The Health Protection Agency can confirm that its Surrey health protection unit is involved in an investigation, with the Health and Safety Executive and local environmental health officers, of a reported case of legionnaires' disease with alleged links to the Institute of Animal Health at Pirbright, in Surrey.

Early findings covered investigation into the management systems and documentation relating to the ISO10 building, in which the individual had been working.

These findings, backed up by temperature monitoring in the same area, suggested that the institute was carrying out all necessary maintenance and monitoring work in compliance with the approved code of practice for the control of legionella. Results of subsequent sampling over a wider area are still awaited.

The HPA follows national guidance when investigating cases of legionnaires' disease. As part of the investigations, everywhere the patient has been in the 10-14 days before falling ill, including their home, place of work and anywhere they may have travelled to or visited, is assessed to establish whether there is any potential source of infection which may need further investigation and/or testing.

Legionnaires' disease is caused by a type of bacterium that is found in the environment and which causes a problem if it is converted into an aerosol form from a water source - eg in showers or spas - and inhaled. It cannot be spread from one person to another.

It can affect people of all ages, but it mostly affects those over the age of 50 years, and more often men than women.

Symptoms include a flu-like illness with muscle aches, tiredness, headaches, dry cough and fever, leading to pneumonia. Sometimes, diarrhoea occurs and confusion may develop. It can be treated with antibiotics.