Press Release
Update on CHP's investigation into Legionnaires' Disease case
3 September 2012
The Centre for Health Protection (CHP) of the Department of Health provided an update on its investigation on an earlier case of Legionnaires' Disease (LD) involving a 68-year-old man.
The patient, who had 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 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, CHP collected water samples and environment samples from the hospital and the patient’s residence. Preliminary laboratory results on the 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 pneumophilia was detected in the water samples at the water tank of the hospital, nor the patient’s residence. Laboratory testing is still on-going. As legionnaire 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 characterization, are needed to draw a more solid conclusion to 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 were 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.
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 aqueous environment such as water tanks, cooling towers, whirlpool and spas, water fountains and apparatus that support breathing. Design, operate and maintain man-made water systems properly could 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 (This link will open in a new windowwww.emsd.gov.hk/emsd/eng/pps/oa_ld_pub_cp.shtml ).