The Adaptability of Malaria’s Parasite
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The virulent strain of the malaria parasite has grown resistant to
chloroquine, the most common drug used to combat the disease. So
several million mostly African children die every year even though
many of their desperate parents buy them medicine that they think is
going to work
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The economics of the situation are perverse. Chloroquine costs 10
cents a day, something poor people can afford. Drugs that work like
artemisinin (the fast-acting, fast-clearing drug is used in
combination with older drugs to avoid its falling victim to
resistance) costs $2.50 a day. If you made $2 a day or less like most
people in Africa, which would you choose?
Today's New England Journal of Medicine contains a report from Malawi
showing that if chloroquine is discontinued for a decade or so, the
malaria parasite evolves to the point where it once again become
susceptible to the drug's action. It turns out that the genetic
mutation that confers resistance makes the parasite somewhat weaker
overall. Without the selective pressure of the drug, the susceptible
strain resumes its dominance in the overall population.
So should chloroquine be reintroduced in those countries that are
following the World Health Organization's advice and switching to
artemisinin-based combination therapy for treating malaria?
Absolutely not, says Nicholas White of Mahidol University in Bangkok,
who is probably the world's leading malariologist. In an accompanying
perspective article, White points out that "if chloroquine were
reintroduced alone, resistant parasites would probably return
rapidly, imported in people from neighbouring areas." He holds out
hope that chloroquine can once again become a useful drug, but not
until it is stopped everywhere for a long period of time. "It needs
to leave before it can come back."
Meanwhile, the World Bank and other multi-lateral aid organizations
are dragging their feet in implementing the 2004 Institute of
Medicine report that called for setting up a global fund to purchase
500 million doses of ACT a year for use in the developing world (it
would cost about $1.5 billion a year). This central authority could
then distribute it through the same channels that currently
distribute chloroquine -- and at the same price.
That way, the desperate mothers of the two million children who die
each year could not only afford to buy their children medicine, but
they would be assured that the medicine they give them works.
Source: e-drugs (http://list.healthnet.org/mailman/listinfo/e-drug)
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