In just four decades, Ebola has
wiped out one third of the world’s chimp and gorilla populations. If it
continues, the results will be devastating.
While
coverage of the current Ebola epidemic in West Africa remains centered
on the human populations in Guinea, Sierra Leone, and Liberia, wildlife
experts’ concern is mounting over the virus’ favorite victims: great
apes.
Guinea, where the epidemic originated, has the largest population of chimpanzees in all of West Africa. Liberia is close behind. Central Africa is home to western lowland gorillas, the largest and most widespread
of all four species. Due to forest density, the number of those
infected is unknown. But with hundreds of thousands of ape casualties
from Ebola, it’s doubtful they’ve escaped unscathed.
Animal activists are ramping up efforts to find an Ebola vaccine for
great apes, but with inadequate international support for human
research, their mission could be seen as competing with one to save
humans. Experts from the Jane Goodall Institute of Canada insist such apprehension would be misplaced. Two streams of funding—one for humans, one for apes—can coexist in this epidemic, they assert, and must.
“The media was really focusing on human beings,” Sophie Muset,
project manager for JGI, says. “But it has been traumatic to [the great
ape] population for many years.”
Over the course of just four decades, Ebola has wiped out one third of the world’s population of chimpanzees and gorillas, which now stand at less than 300,000 and 95,000 respectively.
The
first large-scale “die-offs” due to Ebola began in the late 1990s, and
haven’t stopped. Over the course of just four decades, Ebola has wiped
out one third of the world’s population of chimpanzees and gorillas,
which now stand at less than 300,000 and 95,000 respectively. Both
species are now classified as endangered by the International Union for Conservation of Nature; western gorillas are “critically” so.
One of earliest Ebola “die-offs” of great apes came in 1994, when an Ebola outbreak in Minkébé decimated the region’s entire population—once
the second largest in the world. In 2002, an outbreak in the Democratic
Republic of Congo wiped out 95 percent of the region’s gorilla
population. And an equally brutal attack broke out in 2006, when Ebola
Zaire in Gabon (the same strain as the current outbreak) left an
estimated 5,000 gorillas dead.
The
dwindling population of both species, combined with outside poaching
threats, means Ebola poses a very real threat to their existence. To
evaluate the damage thus far, the Wild Chimpanzee Foundation is
conducting population assessments in West Africa, with the goal of
getting a rough estimate of how many have died. Given the combined
damage that Ebola has inflicted on this population, the results are
likely to be troubling.
In a way, great apes are Ebola’s perfect
victims. Acutely tactile mammals, their dynamic social environments
revolve around intimacy with each other. Touching hands, scratching
backs, hugging, kissing, and tickling, they are near constantly
intertwined—giving Ebola a free ride.
In a May 2007 study from The American Naturalist,
researchers studying the interactions between chimpanzees and gorillas
found evidence the Ebola can even spread between the social groups. At
three different sites in northern Republic of Congo, they found bacteria
from gorillas and chimps on the same fruit trees. For a virus that
spreads through bodily fluids, this is an ideal scenario.
“They
live in groups [and] they are very close,” says Muset, who has worked
with chimps on the ground in Uganda and the DRC. “Since Ebola
transmission happens through body fluids, it spreads very fast.”
For gorillas in particular, this culture proves deadly, making their mortality rate for this virus closer to 95 percent.
But like humans, the corpses of chimpanzees and gorillas remain
contagious with Ebola for days. While the chimps and gorillas infected
with Ebola will likely die in a matter of days, the virus can live on in
their corpse for days—in turn, spreading to humans who eat or touch
their meat.
It is one such interaction that could result in the
spread from apes to humans. But in this particular outbreak, experts
have zeroed in on the fruit bat (believed to be the original carrier) as
the source. The index patient, a 2-year-old in Guinea, was reportedly
playing on a tree with a fruit bat colony.
Whether or not a great
ape was involved in the transmission of the virus to humans during this
outbreak is unknown. Such an interaction is possible. Interestingly,
however, it’s not the risk that great apes with Ebola pose to humans
that wildlife experts find most concerning. It’s the risk that their
absence poses to the wild.
Owing to a diet consisting mostly of
fruit, honey, and leaves, gorillas and chimpanzees are crucial to forest
life. Inadvertently distributing seeds and pollen throughout the
forest, they stimulate biodiversity within it. Without them, the
biodiversity of the vegetation may plummet, endangering all of the
species that relied on it—and, in turn, the people that relied on them.
“They are not the only ones who act as seed dispersers,” says Muset.
“But they are the big players in that field. So when [a die-off]
happens, it can decimate an entire forest.”
Wildlife experts worldwide are working
to raise both awareness and funds for a vaccination process. It’s a
battle that she says was gaining speed last January, when a researcher
announced that he had found a vaccine that could work in chimps But as
the epidemic in West Africa grew, the focus shifted.
But Muset says its time to return to the project. “There is a
vaccine, but it has never been tested on chimpanzees,” she says.
“Progress has been made, and preliminary testing done, but testing in
the field need to happen to make it real.”
As to the question of
whether it’s ethical to be searching for a vaccine for wild animals when
humans are still suffering as well, Muset is honest. “For sure there is
a direct competition here. But wildlife and humans have a lot of
diseases in common that they can transmit from one to the other,” she
says. “And I think you can think of it as two streams of funding, one to
wildlife and the other to human beings.”
While it’s great apes
that wildlife experts are seeking to save, human nature as a whole,
Muset argues, is at stake. “If you want a healthy ecosystem, the more
you have to invest in health for wildlife and humans,” she says. “Then,
the better place it will be. Because really, it all works together.”
No comments:
Post a Comment