Monday, January 2, 2023 | 2:30 p.m.
According to an agency article telamthe National Atomic Energy Commission (Cnea) is advancing in the investigation of the use of the Sterile Insect Technique (SIT) in the Aedes aegypti mosquito, which is responsible for transmitting the dengue virus, zika and chikungunya fever.
The method consists of breeding and sterilizing the males, through radiation, for their subsequent release into the environment and control of species that may be harmful to public health.
After a delay caused by the most difficult years of the pandemic, the project was reactivated and is once again breeding strains of the Aedes aegypti species from the Buenos Aires town of Ezeiza and locals from the Posadas area.
Based on the studies, they managed to define the optimal dose of gamma radiation, 70 gray, which allows “to achieve the sterility of the insects without impairing their performance so that they have a good enough state that allows them to compete with field males and copulate with females”, indicated the head of Cnea’s Agricultural Applications Department, Malter Terrada.
The Cnea project also obtained good results in the first release on its Ezeiza property of 4,328 males of the strain present in a nearby neighborhood and bred in the laboratory.
During the test, the adult mosquitoes had an average life expectancy of 4 days after release and an average flight distance of close to 104 meters, results that are within a good standard. Furthermore, this information is relevant for the design of the pilot release to be carried out in 2023 and to estimate the effectiveness of the application of this tool.
“If the life expectancy is every four days, the releases will have to be based on that period and if my mosquito moves, for example, 50 meters, I have to plan my release every 50 meters or less,” explained the Laboratory researcher. of Mosquito Control, Marianela García Alba.
In addition, the professionals explained that to these tests are added the competitiveness tests that “are carried out in large cages in which the density that would be in the field is simulated to test the number of sterile mosquitoes to be released,” adds the biologist.
The increase in the competitiveness of sterilized insects is achieved through a greater number of those found in the wild, so this technique requires an “inundative release”.
According to García Alba, “you will release more because they will always be less competitive than those that are in the field because you raised them in the laboratory, irradiated them, took them out and cooled them for handling and transfer.”
For reasons of safety testing of the technique, because a perfect separation between males and females is not always achieved, the latter were also irradiated, obtaining good results.
Aedes aegypti females can transmit viruses that cause diseases such as dengue, but males cannot. They are the ones that bite since they need blood for egg production.
They also announced that during the next year, the researchers plan to expand the laboratory to scale up the production of sterile mosquitoes with the contribution of materials from the IAEA.
In 2022 there were 282 anti-dengue operations
In 2022, 282 environmental sanitation operations were carried out in Posadas with the aim of eliminating breeding sites for the Aedes aegypti mosquito, a transmitter of the dengue, chikungunya, zika and yellow fever viruses. At the same time, 1,795 tons of useless objects were removed from the patios of the houses. This action plan has included tasks of comprehensive cleaning, weeding, fumigation and debris removal. It is about focal control, through which municipal agents have entered house by house to search and remove the elements that could become water reservoirs.
