5 unexpected ways you can catch pneumonia

Together with the flu, pneumonia is a top cause of death in the United States, according to the Centers for Disease Control and Prevention. Part of what makes pneumonia so lethal is that it isn’t just one disease. Instead, it’s a general term for infections in the lung.

“Technically, pneumonia is an inflamed lung, and the inflammation comes from an infection,” says Thomas Grookett, MD, a pulmonologist in Willingboro, New Jersey.

Since pneumonia can be caused by bacteria, viruses, and other airborne hazards, it’s tough to avoid. “The lungs are one of the only vital organs exposed to the environment,” says Dr. Grookett. “Everything else—the heart, the brain, everything—is enclosed in your body. That’s why lung infections are always challenging the immune system.”

Pneumonia puts hundreds of thousands Americans in the hospital every year, and more than 45,000—mostly people over age 65—will die from the illness annually. The Pneumococcus bacterium and a bacterium called Haemophilus influenzae are two of the most common causes, but far from the only ones. Here are some of the more surprising ways to develop the condition.