Legionnaires’ Disease
Legionnaires’ disease is an uncommon form of pneumonia caused by the legionella bacterium. The majority of cases are reported as single (isolated) cases but outbreaks can occur. All ages can be affected but the disease mainly affects people over 50 years of age, and generally men more than women. Smokers and the immunocompromised are at a higher risk.
The early symptoms of Legionnaires’ disease include a ‘flu-like’ illness with muscle aches, tiredness, headaches, dry cough and fever. Sometimes diarrhoea occurs and confusion may develop. Deaths occur in 10-15% of the general population and may be higher in some groups of patients. The incubation period can range from 2 to 19 days with a median of 6 to 7 days after exposure.
People become infected when they inhale legionella bacteria which have been released into the air in aerosolised form from a contaminated source. Once in the lungs the bacteria multiply and cause either pneumonia or a less serious flu like illness (Pontiac fever ).
The bacteria are widely distributed in the environment. They can live in all types of water including both natural sources such as rivers and streams, and artificial water sources such as water towers associated with cooling systems, hot and cold water systems and spa pools. They only become a risk to health when the temperature allows the legionellae to grow rapidly, such as in water systems which are not properly designed, installed and/or maintained.
Control and prevention of the disease is through treatment of the source of the infection, i.e. by treating the contaminated water systems, and good design and maintenance to prevent growth in the first place.
Chlorination / BS6700
| The cleanliness of all water systems is identified within L8 The approved code of practice to be of paramount importance in maintaining water hygiene. Regular monitoring of cold water storage tanks, calorifiers and their associated hot & cold water systems is required to identify build up of scale, sediment, biofilms and corrosion all of which develop naturally and progressively over time with water systems. The most effective way of combating the natural deterioration of system water hygiene is to undertake regular inspections and bacterial sampling, this may indicate if there is a need to undertake clean and disinfections.
Disinfections are frequently undertaken to conform with the requirements of BS6700 which is normally associated with newly installed systems or L8 which specifies disinfection options for existing and new systems. The provision also exists within L8 to undertake different disinfection procedures, provided they are at least as effective as L8. The introduction of new WRC approved drinking water products, new techniques and state of the art equipment have made our disinfections more effective, non intrusive, utilise less water and is significantly better than chlorine for the environment. |