Updated

The Aria Resort & Casino on the Las Vegas Strip is warning guests who stayed during a two week window that they may have been exposed to high levels of the bacteria that causes Legionnaires' disease.

Spokeswoman Stephanie Bethel of the Southern Nevada Health District said Thursday that six cases of the sometimes-deadly form of pneumonia have been reported among Aria guests by the Centers for Disease Control and Prevention.

Bethel says all six people were treated and have recovered.

Hotel officials say water tests in several guest rooms between June 21 and July 4 detected elevated levels of the bacteria Legionella.

The hotel says in a letter to guests that it added additional water treatment and the latest tests show no detectable levels of the bacteria.