Ever hear of quarrantine?
ships arriving from ports with a disease were required to not disload for 40 days.
so no, don' t stop flights from Africa, but arriving passengers shoul be reqired to stay in holding facilities for 5 days or 10 days and monitored for symptoms.
True,it would be expensive, but so is an epidemic.
factoid: Elizabeth Seton's husband traveled to Italy in hopes it would help his lungs, but died when the ship was in quarrentine...luckily for her, his Italian friends took her in when they were allowed to disembark.
factoid 2: before Jimmy Carter closed them, the US Public health service had a network of hospitals in port cities to treat sailors who were sick.