AFP extension
ANNOUNCEMENTS•
Yellow fever mosquitoes have been discovered in Vietnam and Cambodia that are extremely resistant to the harshest insecticides. Japanese researchers write it in the scientific journal The progress of science. 78 percent of the mosquitoes studied were genetically engineered such that they were well protected by the most commonly used pesticides, which is of great concern to scientists.
The mosquito species in question is Aedes aegypti, which in addition to yellow fever also spreads infectious diseases such as dengue (dengue fever), Zika and chikungunya. Researchers have discovered ten new sub-strains of this mosquito with one mutation. One such mutation, called L982W, occurred in 78% of mosquitoes. In one specific region of Cambodia, as many as 90% of mosquitoes carried the mutation.
In laboratories, mosquitoes with this mutation, or a combination of other genetic mutations, have proven much more difficult to kill with pyrethroids, the most commonly used pesticide against mosquitoes. Even against greatly increased doses of the drug, these “super-tough mosquitoes” fared better than the researchers have ever observed.
21,000 dead
“It’s concerning that this is being seen, but it’s also not surprising given our heavy reliance on that group of pesticides for control,” says associate professor of medical and veterinary entomology Sander Koenraadt of Wageningen University in the NOS Radio 1 Newspaper. “The more these pesticides are used, the more resistant mosquitoes develop.”
Dengue fever is a major problem worldwide, Koenraadt said. “More than 400 million people get this infection. There are still an estimated 21,000 deaths every year. Local governments in Asia and South America in particular are at a loss because you see outbreaks of this disease every year.”
The yellow fever mosquito is native to Africa and is now also found in tropical regions of Asia, South and Central America. The area where the mosquito is found has grown in recent years and experts have already warned that the insect could cover an even larger area due to climate change.
Make mosquitoes sterile
“If indeed nearly 80 percent of mosquitoes are insensitive, then those mosquitoes will keep flying and keep spreading that disease,” says Koenraadt, who points out that this is precisely why alternatives to insecticides are being sought. “There’s also a special focus on non-chemical agents.”
Examples of non-chemical pesticides with which there is good experience are mosquito traps, which can be used on a large scale. “And, for example, the use of the Wolbachia bacterium is also on the rise. It is also being tested on a larger scale. The idea behind this is that you release mosquitoes and then cause sterility in the population. Those mosquitoes cannot therefore they have more offspring, so their populations plummet,” says Koenraadt.
Another alternative against dengue is vaccination. “There are also initiatives to develop a dengue vaccine and thus protect people from infection.”
