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Decoding of malaria genomes opens new era public health

New drugs, new insecticides expected to revive struggle against a major killer

Today’s announcement of the decoding of the genomes of the most dangerous malaria parasite, Plasmodium falciparum, and of the most important mosquito which transmits it, Anopheles gambiae, signal a turning point for global public health. Now, the most advanced tools of science are at last being trained on one of biggest killers in the developing world.

"This is an extraordinary moment in the history of science," said Carlos Morel, director of TDR the Tropical Disease Research program. "At last, the enormous power of modern technology is penetrating the mysteries of an ancient disease, a disease which continues to kill millions."

Malaria infects more than 300 million people every year, killing at least one million of them. About 90% of the deaths are in children under five.

And it’s getting worse. Public health campaigns against malaria have been stymied over the last decade as both the mosquito and the parasite have evolved mechanisms to escape the limited, affordable technologies available in the developing world.

Drugs targeting the parasite are losing their effectiveness. Today, resistance to choloroquine, which is the cheapest and most widely used antimalarial, is common throughout Africa. The next most effective but more expensive drug, sulfadoxine-pyrimethamine (SP), is also succumbing to resistance in highly endemic areas of eastern and southern Africa.

The mosquito has proven just as wily a foe. Anopheles gambiae is an extremely efficient transmitter of the disease. Public health experts have long called the mosquito the “most important insect in the world.” Unlike other mosquitoes, A. gambiae has earned the epithet of “malaria machine” because it has a strong preference for humans and those humans within its range can be bitten literally hundreds of times a day. Elimination strategies, which have been successful in industrialized countries, have stalled in the developing world as cheap insecticides are losing their potency to resistance and environmental concerns have reduced their availability.

To open new research paths, TDR and its partners, including its co-sponsor the World Health Organization, have pushed for over a decade to bring genetics into the struggle against malaria. Seeds of this “molecular entomology” were first planted in 1991 when scientists called to a TDR and MacArthur Foundation meeting first proposed the then-unorthodox approach of attacking malaria through genetics. In 2001, another TDR meeting, arranged in collaboration with Institut Pasteur, launched the A. gambiae genome initiative. Now that work is done.

The breakthroughs announced this week in Nature and Science open an entirely new field to public health researchers. With this new knowledge, malaria scientists will be able to pry out information long hidden in the genomes which can be used to design new insecticides, new repellants and new drugs.

“We now have the master plans for man, Plasmodium and mosquito,” says Morel. “This has opened a completely new field of work for everyone. Now, anyone with a computer and access to the internet will be able to look for targets for new drugs and new insecticides.”

The genetic codes themselves would be useless if there were not trained researchers poised to exploit the information. Anticipating this day, TDR has for the last two years been training over 100 scientists from Latin America, Africa and Asia in how to search the genomes, identify vulnerabilities, and build new genetically-based drugs and insecticides.

While exuberant at the announcements, it is obvious from the pace of developments following the decoding of the human genetic code that the fruit of genomics takes a long time to mature. Still, for scientists who have been stymied by the disease for years, the elucidation of the genomes has electrified the field.

“There is now information for everyone to work 24 hours a day to find solutions which can save millions of lives,” says TDR director Carlos Morel.

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For more information contact:

Mr Iain Simpson
Telephone: +41 22 791 3215
Mobile phone: +41 79 475 5534
E-mail: simpsoni@who.int

Mr Dick Thompson
Telephone: +41 22 791 2684
Mobile phone: +41 79 475 5475
E-mail: thompsond@who.int