There have been several outbreaks of Legionnaires' disease in the United States this summer, with more than 100 people becoming sick and 19 deaths. This may seem like a lot, but it is a typical pattern with this disease, which tends to appear in warm weather and is most dangerous for people who already are sick or weakened.
Outbreaks this disease have become more common over the last few years, but this increase in cases may be due to better reporting rather than to the disease itself becoming more common.
Several Legionnaires' outbreaks have occurred in Illinois, including at a veterans home and at a nursing home, where seven already-ill residents died. Six prisoners at San Quentin State prison in California have been diagnosed with the disease, with five more hospitalized with similar symptoms. In these outbreaks, the source of the infection has not been found.
In New York, an outbreak in July and August killed 12 people and sickened more than 100. It was traced to in an air-conditioning unit cooling tower at a Bronx hotel.
Legionnaires' is a bacterial pneumonia. The name comes from an outbreak that occurred among participants at an American Legion convention in Philadelphia in 1976. Symptoms include coughs, breathing trouble, fever, and muscle aches. Elderly people and those with chronic illnesses are most at risk. Antibiotics can treat the disease, but it is fatal for between 5% and 30% of patients, Moore said.
The bacterium that causes Legionnaires' disease thrives in warm water. People get sick if they inhale mist or vapor from contaminated water systems, such as in cooling towers, air conditioners, and fountains, but it does not spread from person to person.
Between 8,000 and 18,000 people are hospitalized with Legionnaires' each year, usually in summer and early fall, according to the U.S. Centers for Disease Control and Prevention. The CDC has asked state and local health departments to report all cases of Legionnaires', but many cases are not reported, including many hospitalizations.
