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The Centre for Health Protection (CHP) of the Department of Health today (September 3) provided an update on its investigation into an earlier case of Legionnaires' Disease (LD) involving a 68-year-old man.
The patient, who had a chronic medical condition, had onset of fever, cough and shortness of breath on August 18 and was diagnosed as having Legionnaires' Disease on August 24. During the incubation period, besides staying at home, the patient had stayed for a few days in two wards of Pamela Youde Nethersole Eastern Hospital (PYNEH).
In relation to the investigation of the possible source of infection of this case, the CHP collected water samples and environment samples from the hospital and the patient's residence. Preliminary laboratory results for three out of eight pairs of water samples taken from water outlets in two wards of PYNEH where the patient had stayed during the incubation period revealed the presence of Legionella species (Group-one Legionella pneumophila), the bacteria linked to LD. The levels ranged from 0.1 to 0.5 cfu/ml, and this may change over the next few days when final laboratory results become available.
"Up till now, no Legionella pneumophila was detected in the water samples at the water tank of the hospital, nor at the patient's residence. Laboratory testing is ongoing. As Legionella bacteria can be widely found in the environment, we cannot establish at this juncture a causal relationship between the case and the preliminary laboratory finding in the hospital water samples. Further laboratory investigation, including genetic characterisation, is needed to draw a more solid conclusion on the source of infection," the spokesman said.
Meanwhile, the Centre and PYNEH are enhancing medical surveillance in wards where the patient stayed. So far, no additional cases have been identified.
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 PYNEH on appropriate follow-up measures, including the suspension of related water supply facilities for disinfection. PYNEH has also stepped up relevant infection control measures.
The patient's current condition is stable.
Legionella bacteria are found in various environmental settings and grow well in warm water (25 degrees Celsius to 40 degrees Celsius). They can be found in moist environments such as water tanks, cooling towers, whirlpools and spas, water fountains and apparatus that support breathing. Proper design, operation and maintenance of man-made water systems can prevent LD. For more information, please visit the website of the Electrical and Mechanical Services Department for the Code of Practice issued by the Prevention of LD Committee (www.emsd.gov.hk/emsd/eng/pps/oa_ld_pub_cp.shtml).
Ends/Monday, September 3, 2012
Issued at HKT 19:50
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