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A spokesman for the Centre for Health Protection (CHP) of the Department of Health said today (January 2) that final laboratory results on the water samples taken from the water tap at a private washroom inside a 67-year-old male patient¡¦s office confirmed the preliminary ones announced earlier, with the level of Legionella species (including Legionella pneumophila serogroup 1) to range from 0.7 to 14.2 cfu/ml.
Legionnaires' Disease (LD) is usually caused by Legionella pneumophila serogroup 1.
No Legionella bacteria was detected in the water samples collected at the water tank of the same building, suggesting that the water source is free from contamination.
Water samples collected at the patient's residence were all negative for Legionella bacteria.
According to international standards, immediate control measures including disinfection should be taken when the levels for Legionella bacteria in hot and cold water systems exceed 0.1 -1 cfu/ml.
"The CHP has advised the building's management office on appropriate follow up actions including disinfection and risk mitigation measures.
"Disinfection of the office building by the Architectural Services Department will be completed early tomorrow morning. The CHP will subsequently collect post-disinfection water samples tomorrow," the spokesman said.
Legionella bacteria are found in various environmental settings and grow well in warm water (25 to 40 degrees Celsius). They can be found in aqueous environments such as water tanks, cooling towers, whirlpool and spas, water fountains and apparatus that support breathing. Proper design, operation and maintenance of man-made water systems could prevent LD.
For more information about proper design, operation and maintenance of man-made water systems, please visit the EMSD's website (www.emsd.gov.hk) for the Code of Practice issued by the Prevention of LD Committee.
Investigation continues.
Ends/Monday, January 2, 2012
Issued at HKT 13:14
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