“The mosquitoes being produced in this factory carry bacteria called Wolbachia that block them from transmitting dengue and other viruses, such as Zika, chikungunya and yellow fever, to humans. By releasing them to reproduce with wild mosquitoes, they spread the bacteria, reducing virus transmission and protecting millions of people from illnesses.”
Article: https://www.gatesnotes.com/Health/Mosquito-Factory
Interestingly, these are the same viruses Ivermectin was shown to treat:
– https://www.science.org/content/article/antiparasitic-drug-has-bonus-effect-mosquitoes