Fifteen countries have strict restrictions on traveling to and from Uganda, including the US.
More than 750 have died from Ebola in the past 2 months.
The antiviral would be given as post-exposure prevention.
The case-fatality rate this year is now 24%.
A second American has contracted Ebola in the Democratic Republic of the Congo, and the death count has now topped 700.
Acting CDC Director Jay Bhattacharya addressed CDC staff in an internal email on outbreak response.
The strike, over poor pay and scant supplies, could hamstring a clinical trial of potential therapies.
The first patient was randomized today in a clinical trial to see whether 2 antiviral therapies can improve survival in people with Bundibugyo virus.
Investigators are tracking people who may have been exposed to Ebola in more DR Congo provinces.
If the Ebola outbreak continues to spread, it could cost the continent as much as $3.6 billion.
