Search for a malaria vaccine is boosted by new findings

Scientists have opened up a new front in the war against malaria with the publication of the genetic blueprint of both the organism…

Scientists have opened up a new front in the war against malaria with the publication of the genetic blueprint of both the organism that causes the disease and the mosquito that carries it.

The dramatic findings promise new ways to thwart the disease, which is a major killer.

Extensive details of the research that went into this two-pronged assault against malaria are released today in a most unusual joint publication by two of the world's leading research journals, Nature and Science.

Together the two journals have released more than a dozen research papers looking at various aspects of the organisms responsible for the disease. Some of the papers also describe possible new avenues of attack that could bring an end to the worldwide suffering caused by the disease.

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Malaria threatens 40 per cent of the world's population and kills up to 2.7 million people every year. More than 90 per cent of cases occur in sub-Saharan Africa and most of the resultant deaths occur in children under five years old.

The most deadly form of the disease is caused by the blood-borne parasite, Plasmodium falciparum, which kills one child every 20 seconds. There are an estimated 500 million new cases of malaria every year. Climate change is increasing the range within which the parasite and the mosquito that carries it from victim to victim can operate.

Ironically, the genetic blueprint or genome of the parasite used in the research was actually taken from a 10-year-old Dutch girl who contracted malaria after being bitten by a mosquito near Schiphol Airport in July 1979.

The release of the Plasmodium genome and that for the most common mosquito carrier, Anopheles gambiae, gives scientists a remarkably detailed road-map into the genetic secrets of these two killers. The genome for the third element in disease transmission, humans, has already been published and together the three genomes will point towards new ways of controlling this disease.

An international team of 150 scientists in labs around the world took six years to work out the entire genomes of these two species. They provided a list of the working genes important to the life cycles of the two.

Additional research released today includes a "proteomic analysis" or shopping list of the essential proteins produced by the malaria parasite. Blocking any one of these could offer a completely new way to defeat a disease that has shaped human evolution and killed millions.

Fresh knowledge about the mosquito genome should help scientists develop new and more effective mosquito repellents, insecticides and even mosquito vaccines. The authors of this research did a special study to find the genes that were switched on or off when the female mosquito feeds on blood, information that should help find agents that interfere with this process.

Another paper suggests the use of genetically-modified mosquitoes to control malaria. These would be mosquitoes modified so that their internal systems would kill off the parasite once taken up in blood, in effect breaking the cycle of infection and reinfection. These mosquitoes have been developed but have yet to be released.

Another paper studies natural resistance to the parasite in some mosquitoes. It identifies specific areas of the genome responsible for this resistance, characteristics that could potentially be enhanced.

"What they have done is a major leap in the vaccine discovery programme," one of Ireland's leading malaria researchers, Prof John Dalton, director of molecular parasitology at Dublin City University, stated.

"Information like this is available to everyone and work can proceed in labs all over the world. This is the beauty of this information," he said yesterday.

"It is our hope that researchers will use the genome sequences to accelerate the search for solutions to diseases affecting the most vulnerable of the world's population," the lead author of the Plasmodium genome study, Dr Malcolm Gardner of the Institute for Genomic Research, Rockville, Maryland, stated.

"The new information provided by these two genome projects opens up new approaches to the development of drugs, vaccines, insecticides and insect repellants," Prof Brian Greenwood, of the London School of Hygiene and Tropical Medicine in London, said.

Dick Ahlstrom

Dick Ahlstrom

Dick Ahlstrom, a contributor to The Irish Times, is the newspaper's former Science Editor.