Drone take a look at offers breakthrough in using core methods to regulate mosquitoes – IAEA research
According to a study by the International Atomic Energy Agency (IAEA), the use of drones can significantly increase the effectiveness of a nuclear technique used to suppress disease-causing mosquitoes and reduce costs. The finding is an important step towards a large-scale use of this method to combat the vectors dengue fever, yellow fever and Zika.
The study, published this week in the journal Science Robotics, tested the use of a drone to release sterile mosquitoes as part of the Sterile Insect Technique (SIT) – a form of insect birth control that has been used successfully to control agricultural pests for decades like the Mediterranean fruit fly and tsetse flies. Scientists have been working in recent years to develop the method for mosquitoes as well.
SIT uses radiation to sterilize mass-reared male insects, which are then released to mate with wild females. Since these do not produce offspring, the insect population decreases over time.
The method requires the steady release of large numbers of sterile male insects in good condition to compete with their wild counterparts. The drone prototype tested in Brazil in April 2018 can transport up to 50,000 sterile mosquitoes per flight and release them to 20 hectares of land within ten minutes without any loss of quality.
“The results represent an important breakthrough in expanding the use of SIT against mosquitoes,” said lead author Jeremy Bouyer, medical entomologist with the United Nations (FAO) / IAEA Joint Program on Nutritional Techniques for Nuclear Techniques in Food and Agriculture.
With long, fragile legs and delicate wings, mosquitoes can be easily damaged by air release methods commonly used in the application of SIT against other insects such as airplanes and gyrocopters. Heretofore, sterile male mosquitoes have instead been spread with costly, labor-intensive, and time-consuming soil releases.
“The areas covered by a 10-minute drone flight, for example, would take two hours and twice as much manpower if they were done on the ground,” said Bouyer. “We estimate a significant reduction in operating costs while maintaining the quality of the sterile insect.”
The World Health Organization (WHO) estimates that vector-borne diseases account for 17 percent of infectious diseases, causing more than a million deaths each year. However, there is often a lack of resources in countries for extensive mosquito control programs.
The advances shown in the study were critical in approaching inexpensive mosquito control methods, said Eric Rasmussen of the University of Washington’s School of Public Health in a comment also published in Science Robotics. “This new drone release technology is cheap enough to alleviate the misery of mosquito-borne diseases almost everywhere. This is exciting news. ”
Bouyer said the fieldwork testing the drone had the added benefit of proving that radiation-sterilized mosquitoes are competitive to mate with wild women. “The study shows that irradiated males can be very competitive when processes like mass rearing and handling are mastered.”
The IAEA, in cooperation with the FAO and the Swiss-American non-profit group WeRobotics, developed the drone-based release mechanism. The field test was carried out in collaboration with the country’s Moscamed program in the city of Juazeiro in the Brazilian state of Bahia.
The IAEA and its partners are currently working on developing a smaller version of the drone that can move around 30,000 mosquitoes. This is critical, Bouyer said, as lighter models meet strict regulations for flying drones over urban areas, where disease-transmitting Aedes mosquitoes tend to be concentrated.
As part of the SIT package for mosquitoes, the IAEA is also working to refine methods for separating male and female insects during the mass rearing process. This crucial step in the process is still being done by hand, which adds to the cost. Separation is important to ensure that female mosquitoes are not released as they bite and transmit disease.
The SIT has been used to control agricultural pests for over 60 years and has only recently been adapted for use against mosquitoes. The insect control method can be particularly useful against vectors that are difficult to handle using conventional techniques, such as nets impregnated with insecticides, or when pesticide use needs to be reduced.
The IAEA is working with the WHO to collect epidemiological data on the effectiveness of SIT as a mosquito control method to reduce disease transmission.