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| {{Infobox_Disease | | | {{Infobox_Disease | |
| Name = Legionellosis | | | Name = Legionellosis | |
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| ==Overview== | | ==[[Legionellosis overview|Overview]]== |
| '''Legionellosis''' is an [[infectious disease]] caused by [[bacteria]] belonging to the [[genus]] ''[[Legionella]]''.<ref name=Sherris>{{cite book | author = Ryan KJ, Ray CG (editors) | title = Sherris Medical Microbiology | edition = 4th ed. | publisher = McGraw Hill | year = 2004 | isbn = 0838585299 }}</ref> 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).<ref>[http://www.cdc.gov/ncidod/dbmd/diseaseinfo/legionellosis_t.htm CDC: Etiologic Agent]</ref>
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| Legionellosis takes two distinct forms: | |
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| * ''Legionnaires' disease'' is the more severe form of the infection and produces [[pneumonia]].<ref name=Baron>{{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 }}</ref>
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| * ''Pontiac fever'' is caused by the same bacterium, but produces a milder [[upper respiratory infection|respiratory illness]] without pneumonia which resembles [[Acute (medicine)|acute]] [[influenza]].<ref name=Baron />
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| Legionnaires' disease acquired its name in 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''.
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| An estimated 8,000 to 18,000 people get legionellosis in the United States each year.<ref> [http://www.cdc.gov/ncidod/dbmd/diseaseinfo/legionellosis_t.htm CDC: Incidence]</ref> Some people can be infected with the ''Legionella'' bacterium and have only mild symptoms or no illness at all.
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| 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.
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| == Epidemiology and Demographics ==
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| ===Infection in the U.S.:===
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| Each year, between 8,000 and 18,000 people are hospitalized with Legionnaires' disease in the U.S. However, many infections are not diagnosed or reported, so this number may be higher. More illness is usually found in the summer and early fall, but it can happen any time of year.
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| LD is a reportable condition in most states; because of under-diagnosis and underreporting, however, only 2%-10% of estimated cases are reported.
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| ===Worldwide infection:===
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| Below is a list of Legionnaires' disease outbreaks, followed by a discussion of many of them:
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| {| class="wikitable"
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| ! Suspected Source !! Cases !! Deaths !! Date !! Location
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| |Cooling Tower||align=right|18||align=right|2||July - August 2007||Benalmadena, Spain
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| |Institute of Animal Health||align=right|1+||align=right|0||2007||Pirbright, Surrey, UK
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| |Water supply ||align=right|167||align=right|5||July - August 2007||Verkhnyaya Pyshma, Sverdlovsk oblast, Russia <ref>[http://gzt.ru/incident/2007/07/30/105145.html The cause of the pneumonia outbreak in Sverdlovskaya oblast is Legionella bacterium (in Russian)]</ref>
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| |Cooling tower ||align=right|7||align=right|0||31st Dec 2006 - 1st Jan 2007||Australia, Sydney <ref>[http://www.hcinfo.com/outbreaks-news.htm#0701Sydney HC INFO- Recent Outbreaks of Legionnaires' Disease, Sydney,6 Cases, Jan. 2007]</ref>
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| |Spa Pool ||align=right|115||align=right|0||August 2006||Sunderland, UK
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| |Cooling tower ||align=right|26||align=right|2||July - Sept 2006||Paris, France
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| |Cooling tower ||align=right|30||align=right|2||July 2006||Amsterdam, Netherlands
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| |Cooling towers||align=right|149||align=right|0||June 2006||Pamplona, Spain
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| |Cooling tower||align=right|10||align=right|1||February 2006||Sydney, Australia
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| |Cooling tower||align=right|20||align=right|0||December 2005||Torrevieja, Spain
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| |Cooling tower||align=right|127||align=right|21||October 2005||Toronto, Canada
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| |Cooling tower||align=right|21||align=right|0||June 2005||New Rochelle, NY, USA
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| |Indoor ornamental fountain||align=right|17||align=right|1||Summer 2005||Rapid City, South Dakota|Rapid City, SD, USA
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| |Air scrubber||align=right|52||align=right|10||May 2005||Fredrikstad, Norway
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| |Cooling tower||align=right|86||align=right|21||2004||Pas-de-Calais, France
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| |Cooling tower||align=right|172||align=right|7||2002||Barrow-in-Furness, UK
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| |Cooling tower||align=right|28||align=right|7||2001||Stavanger, Norway
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| |Cooling tower||align=right|449||align=right|6||July 2001||Murcia, Spain
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| |Whirlpool and humidifier||align=right|200||align=right|32||1999||Bovenkarspel, Netherlands
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| |Hospital||align=right|101||align=right|28||1985||Stafford, UK
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| |Cooling Tower (widely accepted)||align=right|221||align=right|34||1976||Philadelphia, PA, USA
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| |}
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| ====Philadelphia, 1976====
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| The first recognized outbreak occurred on July 27, 1976 at 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. 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.
