Legionella Bacteria - Photo Credit CDC PHIL
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The outbreak of Legionella in the UK I wrote about last week (see HPA Updates The Stoke-On-Trent Legionella Outbreak) has expanded to 18 cases, and today the HPA has announced that they believe they have tracked down the bacteria’s source.
It appears that 17 of the 18 cases visited a JTF Mega Discount Warehouse where hot tubs were displayed and sold. Genetic fingerprinting has determined that the same strain of Legionella found in these patients was present in the hot tub.
As this was a unique strain, not previously encountered, the odds are pretty good they’ve found the source.
The legionella bacteria thrives in warm water, such as is often found in air-conditioning cooling towers, hot tubs, and even ornamental water fountains. Improper maintenance, or poor design, can lead to the bacteria blooming.
When aerated the bacteria can become airborne, and if inhaled by a susceptible host, can cause a serious (and sometimes fatal) form of pneumonia.
This update comes from the HPA.
Stoke-on-Trent Legionnaires’ Disease Outbreak – probable source identified
30 July 2012
Public and environmental health experts investigating the Legionnaires’ disease outbreak at Stoke-on-Trent believe they have identified a probable source.
The probable source is a hot tub based at JTF Warehouse, City Road, Fenton, Stoke-on-Trent. We would like to emphasise that investigations are still ongoing. Environmental Health specialists from the Health and Safety Executive and Stoke-on-Trent City Council have taken and continue to take samples from sites across Stoke.
A spokesperson from the Health and Safety Executive said: "HSE continues to inspect premises where we are the enforcing authority and will do so until we have eliminated those sites from our investigations and are sufficiently assured there are no other possible sources."
The samples from the hot tub at JTF Warehouse were confirmed by the Health Protection Agency’s specialist laboratory in Colindale last night as being an unusual strain legionella bacteria. The strain matched those taken from patients. JTF warehouse are fully cooperating with the investigation.
Dr Sue Ibbotson, regional director, Health Protection Agency West Midlands said: “We have identified the probable source of the Legionnaires' disease outbreak in Stoke. We have the evidence from DNA fingerprinting of samples from the hot tub and the patients being caused by the same previously unseen strain of legionella. The HPA also took detailed histories from the confirmed cases and we know that 17 of the 18 confirmed cases visited this warehouse in the two weeks before they fell ill. Added to that we know that spa pools are known to be effective mechanisms for spreading legionella infection.
“We may still expect to see new cases of Legionnaires’ disease related to this outbreak. JTF Warehouse decommissioned the hot tub on 24 July. It can take up to two weeks following exposure for people to develop symptoms of Legionnaires’ disease and a further few days before they go to see their GP. We continue to work with our partners to investigate this outbreak and continue to take samples across the city in case there are other sites with the same strain of legionnella.”
For an even more unusual source of Legionella, you may wish to revisit a blog from 2010 where we looked at a Study: Wiper Fluid And Legionella.
