From VOA Learning English, this is the Health Report.
The sound of a mosquito can mean trouble in many parts of the world. The bite of the mosquito can be deadly. The insects carry serious diseases like malaria. The World Health Organization estimates that almost 630,000 people died from malaria and malaria-related causes in 2012, most of these cases were in African countries south of the Saharan desert.
In the United States, scientists are seeking new ways to fight malaria. A group of California scientists is working to develop a more effective and less costly substances to protect people from mosquito.
The researchers work at the University of California Riverside. They are investigating the sense of smell in mosquitoes. They found the insects use the same receptor for identifying carbon dioxide in human breath as they do for the smell of our skin.
Anandasankar Ray is leading the investigation. He says scientists tested more than a million chemical compounds until they found a substance called Ethyl pyruvate. He says Ethyl pyruvate makes the mosquitoes' receptor inactive.
"When we apply Ethyl pyruvate to a human arm and offer it to hungry mosquitoes in a cage, then very few of the mosquitoes are attracted to the human arm because only a few of them are able to smell it out," said Ray.
Genevieve Tauxe is a member of the UC Riverside research team. She says it was not easy to find the neurons of noble cells that recognise both the smell of human breath and skin. She describes a device the researchers are using to examine mosquitoes.
"With this apparatus, we are able to insert a very small electrode into the part of the mosquito's nose, effectively, where its olfactory neurons are and where the smell is happening," said Tauxe.
The scientists use these instruments to look for the signals that a mosquito's neurons send to its brain when it finds an interesting smell. Computer screen images show when the sense is strong or weak.
Anandasankar Ray says a product based on Ethyl pyruvate may cost less to manufacture than DEET, the most effective chemical treatment now in use. He says DEET is too costly for most people who live in areas affected by malaria.
"Perhaps by finding odors that can attack other target receptors, we will be able to improve upon DEET and finally have the next generation of insect behavior control products," said Ray.
The scientists believe they will soon be able to find a way to manufacture less costly and more effective products for the fight against mosquitoes.
And that's the Health Report from VOA Learning English. I'm Chirstopher Cruise.
1.receptor n. [生化] 受体；接受器；感觉器官
They are in key receptor areas of the brain.
2.neuro n. 神经
The results are reported in the journal Neuro - Oncology.
3.apparatus n. 装置，设备；仪器；器官
The apparatus is spotlessly clean.
4.electrode n. [电] 电极；电焊条
Two electrodes that measure changes in the body's surface moisture are attached to the palms of your hands.
1.Anandasankar Ray says a product based on Ethyl pyruvate may cost less to manufacture than DEET
based on 英 美 以…为基础，基于
The plan of our country is based on a rising economy.
All of the work we do is based on science.
在全世界很多地方，蚊子的声音都意味着麻烦。被蚊子叮咬可能会致命，这种虫子携带疟疾等严重疾病 。世卫组织估计2012年有近63万人死于疟疾和疟疾相关疾病，大多数是在撒哈拉南部非洲国家 。
Anandasankar Ray说基于丙酮酸乙酯的一种产品的制造成本可能低于避蚊胺（DEET），后者是目前最有效的化学方法。他说对于很多居住在受疟疾困扰地区的人们来说，DEET的成本太高 。