We don't really know that. (We do know that it does not transmit over long distances outdoors). "Close contact" is a term of art that can mean a couple of different things. In a hospital, it means 36"-72" and I'm sure EHF transmits that far, easily.
But the keys to this situation are crowd distances (6'-12') and how infectious contaminated surfaces (blood and vomit) are. If EHF goes 12" and/or if it is persistent on environmental surfaces, once it winds up and lets go in Lagos, it will be very bad.
It can be transmitted through any bodily fluid, including sweat. Or a mosquito bites an infected person and then moves on to other hosts.