There is an explanation. Our fearless leader WANTS to bring Africans into the USA for treatment. In his “mind”, it’s unfair for Africans to have the disease and for Americans to not have it.
So he has deliberately refused to close the borders to people from infected countries. Intentionally, with full knowledge and awareness of the consequences.
I think you are correct. This is under “List of ebola outbreaks in Wiki; very embarrassing for me as a U.S.citizen:
2013-2014
Guinea
Liberia[note 5]
Nigeria
Senegal
Sierra Leone
United States
(Which country is the odd man?)