Legionnaires’ disease is a respiratory disease first discovered in 1976. A rare and potentially fatal form of pneumonia, it is caused by a type of bacteria called Legionella. A serious outbreak at a veterans’ convention led to its recognition by public health chiefs.
The outbreak was traced to a gathering of the American Legion, similar to the British Legion, held in July 1976 at the Bellevue-Stratford Hotel in Philadelphia. The convention was supposed to be celebrating the 200th anniversary of America’s independence, but unfortunately, it was remembered for a different reason, as 34 people died and 221 people became ill.
After only one day, delegates began to fall ill with pneumonia-like symptoms that affected their lungs. They began to return home to different states, some falling ill when they arrived back home, making it difficult for the medical professionals to diagnose the source of the outbreak.
The source didn’t show up during routine microbiological tests on cultures, leading to the opinion this was a new and lethal organism. It took until January 1977 to identify the bacteria and its source – an air-conditioning ventilator in the hotel’s lobby.
The bacteria was called Legionella after the legionnaires’ convention. It thrives in stagnant, warm water and people can contract Legionnaires’ disease after inhaling droplets of infected water.
It is a unique way of contracting the disease, as usually pneumonia either develops from flu, or it can be caused by bacteria at the back of the throat dropping down to the lungs. Legionnaires’ disease comes from infected water systems.
Infected water systems
During the past 40 years, people have been using more artificial water systems, such as water-cooling towers, showers, water spray-producing equipment and air conditioning equipment. Scientists believe this is why significant outbreaks began occurring during this period.
Although it is relatively uncommon, with only 300 to 400 cases reported in the UK each year, Legionnaires’ disease has a high profile, with even single cases reported in the media because it is viewed as a killer disease with a significant death rate. Although the symptoms are similar to pneumonia, the death toll is higher for Legionnaires ‘disease.
In the 21st century, the medical profession understands the disease a little more, although it can still prove fatal, or the symptoms can continue for weeks or even months. It remains shrouded in mystery in this respect, as doctors don’t know why the disease can linger.
Symptoms and treatment
Symptoms can include headache, muscle pain, a cough which contains mucous and sometimes blood, fever, a shortness of breath, chest pains, nausea, diarrhoea, vomiting and confusion or other mental changes. The symptoms begin to develop 10 days after exposure to Legionella bacteria.
At the beginning of the 1980s, John Macfarlane, Professor of Respiratory Medicine at Nottingham University, helped draw up guidelines to help GPs recognise and treat Legionnaires’ disease. The guidelines recognised the importance of spotting the disease and not misdiagnosing it as pneumonia. Legionnaires‘ disease does not respond to penicillin, which is the standard treatment for pneumonia, so doctors were advised to prescribe additional antibiotics.
In the 1980s, erythromycin was recognised as a good antibiotic for treating Legionnaires’ disease. In the 1990s, a safe and simple urine test was developed to recognise the disease early, changing how it was managed.
Water temperature control
Legionella bacteria can be found in water and will multiply in temperatures between 20°C and 45°C when nutrients are available. The Legionella will lie dormant below 20°C and can’t survive in temperatures higher than 60°C.
Water temperature control is commonly used to control the risks of Legionella and prevent the bacteria’s growth. Advice offered by the Health and Safety Executive includes storing water in hot storage cylinders at temperatures of 60°C or higher and distributing it at 50°C or higher. Cold water must be stored and distributed at temperatures below 20°C.
In addition, a competent person must routinely inspect and clean the water system, in accordance with risk assessment procedures. Water testing should be carried out at regular intervals to check for Legionella.
Sound Planning performs water safety and quality management to safeguard against Legionnaires ’ disease in every kind of public building – including schools, colleges, leisure centres, industrial buildings, warehouses, care homes or office blocks.
We will design and implement Legionella control schemes to ensure the long-term safety of the workforce and the general public. Please contact us for further information.