It is well known that through the mosquito bite it is possible to get infected with some viruses such as Zika And West Nile, but what experts are wondering today is whether this annoying little insect can transmit the infection by COVID-19.
Can mosquito bites transmit Covid19?
According to Dr. Daniel Markowski, technical advisor to the American Mosquito Control Association, the answer is no: “There is no evidence that mosquitoes can acquire and transmit the SARS-CoV-2 virus,” said the expert. To understand the mechanisms that prevent mosquitoes from carrying and spreading the SARS-CoV-2 virus, Dr. Markowski explained that it is important to understand how these insects are able to transmit viral particles.
“Typically, the mosquito must first feed on an infected host, who is circulating enough virus in the blood to have some of it present in the small amount eaten during a mosquito’s blood meal,” explained Markowski: “Second, the virus must survive the insect’s midgut, which has a similar array of immune responses to ours. Not only do they have to survive inside the mosquito’s gut, but they must replicate and eventually bind to receptor sites on the gut wall and pass through that barrier into the mosquito’s body cavity, ”added Dr. Markowski.
Once inside the body cavity, Dr. Markowski explained that the virus must bypass the mosquito’s immune system and make its way into the insect’s salivary glands, all while continuing to replicate.
“Now, with the next blood meal, they can be passed on to a new host while the mosquito feeds,” he continued. “As you can see, it is a fairly long and complex journey that each virus takes to pass from one host to another via a mosquito bite. And not many viruses have evolved over the millennia to successfully complete that journey, which is why many viruses such as the flu, coronavirus and monkeypox are not mosquito-borne viruses.
In July 2022, a team of researchers including Doctor Stephen Higgs associate vice president for research and director of the Biosecurity Research Institute at Kansas State University,published a study who found that even under extreme conditions, the virus SARS-CoV-2 did not replicate in the mosquito.
For this reason, the researchers said, the mosquito would not be able to transmit the virus to people even if they fed on someone infected with the SARS-CoV-2 virus: “We didn’t really expect it would infect mosquitoes because, for any reason, coronaviruses simply do not infect mosquitoes or other arthropods, ”said Dr. Higgs.
“What we did in our study was inject SARS-CoV-2 into the mosquito. We know that using this approach you can sometimes infect a resistant mosquito with a virus that would not normally infect it. Even with that unnatural approach, SARS-COV-2 did not infect and multiply mosquitoes, ”the expert added.
Dr Markowski was slightly more cautious in his prediction, but he agreed with Dr Higgs in general: “As soon as you say something can never happen, it probably will! However, I think it is highly unlikely that mosquitoes will be able to transmit the SAR-CoV-2 virus in the future. The number of mutations that would have to occur to allow this process would make it statistically unlikely. If there was evidence that this was indeed possible, I think we would have seen it a long time ago with other viruses, such as the flu, polio, etc. ”.
In June 2022, researchers from the University of Connecticut found that some viruses, such as Zika and dengue, can alter the smell of the infected person’s skin. This makes them more attractive to mosquitoes, attracting insects to bite them, become infected, and potentially transmit the virus to other people.
Could this potentially happen with the SARS-CoV-2 virus? And even if the mosquito cannot be infected with the SARS-CoV-2 virus, could someone with COVID-19 become more susceptible to being bitten by a mosquito infected with a mosquito-borne virus like Zika?
“Studies have shown that COVID-19 patients release a distinctive blend of molecules,” said Dr. Penghua Wang, Assistant Professor in the Department of Immunology at the University of Connecticut and part of the research team.
“Some of these compounds may be mosquito repellent, while others may be attractive. We don’t know for sure that COVID-19 patients might attract more insects to spread other mosquito-borne viruses. As far as I know, there is no such formal study available, ”said Penghua Wang.
“I think it’s extremely unlikely,” Dr. Markowski pointed out: “The reason is that those mosquito-borne viruses evolved with the mosquito and people and through that evolutionary process they developed strategies – such as targeting the bacterial fauna of infected hosts – to aid in their survival. It is highly unlikely that SARS-CoV-2 and other non-mosquito-transmissible viruses will have those evolutionary advantages “, he specified.
Dr Markowski said that the best way to prevent mosquito bites while enjoying the outdoors is to spray yourself with a good mosquito repellent: “There are different types of repellants available on the market,” he noted: “To determine which one you prefer, you will need to read the label and select the correct active ingredient.”
“Generally, a higher concentration of the active ingredient means a longer period of protection from mosquito bites. However, for the DEET it is not recommended to use more than 30% of DEET“, Said the Doctor Markowski.
In addition to using mosquito repellent, Dr. Higgs suggested covering bare arms and legs so the mosquito has less skin to attack. The scientist also advised avoiding going to places where there are many insects or staying outside when they sting, such as summer evenings.
“If you live in an area rich in mosquitoes, try to eliminate places where they can reproduce, especially near the house or even in the house: plant pots with water, old tires and other things where water can accumulate. To prevent mosquitoes from entering the house, make sure you have mosquito nets on the windows, ”concluded the scientist.
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