Unknowns are scary -- and our repertoire on Ebola is far from complete. Viruses can mutate and outwit us. But some things we do know: The average incubation period for Ebola is eight to 10 days, the longest incubation period is 21 days, and patients are not contagious until they show symptoms.
We have to work with these facts. To stop the outbreak we have to quickly diagnose Ebola, immediately isolate anyone with the virus and trace his or her contacts so they can be monitored for early signs of the illness.