Mosquitoes can detect CO2 or human sweat using unique receptors. The latest study, by researchers from Boston University and Rockefeller University, explains why mosquitoes are so good at detecting us, even when researchers genetically turn off human receptors.
According to the study, at least one species of mosquito – the Aedes aegypti (yellow fever mosquito) – has a completely different olfactory system than most animals.
Using CRISPR (a family of DNA sequences found in the genomes of prokaryotic organisms such as bacteria and archaea) as a gene-editing tool, the researchers engineered mosquitoes whose sense of smell would express fluorescent proteins. This allowed the researchers to deduce how different smells stimulate the olfactory system of mosquitoes.
It turns out that the yellow fever mosquito connects multiple olfactory receptors to a single neuron, a process called co-expression. This overturns a basic tenet of olfactory science, which states that each neuron has only one receptor associated with it.
The long-term goal of research is to create improved mosquito repellents that effectively mask human scent, which deters mosquitoes from their meal.
Diseases that can be contracted from mosquito bites, such as dengue fever and yellow fever, kill more than 50,000 people worldwide each year.
Dengue fever, which is common in parts of South America, Mexico, Africa and Asia, kills around 22,000 people each year. However, even more deadly is yellow fever, which affects people in Latin America and Africa the most, claiming 30,000 lives each year.