This is a form of pneumonia that is caused by the bacteria known as Legionella. Annually, around 10,000 to 18,000 individuals are infected with this disease in the United States. Most individuals catch the disease from inhaling the bacteria from the mist that is present in the air-conditioning and showers. This infection is not transmitted by contact from person-to-person. These bacteria can also cause Pontiac fever which resembles flu-like symptoms but can clear on its own but the untreated legionnaire’s disease can become fatal.
Causes
Bacterium Legionella pneumophila is the common cause of this disease. It is naturally present in the soil and water but rarely causing infections. The infection is possible with the exposure to water systems such as the hot tubs, air-conditioners and mist sprays. The infection occurs after inhaling the small water droplets containing the bacteria. Some of the sources of outbreaks include grocery store mist machines, decorative fountains, swimming pools and mist machines. The infection can also be transmitted with aspiration when individuals cough or choke while drinking liquids containing the bacteria or from using the contaminated potting soil. Most healthy individuals do not get the disease after exposure to the bacteria. Individuals with certain factors are at increased risk of developing this condition after exposure to the bacteria. This include people having chronic lung disease such as chronic obstructive pulmonary disease (COPD), having a weakened immune system, being a smoker, being over the age of 50 or taking medications that weaken the immune system.
Symptoms
The incubation time for Legionnaire’s disease is around 2 to 10 days when symptoms begin after exposure to the bacteria. Most of the affected individuals may be admitted to hospital with high fever. The initial sign of lung infection is the cough which can produce mucous. Gastrointestinal problems include diarrhea, vomiting, nausea and stomach discomfort. Additional symptoms include shortness of breath, headache, muscle aches, confusion and chest pain. Some of the individuals can suffer from long-term complications such as fatigue, neurologic symptoms and neuromuscular symptoms after the infection.
Diagnosis
The diagnosis is possible with the identification of the legionella antigen in the urine. Additional tests include the direct fluorescent antibody where the bacteria are stained which can be detected under the fluorescent microscope. A blood test can detect the presence of antibodies that are reactive against the bacteria. In addition, a chest X-ray may be necessary that determines the extent of infection and a CT scan of the brain may be necessary if neurological symptoms are evident.
Treatment
Several antibiotics are very effective against this bacteria. It is important to initiate the treatment sooner to prevent the chance of developing complications or even death in some of the cases.
References
https://www.cdc.gov/legionella/downloads/fs-legionnaires.pdf
https://medlineplus.gov/legionnairesdisease.html
http://legionella.org/about-the-disease/what-is-legionnaires-disease/prognosis-and-outcome/
