Deadly malaria infects half a billion
Pastor Dale Morgan
Deadly malaria infects half a billion*
Tim Radford, science editor
Sept 16, 2006
The Guardian
More than half a billion people - nearly double previous estimates -
were infected by the deadliest form of malaria in 2002, scientists
reveal in a report out today.
They calculate that one in three in the world - a total of 2.2 billion
people - are at risk from the mosquito-borne parasite Plasmodium falciparum.
The discovery that malaria is far more prevalent than anyone had
realised is a jolt to public health chiefs the world over. The disease
claims 1 million lives a year in sub-Saharan Africa alone, most of them
children under five.
Of the four malaria parasites, Plasmodium falciparum is by far the most
dangerous, especially to the undernourished, weak or very young. It is
prevalent throughout the tropics, and has developed resistance to
successive drugs.
Health experts said the new figures were alarming. "There is much more
malaria than has previously been estimated in Asia, than we recognised
before," said Joe Lines of London's School of Hygiene and Tropical Medicine.
In 1998 the World Health Organisation put the global incidence of
malaria at 273m cases. But that was an estimate, with no reliable data
available.
New research published in Nature from Bob Snow, of the Kenya Medical
Research Institute in Nairobi, and the Centre for Tropical Medicine at
the University of Oxford, calculates that in 2002 there were around 515m
cases worldwide. In Africa in that year, there were 365m cases: 1m new
infections every day.
"This is Plasmodium falciparum, the most deadly of the malaria
parasites," Prof Snow said. "We have worked very hard to get the
credible estimate for deaths from malaria in Africa that is largely used
by the WHO: it is about a million people each year. Outside Africa, we
know surprisingly little."
Control depends on safe water, efficient public health measures,
education, supplies of up-to-date drugs and bednets to protect against
the parasite-carrying mosquito.
There is hope: geneticists have unravelled the DNA of both mosquito and
parasite, and have begun to look for weak spots that could lead to weapons.
A new vaccine tested on more than 2,000 children in Mozambique last year
offered at least partial protection against the disease, and confirmed
that an effective vaccine is at least feasible. In January, the British
government, the US billionaire Bill Gates and the Norwegian government
promised more than £1.5bn for new vaccines against childhood diseases,
including malaria.
But malaria is both a disease of poverty and a cause of poverty. Sick
people cannot work. Africa is already hit by a high incidence of HIV
infection and tuberculosis, and malaria alone is estimated to cost the
economy of the continent $12bn (£6.3bn ) a year. But that too could be
an underestimate.