He got sick during the flight.
It should be noted....this wasn’t identified until mid-70’s, and scientists tend to believe it crossed over from monkeys.
It should also be noted that ALL of the symptoms of Ebola...relate to the flu. The minute you show any of these common five items...it could be flu or it could be Ebola.
If you look over the destruction to the body....it goes straight into the liver. The ten percent of society that survive it? Nothing much is said over how they do it, and you have to wonder if they suffer serious liver damage as part of the end-result.