[IWAR] MEDICAL malaria drug resistance

From: Michael Wilson (MWILSON/0005514706at_private)
Date: Wed Nov 26 1997 - 16:41:25 PST

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                  Biologists spot origin of drug resistance in malaria
          Copyright ) 1997 Nando.net
          Copyright ) 1997 Reuters
         Malaria kills 300,000 Nigerians every year
       BOSTON (November 26, 1997 5:23 p.m. EST http://www.nando.net) -
       Researchers in Friday's edition of the journal "Cell" report they have
       pinpointed a chunk of genetic material that makes the malaria parasite
       resistant to a primary drug used to fight the infection that afflicts
       300 million people annually.
       Malaria is passed between people through blood carried by mosquitos.
       The research also confirms that resistance to the drug, chloroquine,
       developed independently in South America and Southeast Asia about 40
       years ago.
       About 300 million people worldwide are affected by malaria each year,
       "Cell" reported. Although it can be prevented by using drugs like
       chloroquine, the disease remains an important threat to people who live
       in warm climates and travelers who visit them.
       Years ago, chloroquine was the primary weapon in the effort to eradicate
       malaria, which causes severe fever and can be fatal if it worsens to
       include the kidneys, brain, and liver.
       But 10 years of exposure to the drug allowed the single-celled parasite
       to develop a resistance to choloroquine. Researchers hope that by
       locating the source of the resistance, scientists may be able to find a
       way to overcome it.
       "My crystal ball has always been cracked on this one, but my dream --
       and this discovery may help make it a reality -- is to take the protein
       (made from the recipe on the resistant gene) and use it to screen for
       new compounds against malaria," said Thomas Wellems, an author and chief
       of the malaria genetics section of the National Institute of Allergy and
       Infectious Diseases.
       "If our hypothesis is right and we get companies interested, a drug
       could be found fairly quickly," Wellems said.
       The Cell study identifies the source of the resistance as a chunk of
       genetic material located on the parasite's seventh largest chromosome.
       The region covers 0.13 percent of the genetic material in the parasite's
       14 chromosomes.
       Called "cg2," there are two variations of the resistant gene, one which
       apparently originated in Indochina and spread to Africa, and the other
       from samples that originated in South America.
       The idea that resistance developed in two locations "is based on
       historical data, and our genetics data seem to support that. Both
       continents were, at the time, using chloroquine extensively," said
       Xin-zhuan Su, a biochemist in Wellems' lab who has spent the last five
       years in a "very intensive" search to find the source of the resistance.

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