The results of a trial of genetically engineered mosquitoes intended to reduce their ability to transmit dengue fever have been published in the journal PLOS Neglected Tropical Diseases.
The mosquitoes, commonly known as “Friendly Aedes aegypti” mosqitoes in Brazil where the trial took place, were developed by a company called Oxitec.
The results of the trial showed that the numbers of the mosquito (Aedes aegypti) that spreads dengue fever, yellow fever, chikungunya, and zika virus were reduced by more than 90%.
“The fact that the number of Aedes aegypti adults were reduced by 95% in the treatment area confirms that the Oxitec mosquito does what it is supposed to, and that is to get rid of mosquitoes,” said Dr. Andrew McKemey, head of field operations at Oxitec. “According to published mathematical models reviewed and recommended by the World Health Organization (WHO) working group on dengue, it would also reduce the number of biting mosquitoes below the disease transmission threshold. The next step is to scale up to even larger studies and run mosquito control projects on an operational basis.”
The study, which took place in the Itaberaba neighborhood of Juazeiro city in Bahia State, was led by the University of São Paulo and Moscamed, a company that specializes in environmentally friendly pest control. The treatment area included a population of approximately 1,800 people.
How it works
This method of control is species-specific. The Oxitec male mosquitoes are released to mate with the pest females, and their offspring die before they can transmit the disease or reproduce because of a self-limiting gene. The mosquitoes also carry a color marker for monitoring, and the insects and their genes do not persist in the environment.
Mosquito control in Brazil
“This invasive mosquito and the diseases it carries is a real challenge,” said Professor Margareth Capurro of São Paulo University. “Aedes aegypti is developing resistance to insecticides, and even when we remove breeding sites they continue to reproduce and transmit diseases because they live in areas that are difficult to treat. This is why we need new tools. We knew that the Oxitec mosquito was a promising tool, so we wanted to independently evaluate its effectiveness here in Brazil.”
Dengue, chikungunya, and zika virus are debilitating diseases. There is currently no vaccine or specific medication for any of them. According to the WHO, the only way to combat dengue at present is to control the mosquitoes that spread the disease.
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