Author | Chen Zhihan Source | Science and Technology Publicity and Cultural Resource Library In the vast sea of people, why do mosquitoes "bite" you? It turns out that your unique body odor may be the reason why you continue to exude charm to mosquitoes. ‍On June 30, a latest s

2024/05/0906:51:32 science 1157

Author | Chen Zhihan Source | Science and Technology Publicity and Cultural Resource Library

In the vast sea of people, why do mosquitoes "bite" you? It turns out that your unique body odor may be the reason why you continue to exude charm to mosquitoes.

‍ On June 30, a latest study published in the journal Cell by the team of Professor Cheng Gong of Tsinghua University verified the above point of view. People or animals infected with dengue virus are more favored by mosquitoes. On this basis, the team also proposed a strategy that is expected to prevent mosquito-borne disease outbreaks...

The threat of infectious diseases is huge

As soon as summer arrives, mosquitoes come one after another.

This annoying creature not only brings endless noise and itching to humans, but also spreads a large number of mosquito-borne viruses, causing widespread infectious diseases (including malaria, yellow fever, dengue fever, etc.). Globally, nearly a million people die from it every year.

Dengue virus and Zika virus (Zika virus) are common mosquito-borne viruses.

Dengue fever caused by the former is one of the most widespread viral infectious diseases in the world. It is mainly carried by the Aedes mosquito and is spread in tropical areas (occasionally in subtropical areas). It can cause rashes, fever and pain in mild cases, and bleeding and even death in severe cases. According to National Institutes of Health (NIH) statistics, more than 50 million dengue fever cases occur around the world every year, and about 20,000 people die, mostly children.

The latter uses another mosquito species of the same genus as its host and is relatively less likely to cause serious diseases in adult populations. However, it is inevitably linked to severe birth defects in newborns. The Zika epidemic that broke out in South America in recent years caused thousands of infected pregnant women to give birth to children with microcephaly.

Human beings have made unremitting efforts to prevent mosquito-borne diseases for a long time. However, due to the special infection mechanism of the virus, a relevant vaccine has not yet been released.

It is for this reason that clarifying the mechanism of the rapid spread of mosquito-borne viruses and taking effective blocking measures have become top priorities.

relies on smell to lock infected people

The continuation of the virus relies on the continuous two-way transmission between humans and mosquitoes. In other words, if mosquitoes always choose to "take blood" from uninfected people for food, the virus will have difficulty surviving.

Mosquito-borne virus transmission cycle. The

research team speculates that the reason why mosquito-borne viruses spread quickly and are difficult to eradicate is most likely because mosquitoes have a way to accurately locate infected people in a huge crowd of people. They then conducted experiments comparing mice infected with dengue virus with healthy mice and found that mosquitoes indeed preferred infected mice.

But why? After in-depth analysis, the research team focused on a volatile molecule called acetophenone .

It turns out that whether mice or humans are infected with dengue virus, the content of acetophenone molecules in their odor increases significantly. This molecule can activate the mosquito's olfactory nervous system, allowing the mosquito to "hear the news" and lock on to the target and rush to it immediately. After applying different concentrations of acetophenone to human arms, researchers also determined that the higher the concentration of acetophenone, the more attractive the arm was to mosquitoes.

This shows that changing the smell of the host may be a necessary means for mosquito-borne viruses to increase their transmissibility.

Mosquito-borne infectious diseases New ideas for prevention and treatment

Where does the acetophenone that makes mosquitoes "fascinate" come from?

It turns out that it is a metabolite of microorganisms (genus) on the skin surface. Further research shows that infection with dengue virus and Zika virus inhibits an important immune factor in the skin - antimicrobial peptide . This promotes the massive proliferation of such microorganisms that inhabit the host's body surface.

This regulatory mechanism helped the research team find inspiration for blocking the large-scale epidemic of mosquito-borne diseases. As long as the expression of antimicrobial peptides is restored, the growth of skin Bacillus will be controlled, acetophenones will be reduced, and mosquitoes will No longer takes special interest in the infected.

In other words, the virus's circulation cycle will also be interrupted.

So, are there any drugs that can achieve the above effects? After repeated trials using mouse models, a vitamin A derivative, isotretinoin, brought hope. After feeding isotretinoin to mice infected with dengue virus and Zika virus, their antimicrobial peptide expression returned to normal and the release of acetophenone was inhibited.

However, whether vitamin A drugs are equally effective on humans remains to be further verified. The research team is currently preparing for the next phase of work and believes that in this difficult and difficult "human-mosquito war", mankind will achieve the final victory.