Caption =
DiseasesDB = 7366
ICD10 =
ICD9 = ICD9|482.84
MedlinePlus = 000616
eMedicineSubj = med
eMedicineTopic = 1273
MeshID = D007876

Legionellosis is an infectious disease caused by bacteria belonging to the genus "Legionella".cite book | author = Ryan KJ, Ray CG (editors) | title = Sherris Medical Microbiology | edition = 4th ed. | publisher = McGraw Hill | year = 2004 | isbn = 0838585299 ] cite book | author = Heuner K, Swanson M (editors). | title = Legionella: Molecular Microbiology | publisher = Caister Academic Press | year = 2008 | url=http://www.horizonpress.com/leg | id = [http://www.horizonpress.com/leg ISBN 978-1-904455-26-4 ] ] Over 90% of legionellosis cases are caused by "Legionella pneumophila", a ubiquitous aquatic organism that thrives in warm environments (25 to 45 °C with an optimum around 35 °C). [ [http://www.cdc.gov/ncidod/dbmd/diseaseinfo/legionellosis_t.htm CDC: Etiologic Agent] ]

Legionellosis takes two distinct forms:
* Legionnaires' disease, also known as "Legion Fever" [ [http://www.scienceclarified.com/Io-Ma/Legionnaires-Disease.html Legionnaires' disease] ] (archaic), is the more severe form of the infection and produces pneumonia.cite book | author = Winn WC Jr | chapter = Legionella | title = Baron's Medical Microbiology "(Baron S "et al", eds.)| edition = 4th ed. | publisher = Univ of Texas Medical Branch | year = 1996 | url = http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mmed.section.2222 | isbn = 0-9631172-1-1 ]
* Pontiac fever is caused by the same bacterium, but produces a milder respiratory illness without pneumonia which resembles acute influenza.

Legionnaires' disease acquired its name in July 1976 when an outbreak of pneumonia occurred among people attending a convention of the American Legion in Philadelphia. On January 18, 1977 the causative agent was identified as a previously unknown bacterium, subsequently named "Legionella".

An estimated 8,000 to 18,000 people get legionellosis in the United States each year. [ [http://www.cdc.gov/ncidod/dbmd/diseaseinfo/legionellosis_t.htm CDC: Incidence] ] Some people can be infected with the "Legionella" bacterium and have only mild symptoms or no illness at all.

Outbreaks of Legionnaires' disease receive significant media attention. However, this disease usually occurs as a single, isolated case not associated with any recognized outbreak. When outbreaks do occur, they are usually recognized in the summer and early autumn, though cases may occur at any time of year. The fatality rate of Legionnaires' disease has ranged from 5 to 30% during various outbreaks.


Patients with Legionnaires' disease usually have fever, chills, and a cough, which may be dry or may produce sputum. Some patients also have muscle aches, headache, tiredness, loss of appetite, loss of coordination (ataxia), and occasionally diarrhea and vomiting. Laboratory tests may show that patients’ renal functions, liver functions and electrolytes are deranged, including hyponatremia. Chest X-rays often show pneumonia with bi-basal consolidation. It is difficult to distinguish Legionnaires' disease from other types of pneumonia by symptoms or radiologic findings alone; other tests are required for diagnosis.

Persons with Pontiac fever experience fever and muscle aches without pneumonia. They generally recover in 2 to 5 days without treatment.

The time between the patient's exposure to the bacterium and the onset of illness for Legionnaires' disease is 2 to 10 days; for Pontiac fever, it is shorter, generally a few hours to 2 days.


Intestinal Infections: These may only occur as part of respiratory infections, and where gastrointestinal symptoms have on occasion been described.

Extraintestinal Infections: "L. pneumophila" is specifically considered as a pathogen of the respiratory tract, where it is a cause of atypical pneumonia, also known as Legionnaires' disease. Other infections have also been reported, including haemodialysis fistulae, pericarditis and wound and skin infections. Bacteraemia is often associated with Legionnaires' disease.

Animal Infections: None specifically recorded.

Infections of Protozoa: Protozoa such as "Harmanella vermiformis" and related protozoa have been shown to be able to support the growth of "L. pneumophila" in tap water. Also "Acanthamoeba", "Naegleria" and "Tetrahymena" can be infected by "L. pneumophila". This pathway may be how these organisms survive in the environment.

