With the International Atomic Energy Agency (IAEA) recently releasing its report on the use of environmental friendly nuclear technology – the Sterile Insect Technique (SIT) – to tackle the scourge of mosquito-borne diseases which take a heavy toll in the developing world, including the Indian subcontinent, the IAEA has now come out with a related study showing that the use of drones can significantly increase effectiveness and reduce costs in the application of the SIT.
The IAEA, last month, released the Guidance Framework for Testing the Sterile Insect Technique (SIT) as a Vector Control Tool against Aedes-Borne Diseases – a product collaboration between the IAEA, the Rome-based Food and Agriculture Organization (FAO), the Special Programme for Training and Research of Tropical Diseases (TDR) and the World Health Organisation (WHO) – which will serve as guidance for governments interested in using the SIT.
In a statement earlier this month, the IAEA said the finding on the use of drones “marks an important step forward towards the large-scale deployment of this method (SIT) to control the vectors of dengue, yellow fever and Zika.” The study, published in the journal Science Robotics tested the use of a drone to release sterile mosquitoes as part of the SIT, which is a form of insect birth control that has been used successfully for decades to fight agricultural pests such as the Mediterranean fruit fly and tsetse flies, and has now been developed also for mosquitoes.
The SIT uses radiation to sterilize mass-reared male insects, which are then released to mate with wild females. These, as a result do not produce any offspring, and the insect population declines over time. According to the global nuclear watchdog, the method requires the uniform 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 carry up to 50 000 sterile mosquitoes per flight, releasing them without loss of quality over 20 hectares of land in ten minutes.
“The findings represent a major breakthrough for expanding the use of SIT against mosquitoes,” study lead author Jeremy Bouyer, a medical entomologist at the joint Food and Agriculture Organization (FAO)/IAEA Programme for Nuclear Techniques in Food and Agriculture,” said in a statement.
With long fragile legs and delicate wings, mosquitoes can easily be damaged through air release methods commonly used in the application of SIT against other insects, such as airplanes and gyrocopters. Until now, sterile male mosquitoes were, instead, spread using costly, labour-intensive and time-consuming ground releases.
“The areas covered with a 10-minute drone flight, for example, would require two hours and twice the amount of human resources if done by ground. We estimate a major reduction in operational costs while maintaining the quality of the sterile insect,” Bouyer said.
The WHO estimates that vector-borne diseases account for 17 per cent of infectious diseases, leading to more than one million deaths each year, but countries often lack resources for large-scale mosquito eradication programmes. The advances shown in the study were critical to getting closer to cost-effective mosquito control methods, according to Eric Rasmussen from the School of Public Health at the University of Washington said in a commentary also published in Science Robotics.
The IAEA developed the drone-based release mechanism in partnership with the FAO and the Swiss-American non-profit group WeRobotics. The field test was carried out around the city of Juazeiro in the state of Bahia, Brazil, in collaboration with the country’s Moscamed programme.
The IAEA and its partners are now working to develop a smaller version of the drone that can carry around 30 000 mosquitoes. This is critical, according to the IAEA, as lighter models meet stringent regulations for flying drones over urban areas, where Aedes mosquitoes that transmit diseases tend to concentrate.
The IAEA said it is also working with the WHO to gather epidemiological data on the efficacy of SIT as a mosquito control method to reduce disease transmission.
