What is Legionnaires' disease?
Legionnaires' disease is a severe form of pneumonia. In other words, it is lung inflammation usually caused by infection. Legionnaires' disease is caused by a bacterium known as legionella. You can't catch legionnaires' disease from person-to-person contact. Instead, most people get legionnaires' disease from inhaling the bacteria directly. Older adults, smokers and people with weakened immune systems are particularly susceptible to legionnaires' disease.
The legionella bacterium also causes Pontiac fever, a milder illness resembling the flu. Separately or together, the two illnesses are sometimes called legionellosis. Pontiac fever usually clears on its own, but if untreated, legionnaires' disease can be fatal. Although prompt treatment with antibiotics usually cures legionnaires' disease, some people continue to experience problems after treatment.
What are the Symptoms of Legionnaires’ Disease?
Legionnaires' disease usually develops two to 10 days after exposure to legionella bacteria. It frequently begins with the following symptoms:
- Headache
- Muscle pain
- Chills
- Fever that may be 104 F (40 C) or higher
By the second or third day, you'll likely to develop other signs and symptoms that may include:
- Cough, which may bring up mucus and sometimes blood
- Shortness of breath
- Chest pain
- Gastrointestinal symptoms, such as nausea, vomiting and diarrhea
- Confusion or other mental changes
Although legionnaires' disease primarily affects the lungs, it can occasionally cause infections in wounds and in other parts of the body, including the heart. A mild form of legionnaires' disease, known as Pontiac fever, may produce signs and symptoms including a fever, chills, headache and muscle aches. Pontiac fever doesn't infect your lungs, and symptoms usually clear within two to five days.
What Causes Legionnaires’ Disease?
The bacterium Legionella pneumophila is responsible for most cases of legionnaires' disease. Outdoors, legionella bacteria survive in soil and water, but rarely cause infections. Indoors, though, legionella bacteria can multiply in all kinds of water systems — hot tubs, air conditioners and mist sprayers in grocery store produce departments. Although it's possible to contract legionnaires' disease from home plumbing systems, most outbreaks have occurred in large buildings, perhaps because complex systems allow the bacteria to grow and spread more easily.
What are the Risk Factors associated with Legionnaires’ Disease?
Not everyone exposed to legionella bacteria becomes sick. You're more likely to develop the infection if you:
- Smoke. Smoking damages the lungs, making you more susceptible to all types of lung infections.
- Have a weakened immune system as a result of HIV/AIDS or certain medications, especially corticosteroids and drugs taken to prevent organ rejection after a transplant.
- Have a chronic lung disease such as emphysema or another serious condition such as diabetes, kidney disease or cancer.
- Are 50 years of age or older.
Legionnaires' disease is a sporadic and local problem in hospitals and nursing homes, where germs may spread easily and people are vulnerable to all kinds of infections.
Legionnaires' disease is primarily treated with antibiotics. The sooner the therapy is started, the less likely the chance of serious complications or in the worst case, death. In many cases, treatment requires hospitalization. Pontiac fever goes away on its own without treatment and causes no further problems. You're likely to start by seeing your family doctor or a primary care provider. However, in some cases, you may be referred to a doctor who specializes in treating lung disease (pulmonologist) or infectious diseases, or you may be advised to go to an emergency department. So, make sure to recognize the symptoms right on time and save yourself from urgent hospitalizing and further health scares!
