Press Release

CHP investigates case of Legionnaires' disease in hospital

17 June 2016

The Centre for Health Protection (CHP) of the Department of Health is today (June 17) investigating a case of Legionnaires' disease (LD) in St Teresa's Hospital (STH), and stressed the importance of using and maintaining properly designed man-made water systems and that susceptible groups should strictly observe relevant precautions.

The male patient, aged 59, has been admitted to STH for management of his underlying illnesses since mid-December 2015. He has developed oxygen desaturation since June 8, 2016, and was transferred to the Special Care Unit for further treatment on the same day. The clinical diagnosis was pneumonia and he was in critical condition.

His tracheal aspirate tested positive for Legionella pneumophila (non-serogroup 1) upon laboratory testing by Queen Mary Hospital.

The patient had no travel history during the incubation period.

"Epidemiological investigations with STH are ongoing to identify potential sources of infection, high-risk exposure and clusters, if any. Relevant water samples and environmental swabs will be collected from potential sources for laboratory testing," a spokesman for the CHP said.

Tracing of contacts including staff and in-patients therein is ongoing and STH has been put under medical surveillance. The CHP has provided health advice against LD to staff and in-patients, including those with weakened immunity who should use sterile or boiled water for drinking, tooth brushing and mouth rinsing.

To date, a total of 27 LD cases (26 community-acquired cases and the above institutional case) have been reported in 2016. In 2015 and 2014, there were 66 and 41 cases respectively.

Legionellae are found in various environmental settings and grow well in warm water (20 to 45 degrees Celsius). They can be found in aqueous environments such as water tanks, hot and cold water systems, cooling towers, whirlpools and spas, water fountains and home apparatus that support breathing. People may get infected when they breathe in contaminated droplets (aerosols) and mist generated by artificial water systems. They may also get the infection when handling garden soil, compost and potting mixes.

Persons with weakened immunity should strictly observe the health advice below:

• Use sterile or boiled water for drinking, tooth brushing and mouth rinsing;
• Avoid using humidifiers, or other mist- or aerosol-generating devices. Showers may also generate small aerosols; and
• If using humidifiers, or other mist- or aerosol-generating devices, fill the water tank with only sterile or cooled freshly boiled water, and not water directly from the tap. In addition, clean and maintain humidifiers/devices regularly according to manufacturers' instructions. Never leave stagnant water in a humidifier/device. Empty the water tank, wipe all surfaces dry, and change the water daily.

The public, including susceptible groups, should take heed of the general precautions against LD below:

• Observe personal hygiene;
• Do not smoke and avoid alcohol;
• Remove strainers in water taps and shower heads quarterly for cleaning;
• If a fresh water plumbing system is properly maintained, it is not necessary to install domestic water filters. Use of water filters is not encouraged as clogging occurs easily, which can promote growth of microorganisms. If water filters are used, the pore size should be 0.2 micrometres and they need to be changed periodically;
• Drain and clean water tanks of buildings at least quarterly;
• Drain or purge for at least one minute the infrequently used water outlets (e.g. water taps, shower heads and hot water outlets) and stagnant points of the pipework weekly or before use;
• Seek and follow medical advice regarding the use and maintenance of home respiratory devices and use only sterile (not distilled or tap) water to clean and fill the reservoir. Clean and maintain the device regularly according to the manufacturer's instructions. After cleaning/disinfection, rinse the device with sterile water, cooled freshly boiled water or water filtered with 0.2-micrometre filters. Never leave stagnant water in the device. Empty the water tank, keep all surfaces dry, and change the water daily; and
• When handling garden soils, compost and potting mixes:

         1. Water gardens and compost gently using low pressure;
         2. Open composted potting mixes slowly and make sure the opening is directed away from the face;
         3. Wet the soil to reduce dust when potting plants; and
         4. Avoid working in poorly ventilated places such as enclosed greenhouses.

More information is available at the webpages below:

• The CHP's LD page (This link will open in a new windowwww.chp.gov.hk/en/view_content/24307.html);
• The Code of Practice for Prevention of LD of the Prevention of LD Committee (This link will open in a new windowwww.emsd.gov.hk/en/supporting_government_initiatives/legionnaires_disease/publications/codes_of_practice/index.html);
• The Housekeeping Guidelines for Cold and Hot Water Systems for Building Management (This link will open in a new windowwww.emsd.gov.hk/en/supporting_government_initiatives/legionnaires_disease/publications/general/index.html); and
• The CHP's risk-based strategy for prevention and control of LD (This link will open in a new windowwww.chp.gov.hk/en/view_content/42729.html).