Air-conditioning - home to deadly bacteria?

Tuesday 30 November 1999

Reproduced in FMUK - Facilities Management U.K. Issue - November/December 2002

The recent tragic outbreak of Legionnaire's disease in Cumbria and Bedfordshire has once again highlighted the necessity of checking your air- conditioning units regularly.

Whilst most systems will be perfectly safe, it is always worth getting that extra bit of security and assurance by having them tested by a professional.
FMUK talks to Mike Wigglesworth, a scientist from the Eclipse Scientific Group, which provides Legionella, Asbestos and Food Testing as well as advice, to explain what Legionnaires' disease is, how it occurs and what you can do.

All facility managers should know that air-conditioning systems and cooling towers are a potential breeding ground for Legionella bacteria - but they are not the only sources.

People have contracted the disease from spa baths, hotel hot water systems, composting processes, humidifiers and maintenance of water systems. Anything that creates moist air is a potential source of infection.

"There are more than 40 different species of Legionella bacteria," says Mike whose company has a London based consultancy business and eight regionally located specialist laboratories. "They are found naturally in environmental soil and water sources and can exist over a wide temperature range. Their ability to survive and reproduce in poorly maintained water systems has given rise to the threat of Legionnaires' disease.

"On average there have been approximately 250 reported cases each year in the UK and a number of cases are associated with travel abroad. It is, however, thought that the prevalence of the disease is underestimated. Reports show that the disease is fatal in approximately 15 per cent of reported cases."

In the UK, Health and Safety Law states that, with regard to premises, employers have to take the necessary precautions to ensure both staff and members of the public are not at risk from infection.

The regulations require the identification and assessment of risk, prevention or minimisation of risk from exposure to Legionella, systems for the management and selection, training and competence of personnel and a record of maintenance, cleaning and disinfection. The requirements are detailed by 'L8' the Approved Code of Practice and Guidance for the control of Legionella bacteria in water systems.

"The recent outbreaks highlight the very real risk that may be hidden in your buildings," says Mike. "Comprehensive risk management, good water hygiene and maintenance practices, including regular monitoring for the bacterium, are essential tools in the control of Legionella.

"The robust nature of the organism and its association with biofilms means that it may take several attempts to remove it. Failure to comply with current regulations may result in serious illness or death and lead to the prosecution of organisations or individuals."

The disease occurs more frequently in men than women and usually affects middle-aged or elderly people, smokers and people with other chest problems, heavy drinkers and those with a weakened immune system. The disease is uncommon in younger people and is very uncommon under the age of 20.

Symptoms are similar to the symptoms of the flu and include high temperature, feverishness and chills, cough, muscle pains, headache; and leading on to pneumonia, very occasionally, diarrhoea and signs of mental confusion

"In response to the growing concern, and long overdue public awareness of Legionnaires' disease and the Legionella bacterium, the Eclipse Scientific Group has launched a 'Legionella Testing Hotline' which draws on expertise at the Ashford Laboratory in Kent where the group's Legionella laboratory is based.

"Calls have been received from companies of all sizes, nationwide, seeking advice on risk assessment and monitoring for the bacterium. A recent increase in the number of samples submitted to the laboratory is evident.

"In the month of August, immediately after the outbreak, there was a 55 per cent increase over the number of samples received in July. In September this figure had risen to 100 per cent. In July, five per cent of the samples tested were found to contain Legionella, and in August this figure was 10 per cent.

"Over the past 3 months in our laboratory Legionella pneumophila was identified in 82 per cent of positive samples, 21 per cent of these were the clinically important serogroup 1."

Figures like these show how prevalent the bacteria are in water - cooled air- conditioning units and other water systems. Simple testing, cleaning and identifying the risk should leave your systems disease free.

For further details on Legionnaires' disease visit www.hse.gov.uk
Mike Wigglesworth can be contacted on 01233 504270.

Eclipse can be contacted on Tel: 01354 695858, Fax: 01354 692215 or by email: sales@eclipsescientific.co.uk.