Global toll of snakebites underrated as crisis grows in anti-venom stocks

September 27, 2015 11:00 pm

 

Many people survive bites but often at the cost of their legs and arms. Photo / Getty Images

Deaths from snakebites are on the rise, recent evidence showing that
hundreds of thousands of individuals across the globe every year are
dying as a result of encounters with cobras, vipers or kraits.
It’s
estimated a resurgence of snakebites in Africa and Asia could soon
account for a quarter of a million deaths every year. In the past,
deaths from snakebites have been poorly reported and the extent of the
crisis underestimated.
However, doctors in India recently carried
out a detailed survey and discovered around 46,000 people in the
country were killed by snakebites every year. Official statistics
suggested the figure was only 1000. Similarly in Bangladesh, a detailed
survey revealed the annual snakebite death toll there was about 6000.
“These
two sets of figures are significant, for they suggest the estimate made
by a World Health Organisation-sponsored study that snakes kill around
100,000 people a year across the globe may be a serious underestimate,”
said Oxford University tropical medicine specialist Professor David
Warrell.

“We now know more than 50,000 men, women and children die in
India and Bangladesh from snakebites each year, and that figure is
coming from just two nations.
“We also know that countries such
as the Democratic Republic of Congo have enormous numbers of venomous
snakes but provide no reliable data of any kind about snakebite deaths
within their borders. So I would say it’s more likely 200,000 or
possibly more deaths a year are caused by snakes across the globe.”
In
developing countries struggling to cope with HIV, malaria, tuberculosis
and other diseases the problem of increasing snakebites is particularly
unwelcome.
“Many nations have no real knowledge of how bad the
problem is within their borders,” added Warrell. This is backed by the
United Nations, which has described snakebites as “a neglected threat to
public health”.
The death rate isn’t the only problem. Many
people survive bites but often at a terrible price. “Victims, who are
often agricultural workers, lose legs or arms or fingers and can’t hold
down their jobs. Children’s limbs become gangrenous after being bitten
by snakes and have to be amputated. They are blighted for life as a
result. Girls have their marriage prospects ruined. The price of
surviving a snakebite is often terrible.”
Lorenzo Savioli, a
former director of WHO’s department for the control of neglected
tropical diseases, said: “Snakebites cause severe disability, bring
misery to families and kill thousands. We need to act effectively to
control the problem.”
Dealing with snakebites will grow harder in
the next few years, because existing stocks of the important anti-venom
Fav-Afrique, made by UK-based Sanofi Pasteur, expire in June. The
company stopped producing the anti-venom last year. “We’re now facing a
real crisis,” said Gabriel Alcoba of Doctors Without Borders.
Pharmaceutical
companies in South Africa, India, Mexico and Costa Rica are working on
replacement anti-venoms, but these have yet to be tested or marketed and
may take years to be ready for wide use.
Scientists say a
handful of species are the main culprits for soaring snakebite deaths in
the developing world. These include carpet vipers, spitting cobras and
puff adders in Africa and spectacled cobras, common kraits, Russell’s
vipers and saw-scaled vipers in India and Southeast Asia. In most cases
the creatures kill by injecting a toxin that either causes serious
internal bleeding or paralysis.
When they bite their natural prey
– rats or mice, for example – this kills them almost instantly. Larger
humans can take much longer to succumb. But as veins and arteries leak,
and serious internal bleeding takes place, death can come in days.
But
these aren’t necessarily the world’s most venomous snakes. The black
mamba’s venom is more toxic than the carpet viper’s, for example, but
the mamba rarely comes into contact within humans. By contrast, the
carpet viper is often found in fields and undergrowth.
“Farm
workers stand on them or startle them and get bitten,” said Warrell.
“Obviously, anti-venom is a crucial part of any treatment. But just
acknowledging the problem and its extent would be a major breakthrough.
Simple preventive measures could be introduced. Providing [bare-footed]
farm workers with boots would be an enormous help.”
Surveys show
46,000 people in India die from snakebites annually.
6000 die of bites each year in Bangladesh.

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