Two American Peace Corps volunteers have been isolated after being exposed to the widening Ebola outbreak in West Africa. This is the largest known outbreak on record with roughly 700 deaths across Liberia, Guinea and Sierra Leone.

Americans living and working abroad are among the infected. From CBS News:

There are at least two U.S. citizens known to have contracted the disease, both medical workers in Liberia, Dr. Kent Brantly and Nancy Writebol.

Another American citizen, Patrick Sawyer, died after flying from Liberia to Lagos in Nigeria. He had been a consultant with Liberia's finance ministry and was originally from that country.

On Wednesday, following the news of the two exposed volunteers, the Peace Corps took some precautionary action: