Scientists Are On The Way To Figuring Out Why Mosquitoes Target Certain People
There is now a near-complete blueprint of a mosquito's genes.
New research mapping the genes of a particular species of mosquito has uncovered a set of genes that could lead to understanding why this insect tends to target certain people, and how the spread of mosquito-borne viruses could be stopped.
An international team of researchers, lead by New York's Rockefeller University, has investigated the genes of Aedes aegypti, otherwise known as the yellow fever mosquito, which is the primary species responsible for spreading dengue fever, and zika and chikungunya virus, globally.
The researchers say they now have a near-complete blueprint of the mosquito's genome, and that by understanding the genes of the mosquito, scientists can slow the spread of the life-threatening viruses the insect transfers to humans.
The study discovered over 50 new genes in Aedes aegypti that could uncover how they smell their targets, why only some carry viruses and how some are immune to repellent.
The genes that show how mosquitoes order smell molecules to understand their environment could indicate why mosquitoes target certain people — although the researchers are yet to understand how exactly those processes work.
Blood type, the amount of carbon dioxide a person exhales, metabolism, clothing colour, pregnancy and the amount of beer or sugar people consume have all been associated with increased risk of mosquito bites. However, there is only weak evidence for these factors and most are only supported by single studies.
The difference between individual microbiota (microorganisms such as bacteria and fungi) that thrive on human skin is thought to be the most plausible theory for why mosquitoes are more attracted to certain people, and this process would be directed by the mosquito's genes.
Dr Gordana Rašić, a senior research officer from Queensland's Berghofer Medical Research Institute and one of the study's authors, told BuzzFeed News that the researchers also found that mutations in certain genes can lead to the mosquitoes developing a resistance to repellents and insecticides. This information could be used to create more effective repellents.
"We are a bit more lucky in Australia than the rest of the world in the sense that these mosquitoes can still be killed by insecticides, but around the world, these mosquitoes are really resistant [to them]," she said.
Rašić notes that the research also uncovered genes that indicate why certain mosquitoes carry dengue and others don't.
"It's almost like when some of us get the flu and some don't ... once we know that, we can alter the genes so mosquitoes can't transmit the virus anymore," she said.
The number of dengue cases internationally has increased dramatically in recent decades, with the World Health Organization reporting a 30-fold increase in the past 30 years; 390 million dengue fever cases are now reported annually.
Rašić believes that the new genome is already helping researchers across the globe to develop disease management techniques and innovative ways of stopping the spread of Aedes aegypti.
"We've created something that other researchers can use, so we hope that this will power biological discovery on this mosquito in many different ways."