New Hampshire health officials have confirmed a fifth case of Legionnaires’ disease in the city of Hampton, NH, but have yet to identify the source of the infections. (Hampton is approximately 50 miles north of Boston.)

Health officials said they’re working with the Centers for Disease Control and Prevention to try to locate the source of the infections and ensure there is no ongoing public health risk.

“I assure you that our staff has been working day and night since we’ve identified the cluster,” said Lisa Morris, director of the New Hampshire Division of Public Health.