From the text:
As it jumped from bed to bed, killing patients left and right, doctors began to notice signs of mental derangement, psychosis, depersonalization, zombie-like behavior. Some of the dying stripped off their clothes and ran out of the hospital, naked and bleeding, and wandered through the streets of the town, seeking their homes, not seeming to know what had happened or how they had gotten into this condition. There is no doubt that Ebola damages the brain and causes psychotic dementia. It is not easy, however, to separate brain damage from the effects of fear.