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| Some do not believe that the air conditioning was conclusively proven to be the cause of the outbreak. According to Dr. Victor L. Yu, chief of the infectious disease section at the Oakland Veterans Affairs Medical Center in Pittsburgh, researchers still haven’t identified the exact source.<ref>[http://www.q-net.net.au/~legion/Legionnaires_Disease_Worlds_First_Outbreak.htm Legionnaires' disease First Outbreak]</ref> Morbidity and Mortality Weekly Report (MMWR), a weekly publication of the US Centers for Disease Control and Prevention (CDC), stated in 1977 that no source was found in this first outbreak of Legionnaires' disease at the Bellevue Stratford Hotel.<ref>[http://www.cdc.gov/mmwr/preview/mmwrhtml/00045731.htm MMWR, January 18 1977, (reprinted January 24 1997 Vol 46(03); 50-56) special issue, Epidemiologic Notes and Reports Follow-up on Respiratory Illness --Philadelphia]</ref><ref>[http://justice.loyola.edu/~klc/BL472/Legionnaire/history.html History of Outbreak at Bellevue Stratford Hotel]</ref>
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| ====United Kingdom, 1985====
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| 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.
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| ====Netherlands, 1999====
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| 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.<ref>[http://www.q-net.net.au/~legion/Legionnaires`_Disease_Netherlands_1999.htm The Westfriese Flora flower exhibition and fair]</ref>
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| ====Spain, 2001====
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| 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%).
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| 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.
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| ====Norway, 2001====
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| 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 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.
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| ====United Kingdom, 2002====
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| 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.
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| ====France, 2004====
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| 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.<ref>[http://members.dodo.net.au/~jamgreen/legionellose_france.index.htm Norox Pas-de-Calais ]</ref>
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| ====Norway, 2005====
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| 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.<ref>[http://www.q-net.net.au/~legion/legionella_norway.htm Borregaard Sarpsborg plant in Norway]</ref>
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| ====New Zealand, 2005====
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| An outbreak of Legionnaire's 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.<ref>[http://tvnz.co.nz/view/page/410965/608556 Television New Zealand report]</ref>
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| ====Toronto, 2005====
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| In October 2005 at least 21 people died [http://english.people.com.cn/200510/25/eng20051025_216524.html] 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.
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| ====Australia, 2007====
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| 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.
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| ====New York 2007====
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| An outbreak of Legionnaire's disease occurred in Long Island, New York. It was believed to have started on September 27, 2007. It occurred in 2 separate nursing homes. 3 people have already died as of 9/27/07.
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| == Risk Factors ==
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| People most at risk of getting sick from the bacteria are older people (usually 65 years of age or older), as well as people who are smokers, or those who have a chronic lung disease (like [[emphysema]]).
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| People who have weak immune systems from diseases like [[cancer]], [[diabetes]], or kidney failure are also more likely to get sick from Legionella bacteria. People who take drugs to suppress (weaken) the immune system (like after a transplant operation or [[chemotherapy]]) are also at higher risk.
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| == Pathophysiology & Etiology==
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| ''Legionella pneumophila'' and other Legionella species. At least 46 species and 70 serogroups have been identified. ''L.pneumophila'', an ubiquitous aquatic organism that thrives in warm environments (32°- 45°C) causes over 90% of LD in the United States. The disease has two distinct forms:
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| *Legionnaires' disease, the more severe form of infection which includes pneumonia, and
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| *Pontiac fever, a milder illness.
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| *Pontiac fever and Legionnaires’ disease may also be called “Legionellosis” (LEE-juh-nuh-low-sis) separately or together.
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| ===How do people get Legionnaires’ disease?===
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| People get Legionnaires' disease when they breathe in a mist or vapor (small droplets of water in the air) that has been contaminated with the bacteria. One example might be from breathing in the steam from a whirlpool spa that has not been properly cleaned and disinfected.
