person transmission has been reported and it occurred in Portugal ( Correia et al ., 2016 ).
While anyone can develop legionnaires ’ disease , some common risk factors for developing an infection include the following : age (> 50 years ), gender ( male ), smoking habits , existing lung conditions ( for example asthma , chronic obstructive pulmonary disease ), previous use of beta-lactam antibiotics , immunosuppressed or immunocompromised status ( such as persons receiving transplants or chemotherapy ; those with kidney disease , diabetes , or AIDS ), and recent surgery or intubation ( Health Canada , 2013 ; Viasus et al ., 2013 ; Newton et al ., 2010 ; WHO , 2007 ; Stout and Yu , 1997 ). The percentage of fatalities from reported cases of legionnaires ’ disease increased with age (> 50 years ) and showed a similar pattern for males and females ( ECDC , 2016 ).
Hospitalisation costs due to legionellosis in the United States are estimated at USD433- million per year ( Collier et al ., 2012 ). Fatality rates are estimated to be 5 – 30 % ( Kutty , 2015 ). The costs associated with loss of productivity and deaths are not included in these estimates and are likely to be significant . Between 3 000 and 4 000 cases of legionellosis are reported to the United States ’ Centres for Disease Control and Prevention ( CDC ) each year . However , the actual number of hospitalised cases is estimated to be between 8 000 and 18 000 ( Kutty , 2015 ; CDC , 2012 ; Marston et al ., 1997 ), since many cases of pneumonia are empirically treated with antibiotics and never tested for legionella ( CDC , 2011 ; Marston et al ., 1997 ).
Legionella has been found in public water systems . Environmental conditions and processing of the water once it enters a building can lead to the growth of legionella , which could result in increased risk of infection . The CDC has identified environmental conditions within premise plumbing as the leading cause of the legionella outbreaks reported between 2009 and 2012 ( CDC , 2015 ; CDC , 2013 ).
The purpose of this document is to summarise the current body of knowledge on the effectiveness of different approaches to control legionella growth in large buildings .
As a result of legionella outbreaks and the potential for legionella to grow in premise plumbing of buildings , many facility owners or operators have decided to take measures to control or mitigate legionella growth . This document summarises information on several legionella control technologies , including :
• Risk management approaches ( including temperature control )
• Chlorine dioxide
This document describes different type of studies , which include laboratory , field , premise plumbing , and distribution system based studies .
• Copper-silver ionization
• Ultraviolet light
• Ozone .
This document provides information on other control technologies that are often used for emergency remediation : superheat-and-flush , shock hyperchlorination , and point-of-use filtration .
A summary of the literature for each technology is provided . The summary includes information about the effectiveness of the technology against legionella , potential water quality impacts that may result from using the technology , and operational considerations .
This document describes different type of studies , which include laboratory , field , premise plumbing , and distribution system based studies . The results from the different type of studies may not be directly comparable to one another given the differences in experimental conditions .
Discussions of legionella control issues related to cooling towers and other systems within the building that do not deliver water for human consumption are not within the scope of this document . The EPA defines human consumption as “ drinking , bathing , showering , hand washing , teeth brushing , food preparation , dishwashing and maintaining oral hygiene ”.
The next issue of Water , Sewage and Effluent will look at occurrence and risk , as well as the regulatory and enforcement context . u
For more information about the Legionella Action Group , contact Rob Stewart on + 27 ( 0 ) 11 489 8578 . networking tech news environment industry infrastructure municipalities
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