Sugar water laced with medicine is not a poison but a way to cure a mosquito of the virus it carries. In the past, mosquitoes were fought with insecticides that kill insects, but they quickly get used to poisons, and the chemicals harm nature. Now scientists are proposing a different path: instead of destroying the carrier, make sure the virus inside it cannot replicate.
In the laboratory, Aedes aegypti mosquitoes, which transmit dengue and chikungunya fevers, were given a sugar solution with one of four antiviral drugs. First, isolated guts were used to check which concentration of 4'-fluorouridine suppresses the chikungunya virus. Then the mosquitoes were fed the bait for three days before blood infection and four days after. At 3, 7, and 14 days, the amount of virus was measured in the body, head with wings, legs, and saliva to understand whether the mosquito could transmit the infection through a bite.
Importantly, the baits did not repel mosquitoes: they readily drank the sweet solution with the drug. The effect on survival and reproduction was weak and depended on the drug and sex: NHC reduced the survival of females, and 4'-fluorouridine that of males, but overall mortality was mainly explained by natural aging, since mosquitoes live about 27 days at 28°C.
This approach differs from traditional insecticidal baits, which kill mosquitoes and create selection pressure for resistance. Here the insect stays alive but ceases to be dangerous because the virus inside it cannot replicate. This reduces the risk of resistance developing and lessens environmental damage.
The next step is to test the baits in semi-field and field conditions, where mosquitoes have access to natural sugar sources and insect behavior differs from the laboratory. We need to understand how often mosquitoes will visit the baits in nature and how stably the drugs persist in the sugar solution. If all goes well, a sweet trap that cures rather than kills will become a new weapon against epidemics.
Aedes aegypti mosquitoes live about 27 days at 28°C, so in the 30-day survival experiment, a significant portion of mortality was natural rather than caused by the drugs.
Not published on arXiv. Here are its page, the PDF and the formalization: you can check it yourself, not only read our account.