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| The bacteria are NOT spread from one person to another person.
| | ==[[Legionellosis classification|Classification]]== |
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| Outbreaks are when two or more people become ill in the same place at about the same time, such as patients in hospitals. Hospital buildings have complex water systems, and many people in hospitals already have illnesses that increase their risk for Legionella infection.
| | ==[[Legionellosis historical perspective|Historical Perspective]]== |
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| Other outbreaks have been linked to aerosol sources in the community, or with cruise ships and hotels, with the most likely sources being whirlpool spas, cooling towers (air-conditioning units from large buildings), and water used for drinking and bathing.
| | ==[[Legionellosis pathophysiology|Pathophysiology]]== |
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| ==Symptoms== | | ==[[Legionellosis epidemiology and demographics|Epidemiology & Demographics]]== |
| Legionnaires' disease can have symptoms like many other forms of [[pneumonia]], so it can be hard to diagnose at first. Signs of the disease can include: a high [[fever]], [[chills]], and a [[cough]]. Some people may also suffer from [[muscle ache]]s and [[headache]]s. [[Chest X-ray]]s are needed to find the pneumonia caused by the bacteria, and other tests can be done on [[sputum]] (phlegm), as well as [[blood]] or [[urine]] to find evidence of the bacteria in the body. These symptoms usually begin 2 to 14 days after being exposed to the bacteria.
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| A milder infection caused by the same type of Legionella bacteria is called '''Pontiac Fever'''. The symptoms of Pontiac Fever usually last for 2 to 5 days and may also include [[fever]], [[headaches]], and [[muscle ache]]s; however, there is no pneumonia. Symptoms go away on their own without treatment and without causing further problems.
| | ==[[Legionellosis epidemiology and demographics|Risk Factors]]== |
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| 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.
| | ==[[Legionellosis screening|Screening]]== |
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| ==Infections== | | ==[[Legionellosis causes|Causes]]== |
| '''Intestinal Infections''': These may only occur as part of [[respiratory infection]]s, and where gastrointestinal symptoms have on occasion been described.
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| '''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.
| | ==[[Legionellosis differential diagnosis|Differentiating Legionellosis from other Diseases]]== |
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| '''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.
| | ==[[Legionellosis natural history|Natural History, Complications & Prognosis]]== |
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| ==Diagnosis== | | ==Diagnosis== |
| | [[Legionellosis history and symptoms|History & Symptoms]] | [[Legionellosis physical examination|Physical Examination]] | [[Legionellosis staging|Staging]] | [[Legionellosis laboratory tests|Lab Tests]] | [[Legionellosis electrocardiogram|Electrocardiogram]] | [[Legionellosis chest x ray|Chest X Ray]] | [[Legionellosis CT|CT]] | [[Legionellosis MRI|MRI]] | [[Legionellosis echocardiography or ultrasound|Echocardiography or Ultrasound]] | [[Legionellosis other imaging findings|Other Imaging Findings]] | [[Legionellosis other diagnostic studies|Other Diagnostic Studies]] |
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| The most useful diagnostic tests detect the bacteria in [[sputum]], find ''Legionella'' [[antigen]]s 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.
| | ==Treatment== |
| | | [[Legionellosis medical therapy|Medical Therapy]] | [[Legionellosis surgery|Surgery]] | [[Legionellosis primary prevention|Primary Prevention]] | [[Legionellosis secondary prevention|Secondary Prevention]] |
| == Risk Stratification and Prognosis==
| | ==Related Chapters== |
| Death occurs in 10%-15% of LD cases: a substantially higher proportion of fatal cases occur during nosocomial outbreaks. Pontiac fever is a self-limited disease that requires no treatment.
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| == Treatment == | |
| Legionnaires' disease can be very serious and can cause death in up to 5% to 30% of cases. Most cases can be treated successfully with antibiotics [drugs that kill bacteria in the body], and healthy people usually recover from infection.
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| Current treatments of choice are the respiratory tract [[quinolones]] ([[levofloxacin]], [[moxifloxacin]], [[gemifloxacin]]) or newer [[macrolides]] ([[azithromycin]], [[clarithromycin]], [[roxithromycin]]). The [[antibiotic]]s 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.<br>[[Rifampin]] 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 [[penicillin]]s, [[cephalosporin]]s, and [[aminoglycoside]]s) 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.
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| Pontiac fever requires no specific antibiotic treatment.
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| ==Prevention==
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| ====Controlling the potential growth of ''Legionella'' in cooling towers====
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| Various studies have shown that some 40 to 60% of cooling towers tested contained Legionella.<ref>[http://cti.org/cgi-bin/download.pl CTI Legionellosis Guideline: Best Practices for Control of Legionella (WTP-148) (06)]</ref>
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| 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.<ref>[http://www.nature.com/nrmicro/journal/v4/n3/full/nrmicro1368.html Long-range transmission of Legionella]</ref>
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| Temperature affects the survival of ''Legionellae'' as follows:<ref>[http://www.relianceworldwide.com/site/fs_main_home.htm What is Legionnaires' disease?]</ref>
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| <blockquote style="background: #F9F9F9; border: 1px solid black; padding: 1em; width: 60%">
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| *70 to 80 °C (158 to 176 °F): Disinfection range
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| *At 66 °C (151 °F): Legionellae die within 2 minutes
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| *At 60 °C (140 °F): Legionellae die within 32 minutes
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| *At 55 °C (131 °F): Legionellae die within 5 to 6 hours
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| *Above 50 °C (122 °F): They can survive but do not multiply
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| *35 to 46 °C (95 to 115 °F): Ideal growth range
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| *20 to 50 °C (68 to 122 °F): Legionellae growth range
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| *Below 20 °C (68 °F): Legionellae can survive but are dormant
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| </blockquote>
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| 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<ref>[http://www.ehponline.org/docs/1998/106-12/innovations.html Studying Slime Paragraph 12]</ref> <ref>[http://www.edstrom.com/Resources.cfm?doc_id=23 An Introduction to Biofilms]</ref>.
