The Legionella pneumophila bacterium causes Legionnaires' disease, an "atypical," but serious, form of pneumonia. "Typical" pneumonia caused by pneumococcus (Streptococcus pneumoniae) is typical because it responds well to penicillin but not as well to tetracycline, whereas "atypical" pneumonias respond to tetracycline but not at all to penicillin.
Legionnaires' Disease Infection Information
You can contract Legionnaires' disease by inhaling water droplets that contain the disease-causing bacteria. The bacteria can be spread through showers, hot tubs, whirlpools, cooling towers, hot water tanks, and the air-conditioning systems of large buildings. L. pneumophila is not transmitted person to person. The disease was named after a large outbreak at a Philadelphia hotel during an American Legion convention in 1976.
The disease causes fever, chills, cough, muscle aches, headache, fatigue, chest pain, and sometimes nausea, vomiting, and diarrhea. These symptoms appear two to 14 days after exposure to L. pneumophila. The disease is best treated with certain antibiotics (not penicillin), and most people recover with no complications; however, in its most serious form, especially in those who already have lung disease, it can be fatal. Pontiac fever is a milder form of Legionnaires' disease that comes with flulike symptoms that appear about three to five days after exposure. It usually clears up on its own.
Who's at Risk for Legionnaires' Disease?
People who are most susceptible are the elderly and those who smoke, have lung disease, or have impaired immune systems.
Defensive Measures Against Legionnaires' Disease
Protecting yourself can be difficult because Legionnaires' disease is spread through the environment and not from person to person, but there are preventive steps you can take:
- Demand diligent disinfecting. Taking steps to kill the bacteria before it has a chance to contaminate the water is essential. If you use the shower or whirlpool at a gym or other water-sharing facility and see signs the water or faucets are dirty, tell someone. L. pneumophila thrives and grows in stagnant water.
- Learn a little history. If you're planning a stay in a hotel or on a cruise ship (another potential hotbed for Legionnaires' disease outbreaks), ask if there have been any recent pneumonialike illnesses reported. Also ask how the air-conditioning system is maintained and how often it is cleaned (the Occupational Safety and Health Administration recommends twice-yearly cleanings of large systems).
- Don't smoke. Smokers are more likely to get lung infections such as Legionnaires' disease.
During a pneumonia infection, the lung tissue in one or both lungs becomes inflamed and the microscopic air sacs fill with fluid. Go to the next page to learn more about this respiratory infection.This information is solely for informational purposes. IT IS NOT INTENDED TO PROVIDE MEDICAL ADVICE. Neither the Editors of Consumer Guide (R), Publications International, Ltd., the author nor publisher take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading or following the information contained in this information. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Before undertaking any course of treatment, the reader must seek the advice of their physician or other health care provider.