capture-recapture model, not previously used for estimating infectious disease incidence, was specified and estimated 886 LD patients (95% confidence interval 827-1022). Estimated under-notification was 57.9%. Notified, ascertained and estimated average annual incidence rates of LD were 1.15, 2.42 and 2.77/100 000 inhabitants respectively, with the highest incidence in the southern region of The Netherlands. Covariate capture-recapture analysis acknowledging regional differences of LD incidence appears to reduce bias in the estimated national incidence rate.

Background: Cases of legionellosis sometimes arise in the form of aggregations which are difficult to interpret. This study provides an analysis of these groupings having arisen one summer in Castellon., Methods: Microbiological, clinical and epidemiological field methods were employed., Results: Within a few days, there were five (5) cases of legionella pneumonia in workers related to various ceramic industries within an area where a large number of these plants are located. Two constituted a minor outbreak. By means of molecular biology techniques performed on the strains, the common origins of three of the cases were ruled out., Conclusions: It is debated whether this episode of an outbreak having arisen within the context of a broader-ranging cluster of cases of a multi-focal origin was a chance event or whether it was the manifestation of a risk related to this industrial activity which might repeat itself.

Objective: Description of an outbreak of legionnaires' disease originating in one of the cooling towers of a hospital., Patients and Methods: This study included patients with confirmed pneumonia caused by Legionella pneumophila serogroup 1 and related to the Vallcarca neighborhood of Barcelona (Spain) in August 2004. Exposure was determined by a standardized questionnaire. An environmental investigation was carried out to identify the source of the outbreak. A descriptive analysis including incidence rates estimation was performed, as well as molecular study to document the genetic identity among human and environmental strains., Results: Thirty-three cases of L. pneumophila pneumonia were detected. Median age was 68 years and 70% of the affected patients were men. Incidence rate among residents in less than 200 meters of the source and older than 65 was 888.9 cases/100,000 inhabitants. Lethality rate was 6%. Four seasonal cooling towers that were not registered with the authorities were identified in a health care center. L. pneumophila was isolated from all four and at least one colony in each tower had the same genetic profile as the strains isolated from patients., Conclusions: An association was demonstrated between a community outbreak of legionellosis and unregistered seasonal cooling towers located in a hospital. All risk facilities should be registered and inspected to ensure that they fulfill current legislation requirements.

Legionnaires' disease (LD), first reported in 1976, is an atypical pneumonia caused by bacteria of the genus Legionella, and most frequently by L. pneumophila (Lp). Subsequent research on exposure to the organism employed various animal models, and with quantitative microbial risk assessment (QMRA) techniques, the animal model data may provide insights on human dose-response for LD. This article focuses on the rationale for selection of the guinea pig model, comparison of the dose-response model results, comparison of projected low-dose responses for guinea pigs, and risk estimates for humans. Based on both in vivo and in vitro comparisons, the guinea pig (Cavia porcellus) dose-response data were selected for modeling human risk. We completed dose-response modeling for the beta-Poisson (approximate and exact), exponential, probit, logistic, and Weibull models for Lp inhalation, mortality, and infection (end point elevated body temperature) in guinea pigs. For mechanistic reasons, including low-dose exposure probability, further work on human risk estimates for LD employed the exponential and beta-Poisson models. With an exposure of 10 colony-forming units (CFU) (retained dose), the QMRA model predicted a mild infection risk of 0.4 (as evaluated by seroprevalence) and a clinical severity LD case (e.g., hospitalization and supportive care) risk of 0.0009. The calculated rates based on estimated human exposures for outbreaks used for the QMRA model validation are within an order of magnitude of the reported LD rates. These validation results suggest the LD QMRA animal model selection, dose-response modeling, and extension to human risk projections were appropriate.

A prospective surveillance study of legionnaires disease and an environmental survey of Legionella species were performed simultaneously in a general hospital. During a period of 3 years, 705 patients with pneumonia were screened with a Legionella urinary antigen test, and pneumonia was confirmed by culture and serological tests. Twelve cases of legionnaires disease were identified, none of which were hospital acquired, despite the fact that 60% of hospital water samples were contaminated with Legionella pneumophila at a concentration of more than 10(3) colony-forming units/L. The probable source of infection was identified for only 2 community-acquired cases. The results show that environmental contamination alone is not able to predict the risk of legionnaires disease. If no cases are present, monitoring of hospital water systems is of little significance; clinical surveillance is much more important.

