A group of researchers has found that the Dengue and Zika viruses can manipulate their hosts to entice mosquitoes.
It seems that these viruses are capable of altering your scent in such a way that it attracts mosquitoes which in their turn spread the virus to others.
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Zika is a viral disease caused by the Zika virus that finds its origin in the Zika Forest in Uganda. The disease is commonly spread via daytime-active mosquitoes such as the yellow fever mosquito. The disease is not particularly deadly for grown-ups, but it can induce severe congenital disabilities.
Dengue fever is a tropical disease that sometimes spreads to more northern areas such as the united states, with 117 cases reported last year. Worldwide it is responsible for 22.000 deaths each year, mainly children. Akin to Zika, Dengue is also mainly spread by mosquitoes. Both viral diseases are part of the same family.
Increasing the odds of spreading
The Dengue and Zika viruses must continue to infect both mosquitoes and their animal hosts in order to spread. The virus vanishes if one of these conditions isn't met. For instance, the 1793 yellow fever outbreak in Philadelphia was brought to a complete stop when the local mosquito population died out due to the arrival of the fall frosts.
People living in tropical areas have no such luck as no frost occurs, meaning that there exists a continuous supply of mosquitoes. Chinese scientists have discovered that both Dengue and Zika viruses developed a stealthy method to increase the odds of spreading by altering their scent to attract mosquitoes.
The scientists tested their hypothesis by first determining whether mosquitoes exhibited a preference for infected mice. Indeed, when given the option between healthy mice and mice suffering from dengue fever, mosquitoes were more drawn to the dengue-infected mice.
Consequently, the team studies the scent-producing molecules found on the skin of their test subjects. They detected various molecules that were more widespread in mice that carried the infection compared to those that were not infected.
It turns out that these particular molecules drew the attention of mosquitoes. After collecting samples from humans that suffer from dengue fever, the team identified the same mechanism.
How can viruses alter the scent of humans?
The molecule acetophenone turned out to be the most effective of the bunch. Acetophenone is created by Bacillus bacteria that exist both on the skin of mice as well as humans.
Under normal circumstances, our skin creates an antibacterial peptide that controls these bacterial populations. However, the researchers found that mice infected with the Zika virus and Dengue virus create less of the antimicrobial peptide, which causes the Bacillus to grow more quickly.
These findings could be an explanation of why viruses like Zika and Dengue manage to sustain themselves for such long periods of time.
A possible solution
In addition to their primary research, the team also looked for possible ways to prevent this mechanism from working. They found that 13-cis-retinoic acid, commonly used to treat severe acne problems, reduced the attractiveness to mosquitoes.
The researchers plan to continue their research by involving more human subjects to further test their findings under real-world conditions. In addition, the team plans to examine the effectiveness of 13-cis-retinoic acid on humans as a solution to the scent issue.
The team published their findings in the peer-reviewed journal Cell. If you are interested in more details about the research, be sure to check it out below.
Sources and further reading:
Dengue Fever (National Institute of Allergy and Infectious diseases)
Zika Virus (National Institute of Allergy and Infectious diseases)
A volatile from the skin microbiota of flavivirus-infected hosts promotes mosquito attractiveness (Cell) - (doi: https://doi.org/10.1016/j.cell.2022.05.016)
Resistin-like Molecule α Provides Vitamin-A-Dependent Antimicrobial Protection in the Skin (Cell) - (Previous research into malaria, showing a similar mechanism of altering scent to attract mosquitoes - red.)
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