Legionnaire’s Disease (LD) is an infectious respiratory and/or lung disease caused by a group of bacteria called Legionella sp., and among all of its “family members”, Legionella pneumophila is the most common species found. This bacteria was first identified in 1976 in America, during the 58th annual convention of the American Legion. And this is how the bacteria got its name. In milder manifestations, a non-pneumonial illness is called Pontiac Fever.
Legionella bacterium is a Gram-negative waterborne bacterium. So, water is its major environmental reservoir. It can also infect and grow within other amoebas living in both natural and manufactured water system, ie: hot tubs, cooling towers, hot water tanks, large plumbing systems, or parts of the air-conditioning systems of large buildings. They do not seem to grow in car or window air-conditioners. Furthermore, Legionellae can resist low levels of chlorine used in water distribution systems.
The transmission of the bacteria into our body is thought to come from inhalation of aerosol mist from water sources (eg: whirlpools, showers, cooling towers), contaminated with either the bacterium or amoebic cells infected with the bacterium. So far, transmission form person to person has never been documented.
Who can get LD?
Men are thought to be more prone to get LD. Those who are in extreme age (children, elderly), who have previous lung problem (ie: emphysema), who have other conditions that weaken their immune system (ie: uncontrolled diabetes, HIV/AIDS, cancer), and smokers are also more prone to LD. However, anyone in general can get LD.
Just like many other forms of pneumonia, it can give you any of the symptoms as follows: high fever (may reach above 40’C/102’F), chills, joint aching, general body aching, dry cough or productive cough (90% of cases), pleuritic chest pain, breathing problem, and may be associated with diarrhea (25-50% of cases), nausea/vomiting (10-30% of cases). Your X-Ray will show signs of pneumonia. These symptoms may occur 2-10 days after exposure. They may last for weeks, and might need hospitalization.
Pontiac Fever may give you symptoms of influenza: fever, chills, milder cough, or general fatigue; but, there is no evidence of pneumonia (lung infection). This may occur averagely 1-2 days after exposure, and may last for about 2-5 days. Pontiac Fever goes away on its own without any treatment.
Is there any treatment for LD?
LD can be treated with antibiotics, and most treatment cases are successful. In addition, supportive treatments are also required, for example: cough medicine, anti-pyretic, etc. Hospitalization might also be required.