Hospital-acquired infection is the cause of about 5,000 deaths a year in the UK. In New Zealand, there are more than three times as many such deaths as from the annual road toll. The costs in loss of income, in pain and suffering and in direct costs to hospitals are staggering.

Background: A long-term care facility (LTCF) reported an outbreak of Legionnaires' disease (LD) in September 2004., Methods: We conducted case finding through enhanced surveillance, medical record review (n = 131), and community surveys (n = 258). We cultured water samples from the LTCF and assayed their outdoor air-intake filters for Legionella DNA. We also investigated a cooling tower, the only nearby outdoor aerosol source., Results: Among 7 confirmed cases, 2 LTCF residents never exited, and 2 community residents never entered the LTCF during the incubation period. Among 63 water and biofilm samples collected from throughout the LTCF, we found no evidence of Legionella colonization, either in the potable water or air-handling systems. Conversely, we isolated a common outbreak-causing strain of Legionella pneumophila serogroup 1 from an industrial cooling tower located 0.4 km from the LTCF and recovered L pneumophila DNA from the LTCF's outdoor air-intake filters, suggesting that aerosolized Legionella from the cooling tower most likely entered the LTCF through the air-intake system or, possibly, through open windows., Conclusion: Residents of LTCFs can acquire LD from community sources. A cluster of LD cases among LTCF residents does not necessarily indicate transmission from within the LTCF.

We describe the case of a patient with a culture-proven infection of the ascending aorta caused by Legionella pneumophila 16 months after cardiac transplantation. Serology follow-up and surveillance culture of the hospital water supply suggested a nosocomial acquisition of the infection during the post-transplantation period. The diagnosis was made after 5 months of recurrent unexplained febrile episodes. A Teflon ring implanted around the aortic suture line during the intervention may have contributed to the unusual localization of the infection. The patient was successfully treated with antibiotics and aortic reconstruction.

Legionnaires disease, more formally known as legionellosis, is a relatively common form of severe pneumonia caused by Legionella, a genus of waterborne bacteria. Legionellosis is acquired by inhalation of legionellae from contaminated environmental sources. Legionella pneumophila serogroup 1 is responsible for more than 80% of cases in most countries. More than 1500 cases were reported in France in 2005. Initial diagnosis is based on tests for urinary antigens. The mortality rate for legionellosis depends on the promptness of appropriate antibiotic therapy. Macrolides (erythromycin or intravenous azithromycin, which is preferred to erythromycin for its better pharmacodynamic properties) and fluoroquinolones (levofloxacin) are the antibiotics of choice for severe legionellosis.

Legionella pneumophila causes community- and hospital-acquired pneumonia. Lung airway and alveolar epithelial cells comprise an important barrier against airborne pathogens. Cyclooxygenase (COX) and microsomal PGE(2) synthase-1 (mPGES-1)-derived prostaglandins like prostaglandin E(2) (PGE(2)) are considered as important regulators of lung function. Herein we tested the hypothesis that L. pneumophila induced COX-2 and mPGES-1-dependent PGE(2) production in pulmonary epithelial cells. Legionella induced the release of PGE(2) in primary human small airway epithelial cells and A549 cells. This was accompanied by an increased expression of COX-2 and mPGES-1 as well as an increased PLA(2) activity in infected cells. Deletion of the type IV secretion system Dot/Icm did not impair Legionella-related COX-2 expression or PGE(2) release in A549 cells. L. pneumophila induced the degradation of IkappaBalpha and activated NF-kappaB. Inhibition of IKK blocked L. pneumophila-induced PGE(2) release and COX-2 expression. We noted activation of p38 and p42/44 MAP kinase in Legionella-infected A549 cells. Moreover, membrane translocation and activation of PKCalpha was observed in infected cells. PKCalpha and p38 and p42/44 MAP kinase inhibitors reduced PGE(2) release and COX-2 expression. In summary, PKCalpha and p38 and p42/44 MAP kinase controlled COX-2 expression and subsequent PGE(2) release by Legionella-infected lung epithelial cells. These pathways may significantly contribute to the host response in Legionnaires' disease.

A statement released last week by the Health Protection Agency highlighted a recent increase in the incidence of Legionnaire's disease in England and Wales. Although an upsurge in cases is common at this time of year due to people returning from holidays abroad, only a small proportion of the recent cases can be attributed to foreign travel. Nurses need to be aware of the symptoms and what health measures they can take.

Legionella infections are uncommon in childhood. We report the case of an infant who developed multiple pulmonary abscesses caused by Legionella pneumophila after receiving prolonged corticosteroid treatment of severe croup. Diagnosis was not suspected because immunosuppression was not initially considered. Caution should be used when prolonging high-dose corticosteroids in children with respiratory diseases.

