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From VOA Learning English, this is the Health Report.
The sound of a mosquito can mean trouble in many parts of the world. But the bite of a mosquito can sometimes kill. The flying insect can carry diseases like malaria. The World Health Organization estimates that almost 630,000 people died in 2012 from malaria and causes linked to the disease. Most of these deaths were in African countries south of the Sahara Desert. In the United States, scientists are seeking ways to fight malaria. The University of California Riverside is working to develop a more effective and less costly product to protect people from mosquitoes. Scientists there are investigating the sense of smell in mosquitoes. They found the insects use the same receptor to identify carbon dioxide in human breath and to smell our skin. Anandasankar Ray is leading the investigation. He says scientists tested more than a million chemical compounds until they found a substance that blocks the mosquito’s receptor. The substance is called Ethyl pyruvate. He says they found that hungry mosquitoes showed no interest in attacking a human arm because only a few of them could smell it. Genevieve Tauxe was a member of the research team. She says it was not easy to find the neurons, or nerve cells, that recognize both the smell of human breath and skin. The scientists use special instruments to identify the signals that a mosquito’s neurons send to its brain when it finds an interesting smell. Anandasankar Ray says a product based on Ethyl pyruvate may cost less than the most effective treatment now in use. That treatment, called DEET, is too costly for most people in areas affected by malaria.