New facility will integrate innovative automated technologies to achieve scalability, to enable the National Environment Agency (NEA) to expand male mosquito releases for Project Wolbachia – Singapore to more neighbourhoods over the next few years.

Climate change is anticipated to worsen the spread of mosquito-borne diseases like dengue. It facilitates the spread of mosquito vectors, viruses and epidemics. There is thus a need to continually innovate and design sustainable solutions to deal with these environmental public health challenges. Singapore’s National Environment Agency (NEA) has established a new, highly automated facility that will allow researchers to eventually increase their production capacity of Wolbachia-carrying Aedes aegypti mosquitoes by more than 10-fold, compared to its previous production facility. This boost in capacity is critical for NEA’s plans to scale up Project Wolbachia – Singapore, in preparation for future deployment of the novel vector control technology. The new facility, located at Techplace II in Ang Mo Kio, was officially opened on 2 December 2019 by Dr. Amy Khor, Senior Minister of State, Ministry of the Environment and Water Resources (MEWR).

Expanding Project Wolbachia ­– Singapore

NEA’s Project Wolbachia – Singapore involves the release of male Wolbachia-Aedes aegypti mosquitoes to suppress the urban Aedes aegypti mosquito population. Aedes aegypti is the primary vector of dengue, chikungunya and Zika in Singapore. When the released male Wolbachia-Aedes aegypti mosquitoes mate with urban female Aedes aegypti mosquitoes that do not carry Wolbachia, the resulting eggs do not hatch. Over time, continued releases of male Wolbachia-Aedes aegypti mosquitoes are expected to bring about a gradual reduction in the urban Aedes aegypti mosquito population, and hence lower the risk of dengue transmission.

Phase 3 of Project Wolbachia – Singapore, carried out from February to November 2019, achieved more than 90 per cent suppression of the urban Aedes aegypti mosquito population at the study sites, comprising 144 residential blocks at Tampines West and Nee Soon East. This is an improvement on the 70 to 80 per cent suppression achieved at the conclusion of the Phase 2 field study in January 2019 and demonstrates the effectiveness of Wolbachia-Aedes technology in Singapore’s high-rise and high-density urban landscape. Importantly, continued releases have kept the urban Aedes aegypti mosquito populations at both study sites at low levels, which thus pose low dengue risk.

With the success of the Phase 3 field study, Project Wolbachia – Singapore progressed to a Phase 4 field study in November 2019, to determine if the Aedes aegypti mosquito population suppression can be sustained over larger areas. The Phase 4 field study covers 284 residential blocks at Tampines West and Nee Soon East. This is a seven-fold expansion compared to Phase 1 in 2016. The current Phase 4 field study will further expand in early 2020.

NEA’s new facility will provide the scalability in production and release of Wolbachia-Aedes aegypti mosquitoes needed for the expansion and future field deployment for Project Wolbachia – Singapore. Associate Professor Ng Lee Ching, Director of NEA’s Environmental Health Institute, said, “The new facility has a target capacity of five million male Wolbachia-Aedes aegypti mosquitoes per week—a 10-fold increase over the previous facility. It is also equipped with a water recycling system, allowing the efficient and improved use of water.”

Incorporation of innovative technologies for scalability

Together with partners such as Orinno Technology Pte. Ltd., Verily, and the Joint Food and Agricultural Origanization of the United Nations (FAO)/International Atomic Energy Agency (IAEA), NEA researchers have developed innovative solutions to implement Wolbachia-Aedes technology and scale up the Project. This entails the effective integration of multiple technical disciplines, including biotechnology, engineering, and data analytics.

At the new facility, these solutions boost production capacity and increase productivity. Besides the automated larvae counter and pupae counter previously developed, new systems include a male-female pupae sorter. Many of these have been co-developed by NEA and Orinno Technology Pte. Ltd. Another automated sorting technology developed by Verily, with improved efficiency, will also be used. More devices, such as a high-throughput larvae rearing system designed by FAO/IAEA and Orinno, are in the pipeline to further improve scalability in the near future.

NEA has also worked closely with FAO/IAEA to incorporate low-dose X-ray irradiation in the production workflow. This step serves to render infertile any small number female Wolbachia-Aedes aegypti mosquitoes that may be inadvertently released alongside the males. This additional step provides additional safeguard to prevent any build-up of female Wolbachia-Aedes mosquitoes, which would hamper the effectiveness of Wolbachia-Aedes mosquito releases for suppressing urban Aedes aegypti mosquitoes.

“The impact of Project Wolbachia – Singapore goes beyond the realm of public health. The innovative solutions developed and collaborations formed through this important scientific initiative, have also advanced research and provided economic opportunities in Singapore”, said Dr. Amy Khor, Senior Minister of State, Ministry of the Environment and Water Resources, at the opening ceremony.

Building regional capacity to fight dengue

The opening of the new facility coincided with the first day of the IAEA Regional Training Course (RTC) on Methods for the Mass Rearing, Irradiation and Release of Sterile Male Aedes Species. Co-organised and hosted by NEA’s Environmental Health Institute (EHI) at the new facility from 2 to 6 December 2019, the RTC involves 22 participants from 12 countries, who will be trained in the use of sterility-based approaches to suppress mosquito vector populations.

“The Sterile Insect Technique and the Incompatible Insect Technique share many common components and challenges, and their combination has several advantages,” said Dr. Jérémy Bouyer, Medical Entomologist, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture. He added, “This RTC is therefore an opportunity for the mutual exchange of ideas and knowledge sharing, which will help facilitate further collaboration, and will accelerate the development of novel technologies to tackle dengue, Zika, and other Aedes-borne diseases.”

Mr. Tan Meng Dui, CEO of NEA, added, “This facility serves multiple functions. Besides providing us with the scalability we need to expand male Wolbachia-Aedes mosquito releases, it also serves as an incubator and testbed for innovative solutions, and provides a space for learning and mutual exchange of ideas”.