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LC Urgent Q1: Legionella bacteria found at the new CGC and LegCo Complex

     Following is a question by Dr Hon Joseph Lee under Rule 24(4) of the Rules of Procedure and a reply by the Chief Secretary for Administration, Mr Stephen Lam, in the Legislative Council today (January 11):


     The new Central Government Complex ("new CGC") and the Legislative Council Complex ("LegCo Complex") were completed only half a year ago, yet after the Secretary for Education was confirmed to have contracted Legionnaires' disease, Legionella bacteria have recently been found on various floors of the new CGC and LegCo Complex, involving such important institutions as the Executive Authorities and the Legislature as well as various government departments, and the impact is extensive.  In this connection, will the Government inform this Council:

(a) of the reasons why Legionella bacteria have been found at the new CGC and LegCo Complex which were completed only half a year ago; whether problems exist during the construction as well as inspection and acceptance procedures; whether the authorities will take remedial measures immediately to prevent the spread of Legionella bacteria and outbreak of the disease; moreover, whether the authorities have any preventive measures in place to prevent other people from Legionella bacteria infection;

(b) as the locations affected are where important executive and legislative institutions of Hong Kong are accommodated, involving senior government officials and staff of various government departments, affecting governance and having extensive impact, whether the authorities will immediately conduct health assessments for the personnel concerned to ensure their safety; furthermore, whether the authorities have formulated contingency measure in case of a major outbreak; if they have, of the details; if not, the reasons for that; and

(c) to safeguard public safety and interest, whether the authorities will immediately conduct relevant assessments on the buildings of the Executive Authorities, the Legislature and the Judiciary of the whole territory, as well as on public places and buildings, and take preventive measures to prevent the recurrence of a similar incident; if they will, of the details; if not, the reasons for that?



     My reply to Dr Hon Joseph Lee's question is as follows íV

(a) Legionnaire's Disease (LD) is an infectious disease caused by Legionella bacteria.  The bacteria are naturally occurring in various aqueous environments and grow well in warm water (25 to 40 degrees Celsius).  LD is not transmitted by person-to-person contact or through eating or drinking.

     On December 21, 2011, the Centre for Health Protection (CHP) was notified of a case of LD involving a 67 year-old gentleman working in the Central Government Offices (CGO) at Tamar.  On December 22, 2011, CHP visited the patient's office at Tamar and collected a total of five water samples for testing.  On December 28, 2011, preliminary test results of the water samples obtained from the water tap of the patient's private toilet in office suggested the presence of Legionella bacteria, the bacteria that causes LD.  As a precautionary measure, CHP collected a total of 38 water samples from CGO, Chief Executive's Office (CEO) and LegCo Complex on December 28 and 29,2011.  

     As soon as the preliminary test results of the first batch of water samples from CGO were known, the Administration arranged a thorough disinfection for CGO, which commenced in the evening of December 30, 2011 and completed in the early hours of January 3, 2012.  

     Soon after the preliminary test results of the water samples in CEO, LegCo Complex and Tamar Park were known, the Administration also arranged a thorough disinfection for the concerned areas on January 3, 2012.  The disinfection was completed in phases with the last one finished on January 8, 2012.

     Following the disinfection exercise, the Architectural Services Department, Water Supplies Department and CHP have conducted systematic post-disinfection sampling of water samples at CGO, LegCo Complex, CEO and the Tamar Park to ensure that Legionella bacterial count has returned to normal levels.  Moreover, Professor Yuen Kwok-yung of the Department of Microbiology of the University of Hong Kong has also assisted in the testing of the post-disinfection water samples.  He has identified only a small amount of genetic fragment of Legionella bacteria in one out of 227 samples extracted from shower heads and water taps.

     The design, materials, installation and testing (including handover procedures) of the whole water supply system in the Tamar are in compliance with the current legislation and in line with other government and private projects.  

     Based on the current available information, probable causes on the presence of Legionella bacteria in the pipes can be identified as follows -

(i) The majority of the water samples with positive Legionella bacteria results are collected from outlets of low utilisation, e.g. private toilets of the Directors of Bureaux and kitchen sinks infrequently used.  The water in the water pipes connecting to these outlets is kept in stagnant condition for a long period.  Stagnant water has a higher chance to become a medium for breeding Legionella bacteria;

(ii) Hot water supply pipes in the fresh water supply system are insulated.  Insulated pipework can keep warm water inside the pipe for a longer period of time.  The amount of warm water retained in pipework increases with the length of pipework between heater and water outlets; and

(iii) A combination of the two factors in (i) and (ii) could provide a favourable breeding environment for Legionella bacteria which grow well in water of 25 to 40 degrees Celsius.  Therefore, water inside pipework connected to outlets of low utilisation and with hot water supply could easily become breeding ground for Legionella bacteria.

     In order to minimise the risk of Legionella bacteria, we will prepare housekeeping guidelines to advise building management and users on the need of regular cleansing and flushing programme for water taps and shower heads.  In particular, hot water outlets which are infrequently used should be flushed for a period of time before use to reduce the stagnant water inside the pipework.

(b) LD is a statutorily notifiable infectious disease.  CHP will conduct epidemiological investigation for each case, including examining places the patient has visited or come across in order to track the source of infection. In response to this incident in which a colleague in CGO was infected, CHP undertook epidemiological investigation, sampling and study in accordance with normal practice.

     Upon the discovery of the Legionella bacteria on December 21, 2011, CHP issued a press release to remind the members of the public to be vigilant about LD.  In view of the concerns of staff in CGO and LegCo Complex, CHP has prepared health education leaflets on health advice on LD.  It has also conducted health talks and briefings for Government employees, media, LegCo Members and journalists.  One may also call the CHP hotline (2125 1122) to enquire about issues related to LD.

     Moreover, colleagues in CGO and LegCo Complex who do not feel well may seek assistance from healthcare workers in the designated help desk at the Accidents and Emergency Department (A&ED) of Ruttonjee Hospital.  There has not been any new case of LD since the set-up of the help desk at 2pm on January 4.  The on-duty healthcare workers in the A&ED of all hospitals have also undertaken corresponding preparations to handle suspected LD cases expeditiously.

     The Administration Wing has, on the advice of CHP, taken precautionary measures in CGO.  These include installing filters in all pantries, providing alcohol-based handrub facilities in the toilets of various floors and lift lobbies as well as other communal areas, reminding staff to temporarily stop the use of aerosol generating devices (e.g. shower, steamer etc.) and to clean water outlets regularly to avoid the stagnation of water within pipes.

(c) In the past two years, the number of reported LD cases has remained stable and all the reported cases were sporadic cases.

     In addition, we have invited Professor Yuen Kwok-yung of the Department of Microbiology of the University of Hong Kong to help investigate the issue of the presence of Legionella bacteria at Tamar.  His preliminary finding does not suggest any special abnormality and the concerned problem has basically been resolved following the disinfection work.  Professor Yuen is of the view that it is unnecessary to monitor Legionella bacteria in various types of buildings regularly unless a case has been found.  That said, we will discuss with experts, including those from the Prevention of Legionnaire's Disease Committee, on possible improvement measures to prevent the recurrence of similar incidents.

Ends/Wednesday, January 11, 2012
Issued at HKT 14:39


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