Frequently asked questions and answers about Releasing Sterile males.
1. How does releasing sterile male mosquitoes stop the spread of viruses like dengue and Zika?
Our research is wholly focused on the Aedes aegypti mosquito. The female Aedes aegypti is responsible for transmitting the dengue, chikungunya and Zika viruses.
It is found in tropical regions in more than 120 countries. It is not a native mosquito to Australia but arrived from Africa over 100 years ago. If we can remove the mosquito we can remove the threat of it spreading these diseases.
2. How does the technology - the Sterile Insect Technique - work?
The success of our work is dependent on the sterile males we release finding a wild female Aedes aegypti (competing with wild Aedes aegypti males) to mate with. If the sterile male mates with a wild female, the eggs she lays wont hatch, so limiting the number in the next generation of Aedes aegypti. If we get our numbers right this would mean that the Aedes aegypti population would quickly die-off.
3. What method of sterilisation are you considering for the male mosquitoes?
We have looked into a number of methods of sterilisation and the most compelling method is through the use of a natural bacterium called Wolbachia. This bacteria naturally occur in many insect species but not in Aedes aegypti. The Aedes aegypti mosquito can be infected by Wolbachia (originally through microinjection of eggs in the lab, the bacteria is than passed to the next generation in the lab rearing process) and when males carrying this bacteria mate with females that do not have the Wolbachia bacteria, the eggs she lays will not hatch.
4. When do you plan to carry out these studies?
We hope to carry out initial small studies to begin testing our tools in communities in the Innisfail area mid 2017; this will involve releasing sterile male mosquitoes. If this small study is successful we will plan for a larger study towards the end of 2017.
5. Where else in the world is this sterile insect technology (SIT) being developed and tested?
Researchers around the world are currently trialling this Wolbachia-based sterile insect technology including in the US, China, Malaysia and Singapore.
6. How does this research differ to the work being carried out by the Eliminate Dengue project team in Queensland?
The work that the Eliminate Dengue project has been carrying out in Queensland since 2011 is not identified as sterile insect technology (SIT) as that project’s method releases male and female mosquitoes that replace the wild mosquito population with mosquitoes that are unable to transmit diseases. The SIT method aims to reduce or remove mosquitoes that transmit diseases by releasing sterile male mosquitoes only.
The Eliminate Dengue method is showing great promise in controlling dengue outbreaks in Queensland and the project is successfully expanding its activities globally and considering ways to take its method to large cities. We believe it too may benefit from the technologies Verily will be developing with CSIRO and other international partners.