Asides from mosquitoes being a pure nuisance with their buzzing sounds, and itchy bites, they are one of the deadliest animals in the world with respect to causation since they are responsible for carrying disease causing organisms and causing disease in humans that can lead to their death.
While I am not dead and do not think I will be dying anytime soon, I just treated myself of malaria which is caused by a parasite known as plasmodium. I can tell you that the few days which I suffered from that disease was one of the worst days of my life on earth but then, different people will tell you different stories about their experiences with mosquitoes, as well as the disease they had when bitten my those tiny little monsters.
With this said, I was shocked to hear that a factory that breeds mosquitoes in Brazil intends to release 5 billion infected mosquitoes into the atmosphere. The first thing that came to my mind was "Is this the beginning of the end?" but then I realize that it might be the end of something but definitely not us.
What would happen if mosquitoes actually died completely? Well, the answer according to nature journal showed that there will be no really much effects on the ecosystem as first, very few organisms feed on mosquitoes, such as some birds, fishes, bats, and dragon flies, and it isn't their first choice of food since they can be replaced by another type of food. Although they can help with pollination, they aren't the only insect that can pollinate plants and it isn't like we rely on them that much.
It isn't like all the species of mosquitoes bite humans seeing that only 200 species of the about 3200 species of mosquitoes that exists bite humans but even that small percentage that feed on our blood are responsible for the about 247 million people that are infected with malaria yearly of which I am one of them this year, not including Dengue fever, Zika virus and a myriad of other diseases that infect humans all round the year.
Scientist have been looking for a way to stop Dengue without killing mosquitoes, with the help of a bacteria called Wolbachia. Research are showing that if wolbachia is added to mosquitoes that transmit viruses to people like Yellow fever, Chikungunya, Dengue, and so on, the viruses wouldn't grow well in the mosquitoes as the bacteria are out-competing the viruses in the mosquito as it cannot proliferate properly.
The reason for releasing these mosquitoes is to allow them infect other mosquitoes with this bacteria. The way it works, if an infected male mates with a non-infected female, the eggs laid by the female will not hatch but if a non-infected male mates with an infected female the eggs will hatch but the offspring will all be infected with Wolbachia and the same happens if both male and female have Wolbachia. This causes Wolbachia generations to increase while non-wolbachia generation starts to die off.
A comprehensive study on the efficacy of Wolbachia-infected mosquito deployed for the control of dengue showed significant drop on the first comprehensive study in Indonesia of about 77.1% which means that people are 4 times less likely to develop dengue. Some regions also saw quite a little reduction in percentage up to 38% but that is a good reduction for a disease like dengue and in places like Aburra Valley in Colombia, there was a 95% decline in Dengue.
Is there a risk of having Wolbachia infecting humans? Currently, there is no link between Wolbachia and any negative effect on human but currently, the World Mosquito Program under the WHO is still evaluating the technology before it can be used in other countries. If this works, it is not meant to discourage the Dengue vaccines but it is going to be a supplementary measure for dengue fever.
Reference
https://www.nature.com/articles/d41586-023-01266-9
https://www.nature.com/articles/d41586-020-02492-1
https://www.worldmosquitoprogram.org
https://www.nature.com/articles/466432a
https://www.worldmosquitoprogram.org/