The Centre for Health Protection (CHP) of the Department of Health today reported the latest number of cases of Legionnaires’ disease (LD) in Hong Kong, and stressed the importance of using and maintaining properly designed man-made water systems, and that susceptible groups should strictly observe relevant precautions.

Legionella pneumophila bacteria/CDC
Legionella pneumophila bacteria/CDC

From March 12 to 18, one community-acquired LD case was reported. The male patient aged 77 with underlying illnesses lives in Hung Shek House, Ping Shek Estate, Kwun Tong.

“Epidemiological investigations are under way to identify potential sources of infection, high-risk exposure and clusters, if any,” a spokesman for the CHP said.

As of March 18, a total of 11 LD cases had been reported in 2017. In 2016 and 2015, there were 75 and 66 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.