THE BRONX (PIX11)– Two people have died and four others are hospitalized after a legionnaires outbreak in the Bronx, officials said.

The Highbridge section of the borough is on high alert after cases of legionnaires have more than doubled in the last week, from 10 to 24. The outbreak is clustered in zip codes 10452 and 10456, which include sections of Highbridge, Concourse, and Morrisania.

Health officials say adults who experience flu-like symptoms and have traveled through the affected areas since early May should be tested immediately.

The disease only spreads from breathing in contaminated water vapor. The bacteria grow in warm water and thrive in cooling towers. Health officials say four cooling towers have tested positive for the legionnaires’ bacteria and were remediated last week.