Researcher links Ebola to forests

A study found deforestation in West Africa displaced bats and spread the virus to humans.

by Ethan Nelson

A University of Minnesota researcher’s recent work may have found a link between deforestation and the ongoing Ebola epidemic.

As large corporations have spent the past two decades cutting down large forested areas in West Africa to make room for plantations, displaced bats — some of which can carry Ebola — have begun moving to those plantations. The people who work on them are then exposed to the disease.

Though researchers disagree on exactly which species of bat was displaced, reports analyzed by University researcher Robert Wallace show that major policy changes in West African countries can promote the emergence of infectious diseases.

“This kind of thing just doesn’t come around randomly,” said Wallace, who is also a visiting scholar at the Institute for Global Studies.

Various companies in Guinea and Liberia have replaced much of the countries’ forests with large plantations, Wallace said, which make for ideal habitats for fruit- or insect-eating bats.

Katey Pelican, a veterinary population medicine associate professor who studies wildlife health, said influenza and HIV are examples of other diseases that transmit from animals to humans.

“These changes in land use and human population and movement seem to be associated with emerging diseases,” she said.

Nearly 30 percent of Liberian land is leased to multinational companies, Wallace said. As West African countries have become more welcoming to those companies, they have begun to lease more land, he said.

Ebola has been circulating in West Africa for the last decade, according to the study. Cases of the deadly virus were documented several times in the past, but the circumstances weren’t right for it to spread beyond a few isolated villages in the jungle, Wallace said.

“Previously, there wasn’t enough to create a chain of transmission,” he said.

While other studies have focused on inadequate local health care infrastructures and the lack of a coordinated global response as causes of the Ebola’s spread, Wallace’s study focused more on the global economy, he said.

Other experts have suggested that the virus’ spread was the result of a spontaneous outbreak, said Dominic Travis, an associate professor of veterinary population medicine.

Travis, whose research focuses largely on the intersection of human and wildlife health, said replacing forests with plantations is becoming more common.

“There’s this pattern of interesting yet scary diseases emerging via this kind of relationship, and especially with bats,” Travis said.

A report the World Health Organization released last month also connects deforestation to the beginning of the Ebola outbreak.

The first documented cases of the most recent Ebola outbreak were centered north of the Guinean city of Guéckédou, located in the middle of a forest with a population of about 200,000. The first documented case was an 18-month-old boy who had been playing near a tree stump infested with bats.

Since the outbreak began in March, 8,810 people have died of the virus.

Now, the outbreak’s spread seems to be slowing down. For the first time since June, there have been fewer than 100 new confirmed cases reported in a week in Sierra Leone, Guinea and Liberia combined, according to data from WHO.

Travis said it’s not clear whether the outbreak is slowing naturally or is a result of relief efforts.

“If we let up, there’s a danger this thing will blow back up,” Travis said.