While such outbreaks have become more common in recent years, experts don't know if that's because of better reporting or surveillance, or if the disease, a type of pneumonia, is truly becoming more prevalent, said Dr. Matthew Moore, a medical epidemiologist at the federal Centers for Disease Control and Prevention. —In Illinois, an outbreak reported last week at the Illinois Veterans Home in Quincy, an assisted living and nursing home southwest of Chicago, has led to the deaths of seven elderly residents, all with underlying conditions. —In California, six inmates at San Quentin State prison have been diagnosed with the disease since last week; five others are hospitalized with pneumonia-like symptoms and 73 inmates are under observation and being treated for respiratory illness in a prison medical unit, said prisons spokeswoman Dana Simas. —In New York, an outbreak in July and August that killed 12 people and sickened more than 100 was traced to bacteria found in an air-conditioning unit cooling tower at a Bronx hotel. —High levels of Legionella bacteria were found last week in the water system at a substance abuse treatment unit in Arizona at the Phoenix Veterans Affairs Health Care System, leading authorities to relocate 20 patients. Named after a 1976 outbreak among participants of an American Legion convention in Philadelphia, the disease can cause coughs, breathing trouble, fever and muscle aches.