Background and Objective: Superheat-and-flush is one of the methods of disinfection used against Legionella in hospital water distribution systems. An outbreak of nosocomial legionellosis (NL) was detected in the hospital Germans Trias i Pujol in January 1996. The aim of this study was to evaluate the impact of this disinfection technique at an environmental and clinical level., Material and Method: Water samples were collected daily from central and tap water points 3 days prior to 15 days after superheating and flushing. Clinical surveillance of NL was performed 30 consecutive days following disinfection., Results: After superheat-and-flush, the inoculum of Legionella pneumophila decreased in the central points but increased after day 11, achieving maximum values at 15 days. On the other hand, L. pneumophila was not detected in tap water points after 4 days but recolonization was observed after day 7, achieving 66% at day 9. No clinical cases of NL were detected during the study period., Conclusions: Superheat-and-flush is an effective albeit transitory method of rapid disinfection in outbreaks of NL.

Poor indoor air quality has been implicated in the increase in allergic and respiratory diseases seen in industrialized countries in recent decades. Although air pollution in the workplace is well studied, much less is known about the consequences of poor air quality in homes. In an attempt to halt or slow down the increase in allergic and respiratory diseases, the European Federation of Allergy and Airways Diseases Patients Associations (EFA) carried out the EU-funded project entitled 'Towards Healthy Air in Dwellings in Europe' (THADE). The aims were to: compile an overview of evidence-based data about exposure to indoor air pollution and its health effects, particularly in relation to allergies, asthma and other respiratory diseases such as chronic obstructive pulmonary disease; review cost-effective measures and technology to improve indoor air quality; review legislation and guidelines on indoor air pollution; produce maps of pollutants in dwellings; and recommend an integrated strategy that defines appropriate indoor air quality policies for implementation in Europe. This paper summarizes the information about air quality in dwellings and indoor environment-related diseases collected by expert consultants within the framework of THADE and terminates with recommendations for actions aimed at improving air quality in homes. The results of this project confirmed that air pollution in dwellings is a relevant health problem. It is a complex problem that must be addressed at European and international levels, and it involves the medical profession, scientific societies, patients' organizations, lawmakers, architects and the building industry. The complete THADE report is available at http://www.efanet.org/activities/documents/THADEReport.pdf.

Legionella species are ubiquitous in aquatic environments. About 50 years ago they entered the engineered (technical) environment, i.e. warm water systems with zones of stagnation. Since that time they represent a hygienic problem. After transmission to humans via aerosols legionellae might cause Legionella pneumonia (legionnaires' disease) or influenza-like respiratory infections (Pontiac fever). Epidemiological data suggest that Legionella strains might differ substantially in their virulence properties. Although the molecular basis is not understood L. pneumophila serogroup 1 especially MAb 3/1-positive strains cause the majority of infections. The main virulence feature is the ability to multiply intracellularly. After uptake into macrophages legionellae multiply in a specialized vacuole and finally lyse their host cells. Several bacterial factors like surface components, secretion systems and iron uptake systems are involved in this process. Since the clinical picture of Legionella pneumonia does not allow differentiation from pneumoniae caused by other pathogens, microbiological diagnostic methods are needed to establish the diagnosis. Cultivation of legionellae from clinical specimens, detection of antigens and DNA in patients' samples and detection of antibodies in serum samples are suitable methods. However, none of the diagnostic tests presently available offers the desired quality with respect to sensitivity and specificity. Therefore, the standard technique is to use several diagnostic tests in parallel. Advantages and disadvantages of the diagnostic procedures are discussed. Therapeutic options for Legionella infections are newer macrolides like azithromycin and chinolones (ciprofloxacin, levofloxacin and moxifloxacin).

In January 2003, two cases of Legionnaires' disease associated with a ship's cruise were registered in the database of National Epidemiological Surveillance of Infectious Diseases. A 70-year-old male heavy smoker with mild emphysema contracted the disease during a cruise. Legionella pneumophila serogroup (sg) 5 was isolated from the patient's sputum and the ship's indoor spa. The isolate from the spa matched the patient's isolate by genotyping performed by pulsed-field gel electrophoresis (PFGE). The second case was in a 73-year-old female. During epidemiological investigation, a third case of Legionnaire's disease in a 71-year-old male was subsequently diagnosed among passengers on the same ship on the following cruise. Environmental investigation revealed that porous natural stones (Maifanshi) in the filters of the spas had harboured L. pneumophila, a phenomenon which has not been reported except in Japan. This is the first documented evidence of L. pneumophila sg 5 infection on a ship and of porous stones as a source of Legionella infection.

