Yesterday I wrote about a recent outbreak of Legionnaire's Disease in guests staying at the Plim Plaza Hotel in Ocean City, Maryland.
As a Legionnaire's Disease attorney, I want to use today's blog to talk more about what Legionnaire's Disease is, and how people get it.
The Origins of Legionnaire's Disease as a Named Illness
Legionella existed long before it had a name. But with the advent of air conditioning and hot tubs, people created environments that enabled the bacteria to breed and become airborne.
Legionella pneumophila, the type of bacteria that cause Legionnaire's disease, is found naturally in water such as lakes and rivers. In nature, however, legionella is rarely dangerous, because it is so diluted.
The illness caused by legionella is called Legionellosis, and it comes in two forms: Legionnaire's disease is the more serious form and involves pneumonia; the milder version is called Pontiac Fever.
Scientists actually discovered the milder form - Pontiac Fever - first. Pontiac Fever was first recognized after a major outbreak in Pontiac, Michigan, in 1968. 95 of 100 employees of the Oakland County Health Department, and 49 of 170 visitors to the Department, became sick. CDC sent three investigators into the building, and they, too, became sick. CDC dispatched three more investigators, and these three also became sick. Investigators finally discovered that the outbreak was stemming from an evaporative condenser in the basement. This condenser was vented to the roof, and the vent emerged just two meters from an air intake unit - meaning the legionella was being pulled back into the building. See Legionnaire's Disease Pathogenicity and Design Considerations, Penn State's Department of Architectural Engineering, at http://www.engr.psu.edu/ae/iec/abe/topics/legionnaires.asp.
Then, in 1976, a group of people attending the American Legion Convention in Philadelphia came down with a mysterious illness. When several people died, investigators were brought in. Medical experts traced the outbreak to bacteria found in the air conditioning unit at the hotel where the conventioneers had stayed. The disease was called Legionnaire's Victims because it had affected Legionnaires attending the convention. See http://www.cdc.gov/ncidod/dbmd/diseaseinfo/
legionellosis_g.htm.
Who Are the Victims of Legionnaire's Disease?
Because Legionnaire's disease strikes the lungs, it disproportionately affects smokers and people with chronic lung disease. It also is more common and more dangerous for people with weakened immune systems (premature infants, transplant recipients, AIDS sufferers, hospital inpatients, etc.). Outbreaks of Legionnaire's disease in hospitals are extremely dangerous because hospitals are filled with the people most vulnerable to the disease.
How Many People Get Legionnaire's Disease?
CDC estimates that "8,000 to 18,000 people get Legionnaire's disease in the United States each year." A sobering 30% of those people die, according to CDC statistics. Id. Generally Legionnaire's disease has an incubation period of two to fourteen days; Pontiac Fever cases may have a shorter incubation period. Id.
While large outbreaks do receive media attention, experts believe that: "this disease usually occurs as a single, isolated case not associated with any recognized outbreak." See, e.g., Medicinenet.com, http://www.medicinenet.com/legionnaire_
disease_and_pontiac_fever/article.htm. In fact, many experts believe that the incidence of Legionnaire's disease is much higher than reported, because many cases either are not identified as the Legionnaire's disease form of pneumonia, or are never associated with a particular outbreak.
How Does Legionella Breed?
Legionella becomes dangerous when it is allowed to breed in the warm, stagnant water of cooling towers and whirlpools. People become infected when they breathe in the mist that contains the legionella bacteria. Outbreaks have happened in office buildings, hotels and hospitals, and around pools and whirlpools in hotels and cruise ships. A recent outbreak was believed to be the result of water droplets spraying from an air conditioner unit on the top of a building. The spray reached the sidewalk area below, infecting passersby.
Legionella can breed when air conditioners, pools, or whirlpools are not properly cleaned. It also can be distributed through poorly designed buildings or cooling systems that direct contaminated water droplets directly into the air that people breathe. On the other hand, Legionnaire's disease is almost always preventable with good maintenance and building design.
The author of this blog, Legionnaire's Disease attorney Lee Wallace represented six people who contracted Legionnaire's Disease and Pontiac Fever in a 2001 outbreak at a Georgia hotel. In that case, a hotel had failed to clean its hot tub spa, and had not bothered to use enough chemicals to keep the bacteria at bay.
