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The Centre for Health Protection (CHP) of the Department of Health today (June 27) provided an update on its investigation into an earlier case of Legionnaires' Disease (LD) involving a 64-year-old man.
The patient, with an underlying illness, presented with fever and cough on May 28 and was diagnosed as having LD on June 14. He is currently in stable condition. During the incubation period, the patient had stayed in Tuen Mun Hospital (TMH) for a few days apart from staying at home and travelling to Dongguan.
In relation to the investigation into the possible source of infection in this case, the CHP collected water samples and environment samples from the hospital and the patient's residence. Preliminary laboratory results for two (collected from the same site) out of six pairs of water samples taken from water outlets in TMH revealed the presence of Legionella species (Group One Legionella pneumophila), the bacteria linked to LD. The levels ranged from 1 to 1.2 colony-forming units per millilitre (cfu/ml). Laboratory testing is ongoing.
"As Legionella bacteria can be widely found in the environment, a causal relationship between the case and the preliminary laboratory finding in the hospital water samples cannot be established at this juncture. Further laboratory investigation, including genetic characterisation, is needed to draw a more solid conclusion on the source of infection," a CHP spokesman remarked.
Meanwhile, the CHP and TMH are enhancing medical surveillance in the ward 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 to 1 cfu/ml.
The CHP has advised TMH on appropriate follow-up measures, including the suspension of related water supply facilities for disinfection. TMH has also stepped up relevant infection control measures.
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. The public may visit the website of the Electrical and Mechanical Services Department (www.emsd.gov.hk/emsd/eng/pps/oa_ld_pub_cp.shtml) for the Code of Practice issued by the Prevention of LD Committee, Hong Kong.
Ends/Thursday, June 27, 2013
Issued at HKT 21:12
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