Red blood cells infected with the Plasmodium falciparum parasite. Plasmodium is the parasite that triggers malaria in people. Gary D. Gaugler/Science Source hide caption

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A health official takes a blood sample from a child's finger for a malaria test at a clinic in Bong Ti Lang village on the Thai-Myanmar border. Narong Sangnak/EPA /LANDOV hide caption

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By ensuring vaccines are invented and distributed, Bill Gates says, his foundation is dramatically reducing the number of childhood deaths in poor countries. Marie McGrory/NPR hide caption

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A pregnant Somali woman gets a tetanus shot at a clinic in Mogadishu in 2013. The vaccination initiative was launched by the GAVI Alliance, UNICEF and the World Health Organization. Carl de Souza/AFP/Getty Images hide caption

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Yonta, 6, rests with her brother Leakhena, 4 months, under a mosquito bed net in the Pailin province of Cambodia, where deaths from malaria have decreased sharply in the past two decades. Paula Bronstein/Getty Images hide caption

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Children get tested for malaria at a clinic near the Myanmar border in Sai Yoke, Thailand. Drug-resistant strains of the parasite have appeared in the region over the past few years. Surkree Sukplang/Reuters /Landov hide caption

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A health worker administers the malaria vaccine at a clinical trial in Kilifi, Kenya. Joseph Okanga/Reuters /Landov hide caption

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A Cambodian boy gets tested for malaria at a clinic along the Thai-Cambodian border in 2010. Three strains of drug-resistant malaria have emerged from this region over the past 50 years. Paula Bronstein/Getty Images hide caption

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A red blood cell infected with malaria parasites (blue) sits next to normal cells (red). NIAID/ hide caption

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More than a hundred different species of Anopheles mosquitoes can transmit malaria to people. Adam Cole/NPR hide caption

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An extract of sweet wormwood has been used in China for thousands of years to treat malaria, but being able to make mass quantities of the extract has been elusive, until now. Sarah Cuttle/Getty Images hide caption

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Chiara Andolina, a malaria researcher in Thailand, feeds her mosquito colony by letting the insects bite her right arm. These mosquitoes are picky and will dine only on live human blood. Ben de la Cruz/NPR hide caption

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