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FRIDAY, July 1, 2022 (HealthDay News) — When a mosquito bites you and infects you with a virus like dengue or Zika, it also makes you smell good to other mosquitoes, according to new research.
This makes it more likely that another bites, catches the virus, and passes it on to the next victim.
“The virus can manipulate the skin microbiome of hosts to attract more mosquitoes to spread faster!” said study co-author Penghua Wang, an immunologist at UConn Health in Farmington, Connecticut.
The findings could explain how mosquito-borne viruses persist for so long, the researchers said.
Dengue fever affects 50 million people a year and kills 20,000, mostly children, according to the National Institute of Allergy and Infectious Diseases at the National Institutes of Health.
Zika can cause serious birth defects in unborn children of infected pregnant women, although it rarely causes serious problems in adults.
To continue to spread, both viruses require ongoing infections in animal hosts. If all mosquitoes died or all susceptible hosts shed the virus, the viruses would die out.
But there are always mosquitoes in tropical climates without killing frosts, and viruses only need one to bite a host in order to spread.
The researchers suspected that the viruses could somehow alter people’s smell to attract mosquitoes.
They found that mosquitoes seemed to prefer dengue-infected mice to healthy mice.
They then found and tested several more common molecules on infected animals. They applied them both to clean mice and to the hands of human volunteers.
One molecule, acetophenone, was particularly attractive to mosquitoes.
Similarly, the skin odors of people with dengue fever found more acetophenone and that these patients were also more attractive to mosquitoes.
Acetophenone is made by certain Bacillus bacteria that grow on human and mouse skin. An antimicrobial peptide produced by the skin usually keeps it in check, but infected mice don’t produce as much when infected with dengue or Zika, prompting the bacteria to grow faster.
The researchers also tested a potential preventative agent – a vitamin A derivative called isotretinoin that increases production of the skin’s protective antimicrobial peptide. Mice treated with isotretinoin were found to be less attractive to mosquitoes.
The next step is to analyze more human patients with dengue and Zika, Wang said. The goal will be to see if the connection between skin odor and the microbiome holds in real conditions. The researchers also want to see if isotretinoin reduces the production of acetophenone in sick people as well as in sick mice.
The results were published June 30 in the journal Cell.
The National Library of Medicine has more information on mosquito bites.
SOURCE: University of Connecticut, press release, June 30, 2022
By Cara Murez HealthDay Reporter
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