Where the Ebola outbreak is most likely to spread next

August 2014 – DISEASE – There are suspected Ebola cases in Europe, Asia, and North America but none are confirmed. Public health officials are relatively unconcerned about Ebola becoming a big problem in the developed world. That’s because outbreaks persist in countries with poor sanitation and a shortage of resources to contain them, not in resource-rich places like the US. For this reason, spread within Africa is really what public health officials are worried about. “Our first concern is that this is going to go into adjacent areas through people traveling in the region,” said Daniel Bausch, associate professor at the Tulane University School of Public Health and Tropical Medicine, who is working with the WHO and MSF on the outbreak. “In the short term, the main vector is the traveler: local people traveling from one village to the next, on more regional scale, plane travelers.” This pie chart shows the final destinations of travelers originating in the three countries currently most affected by Ebola. As you can see, travel from Sierra Leone, Guinea and Liberia within the continent is much more prevalent than travel elsewhere. All countries in West Africa are already on alert. National authorities in Ghana, Nigeria, Togo and the Côte d’Ivoire are working with the WHO on prevention efforts and monitoring potential cases. To do this, contact tracing is essential, said Bausch.

“With Ebola outbreaks, most of the time there’s one or very few introductions of the virus from the wild into humans, and all the transmission after that is human-to-human transmission. So people who are traveling locally as well as on planes and other modes of transport, that’s the way this would get around.” These efforts are already underway in Nigeria, where the disease hasn’t yet turned into a full-scale outbreak but there are concerns that it might. Some 70 people who came into contact with a recently diagnosed Ebola doctor have been quarantined, said Dr. Ezie Patrick, the executive director for Africa with the World Medical Association who is based in Nigeria. But resources to deal with more potential cases aren’t presenting themselves, he added. “In the current process, we don’t have the facilities to isolate the patients,” he said. When there’s a suspected case of Ebola, it’s reported to the Nigerian centers for disease control and they take over the case management. Patients often need to be moved from their homes to city centers. “When patients are moved from a rural to urban areas,” Patrikck added, “the risk of spread increases exponentially.” Even if the outbreak didn’t move across any other country border, intensification within the already affected areas is the most immediate health threat. “The worst-case scenario is that the disease will continue to bubble on, like a persistent bushfire, never quite doused out,” said Derek Gatherer, a Lancaster University bio-informatician who has studied the evolution of this Ebola outbreak. “It may start to approach endemic status in some of the worst affected regions. This would have very debilitating effects on the economies of the affected countries and West Africa in general.”

This dire situation could come about because of a “persistent failure of current efforts,” he added. “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.” Resources are already extremely constrained in most of the countries affected right now. As Dr. Bausch said, “If you’re in a hospital in Sierra Leone or Guinea, it might not be unusual to say, ‘I need gloves to examine this patient,’ and have someone tell you, ‘We don’t have gloves in the hospital today,’ or ‘We’re out of clean needles,’ — all the sorts of things you need to protect against Ebola.” When Bausch was in Sierra Leone last month, he said all the nurses went on strike in one of the hospitals where he was working. “There were 55 people in the Ebola ward,” he said, “and myself and one other doctor.” He’d walk into the hospital in the morning and find patients on the floor in pools of vomit, blood, and stool. They had fallen out of their beds during the night, and they were delirious. “What should happen is that a nursing staff or sanitation officer would come and decontaminate the area,” he said. “But when you don’t have that support, obviously it gets more dangerous.” So the disease spreads. In these situations, local health-care workers — the ones most impacted by the disease — start to get scared and walk off the job. And the situation worsens. -VOX