Human Legionella infections mainly consist of community-acquired and nosocomial pneumonia and rarely affect children. We describe a nosocomial infection with Legionella pneumophila, serogroup 1, subgroup OLDA, in an immunocompromized 2-y-old girl at a paediatric clinic. L. pneumophila identical to that of the patient was found in the hospital's cold-water but not in the hot-water distribution system. Transmission of Legionella to the girl most probably occurred by Legionella-contaminated cold water mixed and heated by water from the hot-water system. Mixing of hot and cold water probably occurred through thermostatic water mixing valves connected to showers regulated by a handle at the shower head. Nosocomial Legionella infection might thus have occurred, although circulating hot water temperatures never dropped below 53 degrees C and cultures for surveillance of Legionella from central parts of the hot-water system have been consistently negative. Legionellae were successfully eliminated from the hospital's cold-water distribution system by hot water flushing at 73 degrees C for 1h.

Legionella pneumophila is an important cause of community-acquired pneumonia. Domestic sources of infection have been increasingly recognised among community-acquired cases. This report summarises the public health investigations and management of a single community-acquired case of Legionnaires' disease in Queensland, commenced in the context of a suspected outbreak. Legionellae from the case's domestic water supply were indistinguishable from the clinical isolate. The implications for future investigation of sporadic cases are discussed.

Objective: To investigate the potential source of a case of Legionnaires' disease caused by an unusual serotype of Legionella pneumophila serogroup 1 (Lp1) in regional Victoria in May 2001., Method: Epidemiological and environmental investigation of the source of infection of a case of Legionnaires' disease in regional Victoria in May 2001., Results: Extensive environmental investigations did not reveal any cooling water tower systems close to the residence or the shopping centre that the case visited prior to illness. The sputum culture and a soil sample from the field at the plant nursery where the case worked prior to illness were both positive for Legionella pneumophilia serogroup 1, MDU pulsovar 97:103., Conclusion: Legionella pneumophila has been found in soil and was further found to be associated with a case of Legionella pneumophila., Implications: Public health authorities should consider exposures to soil and potting mixes when investigating cases of Legionella pneumophila where the case has no apparent association with cooling towers. Safe gardening practices should be promoted among the community.

The authors discuss the case of a 79-year-old patient who suffered from a swallowing disorder and developed Legionnaires' disease 2 days after her dismissal from an orthopedics ward, where she had recovered from hip surgery. To determine the source of the Legionnaires' disease, the authors performed an environmental investigation, which included a national, standardized questionnaire and a microbiological investigation of suspected sources. The investigation revealed ice from an ice-making machine in the hospital as the most probable source of the infection through aspiration, even though the hospital had rigorously adhered to strict assessment and decontamination schedules. The infectious serogroup was one that was not common to the area. From the data available, the authors inferred that a dose of 1-2000 colony-forming units might have caused Legionnaires' disease in this patient.

In three male patients with lower respiratory disease, aged 51, 32 and 63 years, Legionnaires' disease was diagnosed by urinary antigen test and culture of the respiratory-tract fluid. In the second patient, the bronchoalveolar fluid also contained Streptococcus pneumoniae and Haemophilus influenzae. All three patients recovered after treatment with azithromycin in the first, cefotaxime, vancomycin and levofloxacin in the second, and erythromycin and ciprofloxacin in the third, respectively. Legionella pneumophila pneumonia is clinically not clearly distinct from other pneumonias and has a high mortality rate when not treated with the proper antibiotics. For that reason, adequate and swift diagnosis is of great importance. The urinary antigen test meets both of these criteria. Still, it is advisable to use culture and serology as well if Legionnaires' disease is suspected in a patient, since the urinary antigen test has limitations. In addition, patient isolates are ofepidemiological importance for public health. By comparing available patient isolates with Legionella strains from water sources, it is possible to identify sources of infection. In 2002, based on this principle, a project was started in The Netherlands aimed at identifying sources of infection, thereby preventing outbreaks of Legionnaires' disease by swift elimination of the source. Since the start of the project, 29 sources have been identified. In the cases described above these were a sauna, a cooling tower and a caravan, respectively. In suspected cases, respiratory-tract fluid must be collected to make possible such a source investigation.

