Malaria fighters' latest chemical weapon may not last long

doi:10.1126/science.369.6508.1153

GSTDTAP > 气候变化

DOI	10.1126/science.369.6508.1153
	Malaria fighters' latest chemical weapon may not last long
	Munyaradzi Makoni
	2020-09-04
发表期刊	Science
出版年	2020
英文摘要	An insecticide about to be widely deployed inside African homes to combat malaria-carrying mosquitoes is already losing its punch. Two years ago, the World Health Organization (WHO) gave the green light for clothianidin, long used in agriculture to kill crop pests, to be added to the current mainstays of indoor mosquito control, which are losing their effectiveness as the insects develop resistance. Since then, many African countries have been laying plans to spray walls with the pesticide, which represents the first new class of chemicals adopted for such home use in decades. They've also been looking anxiously for pre-existing resistance. Now, scientists at Cameroon's Centre for Research in Infectious Diseases have found it. They recently sampled mosquito species, including two key malaria carriers, from rural and urban areas around Yaoundé, the capital. In one standard assay, exposure to clothianidin for 1 hour killed 100% of Anopheles coluzzii . But in some A. gambiae samples as many as 55% of the mosquitoes survived, the group reported in an online preprint last month. Corine Ngufor, a medical entomologist at the London School of Hygiene & Tropical Medicine, says this appears to be the first report of clear resistance to clothianidin in malaria-carrying insects. “It may spread very quickly and make this new class of insecticide almost useless for malaria vector control within a few years,” she warns. Colince Kamdem, who led the study, says agricultural use of neonicotinoids—the class of chemicals to which clothianidin belongs—likely drove the emergence of the resistant mosquito strains. “WHO would never have recommended this insecticide if such data were available,” he contends. Bed nets coated with long-lasting insecticides and indoor spraying have helped halve malaria mortality and morbidity in the past 2 decades. These programs use four classes of insecticides but rely most on pyrethroids, which are cheap and considered safe around people, Kamdem says. To combat the rise of pyrethroid-resistant mosquitoes, WHO added clothianidin to its “prequalified” list of chemicals acceptable for indoor spraying (and potentially nets). Neonicotinoids have become controversial because of their impacts on pollinators; Europe has banned their use in agriculture. But farms in Africa still heavily use them. In agricultural areas, Kamdem says, pesticide residues contaminate standing water that serves as breeding sites for mosquito larvae, favoring the evolution of neonicotinoid resistance. WHO has not reviewed the Cameroon study because it has not yet been published in a peer-reviewed journal, says Deusdedit Mubangizi, who coordinates the agency's “prequalification” assessments, including those of insecticides used for mosquito control. But he thinks the chemical could still be an asset against malaria. “Resistance to clothianidin is much less prevalent than to other alternative insecticides in current use,” he says. How long that will last is the great unknown—and concern.
领域	气候变化 ; 资源环境
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文献类型	期刊论文
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/293248
专题	气候变化资源环境科学
推荐引用方式 GB/T 7714	Munyaradzi Makoni. Malaria fighters' latest chemical weapon may not last long[J]. Science,2020.
APA	Munyaradzi Makoni.(2020).Malaria fighters' latest chemical weapon may not last long.Science.
MLA	Munyaradzi Makoni."Malaria fighters' latest chemical weapon may not last long".Science (2020).