Mosquitoes spread so many diseases, how can they be all right? Science reveals the specialities of mosquito immune cells.

What is the most murderous animal on earth? It's a mosquito.
's not alarmist.
mosquitoes kill more people every day than sharks have killed in 100 years.
the danger of mosquitoes is that they are excellent disease "intermediaries".
they can carry pathogenic parasites or viruses into humans while biting and sucking blood.
the world, mosquito-borne diseases include malaria, dengue fever, encephalitis, silkworm disease, Zika, yellow fever, chikungi, and so on.
speak of malaria alone.
the World Health Organization, the deadly disease has more than 200 million cases worldwide, killing about 400,000 people, most of them children under the age of five, in 2018 alone.
every day, one child dies of malaria every two minutes.
why do mosquitoes tolerate malaria parasites (the pathogens of malaria) or viruses in the body and help spread disease? Why do they have immunity against infection? The answers to these questions will help humans find effective ways to control mosquito-borne diseases.
scientists decided to test the mosquito's immune system.
to this end, a multinational team of researchers collected more than 8,500 blood cells (hemocyte, the equivalent of white blood cells) from the Gambia's two main disease-transmitting mosquitoes, the Aedes aegypti mosquito, to map the first mosquito immune cells at the resolution of individual cells.
study was published in the latest issue of Science, a leading academic journal. Dr Gianmarco Raddi, lead author of the
study and from the Wellcome Sanger Institute, said: "We conducted the first large-scale survey of the immune system of mosquitoes, using single-cell sequencing techniques to discover new types of immune cells and cell states that have never been seen before.
we also looked at mosquitoes infected with malaria parasites, studied the immune response of mosquitoes at the molecular level for the first time, and identified cell types and signaling path paths involved in this process.
" in this cell map, scientists can know which genes each blood cell opens up and mark different types of cells with specific molecules by identifying specific proteins expressed by the cells.
past, only three blood cells could be distinguished by morphological observation, and the new method reveals that the types of immune cells by mosquito and Aedes aegypti are actually more diverse, at least twice as diverse as previously seen.
particularly noteworthy, comparing the types of immune cells of the two mosquitoes found that there is a unique class of immune cells in the mosquito body that the Aedes aegypti mosquito does not have.
the two mosquito-borne diseases are not the same, with mosquitoes the main transmitters of malaria, while the Aedes aegypti mosquito transmits dengue, yellow fever and Zika viruses.
, different types of immune cells may be key to participating in the spread of different diseases.
researchers named the rare immune cells found in mosquitoes as megacytes because of their relatively large heads.
these cells are characterized by a large number of expressions of a transcription factor "lipid polysaccharin-induced tumor necrotologist" (LL3).
further experiments have shown that the mosquito's "immune initiation" process is affected when the key molecule is removed artificially - an essential immune response after a mosquito infects the malaria parasite.
, co-author of the study, said: "This is the first time that a specific type of mosquito cell has been found to play a role in the regulation of malaria parasite infection. Now, we need to conduct further research to verify this, and the researchers tracked the location and number of various types of immune cells in the mosquito's circulatory system, intestines, and other areas, and observed how the status of those cells changed after the mosquitoes took blood and contracted the malaria parasite.
found that certain types of immune cells increase in number in response to infection, some of which develop into other immune cells.
"It can be seen that mosquitoes seem to have a just right immune response to parasites such as malaria parasites: they are effective against infections so that they don't kill mosquitoes, and they don't have the strong ability to kill parasites."
Dr. Sarah A. Teichmann, another of the authors of the paper, said, "The information provided by this cell map will provide valuable resources for further research, and we may be able to try to modify the immune response of mosquitoes to prevent them from transmitting disease to humans."
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