When an Ebola outbreak lasts for months and continues to show up in new cities, health officials take notice. That's exactly what's happening in West Africa. An outbreak that started in Guinea last February has surged in the past few weeks. It's now the deadliest outbreak since the virus was first detected in 1976. Ebola often kills around two-thirds of the people it infects. And it kills quickly, sometimes within days, sometimes within weeks. That actually makes outbreaks relatively easy to stop, says UTMB’s Thomas Geisbert. “Typically an outbreak starts in Central Africa,” Geisbert says. “The WHO goes in and quarantines the area and within a few months, they've contained the outbreak.” But the pattern is different in West Africa, Geisbert says. The virus continues to pop up in new locations.