Legionnaires’ disease is a type of pneumonia. It is very serious disease. It is caused by a type of bacteria called Legionella. It is estimated that in the United States there are between 10,000 and 50,000 cases of Legionnaires’ disease each year. Both the disease and the bacterium were discovered following an outbreak traced to a 1976 American Legion convention in Philadelphia.Legionnaires’ disease was named after an outbreak of severe pneumonia which affected a meeting of the American Legion in 1976.

More than 43 species of Legionella have been identified and more than 20 linked with human diseases. Legionellosis is the term for the diseases produced by LDB. Two distinct illnesses, Legionnaires’ disease and Pontiac fever, have been associated with the Legionella species. It is also known as Legionellosis, is a rare form of pneumonia. Other than L pneumophila, 34 species of Legionella have been identified, mostly from immunocompromised patients with pneumonia.

The first known outbreak of Legionnaires` Disease was at a convention for ex-service personnel in Philadelphia. Legionella species are poorly staining, obligate, aerobic, gram-negative bacilli. More illness is usually found in the summer and early fall, but it can happen any time of year. About half the cases of legionnaires’ disease are caught abroad. The other half are the result of infections acquired in the UK. Pontiac fever is a mild, non-pneumonia influenza-like illness. It is not clear why the same causal agent can produce two distinct illnesses.

Although pneumonia is the most common presenting problem, other pulmonary manifestations are frequent. Control and prevention of the disease is through treatment of the source of infection i.e. the contaminated water systems. The source of the bacterium was found to be contaminated water used to cool the air in the hotel’s air conditioning system. Legionella bacteria account for 2-15% of the total number of pneumonia cases requiring hospitalization in the United States.

Causes of Legionnaires’ Disease

The comman causes of Legionnaires’ Disease include the following:

• Legionellosis is an infection caused by the bacterium Legionella pneumophila.
• Most cases are caused by L. pneumophila, serogroup 1.
• Cancer, particularly hematological or pulmonary malignancy.
• Respiratory therapy equipment.
• Whirlpool spas.
• Aids.
• Legionnaires’ Disease is also Caused by smoking.
• Alcohol abuse.
• Persons who have some other medical problem such as heart disease, cancer, or kidney disease are also believed to be more susceptible.

Symptoms of Legionnaires’ Disease

Some sign and symptoms related to Legionnaires’ Disease are as follows:

• Legionnaires’ disease usually begins with a headache, pain in the muscles and a general feeling of unwellness.
• Cough is present in 90% of cases; cough usually is nonproductive at first but may become productive as the disease progresses.
• Nausea.
• Nonpulmonary symptoms are prominent early in the disease.
• Vomiting.
• Diarrhea.
• Anorexia.
• Musculoskeletal symptoms include arthralgias and myalgias.
• High fever.
• Chills.
• Shortness of breath.
• Chest pains.
• Excessive sweating.

Treatment of Legionnaires’ Disease

Here is list of the methods for treating Legionnaires’ Disease:

• Oxygen therapy is the mainstay of prehospital therapy.
• Intravenous (IV) access and fluid therapy may be indicated for dehydration.
• The risk of Legionnaires’ can be reduced with appropriate maintenance and cleaning of possible sources of the bacterium, such as air conditioning systems.
• Treatment includes an antibiotic, usually erythromycin, azithromycin (Zithromax), ciprofloxacin (Cipro), or levofloxacin (Levaquin).
• Hospitalization may be required.
• Restraints may be required for patients with altered mental status. Seizure precautions may be indicated.
• Other medication may include: anti-clotting medication, medication to control irregular heartbeat, medication to control palpitations and medication to open the blood vessels.