New York City Mayor Bill de Blasio says 12 people have now died from a Legionnaires’ disease outbreak.

De Blasio said Monday that cases now total 113. That number went up slightly because people were diagnosed after the fact. There have been no new cases in the last week, and authorities say there’s no sign of anyone else getting sick.

The outbreak is the largest in city history. It is centered in the South Bronx, where 12 buildings have tested positive for the bacteria.

The disease is a form of pneumonia. It’s caused by breathing in mist contaminated with the Legionella bacteria.

It’s especially dangerous for the elderly and for people with underlying health issues.

It’s not clear what triggered the outbreak, which began last month.

(AP)