Genetically modified mosquitoes have spread in Brazil after a field experiment aimed at fighting mosquitoes carrying viruses.
In the latest issue of the Scientific Report journal, Brazilian researchers said they found traces of human genetic intervention in the genome of 10 to 60 percent of yellow fever mosquitoes (also known as Aedes aegypti) from samples they analyzed in Jacobina, northeastern Brazil.
The Testbiotech Institute, which is critical of genetic engineering, slammed the experiment in a statement, saying: "The long-term consequences of disease spread, mosquitoes breeding and interactions with the environment cannot be underestimated."
Between 2013 and 2015, the British firm Oxitec had released about 450,000 male mosquitoes every week in the city of Jacobina. The scientists had modified the genome of these mosquitoes to limit their breeding, aiming at controlling infectious diseases like dengue, zika and yellow fever. These viruses can be transmitted by the female mosquitoes only.
Although the number of mosquitoes has actually decreased by 80-95 percent, according to various studies, some mosquitoes have survived and are now carrying a different genome.
"The release of mosquitoes was carried out hastily without any points having been clarified," the Brazilian biologist José Maria Gusman Ferraz told the Folha de S. Paulo newspaper.
The Testbiotech Institute has also criticized the fact that the field experiment had been conducted with no sufficient studies.
"Oxitec's trials have led to a largely uncontrollable situation," said Testbiotech's CEO Christoph Then.
Christoph Then warned that, in the worst case, the damage caused by the experiment could not be avoided through insurance companies or emergency procedures.
"Lessons must be learned and applied in case scientists insisted on using the genetic modification techniques," he said.
He also stressed that the spread of genetically modified organisms among natural living groups should be prevented. Scientists do not know the consequences of the transmission of modified genomes on the future generations of yellow fever mosquitoes, reported the Scientific Reports journal.
Research team led by Jeffrey Powell from the Yale University in New Haven, said the genetically modified mosquitoes have likely become resistant to pesticides, explaining that "these findings highlight the importance of adopting a monitoring program when releasing genetically modified creatures in the nature, in order to avoid any unwanted consequences."
