The season of swatting is nearly upon us, and with it the inevitable question about whether mosquitoes will spread an already terrible pandemic. The good news is, there’s not much chance of that.
That’s the simple version. But scientists like to hedge.
“I mean in science we want to be very cautious. All of the evidence from WHO and CDC and every expert in the field says it is essentially no,” says post-doctoral research scientist Emily Gallichotte. She is a PhD with Colorado State University’s Department of Microbiology, Immunology and Pathology.
In reality, very few viruses are transmitted by mosquitoes.
“And that’s consistent for what we know for other human coronaviruses such as SARS and MERS and the other coronaviruses that cause the common cold in people,” said Gallichotte.
Mosquitoes and people have big genetic differences.
“Mosquitoes are at different temperatures than humans. They have different fluids in them. They don’t work the same way as people,” said Gallichotte.
Viruses can be viable on their own, but there’s a limit. They need to infect a living thing to replicate. In human cells, the viruses “bind to receptors on the surface, and mosquitoes have entirely different receptors on their surface.” So there doesn’t appear to be anywhere for this coronavirus to latch on.
That’s one part of many things in a chain that is simply not complete.
“In order for a mosquito to even be exposed to the virus,” notes Gallichotte, “it has to bite someone who has the virus in their blood. And what we know about this virus is it’s a respiratory virus and it’s really primarily located in the lungs and the respiratory tract. And very few people even get the virus into their blood.”
That does happen with mosquito-transferred viruses like West Nile and dengue fever.
Even then, mosquitoes do not do a direct deposit.
“Mosquitoes aren’t just syringes that transfer blood possibly with virus from one person to another. It takes that blood, it gets into their gut and then it has to survive seven days at least to make its way and replicate through the mosquito’s body and end up in the saliva to then be transferred to that next person.”
The saliva is the anti-coagulant mosquitoes inject that creates our body’s immune response, leading to all that itching. That is a nuisance, but not a serious health threat.
So this summer, when the mosquitoes come calling, worry about other things, but not this one, agreed Gallichotte.