The Ecuadorian government has released 100,000 sterile male Aedes aegypti mosquitoes in the town of Bellavista, in the Galapagos Islands, as part of a pilot project that aims to partially block the reproduction of these insects and, in this way, try to control their populations and reduce the risk of transmitting diseases such as dengue, chikungunya and zika.
The Ecuadorian authorities and the experts leading this project consider that the release into the environment of this type of sterile mosquitoes will have a positive impact on the health of residents and tourists of these well-known islands and will not cause any harm to local nature.
The release of these sterile insects took place at 4:00 p.m. on March 10, and since then a surveillance system has been maintained to ascertain the effectiveness of this measure, which the authorities have described as a “historic event for Ecuador.”
The generation of these insects and, finally, their distribution for sanitary purposes, “is the result of 6 years of research” by experts from the National Institute for Public Health Research, the Center for Research in Infectious and Vector Diseases), who have achieved adapt health projects to the so-called Sterile Insect Technique (SIT), “as a complementary method to control the reproduction of the Aedes aegypti mosquito, a vector that transmits diseases.
The project is co-financed by the Technical Cooperation Program of the International Atomic Energy Agency (IAEA), co-executed with the Agency for the Regulation and Control of Biosafety and Quarantine for Galapagos (ABG); and, it has the scientific collaboration of Researchers from the Department of Nuclear Sciences of the National Polytechnic School.
The Ecuadorian authorities have detailed that the project has several phases, including: 1) reproduction, mass breeding, and sterilization of male Aedes aegypti mosquitoes; 2) field trial and release of mosquitoes in at least one locality in continental Ecuador and in the Galapagos Islands; and, 3) monitoring and evaluation of the effectiveness of the SIT technique.
The reduction of the mosquito population in the Galapagos Islands also meets several objectives: improve the health conditions of the population, prevent the transmission of diseases to tourists, making the Galapagos a safe place for visitors, the reduction in the use of chemical products used in fumigation, care for nature and endemic species; among others, as highlighted by the government of Ecuador in an official note. It must be remembered that, being male, these released sterile mosquitoes do not bite humans (only females do).
The principal investigators of this project belong to the National Institute for Public Health Research – INSPI ‘Dr. Leopoldo Izquieta Pérez’, an entity attached to the Ministry of Public Health whose main attributions are the execution of investigations, specialized laboratory tests and quality control of the laboratories of the Comprehensive Health Network, as well as the development of products, with with the purpose of contributing to the detection, surveillance and control of diseases of sanitary importance in Ecuador.
The Sterile Insect Technique was developed over 50 years ago and is considered a method of controlling insect pests with no known substantial harm to the environment. SIT includes the mass rearing and sterilization, by means of radiation, of the insects that cause a specific pest. Once sterilized, the males are systematically released from the air in defined areas, where they mate with wild females without having offspring, thus reducing the population that causes the plague. In many cases, the irradiation that sterilizes the males is produced by gamma rays and X-rays.
The International Plant Protection Convention classifies sterile insects as beneficial organisms because they do not self-replicate and therefore cannot establish themselves in the environment, breaks the reproductive cycle of a pest, also known as autocidal control, reduces use of insecticides and does not involve the production and release of transgenic insects (which is another new and growing resource).