Ebola killed 5,000 gorillas

Urgent need for a vaccination campaign

Protected habitat of apes populations. Peter Walsh, Max Planck Institute for Evolutionary Anthropology
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Outbreaks of the deadly Ebola disease in Africa have been associated with the death of chimpanzees and gorillas in the neighboring forests in recent years. It was highly controversial, whether it was only isolated events or signs of mass extinction among the monkeys. Now an international research team has ended this debate with new findings that convincingly prove that Ebola killed more than 5, 000 gorillas in a single protected area in a short time. A targeted vaccination campaign could significantly reduce the devastating effects of Ebola on free-living gorillas and chimpanzees, according to the results of the study now published in the science journal Science.


Ever since the 2003 report of the deaths of many monkeys, skeptics have repeatedly questioned whether this is really a mass extinction and whether Ebola really is the cause. The study, published under the direction of Magdalena Bermejo of the University of Barcelona, ​​dispels these doubts because it was conducted in a well-controlled population of gorillas. Genetic tests clearly confirmed Ebola as a cause of death.

Bermejo and her colleagues from the Max Planck Institute for Evolutionary Anthropology and Uppsala University showed for the first time that 93 percent (221 out of 238) of the individually known gorillas in the Lossi Conservancy in northwest Congo were killed by Ebola during the 2002 and 2003 outbreaks. By counting, the researchers showed that the 95 percent gorilla death rate covers a much larger area of ​​several thousand square kilometers. Even the chimpanzees were severely affected with a death rate of 77 percent.

A quarter of the world's gorilla population died?

However, Lossi is just one of many other sites with gorillas and chimpanzees mass killing caused by Ebola in the past twelve years. Exact numbers of how many monkeys have actually died are not available. But given the large number of affected habitats, these Ebola outbreaks are estimated to have killed about a quarter of the world's gorilla population. Particularly strong were the consequences of large, far-away protected areas, which were actually intended as the last refuge for the monkeys. Although Ebola has not completely eradicated the monkeys there, it once greatly decimated large populations, making them far less resistant to illegal hunting and other dangers. display

Also worrying are new studies showing that Ebola infections are rapidly spreading towards some of the last protected areas remaining in the region. However, the results of the new study suggest that protecting the remaining monkey populations against Ebola could be much easier than previously thought. In Lossi, most of the gorillas were not directly infected by a host in the protected area, as previously thought. Rather, the epidemic seems to be moving from one social group to another.

Good opportunity for targeted vaccination strategies

This opens up the possibility of targeted vaccination strategies that, by disrupting the transmission chain, could be much more efficient than outbreaks that are completely driven by direct transmission. The predictability of the transmission rate of the Ebola infection wave would allow the vaccine to be placed directly in front of the advancing wave of infection, thus stopping it.


The lack of vaccination programs so far is not due to a lack of vaccination options, since various vaccinations mean that it is now possible to protect laboratory monkeys from Ebola and large vaccine laboratories are interested in helping. "Rather, it is the uncertainty over whether a comprehensive Ebola control is necessary or even possible, which has paralyzed the major donors and aid organizations, " says Peter Walsh, co-author of Study by the Leipzig Max Planck Institute for Evolutionary Anthropology. "We hope that the clarity of our findings will encourage some public or private donors to provide the $ 2-3 million needed to develop a safe and effective Ebola vaccine for free-ranging monkeys needed. "

Vaccination instead of poaching

Walsh emphasizes that Ebola vaccine is a cost-effective method of protecting monkeys. "Many of the wildlife conservationists are intimidated by the initial cost of vaccination and instead would rather invest the money in controlling poaching. What they do not take into account is the fact that Year Ebola vaccine could save as many monkeys life as ten years fighting against poaching, we have to do both. "

Walsh also emphasizes that Ebola has the potential to destroy years of investment in ecotourism within a short period of time. For example, the gorilla settlement program of Magdalena Bermejo in the Lossi Sanctuary in the mid-1990s, in cooperation with the European Union's Ecosystem Forestiere d Afrique Centrale (ECOFAC), was also set in motion to assist the local community Population to earn a living from ecotourism. But Ebola not only killed many of the gorillas settled in Lossi, but also neutralized years of investments in ecotourism in the neighboring Odzala National Park by destroying the gorillas there.

"We are in a period when relatively little investment in both Ebola control and poaching could make it possible in the long run to truly secure the future of our closest relatives", says Walsh. "Let's not miss this opportunity."

(idw - MPG, 11.12.2006 - DLO)