CHP investigates case of Legionnaires' disease
The male patient, aged 68 with underlying illnesses, was admitted to St Paul's Hospital (SPH) on January 2 for pneumonia and his symptoms showed improvement after treatment. He developed shortness of breath on January 19 and was transferred to the Intensive Care Unit when he developed fever on January 20. Subsequently he was transferred to Ruttonjee Hospital for further management on January 22. The patient is currently in stable condition.
Upon laboratory testing, the sputum specimen collected from the patient on January 20 tested positive for Legionella pneumophila serogroup 1, and his urine sample collected on January 21 also tested positive for Legionella pneumophila serogroup 1 antigen.
Initial enquiries revealed that the patient lived in the Mainland and travelled to Hong Kong for medical treatment on January 2.
"Epidemiological investigations with SPH are ongoing to identify potential sources of infection, high-risk exposure and clusters, if any. Relevant water samples and environmental swabs have been collected from potential sources for laboratory testing," a spokesman for the CHP said.
Tracing of contacts including staff and in-patients in SPH is ongoing and those identified have 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.
Apart from the above case, as of January 20, three LD cases had been reported in 2018. In 2017 and 2016, there were 72 and 75 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. A shower 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 micro-organisms. In case 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 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 soil, compost and potting mixes:
- Water gardens and compost gently using low pressure;
- Open composted potting mixes slowly and make sure the opening is directed away from the face;
- Wet the soil to reduce dust when potting plants; and
- Avoid working in poorly ventilated places such as enclosed greenhouses.
More information is available in the CHP's LD page, the Code of Practice for Prevention of LD and the Housekeeping Guidelines for Cold and Hot Water Systems for Building Management of the Prevention of LD Committee, and the CHP's risk-based strategy for prevention and control of LD.
Ends/Wednesday, January 24, 2018
Issued at HKT 19:50
Issued at HKT 19:50