What Is Legionnaires Disease

The agent that causes Legionnaires’ disease is a bacterium called Legionella Pneumophilia.

The Legionnaires’ disease was named in 1976 in response to a pneumonia-type disease which affected attendees of an American Legion Convention in Philadelphia.

It is one of a group of similar diseases collectively known as legionellosis. The other forms, eg Pontiac Fever and Lochgoilhead Fever, have similar symptoms but are not as serious as Legionnaires’ disease.

Where Does It Come From

The bacterium that causes Legionnaires’ disease is widespread naturally, living mainly in water, e.g. ponds, and won’t usually cause problems. Normally outbreaks occur from purpose-built water systems when conditions are right, if nutrients are present such as rust, scale, algae, sludge or other bacteria and temperatures are in the range of 20-50°C encouraging the Legionella bacteria to thrive.

Symptoms & Treatments

The elderly seem more susceptible to Legionnaires’ disease, with men seeming to be at a higher risk than women, especially smokers aged 45 and over, alcoholics, diabetics and patients with cancer, chronic respiratory or kidney disease.

Early flu-like symptoms are often confused with the first symptoms of the disease. These include a high fever, chills, headache and muscle pain. The patient may have a dry cough and experience difficulty with breathing as the disease progresses. Some infected patients may also develop diarrhoea, vomiting and may become confused and delirious.

Incubation is normally 2 – 10 days, but normally this tends to be 3 – 6 days with not all people developing all of the symptoms. It can be confused with a mild flu-like infection.

After a blood or urine test to confirm diagnosis, treatment is by antibiotics such as erythromycin. Legionnaires’ disease is fatal in up to 30% of cases.