Some Viruses Make You Smell Tastier To Mosquitoes

The deadliest animal in the world is smaller than a pencil eraser and weighs around two-thousandths of a gram — less than the weight of a single raindrop. Every year, it kills an estimated 700,000 people by partaking in what scientists grimly call a “blood meal.” Mosquitoes do not kill the way a shark or a lion does. Instead, they are “vectors” for many painful and life-threatening diseases, from dengue fever to malaria to chikungunya. When a mosquito “bites” someone, by stabbing a needle-filled proboscis deep into a blood vessel — it both sucks out blood and leaves some of its own saliva behind.

How do Mosquitoes have more liking to people with diseases? A new study shows that mosquitoes are attracted to certain viruses such as Zika and dengue fever viruses. In their study, the researchers said that the viruses alter the scent of mice and humans they infect) which makes it quite attractive for the mosquitoes.


Researchers from UConn Health, Tsinghua University in Beijing, Institute of Infectious Diseases in Shenzhen, the Ruili Hospital of Chinese Medicine and Dai Medicine, Yunnan Tropical and Subtropical Animal Virus Disease Laboratory, and Chinese Center for Disease Control and Prevention conducted the study.

They suspected that dengue and Zika might be manipulating the hosts in some way to attract mosquitoes. Both malaria and general inflammation can change people’s scent. Viral infection by dengue and Zika, they thought, night do the same thing.

As a first step towards their research, they tested whether mosquitoes showed a preference for infected mice. When mosquitoes were offered a choice of healthy mice and mice sick with dengue, the mosquitoes were more attracted to the dengue-infected mice. After this, they analyzed the smelly molecules on the skin of infected and healthy mice. They found that several molecules that were more common on infected animals, and tested them individually. They applied them both to clean mice, and to the hands of human volunteers, and found that one odoriferous molecule, acetophenone, was especially attractive to mosquitoes. Skin odorants collected from human dengue patients showed the same thing: more attractive to mosquitoes and more acetophenone production.

Acetophenone is made by some Bacillus bacteria that grow on human (and mouse) skin. Normally skin produces an antimicrobial peptide that keeps Bacillus populations in check But it turns out that when mice are infected with dengue and Zika, they don’t produce as much of the antimicrobial peptide, and the Bacillus grows faster. An inmunologist at UConn Health and one of the study authors Penghua Wang said that the virus can manipulate the hosts skin microbiome to attract more mosquitoes.

The researchers also gave mice with dengue fever a type of vitamin A derivative, isotretinoin, known to increase the production of the skin’s antimicrobial peptide. The isotretinoin-treated mice gave off less acetophenone, reducing their attractiveness to mosquitoes and potentially reducing the risk of infecting others with the virus. Wong says the next step is to analyze more human patients with dengue and Zika to see if the skin odormicrobione connection is generally true in real world conditions, and to see if isotretinoin reduces acetophenone production in sick humans as well as it does in sick mice.


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