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| ====Action levels following microbial monitoring for cooling towers====
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| The European Working Group for Legionella Infections (EWGLI)<ref>[http://www.ewgli.org European Working Group for Legionella Infections]</ref> 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 )<ref>[http://www.ewgli.org/data/european_guidelines/eg_supplement1a.pdf EWGLI: Technical Guidelines for the Control and Prevention of Legionella in Water Systems]</ref> 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):<br>
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| {| class="wikitable"
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| !width=22%|Aerobic count!!Legionella!!Action required
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| |align=center|10,000 or less||1,000 or less||System under control.
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| |align=center|more than 10,000<br>up to 100,000||more than 1,000<br>up to 10,000||Review program operation. The count should be confirmed by immediate re-sampling. If a similar count is found again, a review of the control measures and risk assessment should be carried out to identify any remedial actions.
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| |align=center|more than 100,000||more than 10,000||Implement corrective action. The system should immediately be re-sampled. It should then be ‘shot dosed’ with an appropriate biocide, as a precaution. The risk assessment and control measures should be reviewed to identify remedial actions.
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| |}
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| 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
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| Legionella, bacteria cfu/litre. Determined in accordance with ISO 11731(20).
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| 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 up right.
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| ===Guidelines for control of ''Legionella'' in cooling towers===
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| 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:
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| *[http://spxcooling.com/pdf/guide12.pdf SPX (Marley) Cooling Technologies] - ASHRAE Guideline 12-2000 - Minimizing the Risk of Legionellosis
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| *[http://www.ewgli.org/data/european_guidelines/eg_supplement1a.pdf EWGLI] Technical Guidelines for the Control and Prevention of Legionella in Water Systems
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| *[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)
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| *[http://www.cti.org/downloads/legion_2000.pdf Cooling Technology Institute] - Best Practices for Control of Legionella
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| *[http://www.osha.gov/dts/osta/otm/legionnaires/cool_evap.html#Maintenance OSHA - How to maintain these systems - Frequency of cleaning]
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| *[http://www.osha.gov/dts/osta/otm/otm_iii/otm_iii_7.html OSHA page on Legionellosis] - US [[Occupational Safety and Health Administration]]
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| *[http://www.awt.org/Legionella03.pdf Association of Water Technologies] - Legionella 2003
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| *[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
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| *[http://spxcooling.com/pdf/M06-1310.pdf SPX (Marley) Cooling Technologies] - Cooling Towers Maintenance Procedures
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| *[http://www.marleyct.com/catlinks/M92-1474C.pdf Marley Cooling Technologies] - Cooling Tower Inspection Tips {especially page 3 of 7}
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| *[http://www.towertechinc.com/documents/Legionella_Control_White_Paper_05072004.pdf Tower Tech Modular Cooling Towers] - Legionella Control
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| *[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
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| *Wisconsin Division of Health, ''Control of Legionella in Cooling Towers: Summary Guidelines'', June 1987, Wisconsin Department of Health and Social Sciences.
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| ====Regulations & 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. <ref>[http://www.hse.gov.uk/lau/lacs/46-2.htm#para8 UK: Health and Safety Executive Microbiological monitoring (weekly dip slide)]</ref>
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| The City of Garland, TX requires yearly testing for legionella bacteria at Cooling towers at apartment buildings. <ref>[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]</ref>
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| 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. <ref>[http://www.doi.gov.mt/EN/legalnotices/2006/01/LN5.pdf MALTA Control of Legionella Regulations, 2006]</ref>
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| ==References==
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| {{Reflist|2}}
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| ==See also==
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| *Cooling towers | | *Cooling towers |
| *[[Legionella]] | | *[[Legionella]] |
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| [[Category:Bacterial diseases]] | | [[Category:Bacterial diseases]] |
| [[Category:Medical disasters]] | | [[Category:Medical disasters]] |
| [[Category:Infectious disease]]
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| [[Category:Pulmonology]]
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| [[Category:Overview complete]] | | [[Category:Overview complete]] |
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