Some information about legionella

Legionellosis is an infection caused by the bacterium Legionella pneumophila. The disease has two distinct forms:

Severe - legionnaires' disease, a well-known potentially fatal pneumonia , and
Mild – less severe illness, also known as Pontiac fever and Lochgoilhead fever.

Legionnaires' disease acquired its name in 1976 when an outbreak of pneumonia occurred among persons attending a convention of the American Legion in Philadelphia . Later, the bacterium causing the illness was named Legionella.

Why is it important?

Legionnaires' disease can be very serious and can cause death in up to 5% to 30% of cases. Most cases can be treated successfully with antibiotics and healthy people usually recover from infection. Infection is caused by breathing in small droplets of water contaminated by the bacteria. The disease cannot be passed from one person to another.

Who is affected/most at risk?

Everyone is potentially susceptible to infection but some people are at higher risk e.g. those over 45 years of age, smokers and heavy drinkers, those suffering from chronic respiratory or kidney disease, and people whose immune system is impaired. Legionnaires’ disease is serious in elderly and infirm patients; pneumonia is a common cause of death in people over 70.

What can be done?

Legionella bacteria are common in natural water courses such as rivers and ponds. Since legionella are widespread in the environment, they may contaminate and grow in other water systems such as cooling towers, evaporative condensers and hot and cold water services. They survive low temperatures and thrive at temperatures between 20°C- 45°C if the conditions are right, e.g. if a supply of nutrients is present such as rust, sludge, scale, algae and other bacteria. They are also killed by high temperatures.Simple steps can be taken by the owners of premises to ensure these unfavourable conditions are avoided. In relation to water systems, a wide range of organisations, groups or self-employed individuals providing residential accommodation who are responsible for the water system(s) in their premises will have duties in this regard, including:

vocal authorities;
universities;
housing associations, including housing companies;
charities;
hostels;
landlords in the private renting sector;
managing agents;
hoteliers, B&B, guest house and holiday camp owners; and
caravan and camping site owners, including fixed caravan sites.