Reviewing progress on sterile insect technique to control dengue
New approaches to controlling mosquito vectors, particularly as they relate to dengue, were the subject of an African regional workshop held 23-27 October in Mauritius. New genetic control methods that strongly reduce the numbers of mosquito vector densities have been recommended for field trials by the independent Vector Control Advisory Group set up by the World Health Organization (WHO).
Dengue has rapidly spread in all regions of WHO in recent years. There are no vaccines or treatments, so prevention and control of the vectors are critical.
The Vector Control Advisory Group has reviewed new vector control technologies based on genetic control. One is the sterile insect technique, which uses gamma or x-ray radiation to sterilize artificially reared male mosquitoes, which are then released to mate with field females. Through successive generations, the numbers of mosquitoes capable of transmitting the virus are thus reduced.
Florence Fouque, the TDR team leader for vectors, environmental and society unit, provided the 30 participants from 10 African countries with an overview of the WHO evaluation process and current situation. She outlined how the sterile insect technique is at the evaluation phase, which is step 2 of a 4-step process.
The Vector Control Advisory Group was established by WHO in 2012 as an independent advisory body to review new concepts and interventions, validate the public health value, determine the data required for validation, advise applicants on this and assess the data validity, and support the formulation of WHO policy recommendations. The group is supported by staff from WHO’s Global Malaria Programme, the Department for the Control of Neglected Diseases and TDR.
A framework for this evaluation, along with the hierarchy of study designs, is being published in a new manual that provides guidance for the third step in the process – field studies.
Field trials underway
The sterile insect technique is widely used for agricultural pests in more than 100 countries, and has achieved some success against the screw-worm flies in northern Africa and northern America. It has also been used with the tsetse fly in Africa that transmits African trypanosomiasis, also known as sleeping sickness.
The technology is now being tested against the mosquitoes in more than 10 countries (Thailand, Italy, Mauritius, South Africa, and others). The evidence generated is considered a key step in determining the potential for this technology, which will be reviewed by subgroups of the Vector Control Advisory Group.
For more information, contact: Dr Florence Fouque.