Legionnaires' Disease (LD Legionellosis and Pontiac Fever)

Overview

Legionnaires' disease (LEE-juh-nares) is a type of pneumonia caused by the Legionella bacteria typically found naturally in water. People get Legionnaires' disease when they breathe in a mist or small droplets of water in the air that are contaminated with the bacteria. Some high-profile cases include people who have contracted the disease by breathing in the steam from a hot tub that has not been properly cleaned.

The disease earned its name in 1976 when people attending an American Legion convention in Philadelphia suffered from an outbreak illness that infected the lungs. This disease had existed for much longer but is now being detected more often. It is common to screen for this disease whenever a person contracts pneumonia.

While not common Legionnaires' disease afflicts 1000 or more Canadians each year. However many infections are not reported or properly diagnosed so this number may be higher. Legionnaires' is more commonly found in the summer and early fall but it can be contracted at any time of year.

Causes

Legionnaires' is not spread from one person to another.

Legionella bacteria grow best in warm water environments such as hot tubs hot water tanks or the air-conditioning systems in large buildings. People get Legionnaires disease when they inhale contaminated aerosols from devices such as:

  • cooling towers
  • showers
  • faucets
  • hot tubs and spas
  • air-conditioners
  • aspirate contaminated water into the lungs

Because legionnaires' is spread this way public health officials are less concerned about who has come into contact with a sick person but very concerned about finding out where the person got exposed to the bacteria in the first place.

Older people or those with a lower immune system are at greater risk of contracting Legionnaires'. Others at risk include:

  • smokers
  • diabetics
  • people with a chronic lung or kidney disease

Also at risk are those that take drugs to weaken the immune system such as transplant or chemotherapy patients.

Symptoms

Legionnaires' disease is the more severe form of legionellosis and is characterized by pneumonia commencing 2-10 days after exposure.

Symptoms can include:

  • high fever
  • chills
  • coughing
  • fatigue
  • headache
  • aching muscles
  • chest pain
  • loss of appetite

At the beginning legionnaires can seem like other viral illnesses in which one has a cough fever and chills. However as legionnaires' progresses additional symptoms can include nausea diarrhea or memory loss or confusion. Special tests are usually required to confirm that the illness has been caused by Legionella bacteria.

Another form of the disease is known as Pontiac fever a flu-like illness but not pneumonia. Pontiac fever usually occurs within a few hours to two days of exposure. The symptoms include:

  • fever
  • headache
  • aching muscles

Most people exposed to Legionnaires' do not become ill.

Treatment

Pontiac fever is not associated with pneumonia. In most cases no treatment is required and people recover within two to five days.

If you develop pneumonia your chances of prompt recovery are greatest under certain conditions:

  • you are young
  • your pneumonia is diagnosed early
  • your defenses against disease are working well
  • the infection has not spread
  • you are not suffering from any other illness

Prompt treatment with antibiotics usually cures bacterial and mycoplasma pneumonia. The drug or drugs used are determined by the germ causing the pneumonia. Most patients experience rapid improvement while others have a much more protracted course despite treatment. After temperature returns to normal medication must be continued according to your doctor's instructions otherwise the pneumonia may recur. Relapses can be far more serious than the first attack.

People at risk for Legionnaires' are often at risk for pneumonia in general. You should discuss with your doctor whether you are a candidate for a vaccine called "pneumovax". This can be protective and is especially important given that bacteria such as streptococcus pneumoniae are now capable of resisting and fighting off the powers of antibiotics to destroy them. Such antibiotic resistance is increasing worldwide because these medicines have been overused or misused. Therefore if you are at risk of getting pneumococcal pneumonia you should talk with your doctor about ways to prevent it (see below).

Most cases of pneumonia are treated successfully at home. However children may be hospitalized if they have chronic illnesses that affect the immune system if they are vomiting so much that they cannot take medicine by mouth or if they have recurrent episodes of pneumonia. Hospital treatment may also be required for those who need supplemental oxygen or if a lung infection has spread into the bloodstream.

A vigorous young person may recover from pneumonia within a week. Older adults however may require several weeks before regaining their strength and a general feeling of well-being. To get better and avoid complications:

  • Get plenty of rest
  • Drink lots of fluids especially water
  • Take the entire course of any prescribed medications
  • Keep all follow-up appointments with your doctor

Prevention

At home properly maintain all devices that can produce water vapor or mist including:

  • shower heads
  • hot tubs
  • whirlpools
  • faucets
  • humidifiers
  • air-conditioners

These devices must be disinfected and cleaned regularly according to the manufacturers' directions.

Wash your hands

Your hands come in daily contact with germs that can cause pneumonia. These germs enter your body when you touch your eyes or rub your nose. Washing your hands thoroughly and often can help reduce your risk.

Medical professionals should undertake routine precautions that include:

  • Hand hygiene (always washing hands with soap and water)
  • Glove use when contact with any moist body substances mucous membranes or non-intact skin is anticipated
  • Gowns are recommended during routine patient care activities in which splashing and soiling with body substances is likely to occur
  • Mask and eye protection are recommended for activities that are likely to generate splashes or sprays of blood body fluids secretions or excretions.
  • There is no restriction on patient transfer or staff working at multiple facilities.