Climate change could lead to a surge in Legionnaires' disease

Rebecca Smith, Medical Editor
Last Updated: 12:01pm BST 17/09/2008

Climate change could lead to a surge in cases of Legionnaires' disease, Government scientists have warned.
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A study carried by the Health Protection Agency has found that higher temperatures and increases in humidity are linked with an increase in cases.

The study, one of the first of its kind in Europe, found that heatwaves corresponded to higher cases of the disease than periods of more stable weather.
The findings presented at the Health Protection Agency's annual conference at Warwick University found in 2006 - when temperatures reached 36.5 degrees (97.7F) - there were 551 reported cases and 52 deaths from legionnaires compared with 389 reported cases the previous year, which was cooler.
Kate Ricketts, a scientist specialising in Legionnaires' disease at the Agency's Centre for Infections, said: "In this study there appears to be an increase in cases following warm, humid periods; this was especially pronounced during the summer of 2006.
"The study suggests that the number of cases may be associated with the weather. It remains to be seen what impact the weather will have in the future.
There may be important implications for public health authorities if climate change leads to warmer temperatures."
The infection is known to show seasonal variation, with an increase in cases typically seen during August and September.
The peak in 2006 was thought to be linked to the unusually warm temperatures followed by wet periods that were experienced that year.
Also the cases were spread in small outbreaks and most were not linked to each other, suggesting the cases were linked to the weather and not a common source.
Legionnaires' disease is a type of pneumonia, and on average one in 10 people with symptoms die.
It is a bacterial infection which affects the lungs, originating from water sources such as showers or spa pools and spreading through the air as an aerosol. Most people exposed to the bacteria do not fall ill and it cannot be spread from one person to another.
Symptoms include flu-like' illness with muscle aches, tiredness, headaches, dry cough and fever, leading on to pneumonia.
Sometimes diarrhoea occurs and confusion may develop. It can be most effectively treated with antibiotics when diagnosed early.
Contaminated water sources are the most likely source of infection.
Legionnaires' disease can affect people of all ages but it mainly affects those over 50 years of age and tends to affect men more than women.