During October 2003-February 2004, eight cases (seven confirmed cases and one possible) of Legionnaires disease (LD) were identified among guests at a hotel in Ocean City, Maryland. This report summarizes the subsequent investigation conducted by the Worcester County Health Department (WCHD), Maryland Department of Health and Mental Hygiene (DHMH), and CDC, which implicated the potable hot water system of the hotel as the most likely source of infection. The detection of this outbreak underscores the importance of enhanced, state-based surveillance for timely detection of travel-associated LD and implementation of control measures.

A 88 year old female with active rheumatoid arthritis treated by low dose of prednisolone and methotrexate was admitted to our hospital because of severe bilateral pulmonary infiltration and acute respiratory distress syndrome. On admission, she had consciousness disturbance and was intubated because of severe respiratory failure. We heard from her family of her habit she had taking a private whirlpool bath 2 or 3 times everyday. So, we suspected a Legionella pneumophila infection. We started intravenous erythromycin (EM) (1,500mg/day) and methylprednisolone pulse therapy (1,000mg x 3days) and full controlled mechanical ventilation supported with PEEP. Her respiratory failure was gradually improved and she was discharged on the 44 the hospital day. Legionella pneumophila (serogroup 6) was isolated in her sputum by B-CYE alpha culture. Legionella pneumophila (serogroup 6) was isolated in her private whirlpool bath too. Both samples revealed the same by genetic analysis with pulse field gel electrophoresis (PFGE). This is the first adult case of Legionella pneumophila pneumonia infected from a private whirlpool bath confirmed by genetic analysis. We should always suspect Legionella pneumonia as one of the severe community-acquired pneumonia, because Legionella pneumophila were frequently detected among various water sources including the private whirlpool bath.

Moisture, microbial and in particular mold related indoor exposure and health problems in homes, offices, and public buildings (Kindergartens, schools, library, and hospitals) have been gaining recognition as one of the most common indoor environmental health issues. Proper recognition of microbial related health problems and the differential diagnosis of sick building syndrome (SBS) or building related illness (BRI) are important for early and effective exposure intervention, treatment, referral and prevention of more serious illness.

Legionella pneumophila is commonly found in freshwater environments and is able to invade and replicate within amoebae and ciliated protozoa. Moreover, this bacterium is also able to replicate within human alveolar macrophages causing a severe form of pneumonia, designated Legionnaires' disease. L. pneumophila pathogenesis is not yet completely understood, but the genes responsible for infection and intracellular replication are becoming known. Nonetheless, knowledge as to how these genes are controlled is still very limited. The partially sequenced genome of L. pneumophila was searched for open reading frames encoding proteins with sequence similarity to members of the LuxR family of transcriptional regulators. These were designated LpnR1, LpnR2, LpnR3, and LpnR4. Although these proteins could not be identified as true LuxR proteins, they do act as regulators, as illustrated in this report. LpnR1 negatively affected rpoS expression, whereas LpnR2 and LpnR3 positively affected flagellin expression. Furthermore, LpnR2 proved to be necessary for efficient invasion of Acanthamoeba castellanii and LpnR3 for intracellular replication in this protozoan host. LpnR4 was recently identified as LetA.

We investigated Legionella and Pseudomonas contamination of hot water in a cross-sectional multicentric survey in Italy. Chemical parameters (hardness, free chlorine, and trace elements) were determined. Legionella spp. were detected in 33 (22.6%) and Pseudomonas spp. in 56 (38.4%) of 146 samples. Some factors associated with Legionella contamination were heater type, tank distance and capacity, water plant age, and mineral content. Pseudomonas presence was influenced by water source, hardness, free chlorine, and temperature. Legionella contamination was associated with a centralized heater, distance from the heater point >10 m, and a water plant >10 years old. Furthermore, zinc levels of <100 microg/L and copper levels of >50 microg/L appeared to be protective against Legionella colonization [corrected]. Legionella species and serogroups were differently distributed according to heater type, water temperature, and free chlorine, suggesting that Legionella strains may have a different sensibility and resistance to environmental factors and different ecologic niches.

Legionella pneumophila has become a paradigm for facultative intracellular pathogens that modulate biogenesis of their phagosomes into replicative niches. The ability to alter host cell biology and tailor it into a hospitable host for intracellular proliferation is at the crux of the mechanism of pathogenesis of Legionnaires' disease.

We report a patient with Legionella pneumophila pneumonia after infliximab therapy for rheumatoid arthritis. Arguments are discussed for an emerging incidence of infections with intracellular microorganisms, granulomatous and non-granulomatous, in patients having received anti-TNFalpha therapy. These discussions consist of clinical and epidemiological data, experimental data in animals, theoretical evidence, and we provide a possible pathogenetic mechanism.