蚊子會傳播新冠病毒嗎?

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?

又到蚊子季了，想到這些吸血昆蟲會傳播疾病，人們感到擔憂：蚊子會攜帶新冠病毒嗎？如果可以，它們會不會把新冠病毒傳播給人類，讓人感染上新冠肺炎？

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.

簡單來說，答案是：不太可能。世界衛生組織的官方指南稱，沒有信息或證據顯示，新冠病毒會通過蚊蟲叮咬來傳播。

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.

首先，新冠病毒是一種呼吸道病毒，這種病毒的主要傳播模式是感染者咳嗽或打噴嚏時把帶有病毒的飛沫釋放到空氣中。一隻蚊子要感染上新冠病毒，病毒就必須進入蚊子吸食的血液中。

"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," Emily Gallichotte, PhD, a postdoctoral researcher in the department of microbiology, immunology, and pathology at Colorado State University, tells Health.

科羅拉多州立大學微生物學、免疫學與病理學系的博士後研究員艾米麗·蓋麗洛特博士告訴健康網說：“新冠病毒是一種呼吸道病毒，幾乎完全存在於感染者的肺部和呼吸道中，很少會進入血液中。”

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.

而且，病毒要通過蚊子或其他昆蟲叮咬（比如蜱蟲叮咬）傳播給另一個人，病毒必須能在蚊蟲或蜱蟲體內複製。事實表明，新冠病毒和其他任何一種冠狀病毒都無法做到這點。

"It's quite a complex process," former US Navy entomologist Joseph M. Conlon, who has extensive worldwide experience in mosquito control and is technical advisor to the American Mosquito Control Association (AMCA), tells Health. "First of all, the mosquito would have to pick up the requisite amount of virus during its bite. The virus must then not only survive the digestive process, but replicate within the mosquito and pass through the gut wall to the coelom (main body cavity) of the mosquito. From there it must make its way to the salivary glands and be expressed by the mosquito as part of its salivary secretions."

曾在美國海軍服役的昆蟲學家約瑟夫·M·康倫告訴健康網說：“這是一個相當複雜的過程。” 康倫在蚊蟲控制方面有着豐富的全球經驗，也是美國控蚊協會的技術顧問。“首先，蚊子必須在叮咬過程中吸收足夠的病毒。病毒不僅必須在消化過程中存活下來，還必須在蚊子體內進行復制，並通過腸壁進入體腔。之後還必須到達唾液腺，並作爲唾液分泌物釋放出來。”

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."

此外，蚊子的基因和人類大不相同。蓋麗洛特說：“這讓病毒難以既感染人類又感染蚊蟲。我們的細胞表面有不同的感受器，細胞內部的複製機制也不同。”

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 very long time, and even though many of these end up in our blood, they are still unable to infect mosquitoes," says 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."

能夠既感染人類又感染蚊蟲的人類病毒相對較少。蓋麗洛特說：“絕大多數人類病毒（比如流感、艾滋病和皰疹）很長很長的時間以來一直在感染人類，儘管其中的許多病毒最終都進入了人類的血液，但仍無法感染蚊蟲。反之，許多蚊蟲病毒也無法感染人類或其他任何哺乳動物。目前已知的冠狀病毒還沒有能夠感染蚊子的。”

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. "West Nile virus is able to infect a mosquito to the point where the virus load is abundant in the salivary glands," Melissa Doyle, scientific program manager at the San Gabriel Valley Mosquito and Vector Control District (SGVMVCD), tells Health. "When the mosquito bites a person, the virus is able to travel from the salivary glands into the human body."

能夠通過蚊子傳播給人類的病毒包括引發登革熱的西尼羅河病毒和基孔肯亞病毒，這些病毒都在感染者的血液中循環。聖蓋博山谷蚊及病媒控制區的科學項目經理梅麗莎·道爾告訴健康網說：“西尼羅河病毒能夠感染蚊子，並在蚊子的唾液腺裏大量聚積。當蚊子叮咬人時，病毒能通過唾液腺傳播給人體。”

So it's pretty clear that COVID-19 is the last thing you should be worrying about if a mosquito has been feasting on your leg. Keep swatting them away, though. "Due to the heavy focus on COVID-19, many people may forget that disease threats may already be buzzing right outside their window." SGVMVCD Public Information Officer Levy Sun tells Health.

因此很明顯，如果蚊子叮了你的腿，你完全不用擔心會感染新冠病毒。但是還是應該把它們拍走。聖蓋博山谷蚊及病媒控制區公共信息官萊維·孫告訴健康網說：“由於現在非常關注新冠病毒，許多人也許忘記了窗外嗡嗡響的疾病威脅。”

Conlon points out that mosquitoes can factor into the severity of COVID-19, meaning it's crucial to maintain robust measures to reduce their numbers. "Studies have shown that factors contributing to potentially serious or fatal outcomes attendant to COVID-19 infection involve underlying medical issues, such as neurologic conditions that weaken the ability to cough or an already stressed immune system due to concurrent infection by mosquito-borne viruses," he says.

康倫指出，蚊子會加重新冠肺炎的病情，這意味着持續採取強硬措施來降低蚊蟲數量是至關重要的。他說：“研究顯示，感染新冠病毒後引發致命結果的因素包括潛在的醫療問題，比如減弱咳嗽能力的神經系統疾病，或蚊蟲攜帶病毒導致的併發感染給免疫系統造成的負擔。”

Mosquitoes or no mosquitoes, it's still crucial to keep following healthy coronavirus protocol to protect yourself and others from COVID-19. Clean your hands frequently, practice social distancing, stay home if you're sick, and avoid close contact with anyone who is coughing and sneezing.

無論有沒有蚊子，堅持遵守衛生防疫要求來保護自己和他人免受新冠病毒感染仍然是至關重要的。勤洗手，保持社交距離，病了就在家休息，避免和任何咳嗽或打噴嚏的人密切接觸。