WHO on Transmission of Covid-19 from Mosquito To Humans

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  • 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?

A recently reported article in the Health reveals whether mosquito can spread the coronavirus disease.

A short answer

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.

Respiratory virus

“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.

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.

A complex process

“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.”

Mosquitoes are very genetically different from humans

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.”

Few human virus can affect both

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.”

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.”

 

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Source: Health