Legionnaires' disease is a type of pneumonia caused by bacteria that grows in warm water. It has infected 67 people in a growing cluster of disease in New York.

Three people have died and more than 60 others are sickened in a growing Legionnaires' disease cluster in New York City, according to officials. The cluster, which began July 25, has led to 67 Legionnaires' disease diagnoses in Central Harlem as of Aug.

When it comes to Legionnaires' disease, this doctor explains how buildings can prevent it and what symptoms to watch for an early diagnosis.