The Centers for Disease Control and Prevention issued its highest level of travel notice today, urging people to avoid travel to Guinea, Liberia, and Sierra Leone. The three countries are currently experiencing the worst Ebola outbreak on record.
To give you an idea of how dire this is, on July 31 these are the only three places on Earth with a CDC Level 3 travel warning.
The CDC's statement "urged" all residents to avoid "nonessential" travel to the area. That pretty much means stay out unless you're an aid worker.
Here's a section of the notice about Liberia:
This recommendation to avoid nonessential travel is intended to facilitate control of the outbreak and prevent continued spread in two ways: to protect US residents who may be planning travel to the affected areas and to enable the Liberian government to respond most effectively to contain this outbreak. CDC remains committed to the multinational effort to assist Liberia in controlling the outbreak and is scaling up its response activities by, among other things, deploying additional staff to the affected countries. International humanitarian assistance must continue, and CDC encourages airlines to continue flights to and from the region to facilitate transport of teams and supplies essential to control the outbreak.