Diagnosis and treatment

People of any age may get Legionnaires' disease, but the illness most often affects middle-aged and older persons, particularly those who smoke cigarettes or have chronic lung disease. Immunocompromised patients are also at elevated risk. Pontiac fever most commonly occurs in persons who are otherwise healthy.

The most useful diagnostic tests detect the bacteria in sputum, find "Legionella" antigens in urine samples, or compare antibody levels to "Legionella" in two blood samples obtained 3 to 6 weeks apart. The urine antigen test is simple, quick, and very reliable; however it will only detect "Legionella pneumophila" serogroup #1. Also the urine antigen test will not identify the specific subtyping so it cannot be used to match the patient with the environmental source of infection.

Current treatments of choice are the respiratory tract quinolones (levofloxacin, moxifloxacin, gemifloxacin) or newer macrolides (azithromycin, clarithromycin, roxithromycin). The antibiotics used most frequently have been levofloxacin and azithromycin. Macrolides are used in all age groups while tetracyclines are prescribed for children above the age of 12 and quinolones above the age of 18.
Rifampicin can be used in combination with a quinolone or macrolide. Tetracyclines and erythromycin led to improved outcome compared to other antibiotics in the original American Legion outbreak. These antibiotics are effective because they have excellent intracellular penetration and "Legionella" infects cells. The mortality at the original American Legion convention in 1976 was high (34 deaths in 180 infected individuals) because the antibiotics used (including penicillins, cephalosporins, and aminoglycosides) had poor intracellular penetration. Mortality has plunged to less than 5% if therapy is started quickly. Delay in giving the appropriate antibiotic leads to higher mortality.

Pontiac fever requires no specific antibiotic treatment.


"Legionellosis" infection normally occurs after inhaling an aerosol (suspension of fine particles in air) containing "Legionella" bacteria. Such particles could originate from any infected water source. When mechanical action breaks the surface of the water, small water droplets are formed, which evaporate very quickly. If these droplets contain bacteria, the bacteria cells remain suspended in the air, invisible to the naked eye but small enough to be inhaled into the lungs. [Legionnaires' Disease: Mode of infection – aerosol formation. UK Health Protection Agency available online at http://www.hpa.org.uk/webw/HPAweb&HPAwebStandard/HPAweb_C/1204186178183?p=1191942128209 (accessed 12th May 2008)] This often occurs in poorly ventilated areas such as prisons where a condensating air conditioner can spread it throughout the entire room, infecting anyone not immune to the strand of bacteria. Potential sources of such contaminated water include cooling towers used in industrial cooling water systems as well as in large central air conditioning systems, evaporative coolers, hot water systems, showers, whirlpool spas, architectural fountains, room-air humidifiers, ice making machines, misting equipment, and similar disseminators that draw upon a public water supply. The disease may also be spread in a hot tub if the filtering system is defective. [Silivanch v. Celebrity Cruises, Inc., 171 F.Supp.2d 241 (S.D.N.Y. 2001) (plaintiff successfully sued cruise line and manufacturer of filter after catching disease on cruise)] Freshwater ponds, creeks, and ornamental fountains are also potential sources of "Legionella".cite book | author = Winn WC Jr | title = Legionella. "In:" Baron's Medical Microbiology "(Baron S "et al", eds.)| edition = 4th ed. | publisher = Univ of Texas Medical Branch | year = 1996 | id = [http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mmed.section.2235 (via NCBI Bookshelf)] ISBN 0-9631172-1-1 ] The disease is particularly associated with hotels, cruise ships and hospitals with old, poorly maintained pipework and cooling systems.

"Legionella" will grow in water at temperatures from 20 °C to 50 °C (68 °F to 122 °F). However, the bacteria reproduce at the greatest rate in stagnant water at temperatures of 35 °C to 46 °C (95 °F to 115 °F).

"Legionella longbeachae", an organism in the "Legionella" family, is found in soils and compost. [ [http://www.cdc.gov/mmwr/preview/mmwrhtml/mm4934a1.htm CDC: Potting Soil in CA, OR, WA] ] Thus, the dust from purchased bags of soil, compost, or potting mix is also a potential source of "Legionella".

Epidemiology of Legionnaires' disease

Much has been learned about the epidemiology of Legionnaires' disease since the organism was first identified in 1976. National surveillance systems and research studies were established early, and in recent years improved ascertainment and changes in clinical methods of diagnosis have contributed to an upsurge in reported cases in many countries. Environmental studies continue to identify novel sources of infection, leading to regular revisions of guidelines and regulations. Between 1995 and 2005 over 32,000 cases of Legionnaires' disease and more than 600 outbreaks were reported to the European Working Group for Legionella Infections (EWGLI). In the future, there may be an increase in cases as the population becomes more elderly and climate change perhaps leads to an increased risk of exposure to infection in many countries. There is a shortage of data on Legionella in developing countries and it is likely that Legionella-related illness is underdiagnosed worldwide. [World Health Organization 2007. Legionella and the prevention of legionellosis. Geneva, Switzerland: WHO. Available at: http://www.who.int/water_sanitation_health/emerging/legionella.pdf] Improvements in diagnosis and surveillance in developing countries would be expected to reveal far higher levels of morbidity and mortality than are currently recognised. Similarly, improved diagnosis of human illness related to legionella species and serogroups other than legionella pneumophila would improve knowledge about their incidence and spread. [Fields BS, Benson RF, Besser RE 2002. Legionella and Legionnaires' Disease: 25 Years of Investigation. Clinical Microbiology Reviews. July 2002, p. 506-526, Vol. 15, No. 3. Full-text available at: http://cmr.asm.org/cgi/content/full/15/3/506]

Notable Outbreaks of Legionnaires' disease

Philadelphia, 1976

The first recognized outbreak occurred on July 27, 1976 at the Bellevue Stratford Hotel in Philadelphia, Pennsylvania, where members of the American Legion, a United States military veterans association, had gathered for the American Bicentennial. Within two days of the event’s start, veterans began falling ill with a then-unidentified pneumonia. They had high breathing rates and chest pains. Numbers differ, but perhaps as many as 221 people were given medical treatment and 34 deaths occurred. At the time, the U.S. was debating the risk of a possible swine flu epidemic, and this incident prompted the passage of a national swine flu vaccination program. That cause was ruled out, and research continued for months, with various theories discussed in scientific and mass media that ranged from toxic chemicals to terrorism (domestic or foreign) aimed at the veterans. The U.S. Centers for Disease Control and Prevention mounted an unprecedented investigation and by September, the focus had shifted from outside causes, such as a disease carrier, to the hotel environment itself. In January 1977, the "Legionellosis" bacterium was finally identified and isolated, and found to be breeding in the cooling tower of the hotel’s air conditioning system, which then spread it through the entire building. This finding prompted new regulations worldwide for climate control systems.

Subsequent investigations, "revealed that the bacteria thrived in the Bellevue-Stratford hotel's cooling tower. From that water supply the hotel derived its air conditioning and the bacteria were actively pumped into the hotel. Since 1976, air conditioning changed, with federal agencies all over the world requiring more stringent cleaning and hygiene provisions for cooling towers and large scale air conditioning systems." [ [http://justice.loyola.edu/~klc/BL472/Legionnaire/history.html] ]

United Kingdom, 1985

A large outbreak of Legionnaires' disease was associated with Stafford District General Hospital. A total of 68 confirmed cases were treated in hospital and 22 of these patients died. A further 35 patients, 14 of whom were treated at home, were suspected cases of Legionnaires' disease. All these patients had visited the hospital during April 1985. The BBC reported these statistics as 101 infected with 28 deaths resulting.

Netherlands, 1999

In March 1999, an outbreak in the Netherlands occurred during a flower exhibition in Bovenkarspel. 200 people became ill and at least 32 people died. There is a possibility that more people died from it, but these people were buried before the "Legionella" infection was recognized. The source of the bacteria were probably a whirlpool and a humidifier in the exhibition area. [ [http://www.q-net.net.au/~legion/Legionnaires`_Disease_Netherlands_1999.htm The Westfriese Flora flower exhibition and fair] ]

pain, 2001

The world’s largest outbreak of Legionnaires' disease happened in July 2001 (patients began appearing at the hospital on July 7), in Murcia, Spain. More than 800 suspected cases were recorded by the time the last case was treated on July 22; 636-696 of these cases were estimated and 449 confirmed (so, at least 16,000 people were exposed to the bacterium) and 6 died (a case-fatality rate of approximately 1%).

