Hong Kong reports three new Legionnaires’ disease cases in one week
Hong Kong’s Centre for Health Protection recorded three community-acquired Legionnaires’ disease cases between October 18 and 24, involving men aged 36 to 83. The authority advises vulnerable groups to avoid smoking and alcohol, maintain water systems, and follow hygiene guidelines.
Hong Kong’s Centre for Health Protection (CHP) recorded three new community-acquired cases of Legionnaires’ disease between 18 and 24 October, the Department of Health announced on 26 October. All three patients were men, aged 36, 71 and 83. The 36-year-old, from Yuen Long district, has a history of past smoking. The 71-year-old, from Kwai Tsing district, and the 83-year-old, from Tuen Mun district, both have underlying chronic illnesses.
The CHP has launched epidemiological investigations to identify possible infection sources and high-risk exposures. Preliminary findings indicate the cases are sporadic, with no epidemiological link to earlier confirmed cases in Hong Kong. As of 24 October, 163 cases of Legionnaires’ disease have been recorded this year, compared with 167 in 2025 and 135 in 2024.
Legionnaires’ disease more commonly affects men, people aged 50 or above, smokers, heavy drinkers and those with weakened immune systems. Additional risk factors include poorly maintained water supply systems, use of old-style plumbing, proximity to cooling towers or fountains, use of electric water heaters, spa pools or hot springs, and recent stays in hotels or on ships.
The bacterium Legionella thrives in warm water between 20°C and 45°C. It can survive in water tanks, hot and cold water systems, cooling towers, spa pools, fountains, humidifiers and home respiratory medical devices. Infection occurs when people inhale contaminated water droplets or mist from artificial water systems, or when handling garden soil, compost or potting mix.
Health officials advise immunocompromised individuals to use sterile or boiled water for drinking, brushing teeth and rinsing; avoid using humidifiers or mist-generating devices; or if using such devices, fill them only with sterile or freshly boiled water, clean them regularly according to manufacturer instructions, and empty and dry the water container daily. The general public is urged to practise good personal hygiene, refrain from smoking and limit alcohol consumption.
Other recommendations include regularly checking, cleaning and descaling faucet and showerhead filters; draining and cleaning building water tanks at least quarterly; flushing little-used outlets weekly; and following medical advice for home respiratory devices, using only sterile water. When handling garden soil or compost, the public should wear gloves and a mask, use low water pressure, open compost bags away from the face, dampen soil to reduce dust, and avoid poorly ventilated areas.
The government reiterated that smokers and heavy drinkers are more susceptible to the disease. It encouraged smokers to call the DH Integrated Smoking Cessation Hotline (1833 183) for professional counselling and referral to free cessation services, and to visit the Live Tobacco Free website. Information on alcohol-related harm is available on the DH’s ‘Live a New Healthy Direction’ website.
