Did you know that legionnaires disease affects about 100,000 people per year, and it can be fatal if not diagnosed and treated properly?  It’s unclear how many people develop this nasty bacterial infection annually around the world, but some estimates are as high as 5 million.  A recent outbreak at a major theme park has put a spotlight on this little-known disease because of how it was transmitted, and it should serve as a warning for all of us.

What is Legionnaires?

Legionnaires disease is a bacterial infection of the lungs that causes a certain type of pneumonia.  It is highly-contagious, but it is not transmitted through person to person contact.  It is an airborne pathogen that is usually linked to a contaminated water source that is spread via mist, steam, humid air or from swallowing.  However, it is possible to be exposed from breathing contaminated air as well.  To give you a sense of how outbreaks start, many have been linked to sources such as misters in supermarkets and restaurants, hot tubs and steam baths in fitness centers, air conditioning systems and public fountains.


Legionnaires has an incubation period of anywhere from 2-10 days, and initial symptoms usually include chills, persistent headache, high fever and systemic muscle pain.  Within a few days of initial symptoms, more serious ones develop as the infection settles in the lungs.  Shortness of breath, chest pain, persistent cough with excessive mucous or blood, nausea, vomiting, weakness and confusion.  Left untreated, it can be fatal, and estimates suggest that almost a third of all pneumonia cases that lead to death are caused by exposure to legionnaires.


Treatment is usually very-successful if the infection is identified early and the patient can receive appropriate care.  Most people will make a complete recovery, but some severe infections can leave lasting damage.  Left untreated, the disease can spread beyond the lungs and impact other organs, including the heart and kidneys.   

Sanitation is Key

The single, most-effective way to prevent outbreaks from occurring is to be vigilant when it comes to sanitation, especially when it comes to sources of re-circulating water.  In fact, the reason that only a relatively-small number of people are infected is because we live in a society that maintains high-sanitary standards.

If we ever face a major disaster or off-grid situation, and basic sanitation ceases to be the norm, there is a really good chance that legionnaires could turn into a pandemic.  It is a resilient bacteria that is easily-spread, and large numbers of people can be exposed in one location like a shelter or hospital.  There is also a limited amount of suitable antibiotics available at any given point in time, and chances are that supplies will run out once patient numbers surge.

Wearing a face mask, washing hands and avoiding sources of possible contamination are simple, yet very-effective ways to protect yourself from exposure.  It’s also important be vigilant about sanitizing sinks, tubs, toilets and containers to minimize the chances of bacterial growth.

Take legionnaires disease seriously even if it’s not something that you hear about all that often. It doesn’t take much to cause an outbreak that can turn into a public health nightmare under the right conditions, and you want to be prepared if and when that time comes.