A controlled case study matching 85 patients living outside the city of Murcia with two controls each was undertaken to identify the outbreak source; the epidemiologic investigation implicated the cooling towers at a city hospital (Morales Meseguer Hospital). An environmental isolate from these towers with an identical molecular pattern as the clinical isolates was subsequently identified and supported that epidemiologic conclusion.

Norway, 2001

The first known case of the disease in Norway occurred in 2001 when 28 people were infected in the city of Stavanger, and seven died. At first the authorities were puzzled as several of the victims lived in other locations, including one in Germany and another in England. After a massive investigation a fountain in the small lake of Breiavatnet, in the city centre, was suspected as the source of the outbreak. But the fountain had not sprayed the bacteria into the air, the source was a cooling tower at the nearby SAS Radisson hotel. Only three of the infected had stayed at the hotel, but the exit vent of the cooling tower was at ground level next to a public bus stop, explaining the other victims.

United Kingdom, 2002

In 2002, Barrow-in-Furness suffered the U.K.'s worst outbreak of Legionnaires' disease. Six women and one man died as a result of the illness, another 172 people also contracted the disease. The cause was found to be a contaminated cooling tower at the town’s Forum 28 arts centre. [http://www.multiline.com.au/~mg/legionnaires_disease_Barrow-in-Furness.html] Barrow Borough Council later became the first public body in the UK to be charged with corporate manslaughter, but were cleared. They were, however, along with architect Gillian Beckingham, fined for breaches of Health and Safety regulations in a trial that ended in 2006.

North Wales, PA, 2002

The Abramson Center, a nursing home outbreak where 11 people got ill and 2 died. The facility was only 9 months old at the time of the outbreak. Ten days prior to the outbreak there was a municipal water interruption which resulted in turbid water in the facility for several hours.

France, 2004

Researchers found that the Legionnaires' disease bacteria spread through the air up to 6 kilometers from a large contaminated cooling tower at a petrochemical plant in Pas-de-Calais in northern France. That outbreak killed 21 of the 86 people with laboratory-confirmed infection. [ [http://members.dodo.net.au/~jamgreen/legionellose_france.index.htm Norox Pas-de-Calais] ]

Norway, 2005

In May 2005 there was a second—greater—outbreak in Norway, this time originating in the southeastern town of Fredrikstad. As of 8 June 2005, 52 patients were confirmed infected and ten people were dead. The dead were all from Fredrikstad or nearby cities, in age ranging from 68 to early 90's. The source of the outbreak unexpectedly came from an air scrubber (an industrial air purification facility; this particular one operated by Borregaard Industries in Sarpsborg). Such an installation has never before been reported as a source of Legionellosis anywhere in the world. Although the source was finally identified by DNA matching, it was also fairly well identified by analysing risk increases from people living near suspected sources. [ [http://www.q-net.net.au/~legion/legionella_norway.htm Borregaard Sarpsborg plant in Norway] ]

The first case was a truck driver that delivered sludge from a waste treatment plant at another facility to the one at Borregaard Industries. Because of this the first facility inspected by the health authority was Borregaard Industires however the water was not tested because this type of facility had never been associated with an outbreak.

New Zealand, 2005

An outbreak of Legionnaires' disease hit the New Zealand city of Christchurch in mid-2005, with 20 reported cases (three fatal) between late April and August. A cooling tower at the city's Ravensdown Fertiliser Plant was implicated in the outbreak. The outbreak led to plans by the city council to create a registry of all air-conditioning cooling towers within the city. [ [http://tvnz.co.nz/view/page/410965/608556 Television New Zealand report] ]

Toronto, 2005

In October 2005 at least 21 people died [ [http://english.people.com.cn/200510/25/eng20051025_216524.html People's Daily Online - Another dies of legionnaires' disease in Toronto ] ] and over 100 fell ill during an outbreak at the Seven Oaks Home for the Aged in Toronto, Ontario, Canada. Legionnaire's disease was originally ruled out as being the cause, but post-mortem examinations confirmed that victims had "Legionella" bacteria in their lungs. The outbreak is still being investigated, and researchers believe this particular outbreak may be related to a new strain of the bacteria.

