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Scientists Unravel Genetic Material of 3 Deadly Parasites

An international team of scientists has decoded the genetic material of three deadly parasites that strike millions of people in the developing world. Experts say the organisms have thousands of genes in common, and they hope that will make it possible to develop effective drugs to combat all three.

Roughly 253 scientists from 21 countries worked for five years to decipher the genetic blueprints of the single-cell parasites that cause sleeping sickness, leishmaniasis and Chagas disease. Experts say the disease-causing protozoa, which affect 500 million people in the tropics and sub-tropics at any one time, look identical under the microscope, but are spread by different flying insects.

Leishmaniasis, common in the Middle East, can cause high fever, weight loss and anemia that can lead to death. Sleeping sickness, prevalent in Africa, can cause profound neurological problems and death. A severe variant of Chagas disease common to Central and South America is responsible for organ failure and death.

Scientists say that each tropical disease is notoriously difficult to treat, because the microorganisms evade the immune system by changing their appearance frequently. But the latest findings may stimulate research into cures for the parasitic illnesses.

In three papers published in the July 14 issue of Science, investigators report deciphering the genetic blueprints of the Chagas, leischmaniasis and sleeping sickness protozoa and found that they have 6,200 genes in common.

Researchers say the discovery offers dozens of potential targets for new drugs to fight the microorganisms responsible for all three diseases. But, according to a co-author of one of the studies, molecular biologist Najib El-Sayed of the Institute for Genomic Research in Rockville, Maryland, there's still a lot of work to do.

"Among these 6,200 genes that need further characterization, although there are a good 40 or 50 that definitely appear not to be shared with any other life form so far sequenced, if we can find a core process that are shared by these parasites, then we would have very promising targets," he said.

Dr. El-Sayed hopes the discovery prompts efforts toward a cure. "The excitement about being able to really design drugs that can attack all three is great, because of the obvious large cost in the development of new drugs for these generally neglected diseases. They've been neglected by pharmaceuticals; neglected by the developed world," he explained.

Researchers say they will now work to identify the remaining 1,000 or so genes in the parasites' genetic blue print to discover why there are different forms of the illnesses, and how more specific treatments might be developed.