COVID-19 Report - 18

CASE STUDY 2: THE ROLE OF DEFORESTATION IN EBOLA OUTBREAKS IN WEST AND CENTRAL AFRICA
Suspected host species:
Fruit bats (reservoir),
primates (intermediate) 51

Number of deaths:

11,325

(2014-2016 outbreak) ;
52

2,268

Estimated economic impact:

(2018-2020 outbreak)

53

Over the last 20 years, there have been numerous Ebola
outbreaks in West and Central Africa. The virus is highly
infectious and often fatal, with a mortality rate of around
50 per cent. The largest outbreak in recent years started
in Guinea in 2014 and then moved across land borders to
Sierra Leone and Liberia.56 During this outbreak, 11,325
people died from Ebola57 and 17,300 children lost one or
both parents to the virus.58
Although it is difficult to trace the exact drivers for
these specific outbreaks, many researchers have directly
linked the rates of deforestation in West and Central
Africa to an increased likelihood of Ebola outbreaks. In
deforestation fronts in these regions, forest loss is rapidly
increasing at a rate already higher than 0.5 per cent per
year. In the Guinean forests, which span West Africa, the
cultivation of crops including cacao, palm oil and rubber
is driving extensive forest clearance and widespread
fragmentation.59 The Congo Basin, which contains 20 per
cent of the world's tropical forests, is losing over 1 million
hectares of tree cover per year, driven by increasing
smallholder forest clearance for agriculture as well as
large-scale commercial logging.60,61 Rapid deforestation
risks leaving these ecosystems severely fragmented and
degraded.
Researchers believe that the extensive deforestation
in these regions increases contact between humans
and potential Ebola host species, such as fruit bats and
primates, leading to greater potential for transmission
from hosts to humans.62 The underlying assumption is
that transmission is more likely in fragmented forests due
to an increased density of some host species and closer
proximity between humans and those host species.63 For
example, some researchers have shown that the number
of tropical fruit bats may increase in fragmented habitats
(while insectivorous bats decrease), and the density of
some primate populations may also increase following
habitat disturbance.64 Likewise, fragmentation creates
more entry points for humans to venture into natural
habitats to hunt or forage.65 Although the mechanisms of
Ebola transmission are not certain, it is highly plausible
that humans living close to fragmented forest edges have
greater exposure to zoonotic diseases due to an increased
risk of contact with host species.
The 2014-2016 Ebola outbreak had devastating social and
economic impacts. Researchers estimate that economic
losses were equivalent to around US$2.8-32.6 billion in
lost GDP for the three affected countries - Sierra Leone,
Guinea and Liberia.66 In addition, more than 33 weeks
of education were lost due to school closures,67 and
production volumes of staple crops were reduced by 12
per cent.68 More recently, 2,268 people died during the
2018-2020 Ebola virus outbreak in Democratic Republic
of the Congo.69

WWF INTERNATIONAL 2020

© Michel Gunther / WWF

US$2.8

billion
in lost GDP for affected countries,54
COVID-19 Report

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