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Dengue and Zika viruses alter the host’s scent to attract mosquitoes

Dengue and Zika viruses are transmitted by mosquito bites. Now, a study by researchers in China has shown that when humans and mice are infected with these viruses, they release a chemical that makes them more attractive to the mosquitoes that spread the viruses.

Almost half of the world’s population lives in dengue risk areas. Lack of treatment means many affected regions have high rates of morbidity and mortality. A new study published in the journal magazine cellFound a way to reduce the release of this substance in mice and increase the frequency of mosquito bites: treatment with a commercial acne medication.

Both viruses, genus flaviviruses, They depend on these insects for survival in the wild. When a healthy mosquito bites an infected host, it can contract the infection and then transmit it to other individuals through its bite.

The paper shows that mosquitoes breed Aedes They have a host-seeking behavior that can be triggered by the scent of animals infected with these viruses. species Aedes aegypti i Aedes albopictus They are the vectors for the transmission of Zika and Dengue.

Aedes mosquitoes have a host-seeking behavior that can be triggered by the scent of infected animals.

“Mosquitoes rely on their sense of smell to find their hosts,” explains Gong Cheng, a researcher at Tsinghua University (Beijing) and lead author of the paper. and the feeding of infected mice compared to healthy others”.

A sophisticated strategy to increase infection

To investigate why mosquitoes preferred infected hosts, the team analyzed skin odor samples from both mice and infected humans to study odor molecules in the epidermis. The researchers found that acetophenone, a substance found in abnormally high levels in the skin of infected people, is particularly attractive to mosquitoes.

Some genera of bacteria produce acetophenone in humans and mice Bacillus that grows on the skin. Normally, it produces an antimicrobial protein—called RELmalfa—that keeps the bacillus population at bay.

“Both dengue virus and Zika virus promote the proliferation of acetophenone-producing skin bacteria by suppressing the expression of RELMalfa,” says Cheng. As a result, some bacteria overgrow and produce more acetophenone, making these sick people more attractive to mosquitoes.

“Ultimately, the virus can manipulate the skin microbiome of its hosts to attract more mosquitoes and thus spread faster,” says Penghua Wang, an immunologist at the UConn Health (Connecticut, USA) Academic Medical Center and co-author of the study.

People infected with dengue were more attractive to mosquitoes and exhibited more acetophenone on their skin than healthy people.

After identifying the chemical compound, the researchers found that giving isotretinoin (an acne drug) to dengue-infected mice caused them to release less acetophenone, making them less attractive to mosquitoes.

This medication is a vitamin A derivative known to increase the production of an antimicrobial peptide in the skin.

The experiment was simple. The researchers fed mice with isotretinoin and put them in cages with mosquitoes. They found that mosquitoes did not feed on infected mice that had been treated with the anti-acne drug compared to those that fed on uninfected animals.

As Cheng explains to SINC, “Dietary isotretinoin in flavivirus-infected animals reduces acetophenone production because it alters the bacterial population on the host’s skin.”

Similar mechanisms in other viruses

“Although we do not have data for other flaviviruses, such as yellow fever or West Nile virus, we think there is a strong possibility that these viruses also have similar mechanisms to manipulate their host’s smell. For this reason, we will analyze other mosquito-borne flaviviruses and alphaviruses under the same experimental conditions,” Cheng continues.

In the future, the team plans to apply their findings to the real world. “We plan to introduce isotretinoin into the diet of dengue patients to see if this compound reduces acetophenone production in humans as it does in mice,” says the researcher.

The authors also plan a line of research on mosquitoes: “We want to identify specific olfactory receptors for acetophenone in these insects and eliminate genes from the mosquito population using gene-driven technology,” explains Cheng.

Without the receptors, mosquitoes would no longer be able to smell the skin molecule they love so much, which could ease the spread of dengue and other flaviviruses, the authors conclude.

Source: El Diario





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