Mosquito season is upon us, and considering that these bloodsuckers are known to transmit diseases, people are concerned: Do mosquitoes carry the coronavirus? And if so, can they transmit it to humans and infect a person with COVID-19?

Short answer: It’s unlikely. Official guidance from the World Health Organization (WHO) says there’s no information or evidence to suggest that the new coronavirus could be transmitted through mosquito bites.

For starters, the coronavirus is a respiratory virus, and the main mode of transmission are viral droplets released into the air when an infected person coughs or sneezes. For a mosquito to become infected with a virus, it must be present in the blood the mosquito feeds on.

“SARS-CoV2 (the virus that causes COVID-19) is a respiratory virus that is almost exclusively contained within the lungs and respiratory tract of infected people, and rarely gets into the blood,” said Emily Gallichotte, a postdoctoral researcher in the department of microbiology, immunology, and pathology at Colorado State University.

Plus, for a virus to pass to a person through a mosquito or other kind of insect bite-such as a tick bite-the virus must be able to replicate inside the mosquito or tick. Neither the new coronavirus nor any other type of coronavirus has been shown to do that.

Furthermore, mosquitoes are very genetically different from humans. “This makes it challenging for viruses to have the ability to infect both of us,” says Gallichotte. “We have different receptors on the surface of cells and different replication machinery inside our cells.”

Relatively few human viruses have the ability to infect both humans and mosquitoes. “The vast majority of human viruses (such as influenza, HIV, and herpes) have been infecting humans for a very long time, and even though many of these end up in our blood, they are still unable to infect mosquitoes,” said Gallichotte. “Conversely, there are many mosquito viruses that are unable to infect humans, or any mammals. There are no known coronaviruses that can infect mosquitoes.”

Viruses that can be spread to humans by mosquitoes include West Nile virus, the virus that causes dengue fever, and chikungunya virus, which all circulate in the blood of infected people.

Words to Learn 相关词汇

【飞沫】fēimò  droplet  a tiny drop

【受体】shòutǐ  receptor  a protein molecule, usually on the surface of a cell, that is capable of binding to a complementary molecule, as a hormone, antibody, or antigen

又到蚊子季了，想到这些吸血昆虫会传播疾病，人们感到担忧：蚊子会携带新冠病毒吗？如果可以，它们会不会把新冠病毒传播给人类，让人感染上新冠肺炎？

简单来说，答案是：不太可能。世界卫生组织的官方指南称，没有信息或证据显示，新冠病毒会通过蚊虫叮咬来传播。

首先，新冠病毒是一种呼吸道病毒，这种病毒的主要传播模式是感染者咳嗽或打喷嚏时把带有病毒的飞沫释放到空气中。一只蚊子要感染上新冠病毒，病毒就必须进入蚊子吸食的血液中。

科罗拉多州立大学微生物学、免疫学与病理学系的博士后研究员艾米丽▪盖丽洛特说：“新冠病毒是一种呼吸道病毒，几乎完全存在于感染者的肺部和呼吸道中，很少会进入血液中。”

而且，病毒要通过蚊子或其他昆虫叮咬（比如蜱虫叮咬）传播给另一个人，病毒必须能在蚊虫或蜱虫体内复制。事实表明，新冠病毒和其他任何一种冠状病毒都无法做到这点。

此外，蚊子的基因和人类大不相同。

盖丽洛特说：“这让病毒难以既感染人类又感染蚊虫。我们的细胞表面有不同的受体，细胞内部的复制机制也不同。”

能够既感染人类又感染蚊虫的人类病毒相对较少。盖丽洛特说：“绝大多数人类病毒（比如流感、艾滋病和疱疹）很长时间以来一直在感染人类，尽管其中的许多病毒最终都进入了人类的血液，但仍无法感染蚊虫。反之，许多蚊虫病毒也无法感染人类或其他任何哺乳动物。目前已知的冠状病毒还没有能够感染蚊子的。”

能够通过蚊子传播给人类的病毒包括引发登革热的西尼罗河病毒和基孔肯亚病毒，这些病毒都在感染者的血液中循环。

(chinadaily.com.cn)