Malaria Hits One In 12
Of World Population
By Steve Connor
10 March 2005
The
Independent
More than half a billion people are suffering
from malaria today, twice as many as scientists thought had been affected
by one of the biggest killers in the developing world.
The new figures
are the result of detailed research that gives the most accurate assessment
yet of the disease that kills at least a million people a year. Scientists
now believe there are about 515 million cases of malaria out of 2.2
billion people who are at risk - about a third of the world's population.
The discovery throws
the slow progress of the world's fight against malaria into sharp relief.
In countries such
as Malawi, malaria claims more lives each year than Aids, but attracts
a fraction of the attention. Coachloads of overseas visitors come to
view the Aids projects run by Médicins Sans Frontières
in the country, but few are interested in malaria.
Malaria has never
captured the public imagination as Aids has done, even though children
are its chief victims. Malaria is old and Aids is new. Most important,
malaria is not a disease that affects the West - except for those fortunate
enough to holiday in the tropics - whereas Aids threatens us all. The
scale on which the parasite, transmitted by the mosquito, kills is breathtaking.
A new malaria map of the world suggests that the incidence of malaria
in Africa is some 50 per cent higher than previous estimates by the
World Health Organisation and up to 200 per cent higher for areas outside
Africa, such as in south-east Asia.
Professor Robert
Snow, of the Wellcome Trust Research Laboratories in Nairobi, Kenya,
who led the study, warned that the true figures for the spread of malaria
across the globe may even be higher than these latest estimates.
"We have taken
a conservative approach to estimating how many attacks occur globally
each year but even so the problem is far bigger than we previously thought,"
he said.
"Getting numbers
right is important. Not knowing the size of the problem limits our ability
to articulate how much money we need to tackle the problem - not knowing
where the problem is located means you can't spend wisely," he
said.
For 40 years chloroquine
was the standard treatment for malaria. Patients swallowed a couple
of pills at the onset of the fever and within 48 hours they would be
better. It was safe, effective and cheap.
But over recent
decades, a drug-resistant strain of malaria, Plasmodium falciparum,
has been growing in Africa and now accounts for well over 90 per cent
of cases. Surveys in east Africa show that almost two-thirds of patients
given chloroquine and nearly half of those on its successor, sulfadoxine-pyrimethamine,
have died. The only effective therapies are those based on artemesinin,
a drug derived from a weed that grows wild in Africa and the Far East.
Six years ago the
WHO set a target to halve the number of deaths by 2010, but instead
the toll has risen by at least a quarter, and in some areas by as much
as 50 per cent, because victims have not had the right drugs. Hundreds
of thousands of children have died needlessly and the disease has gone
virtually unnoticed in the West. Malaria has been a scourge of humanity
since antiquity and although it is largely preventable with the use
of mosquito nets and insecticides it remains one of the biggest killers
of children under five.
The disease, caused
by a blood parasite transmitted in a mosquito bite, was eradicated from
industrialised countries of the northern hemisphere about half a century
ago but it still threatens some 40 per cent of the world - mostly in
the poorest countries of Africa, South America and southern Asia.
More than 80 per
cent of malaria deaths occur in sub-Saharan Africa and the WHO estimates
that every day the disease kills 3,000 children. Those that survive
often suffer brain disease or paralysis. Economists for the United Nations
have identified malaria as one of the top four causes of poverty with
many African governments spending up to 40 per cent of their total health
budgets on the medical care or control of malaria.
In Africa alone
the total economic burden of malaria is estimated at $12bn (£6.7bn)
a year, according to the WHO.
The deadliest form
of malaria is the single-cell parasite Plasmodium falciparum and the
latest estimates of its spread suggest that there are more cases in
south-east Asia than previously suggested.
"Our work has
demonstrated that nearly 25 per cent of worldwide cases occur in south-east
Asia and the western Pacific, whereas most people regard Plasmodium
falciparum as a problem particular to Africa," Professor Snow said.
In 1998, the WHO
produced estimates of the extent of malaria based on reports of cases
compiled by individual countries and data on the intensity of transmission
within a particular region. However, it is widely accepted that the
two methods are flawed because many cases of malaria are not reported
to the authorities and transmission rates can vary widely because of
local factors such as the weather.
The new study uses
a more proactive approach with a combination of epidemiological, geographical
and demographic data. "We have taken a science-driven approach
to working out who is at risk, where they are located and what their
chances would be of developing an attack of malaria," Professor
Snow said.
©2005 Independent
News & Media (UK) Ltd.