More legionnaires' deaths spark concern
The Centre for Health Protection vowed to find the cause after the number of legionnaires' disease infections and deaths hit a new high this year.
Twenty-six cases have been reported this year. This is a sharp increase from 13 cases in the whole of last year, 11 in 2007 and 16 in 2006.
Three patients have died from the disease this year, compared with only one fatality in 2006. The death rate was about 12.5 per cent - on par with the world's average. Two of the fatal cases were men who had diabetes and were smokers. The other fatality was a 59-year-old woman who had hypertension and thyroid disease.
All of the 26 cases involved middle-aged patients who were mostly men. Only two cases were women. The youngest was 38 and the oldest 84, with a median age of about 58.
Eight people became critically ill, but only three patients remain in hospital. Sixteen have recovered.
Legionnaires' disease is a type of pneumonia that is caused by Legionella, a type of bacteria found primarily in warm water environments. The disease was named after it was discovered in connection with an American Legion Convention in Philadelphia in 1976.
A Department of Health spokesman said the exact cause of the increase in the number of infections this year was not known, and there was 'no identifiable linkage among the cases'. But he said high-risk groups included men, the elderly, smokers, chronic alcoholics and people with weak immune systems.
University of Hong Kong microbiologist Ho Pak-leung said more cases may have come to light simply because more tests were done this year, both by the department and some private hospitals.
'But that is not sufficient to explain the total picture,' he said. 'The Centre for Health Protection should seriously look into the cases. More environmental samples should be taken for laboratory tests.'
He said the centre should investigate whether the severe cases had a common source of infection by culturing bacteria from their urine samples. Professor Ho said a possible reason for the increase was the more frequent use of air conditioners. 'Legionella is commonly found in vaporised water in air-cons,' he said.