Australia, 2007

The outbreak is believed to have started during New Year's Eve celebrations at Circular Quay, on Sydney's harbour. Thought to have started from a cooling tower (where 1,400 cfu/ml Legionella was found) from an adjacent office building, four cases were initially confirmed, but there were concerns due to the fact that Circular Quay is one of the most populated areas in Sydney on New Year's Eve. As a result, there could have been potentially many more cases. On Saturday, January 20 the NSW Health Authority reported that three more cases had developed overnight, bringing the total reported cases to 7.

New York, 2007

A Legionnaires' disease was confirmed in six residents of New York City nursing homes, all of whom were hospitalized and recovered. It was believed to have spread through the heating radiators located at the facilities. In the upstate community of Rochester, New York, two cases have been confirmed at Rochester General Hospital in 2008.

Orlando, Florida, 2008

It was reported on March 14 by the Orange County Health Department that two people who were staying at a Quality Suites, contracted Legionnaires' disease, possibly from a pool and spa that did not have adequate chlorine. [ [http://www.wesh.com/health/15595698/detail.html Legionnaires' Disease Found At Local Hotel] ]

yracuse, New York, 2008

An outbreak infecting 11 people was confirmed in Syracuse, New York in July 2008, and was traced to an air conditioning cooling tower at Community General Hospital. One infected person died.

In the same month, the health department discovered Legionella bacteria in the water system of the Van Duyn nursing home. They don't believe this is related to the outbreak at Community General Hospital.

Elmira, New York, 2008

An outbreak in Elmira, New York occurred in August 2008 and resulted in 13 confirmed cases and caused the death of two people. The outbreak occurred at the Edward Flannery Apartments, which is overseen by the Elmira Housing Authority. The outbreak occurred one month after a municipal water main break at the edge of the buildings' driveway. [ [http://elmirahousing.org/index.php?n=Main.Announcements Elmira Housing Authority] ]

New Brunswick, New Jersey, 2008

An outbreak in New Brunswick, New Jersey occurred in September 2008. There are 8 confirmed cases and three deaths caused by the infection as of October 6, 2008. The outbreak occurred at Saint Peters University Hospital. Appropriate action is being taken to investigate the water supply as the source. [http://www.nj.com/news/index.ssf/2008/09/second_patient_with_legionnair.html]

Galway, Ireland, 2008

In October, 2008 The Health Service Executive in Ireland announced an outbreak of Legionnaires Disease at University College Hospital in Galway. [http://www.rte.ie/news/2008/1010/legionnaires.html]

Controlling the potential growth of "Legionella" in cooling towers and air scrubbers

Various studies have shown that some 40 to 60% of cooling towers tested contained Legionella. [ [http://cti.org/cgi-bin/download.pl CTI Legionellosis Guideline: Best Practices for Control of Legionella (WTP-148) (06)] ] A recent research study provided evidence that "Legionella pneumophila", the causative agent of Legionnaires' disease, can travel at least 6 km from its source by airborne spread. It was previously believed that transmission of the bacterium was restricted to much shorter distances. A team of French scientists reviewed the details of an epidemic of Legionnaires' disease that took place in Pas-de-Calais in northern France in 2003–2004. There were 86 confirmed cases during the outbreak, of whom 18 perished. The source of infection was identified as a cooling tower in a petrochemical plant, and an analysis of those affected in the outbreak revealed that some infected people lived as far as 6–7 km from the plant. [ [http://www.nature.com/nrmicro/journal/v4/n3/full/nrmicro1368.html Long-range transmission of Legionella] ]

A study of Legionnaires' disease cases in May 2005 in Sarpsborg, Norway wrote: "The high velocity, large drift, and high humidity in the air scrubber may have contributed to the wide spread of Legionella species, probably for >10 km. ... " [ [http://www.unboundmedicine.com/medline/ebm/record/18171215/full_citation/An_outbreak_of_legionnaires_disease_caused_by_long_distance_spread_from_an_industrial_air_scrubber_in_Sarpsborg_Norway_ An outbreak of legionnaires disease caused by long-distance spread from an industrial air scrubber in Sarpsborg, Norway in May 2005] ]

