Hong Kong's Centre for Health Protection, part of the Department of Health, reported on September 14 one community-acquired Legionnaires' disease case for the September 6 to 12 period. The patient is a 73-year-old man with underlying illnesses who lives in Southern District. Initial investigation indicated a sporadic case, with no epidemiological links established to other confirmed cases previously recorded in Hong Kong. Epidemiological investigations are under way to identify potential sources of infection and high-risk exposure.

As of September 12, 140 Legionnaires' disease cases had been recorded this year. The figures for 2025 and 2024 were 167 and 135 respectively. The department noted that men, people aged over 50, smokers, people who consume alcohol heavily and persons with weakened immunity are more susceptible, and listed risk situations including poorly maintained water systems and recent hotel or ship stays. Legionellae grow well in warm water of 20 to 45 degrees Celsius and can spread through contaminated droplets and mist from artificial water systems, or through handling garden soil, compost and potting mixes.

The department advised the public on personal hygiene, regular cleaning of taps and shower heads, quarterly draining and cleaning of building water tanks, and weekly flushing of infrequently used outlets. It also issued precautions for immunocompromised people on humidifiers and home respiratory devices, and urged smokers to quit and people to avoid alcohol.