More and more mosquitoes are becoming resistant to different insecticides. This is a serious issue since mosquitoes can transmit many deadly diseases including malaria, the West Nile virus, and the Zika virus. Insecticide resistance makes it much harder to fight these diseases and the mosquitoes themselves.
When mosquitoes are resistant to insecticides, they become almost invincible. It then becomes impossible to reduce their population and slow down the rate at which they spread disease. Only by knowing how mosquitoes develop insecticide resistance will we be able to create an action plan with new ways to fight them.
What is insecticide resistance?
Basically, mosquitoes are slowly becoming fully resistant to some insecticides. This allows them to survive even large doses of chemicals that would normally be lethal to them.
Insecticide resistance is caused by genetic changes in an insect. These increase the insect’s ability to overcome the effects of different chemicals. This means that certain species of mosquito are becoming resistant to some of the substances designed to kill them. And, since these changes are genetic, the mosquitoes will pass this resistance from one generation to the next. This, in turn, will result in a loss of insecticide efficacy for entire colonies of mosquitoes.
Even though people are starting to fret about this issue, in reality, insecticide resistance is nothing new. It started to develop almost at the same time as the manufacture and use of the first insecticides for malaria eradication in the 1940s.
However, with how much we now use insecticides on a daily basis, this has become a much more common occurrence. The more we use different types of insecticides, the more immune mosquitoes are becoming to these chemicals. So, we might soon experience a time when nothing can kill mosquitoes because they’ll have developed a resistance to all known insecticides.
Why are insects becoming insecticide resistant?
One of the main reasons for the rapid development of insecticide resistance is mutations. Mosquitoes overproduce certain enzymes, which absorb the insecticide before it can get to their nervous system and kill them. The Culex pipiens species, for example, overproduce enzymes esterase A and B. These enzymes absorb the insecticide before it can do any harm to the mosquito.
This enzyme overproduction is due to a simultaneous increase in the number of copies of one or two corresponding genes. So, these mosquitoes have basically adapted to the point where the insecticide is no longer harmful to them. Since these mutations happen in certain areas and apply to specific insecticides, the mosquitoes in an entire region can develop insecticide resistance in a short amount of time.
The good news is that experts and scientists have noticed this problem. Research is being done to find ways to combat insecticide resistance and develop new ways to fight mosquitoes. This research includes steps like entomological observation, data gathering, and the development of innovative vector control tools.
It also includes the creation of new insecticides that can kill mosquitoes but that mosquitoes won’t develop a resistance to. This isn’t a simple task, though. It’s difficult to find chemicals that won’t cause the genetic mutations in mosquitoes that result in insecticide resistance and that will be safe to use around humans and other species as well.
For now, mosquitoes are unfortunately winning the war against insecticides. Over the past decade, large amounts of money have been spent developing and distributing new insecticides, without great results. In the meantime, mosquitoes keep developing insecticide resistance against new types of chemicals. We can only hope that scientists will find a way to overcome insecticide resistance soon.