The Hot Zone post 2

This part of the book seemed less informative and more active. What I want to know is why this strain of Ebola doesn't effect the monkeys the same way as the others do? For instance why did the animals and humans suffering from the Zaire strain show red eyes, while the monkeys in Reston just seemed to be suffering from SHF? And what significance will the other entrance to room H have, the one that's alluded to during Gene Johnson's pre-op of the building?