Temperature affects the survival of "Legionellae" as follows: [ [http://www.relianceworldwide.com/site/fs_main_home.htm What is Legionnaires' disease?] ]

*70 to 80 °C (158 to 176 °F): Disinfection range
*At 66 °C (151 °F): Legionellae die within 2 minutes
*At 60 °C (140 °F): Legionellae die within 32 minutes
*At 55 °C (131 °F): Legionellae die within 5 to 6 hours
*Above 50 °C (122 °F): They can survive but do not multiply
*35 to 46 °C (95 to 115 °F): Ideal growth range
*20 to 50 °C (68 to 122 °F): Legionellae growth range
*Below 20 °C (68 °F): Legionellae can survive but are dormant

Removing slime is an effective control process, because up to 1,500 times more chemicals are needed to kill bacteria in slime than free floating bacteria [ [http://www.ehponline.org/docs/1998/106-12/innovations.html Studying Slime Paragraph 12] ] [ [http://www.edstrom.com/Resources.cfm?doc_id=23 An Introduction to Biofilms] ] .

Action levels following microbial monitoring for cooling towers

The European Working Group for Legionella Infections (EWGLI) [ [http://www.ewgli.org European Working Group for Legionella Infections] ] was established in 1986 within the European Union framework to share knowledge and experience about potential sources of "Legionella" and their control. This group has published guidelines [ [http://www.ewgli.org/data/european_guidelines/eg_supplement1a.pdf EWGLI: Technical Guidelines for the Control and Prevention of Legionella in Water Systems] ] about the actions to be taken to limit the number of colony forming units (i.e., the aerobic count) of micro-organisms per mL at 30 °C (minimum 48 hours incubation):

Aerobic count, cfu/ml at 30 °C (minimum 48 hours incubation). Colony count determined by pour plate method according to ISO 6222(21) or by spread plate method on yeast extract agar.

Legionella, bacteria cfu/litre. Determined in accordance with ISO 11731(20).

Expect to find Legionella CFUs because almost all natural water sources contain Legionella. Legionella samples need to be run within 24 hours. Samples should be kept cold with ice packs, but not frozen, and should remain upright.

Guidelines for control of "Legionella" in cooling towers

Many governmental agencies, cooling tower manufacturers and industrial trade organizations have developed design and maintenance guidelines for preventing or controlling the growth of "Legionella" in cooling towers. Below is a list of sources for such guidelines:

* [http://www.cti.org/downloads/WTP-148.pdf Cooling Technology Institute] - Best Practices for Control of Legionella, July 2006. [Page 6 of 12] As a minimum control ... establish a free halogen residual of at least 1.0 ppm and hold this residual for no less than one hour each day.
* [http://spxcooling.com/pdf/guide12.pdf SPX (Marley) Cooling Technologies] - ASHRAE Guideline 12-2000 - Minimizing the Risk of Legionellosis
* [http://www.ewgli.org/data/european_guidelines/eg_supplement1a.pdf EWGLI] Technical Guidelines for the Control and Prevention of Legionella in Water Systems
* [http://www.cdc.gov/ncidod/dhqp/pdf/guidelines/Enviro_guide_03.pdf Centers for Disease Control and Prevention] - Procedure for Cleaning Cooling Towers and Related Equipment (pages 239 and 240 of 249)
* [http://www.osha.gov/dts/osta/otm/legionnaires/cool_evap.html#Maintenance OSHA - How to maintain these systems - Frequency of cleaning]
* [http://www.osha.gov/dts/osta/otm/otm_iii/otm_iii_7.html OSHA page on Legionellosis] - US Occupational Safety and Health Administration
* [http://www.awt.org/Legionella03.pdf Association of Water Technologies] - Legionella 2003
* [http://www.energy.ca.gov/2005publications/CEC-700-2005-025/CEC-700-2005-025.PDF California Energy Commission] - Cooling Water Management Program Guidelines For Wet and Hybrid Cooling Towers at Power Plants
* [http://spxcooling.com/pdf/M06-1310.pdf SPX (Marley) Cooling Technologies] - Cooling Towers Maintenance Procedures
* [http://www.marleyct.com/catlinks/M92-1474C.pdf Marley Cooling Technologies] - Cooling Tower Inspection Tips {especially page 3 of 7}
* [http://www.towertechinc.com/documents/Legionella_Control_White_Paper_05072004.pdf Tower Tech Modular Cooling Towers] - Legionella Control
* [http://www.gewater.com/pdf/tech73.pdf GE Infrastructure Water & Process Technologies Betz Dearborn] - Chemical Water Treatment Recommendations For Reduction of Risks Associated with Legionella in Open Recirculating Cooling Water Systems
*Wisconsin Division of Health, "Control of Legionella in Cooling Towers: Summary Guidelines", June 1987, Wisconsin Department of Health and Social Sciences.

