World Health Organization (WHO) officials declared the Ebola outbreak in West Africa an international health emergency today. WHO officials say that although Ebola is a known and containable disease, a “coordinated international response” is needed to suppress the ongoing outbreak.

"The possible consequences of further international spread are particularly serious in view of the virulence of the virus, the intensive community and health facility transmission patterns, and the weak health systems in the currently affected and most at-risk countries," WHO officials said Friday, according to CNN. "A coordinated international response is deemed essential to stop and reverse the international spread of Ebola.”

WHO reiterated that they are not overly concerned with Ebola becoming a major health problem in developed nations. First world countries have the medical and sanitary infrastructure in place to contain the virus. But, without international help, the virus could continue spreading throughout less developed areas of Africa.

Leaders from affected areas say their countries are already utilizing all internally available resources.  Liberian President Ellen Johnson Sirleaf says this is why international help is crucial.

"The scope and scale of the epidemic ... now exceed the capacity and statutory responsibility of any one government agency or ministry,” she said.

Where might the Ebola outbreak spread to next? Officials say west Africa is far and away the most at-risk region. 55% of people travelling out of regions afflicted by the virus stay within Africa. 29% go to Europe.

Here’s a chart, courtesy of Bio.Diaspora, showing the final destinations of travelers leaving affected areas:

Derek Gatherer, a bioinformatician who has studied the current Ebola outbreak extensively, told Vox that the outbreak could reach endemic levels in the most-affected regions if not treated immediately.

"The worst-case scenario is that the disease will continue to bubble on, like a persistent bushfire, never quite doused out,” Gatherer said. "Previous successful eradications of Ebola outbreaks have been via swamping the areas with medical staff and essentially cutting the transmission chains. Doing that here is going to be very difficult and expensive. We have little option other than to pump in resources and engage with the problem using the tried-and-tested strategy—but on a scale previously unused."

Sources: CNN, WHO, Vox