Researchers at Children's Hospital in Boston built the app with MIT Media Lab and the support of Google.org, a philanthropy of the search engine company.
With the app, iPhone users can get information on outbreaks of disease. They can also be notified on the device or by e-mail when new outbreaks are reported nearby.
And the app even alerts a user when the customer enters an area where outbreaks have been reported.
The app relies on data gathered at the HealthMap Web site. HealthMap.org was started three years ago to gather information about infectious disease outbreaks.
Officials say the app is the first time users have the opportunity to submit information about disease outbreaks, including school closings or overcrowding at a local hospital.