The venomous Asian Tiger Mosquito scientific name Aedes albopictus, foreign called Asian Tiger Mosquito, also known as forest mosquito, is an exotic species, the name "tiger" comes from the central part of their head and back. A white stripe, like a pattern on a tiger.
This daytime-biting insect is native to Southeast Asia and can transmit harmful diseases such as Eastern Equine Encephalitis (EEE), Zika, West Nile, Chikungunya and Dengue through human activity, especially waste tires commercial transport for dissemination.
With the globalization of the economy, many invasive alien species also came to China on the free ride of economic globalization. Aedes albopictus is one of them, and Aedes albopictus is one of the most invasive species in the world.
In addition, my country has frequent political and economic exchanges with Southeast Asia since ancient times, which provides favorable conditions for the invasion of Aedes albopictus.
Characteristics of Aedes albopictus
The adult mosquitoes have a black body with distinct white stripes, a unique single white stripe running through the back, about 0.5 cm in length, with obvious silver-white bands on the tentacles and tarsus, and the eggs are about 0.1 cm long, Dark brown to black. The eggs are laid in moist areas above the water surface and can survive the winter.
Eggs hatch when submerged, and the immature stages of the life cycle (larvae and pupae) take place in water.
Compared with the eggs of other species of mosquitoes, the eggs of Aedes albopictus have a higher hatching rate and stronger environmental adaptability, which is an important reason for the flooding of Aedes albopictus.
Larvae are filter feeders and live in standing water in discarded tires, small containers, and tree cavities. The pupae are comma-shaped and dark brown.
The venomous pattern is an aggressive biter that feeds primarily during the day and has a wide host range including humans, domestic and wild animals, and birds.
It is a potential vector of encephalitis, dengue fever (all four serotypes), yellow fever and dog heartworm.
Control of Aedes albopictus
Aedes albopictus is so annoying and has the potential to transmit various diseases, so how can we effectively prevent the invasion of the poisonous flower pattern?
In 2019, researchers nearly wiped out populations of the world's most invasive mosquito species, Aedes albopictus, on two islands in Guangzhou.
For the first time, they used a combination of two promising control techniques in a field trial, reducing Aedes albopictus populations by 94 percent. The two-pronged approach was published in the journal Nature on July 17, 2019.
The approach combines the sterilization of female Asian tiger mosquitoes with infection of male mosquitoes with Wolbachia pipientis, a bacterium that hinders the insect's ability to reproduce and transmit disease-causing viruses such as dengue and Zika.
Peter Ambruster, a mosquito ecologist at Georgetown University in Washington, D.C., who wrote a review of the study, said it was one of the most successful eradication trials to date. The two-pronged approach can be a very powerful tool when combined with other control methods such as pesticides, he said.
Studies have shown that X-ray sterilization of large numbers of male pests, such as spiral worms , before releasing them into targeted areas can reduce the size of wild pest populations. But this is an inefficient method of mosquito control, because even though irradiated males can still mate, they are less successful than their unaltered counterparts. Therefore, this method cannot be used to solve the problem of species invasion with toxic patterns.
In another approach, workers infected laboratory mosquitoes with a strain of Wolbachia, which occurs naturally in several insect species, including A. albopictus (strain).
When male mosquitoes infected with a certain combination of Wolbachia strains mate with wild female mosquitoes carrying a different combination, the insects failed to produce offspring.
But Zhiyong Xi, a medical entomologist at Michigan State University who led the study, said it was crucial that only male mosquitoes infected with this particular combination could be released into the wild.
If females carrying these strains are also released, they can mate with males carrying the same Wolbachia (strain) and produce offspring. Their offspring could eventually displace local mosquito populations, making future control attempts that rely on Wolbachia infection more difficult.
To prevent this, facilities that house large numbers of mosquitoes for control purposes often mechanically separate males from females based on size differences.
But Xi Zhiyong said the process was not perfect, so staff had to perform a second manual screening to remove female mosquitoes.
This is a tedious and time-consuming task that limits the total number of mosquitoes that can be released. So Zhiyong Xi and his team set out to eliminate the need for this process.
Experimental improvement
Wild populations of A. albopictus are naturally infected with two strains of Wolbachia, and the researchers infected wild mosquitoes with a third strain of Wolbachia to generate insect laboratory colonies with three bacterial variants.
The team then exposed the colonies to low levels of radiation, which made the females sterile but only slightly reduced the males' ability to mate.
During the mosquito breeding peaks in 2016 and 2017 , the researchers released more than 160,000 mosquitoes per week in residential areas on two islands located in a river in the city of Guangzhou, China, which has the highest dengue transmission rate.
They hope this will drastically reduce mosquito populations, since wild females mated with altered males -- and wild males mated with sterile lab females -- do not produce offspring.
The team tracked declines in adult female mosquitoes as they bite and spread disease. As expected, the average number of wild adult females fell by 83% in 2016 and 94% in 2017.
Male Aedes albopictus mosquitoes carrying three Wolbachia strains await release to the test site.
"It's impressive," said Stephen Dobson, a medical entomologist at the University of Kentucky in Lexington and founder of MosquitoMate, which commercializes Wolbachia in mass production as a control for white streaks. Aedes tool.
Current strategies for controlling A. albopictus — including spraying insecticides and removing water-filled containers where the insects lay their eggs — are ineffective, Dobson said.
He added that the species lays eggs in hidden places that are difficult to monitor and tends to develop resistance to common pesticides, so new tools like the one described in this paper are very much needed.
But scaling the technology to an effective public health strategy over large regions is a challenge, says Gordana Rai, a molecular ecologist at the QIMR Berghofer Institute for Medical Research in Brisbane, Australia.
Maybe, in the future we can really live in an era without mosquitoes.
Epilogue
As one of the most communicable species in the world, Aedes albopictus has a strong transmission ability and can carry a variety of viruses. Fortunately, researchers have now found a way to deal with the poisonous Asian Tiger Mosquito. By sterilizing Aedes albopictus, the The reproductive capacity of Aedes albopictus to effectively control the number of venomous Asian Tiger Mosquitoes.
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