" The Ebola virus particle contains only seven different proteins—seven distinct types of large molecules arranged in a long braided structure that is the stringy Ebola particle. Three of these proteins are vaguely understood, and four of the proteins are completely unknown—their structure and their function is a mystery. Whatever these Ebola proteins do, they seem to target the immune system for special attack. "

― Richard Preston , The Hot Zone: The Terrifying True Story of the Origins of the Ebola Virus