People over 50 years old who smoke or drink heavily are at higher risk for getting Legionnaire’s Disease. So are those with long-term lung diseases like chronic obstructive pulmonary disease and emphysema. And those with weakened immune systems from diseases such as cancer and diabetes and from drugs like cyclosporine and prednisone.
Causes
Legionnaire’s disease is a type of pneumonia caused by Legionella bacteria (Legionella pneumophila). These bacteria normally live in water and have been found in hot tubs, public spas, showers, faucets, ponds, creeks, and wet soil. They do not grow well in cold water and are only rarely spread from one person to another. Legionnaire’s disease is usually a serious illness that can be fatal. It most often occurs in people who have a weak immune system, especially those over 50 years old, smokers, and people with chronic lung diseases like emphysema and COPD. People who have received organ transplants and those taking drugs that suppress the immune system (like chemotherapy or radiation) are also at increased risk.
People get Legionnaire’s disease by breathing in mist or vapor (small drops of water in the air) that contain the bacteria. It is NOT spread from person to person. Outbreaks of Legionnaire’s disease have been linked to contaminated cooling towers in large buildings, as well as contaminated hot water tanks, plumbing systems, and decorative fountains that are not properly cleaned or disinfected. Legionella bacteria can also be spread through the use of nebulizers to deliver medication into the lungs.
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Infection from these sources is usually mild to moderate and may last between two and 10 days. Infected people may develop a fever, cough, muscle aches, shortness of breath, and headache. In some cases, the infection can be life-threatening if it spreads to other parts of the body, such as the heart or brain.
It is sometimes hard to diagnose because the symptoms are similar to other types of pneumonia. A chest x-ray and a test to look for Legionella in the urine or lung secretions (sputum) can help confirm the diagnosis.
People infected with Legionnaire’s disease are typically hospitalized, although outbreaks of the infection can occur in other settings. Infection is more common in those who have recently had surgery, are receiving mechanical ventilation, or are undergoing cancer treatment. It is also more likely to happen when someone in a health care facility has an illness that affects their immune system, such as inflammatory bowel disease or kidney or liver failure.
Symptoms
Legionnaires disease is a serious type of pneumonia (lung infection). It’s caused by bacteria called Legionella. Legionella bacteria are found normally in many places in the environment, including creeks, ponds, and wet soil. They also grow in water, such as hot and cold-water taps and showers, and in large buildings’ air conditioning cooling towers. Outbreaks of Legionnaires disease have been linked to contaminated water systems in hospitals, hotels, and cruise ships. Legionnaires disease is spread when you breathe in droplets of water (mist) containing Legionella. These droplets can be spread by spraying, such as from a decorative fountain or by a misted jug of liquid in a public bath.
Symptoms of Legionnaires disease are similar to those of the flu, such as a high fever, chills, and cough. You may also have headaches and muscle aches. Symptoms usually start 2 to 14 days after exposure to the bacteria. People who have risk factors for Legionnaires disease, such as smoking or having a weakened immune system, are more likely to get the infection.
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Health care providers can diagnose Legionnaires disease by taking a history of your symptoms, where you have been, and your travel and health insurance information. They will do a physical exam and listen to your lungs with a stethoscope. They will also ask about your family history of the disease and other health conditions you have. They may test a sample of your urine and sputum (mucus or phlegm) for Legionella antigens, and they will take a chest X-ray.
Legionnaires disease can be treated with antibiotics. Your doctor will prescribe erythromycin, azithromycin, fluoroquinolones, or rifampicin, depending on your medical history and other health conditions. They will start treatment as soon as possible, before waiting for the results of lab tests. Prompt treatment reduces your chances of severe complications from the infection. You may need oxygen therapy if you have severe symptoms. Most people recover with treatment, especially if they start it early. This includes older adults and those with other health conditions. Some will need care in the hospital. They may need to stay in the intensive care unit.
Treatment
Legionnaires’ disease is a serious form of pneumonia, but it is treatable. Most people infected recover completely after proper treatment. Those who have weakened immune systems may experience more severe illness, including multiorgan failure. A comprehensive, streamlined approach to care optimizes patient outcomes.
Legionella infections occur when humans breathe in small droplets of water that contain bacteria called Legionella. These bacteria are found worldwide in freshwater environments, both natural and artificial. Legionella bacteria grow in warm water and can be dispersed into the air by spray or mist, such as that produced by cooling towers, whirlpool spas, fountains and shower units in large buildings. When inhaled, Legionella can cause Legionnaires’ disease and other severe illnesses in people with weaker immune systems. Legionnaires’ disease can be fatal, and it is especially serious in the elderly and those with suppressed immune systems.
The symptoms of Legionnaires’ disease include fever, chills, cough and difficulty breathing. Muscle aches, headache, fatigue and diarrhea may also be present.
A person with a low immune system might experience more severe symptoms, such as confusion and a very high fever. In the most serious cases, people with Legionnaires’ disease might need to be hospitalized for fluid replacement and respiratory support.
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Treatment options for patients with Legionella pneumonia include the use of antibiotics, such as levofloxacin or azithromycin. Patients with weakened immune systems are typically given these medications by mouth as outpatient treatments. Levofloxacin has been shown to be more effective in immunocompromised individuals than azithromycin.
Sporadic cases of Legionnaires’ disease, which are not linked to an outbreak, should be reported as soon as possible to the health department using a provider or laboratory report form (EPI-2 Initial Provider Disease Report Form). Health departments investigate all community-acquired Legionella pneumonia cases to identify potential environmental sources and to help prevent additional illnesses. Generally, a health department investigates an outbreak only when at least two patients have the same symptoms, and at least one of those patients has a weakened immune system. In addition, health departments investigate all cases of Legionnaires’ disease that are associated with a healthcare facility or long-term care facility.
Prevention
Legionnaires disease is a serious form of pneumonia that can be fatal if not treated promptly. It can occur anywhere that water is used and it tends to develop in warm, humid conditions. It is typically caught by breathing in small water droplets that contain legionella bacteria. The bacterium is present in nature but it becomes dangerous when it builds up in purpose-built water systems such as cooling towers, evaporative condensers and hot and cold water taps or whirlpool spas. People with lung conditions like chronic obstructive pulmonary disease, smokers, people who have a weakened immune system and people who have had an organ transplant or suffer from cancer, diabetes or HIV are more vulnerable to infection.
The bacteria that cause Legionnaires’ disease grow best in temperatures of 20 to 45°C. The water droplets that contain the bacterium are called aerosols. These can be created by purpose-built water systems but also by natural sources such as creeks, ponds and wet soil. People get infected when they breathe in these contaminated mists. Legionnaires’ disease can also be spread by contact with dripping taps, water fountains and humidifiers in the home. It is not spread by person to person or by eating food contaminated with the bacteria.
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In the workplace, employers should make sure that any water system that could create Legionella aerosols is regularly cleaned and tested to ensure it is safe. They should also provide suitable showers and washing facilities to reduce the risks of Legionnaires disease. People with weakened immune systems should not use hot tubs, pools or spas in hotels and other places where the water may have been contaminated by the presence of the bacterium.
If someone starts to get symptoms of Legionnaires’ disease they should seek medical help immediately and tell their doctor where they have been in the days before the illness started. This will allow the doctor to identify the likely source of the infection.
There are a number of laboratory tests that can be used to diagnose Legionnaires’ disease. These can include tests of blood, urine and respiratory secretions.