Newspaper headlines can be misleading. That’s putting it mildly.
That’s the thought that came to mind upon reading of last month’s “outbreak” of Legionnaire’s Disease among people who had visited Disneyland. Television news reporting about the story also made it sound more widespread than it really was.
What Really Happened With Disneyland's Legionnaire's Outbreak?
A close examination of the story reveals that the so-called outbreak was much ado about very little. A total of 9 people who had visited or worked at the park were found to be sickened by exposure to Legionella bacteria. One is too many, of course, but let’s put things in perspective. Disneyland attracts around 18 million visitors a year, or an average of 1.5 million per month. Nine of them were diagnosed with Legionnaire’s Disease after visits during the month of September. After exercising my calculator, I found out that means .000006 percent of September’s visitors were sickened in this event.
I realize that’s little comfort if you or a loved one was among the nine victims, but the word “outbreak” carries with it the risk of exaggeration.
Legionnaire’s Disease got its name when it was first identified from an outbreak at an American Legion convention in Philadelphia in 1976 that killed a bunch of attendees, most of them elderly veterans of World War II and the Korean War. Its symptoms resemble that of pneumonia, and it is spread by Legionella bacteria that thrive in warm mists from stagnant water in plumbing and HVAC systems.
The Disneyland infections were traced to a couple of cooling towers near the New Orleans Square train station. Cooling towers are a common source of the disease, because Legionella bacteria thrive in warm, stagnant water. Cooling towers provide cold air via water evaporation and the remaining warm water can form droplets that spread the disease through air. A recent report from the Centers for Disease Control found that 84 percent of 196 cooling towers tested around the country contained Legionella bacteria.