Can kissing give me Legionnaires' disease? And 6 other Legionnella FAQs

UAB Hospital north pavillion.JPGUAB's North Pavillion hospital. (The Birmingham News/Bernard Troncale) 

In the wake of an outbreak of Legionnaires' disease at UAB Hospital last month, we've put together some questions and answers regarding this uncommon but not rare disease.

The Centers for Disease Control and Prevention says the number of infections is greatly underreported and an estimated 8,000 to 18,000 people are hospitalized each year with it.

 In Alabama, 41 people contracted the disease last year, and at least 18 have so this year, including the nine from the UAB outbreak.

Two people infected in the outbreak at UAB have died.

While Legionnaires' disease, a virulent type of pneumonia, is a dangerous and deadly condition, it usually makes sick only those who have compromised immune systems. And its manner of transmission -- through the inhalation of contaminated water -- limits its spread relative to some other disease outbreaks, such as influenza, for example.

 Can I get Legionnaires' disease by kissing or coming into close contact with someone who is infected?
 Highly unlikely. Legionnaires' disease is transmitted when water infected with  the bacteria is aerosolized, or made into a vapor, and breathed deep into the lungs. Mouth-to-mouth contact is not a transmission route for the bacteria.

 Can I get it from a water fountain?
 Yes, there have been cases documented but it wouldn't be from drinking the water. Instead, infection at a drinking fountain would come from inhaling the water vapor or tiny droplets from the fountain. Let's say you are drinking from a fountain that has the bacteria and the water goes down the wrong pipe.
 "Aspiration of colonized drinking water into the lungs has been suggested as the mode of transmission in some cases of hospital-acquired Legionnaires' disease," according to the American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE).

 How about taking a shower? Am I safe there?
Not necessarily. Legionella bacteria can grow in showerheads, especially if not in regular use. When the water is turned on, some of that is typically vaporized which can lead to inhalation and infection. "Contaminated potable water sources present the greatest risk when dispersed into the air in a very small droplet size that can be inhaled deeply in the lungs," ASHRAE guidelines state.  Actions that may generate small droplets are those that break up the water stream, i.e. shower nozzles, aerators, spray nozzles, water impacting on hard surfaces and bubbles breaking up."

 What are the most common sources of Legionella bacteria that can lead to illnesses?
    The bacteria forms and spreads in warm water.The CDC lists these common sources in no particular order:

  •     Hot tubs
  •     Cooling towers;
  •     Hot water tanks;
  •     Large plumbing systems;
  •     Decorative fountains.

Can I get it from car air conditioners or window air conditioner in my house?
 The CDC says:  The bacteria "do not seem to grow in car or window air-conditioners."

Who are at most at risk from getting sick from Legionella bacteria?
Most healthy individuals do not become infected with Legionella bacteria after exposure, health officials say.
Those that are at risk include:

  •     Older people (usually 50 years of age or older)
  •     Current or former smokers (lungs are more easily infected).

What are the symptoms?
The CDC says Legionairres' disease can be difficult to diagnose at first because its symptoms are like many other forms pneumonia, including:

  •     Cough
  •     Shortness of breath
  •     High fever
  •     Muscle aches
  •     Headaches

The incubation period can be as long as 14 days, which means some may not get sick until up to two weeks after exposure. Those with symptoms should seek a doctor immediately. It is treated with antibiotics.

(Sources: Centers for Disease Control and Prevention, American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE), Alabama and Jefferson County public health resources.)