New Zealand researcher: Ebola linked to deforestation

Researchers have found a potential factor in the outbreak of Ebola virus - deforestation. Photo / 123RF

New research co-authored by a New Zealand scientist has linked deforestation in Central and West Africa to the deadly Ebola virus.

The study, published today in journal Scientific Reports, finds that forested areas that were being cleared were also hotspots for the bat-borne virus, which killed more than 11,000 people in West Africa and caused global panic in the most recent epidemic.

While previous research has addressed how the virus spread among human populations, and how it could be contained after an outbreak, scientists have been trying to better understand the processes that led to the outbreak, in hope of stopping future epidemics before they can start.

Massey University's Dr David Hayman and colleagues looked at forested regions in Central and West Africa where Ebola outbreaks had already occurred, and then analysed how fragmented the forest cover was in these areas.

"This suggests that the risk of Ebola virus disease is increased for people in fragmented forest regions.""We found that Ebola virus disease outbreaks had occurred in areas that were hotspots of deforestation," Hayman said.

In this context, deforestation was a concern as it brought humans into contact with wild animals, some of which could infect people.

"In the case of Ebola virus, it appears bats are reservoirs, and although we do not know the exact mechanisms, other research has shown more generalist fruit bats, such as those that have been linked to Ebola virus, increase in numbers in fragmented forest patches," he said.

"Based on our finding, we speculate that when people fragment the forests they inadvertently are increasing the likelihoods that they will come into contact with Ebola virus hosts."

The new findings suggested that scientists monitoring Ebola should focus on the hotspot areas of habitat fragmentation.

"But more generally it would be good if decision-makers at the local, regional and national levels in these countries could attempt to manage human interactions with the environment in a way that does not lead to habitat fragmentation," he said.

A hammer-headed bat, which has been linked to Ebola virus and is found in Ghana and across the region studied. Photo / David Hayman

"This is much harder, because it means changing peoples' behaviour, but it's probably the most important message to come from this work."

Although Ebola typically occurs in outbreaks in tropical regions of Sub-Saharan Africa, Hayman said the study's main message - that we should consider how we interact with the environment - was applicable to any country.

"One of the problems with studies on African systems is that people think that they are only true for Africa, but that is misguided. It is easy to cast aspersions on people in other regions.

"Here in New Zealand people engage with the environment differently but there will still be consequences that should not be taken lightly."

The research follows another study, co-authored by Hayman and published last year, which used new algorithms to identify potential Ebola virus hosts that hadn't yet been identified as hosts and to map where they lived to help surveillance efforts.

The map shows areas where Ebola outbreaks have occurred, along with degrees of forest cover. Photo / David Hayman

This profile was built using the life history, physiological, and ecological attributes of the 21 bat species known to harbour filoviruses.

With 57 variables, from diet and reproductive behaviour to migratory patterns and species density, the algorithm predicted features that distinguished bats that had tested positive for filoviruses from other bat species with 87 per cent accuracy.

When the world's bat species were compared against this profile, many new potential bat hosts were identified based on their traits.

While many were found in sub-Saharan Africa, they were more widely distributed than first expected, ranging across Southeast Asia and Central and South America.

There was nothing to suggest New Zealand's native bat species could be affected.