“Super” disease-carrying mosquitoes discovered in Asia
#Super #diseasecarrying #mosquitoes #discovered #Asia Welcome to InNewCL, here is the new story we have for you today:
Click Me To View Restricted Videos
An Aedes aegypti mosquito.Image: Shutterstock (Shutterstock)
Researchers in Japan say they’ve discovered “super” resistant mosquitoes in Asia. In a study published this week, they detail how populations of Aedes aegypti mosquitoes – a common disease vector – have been found in Vietnam and Cambodia carrying multiple mutations believed to provide potent protection against the most commonly used insecticides to lend. The discovery should require urgent action to stop these mutations from spreading around the world, they argue.
A. aegypti mosquitoes are one of the most prolific sources of human misery on earth, thanks in part to the wide range of germs they can transmit to us. These mosquito-borne diseases include yellow fever, dengue, zika, and chikungunya, to name a few. The worldwide presence of A. aegypti (along with a related species, A. albopictus) and the diseases they spread has increased in recent years. Many experts predict their range will only widen over the coming decades as the climate continues to warm, including in the southern and eastern parts of the United States. These new findings, published in Science Advances on Wednesday, could add another concern to an already serious problem.
The research was led by scientists from Japan’s National Institute of Infectious Diseases, the country’s equivalent of the US’s National Institute of Allergy and Infectious Diseases (NIAID). They examined samples of A. aegypti mosquitoes recently collected across Asia, looking for mutations in their voltage-gated sodium channel gene. Some mutations in this gene, called knockdown mutations, can help mosquitoes and other insects survive exposure to pyrethroids, a class of chemicals commonly used to control insect populations. To test whether any of the mutations the researchers found actually protected the mosquitoes, they also compared their survival rates to the insecticides to non-resistant mosquitoes in the lab.
The team eventually identified 10 previously unknown substrains of A. aegypti mosquitoes that appeared to carry one or more of these knockdown mutations. In particular, a novel mutation called the L982W substitution was found in over 78% of mosquitoes from both countries. And in one particular area of Cambodia, about 90% of mosquitoes carried one of two pairs of mutations identified as of particular concern.
Laboratory experiments also found that those mosquitoes with combination mutations were much harder to kill, with “substantially higher pyrethroid resistances than any other field population ever reported,” the team wrote. In the title of their work, they describe their findings as “discovery of super-insecticide-resistant dengue mosquitoes in Asia.”
G/O Media may receive a commission
Other studies in recent years have found evidence of increasing pyrethroid resistance in A. aegypti mosquitoes in Asia and America, both in the laboratory and in the real world. And the new study is the latest in the team’s ongoing research project to understand pyrethroid resistance in A. aegypti worldwide. They say it is the first attempt to unravel the molecular mechanisms that led to the appearance of these mutations, particularly in Cambodian mosquitoes.
Non-insecticidal technologies are being developed that might one day keep mosquitoes at bay better, such as B. sterile insect techniques that sabotage populations from within, but none of these interventions are likely to see widespread use any time soon. There is also a newer class of insecticides called neonicotinoids that are increasingly being used to control mosquitoes. However, these chemicals are controversial for their harmful effects on important pollinating insects, and there are already signs that mosquitoes are becoming accustomed to them as well. Also, there are no highly effective and/or inexpensive vaccines and treatments for the most common diseases transmitted by these mosquitoes, particularly dengue.
All of this means that pyrethroids will remain a widely used drug against A. aegypti mosquitoes for now. Given that, much more needs to be done to prevent these worrying mutations from spreading around the world before it’s too late. For example, outside of Vietnam and Cambodia, the L982W mutation has not yet been found in mosquitoes. But “it could spread to other areas of Asia, which may pose an unprecedentedly serious threat to control of dengue fever, as well as other Aedes-borne infectious diseases,” the researchers warn.