Guidelines for control of "Legionella" in ornamental fountains

Indoor ornamental fountains have been confirmed as a cause of legionnaires' disease outbreaks. In all documented cases submerged lighting as a heat source was attributed to the outbreak. Controlling the growth of "Legionella" in ornamental fountains is lightly mentioned in many of the above listed guidlines. Below is a link to the one guideline specifically developed for ornamental fountains which discusses in detail the types of fountains, their inherent risks and methods for legionella control:

* [http://www.legionellae.org/guidelines/guidelines.htm Legionella Risk Management] - Guidelines for Control of Leginella in Ornamental Features, December 2005.

Regulations and ordinances

The guidance issued by the UK government's Health and Safety Executive (HSE) now recommends that microbiological monitoring for wet cooling systems, using a dip slide, should be performed weekly. The guidance now also recommends that routine testing for legionella bacteria in wet cooling systems be carried out at least quarterly, and more frequently when a system is being commissioned, or if the bacteria has been identified on a previous occasion. [ [http://www.hse.gov.uk/lau/lacs/46-2.htm#para8 UK: Health and Safety Executive Microbiological monitoring (weekly dip slide)] ]

The City of Garland, Texas requires yearly testing for legionella bacteria at cooling towers at apartment buildings. [ [http://www.dallasnews.com/sharedcontent/dws/news/localnews/stories/DN-legionella_01eas.ART0.East.Edition1.29739cd.html The Dallas Morning News, Garland tough on bacteria] ]

Malta requires twice yearly testing for legionella bacteria at cooling towers and water fountains. Malta prohibits the installation of new cooling towers and evaporative condensers at health care facilities and schools. [ [http://www.doi.gov.mt/EN/legalnotices/2006/01/LN5.pdf MALTA Control of Legionella Regulations, 2006] ]

ee also

*Cooling towers


External links

* [http://www.who.int/water_sanitation_health/emerging/legionella.pdf WHO LEGIONELLA and the prevention of legionellosis 2007, 276 Pages]
* [http://www.idph.state.il.us/public/hb/hblegion.htm Illinois Department of Public Health page on Legionellosis]
* [http://www.educatedearth.net/video.php?id=3630 Video on how Legionella pneumophila infects the body]
* [http://www.astdhpphe.org/infect/legion.html Directors of Health Promotion and Education page on Legionellosis]
* [http://www.ewgli.org/ European Working Group for Legionella Infections]
* [http://www.legionellae.org/guidelines/guidelines.htm Listing of Legionella guidelines]
* [http://www.hcinfo.com/outbreaks-news.htm Recent Outbreaks of Legionnaires' disease]
* [http://www.multiline.com.au/~mg/legionella.Murcia.Spain1.html Legionella outbreak in Murcia, Spain, 28 June to 14 July 2001]
* [http://www.aftenposten.no/english/local/article1046216.ece River Glomma may have spread the Disease]
* [http://www.hse.gov.uk/legionnaires/barrowreport.pdf Report of the public meetings into the legionella outbreak in Barrow-in-Furness, August 2002]

Images of "Legionella" bacteria:

* http://www.repower.ch/INimg/Newsletter/legionella.jpg
* http://newsimg.bbc.co.uk/media/images/38922000/jpg/_38922367_legionella203.jpg
* http://www.q-net.net.au/~legion/Legionnaires_Disease_Bugs_Of_This_World.htm

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