回复 #5 Kathy0911 的帖子
And we were so hurt at what happened to these people that all the fellows there, even the infantry, we took our spare clothing and gave it to these guys."& c* X& F+ z. x6 J
- [3 U4 N+ `1 V1 P) C. U( y1 rThose stories, a life-saving approach to reducing hospital infections, and more. I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."
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4 J& O% i9 y/ v0 |An important and inexpensive malaria drug is making a strong comeback in the southern African nation of Malawi. Chloroquine had become ineffective as the malaria parasite developed resistance to it. A new study shows that the drug has regained its effectiveness, a decade after Malawi health officials stopped using it. But as we hear from VOA's David McAlary, the researchers are not yet recommending that chloroquine become a treatment mainstay once again.
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McALARY: Public health experts consider chloroquine, introduced widely in the 1950s, to be the most important modern anti-malarial drug. It is inexpensive at about 10 cents per treatment, simple to administer, and in the beginning was highly effective in only a few doses. It helped control malaria and even eradicate the disease in some places during the global campaign of that decade.
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But by the end of the 1950s, resistance had begun to emerge in the deadly form of malaria. Resistant forms of the parasite spread around the world and reached eastern Africa by the late 1970s. 3 P7 ?- B+ M/ U) d3 \% w0 \/ f
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University of Maryland physician Miriam Laufer says in many places, chloroquine's effectiveness dropped below 50 percent.5 Y1 f3 n$ y) K4 U7 [% N
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LAUFER: "By the 1980s, the resistance was so bad that people noticed that there were increased cases of malaria and increased deaths due to malaria. That was attributed to the failure of chloroquine to treat the disease."
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McALARY: In 1993, Malawi become the first African country to shift from chloroquine therapy to a combination of sulfadoxine and pyrimethamine. But these drugs fell to parasite resistance even faster than chloroquine, so nations are switching to the new, but more expensive combination treatments based on the Chinese herb artemisinin.! Y; J5 @1 b! t" M5 W) c' | J! N. T
~/ h8 Z& ?; `: cNow, a team led by Dr. Laufer has shown that the layoff in use has been good for chloroquine, making it a potential candidate for re-introduction. In a trial of 210 Malawian children, chloroquine was 99 percent effective, compared to only 21 percent effectiveness in the group that got sulfadoxine-pyrimethamine.4 X; W4 o& n: M% j7 ~' n! [
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LAUFER: "Chloroquine worked remarkably well. There was only one case of chloroquine treatment failure."; d* I" j: b; P7 e; x
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McALARY: The study, published in the New England Journal of Medicine, attributes chloroquine's renewed success to the disappearance of a genetic mutation in the parasite as a result of the drug's disuse. The mutation had developed to protect the parasite against the compound.6 s% T G! ?+ d, P- M
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Is this good news for public health?
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* l! p! z% W" W. M# ]WHITE: "It is good news, but I do not think we can go back to our reliable old chloroquine as it once was."
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McALARY: Physician Nicholas White is an infectious diseases expert at Mahidol University in Bangkok, Thailand. He, like Miriam Laufer's group, points out that chloroquine should not be re-introduced as a single therapy against malaria in places like Malawi where parasite resistance to it has faded.
