Third U.S. Health Worker Infected With Ebola

A Massachusetts doctor has been identified as the third U.S. health worker to be infected with the Ebola virus in West Africa.

Rick Sacra, 51, was treating pregnant women in the ELWA Hospital in Monrovia, Liberia, when he was infected, according to missionary group SIM.

Sacra, an assistant professor at University of Massachusetts Medical School, was not treating Ebola patients in the hospital's separate Ebola isolation facility, the group said, adding that it was unclear how he contracted the virus. All infected U.S. health workers were working at the ELWA hospital when they contracted the virus.