Resources

The Djibouti Friendly™ Mosquito Program is a partnership formed at the invitation of the Government of Djibouti, between the Djibouti National Malaria Control Program, Association Mutualis and Oxitec, pioneering a new Friendly™ Mosquito solution to combat the invasive urban malaria-spreading mosquito, Anopheles stephensi. 

Friendly™ male mosquitoes are non-biting male mosquitoes that carry two inserted genes. A self-limiting gene allows us to release male-only adult mosquitoes into the environment, which mate with local invasive female mosquitoes, and the self-limiting gene prevents female offspring from surviving. With sustained releases of self-limiting male mosquitoes, the number of pest females in the population is reduced, and the local invasive mosquito population declines. Our insects also carry a fluorescent marker gene which, when collected from traps from the field and viewed under special filters, allows us to distinguish the self-limiting insects from local invasive counterparts, this improves efficiency and aids monitoring.

The invasive Anopheles stephensi mosquito was first detected in Djibouti in 2012 and has fuelled an unprecedented increase in malaria incidence in Djibouti’s capital city and surrounding communities.

Where national annual malaria cases previously numbered in their hundreds, public health authorities are now reporting many tens of thousands of cases annually. Native to Asia, Anopheles stephensi is highly capable of colonising dense, urban locations, unlike many other malaria-transmitting mosquitoes. In Djibouti, where 70% of people live in the capital city, this urban invasion has exposed most of the country’s population to a very new and deadly threat.

Anopheles stephensi evades conventional vector-control tools, as it bites during the daytime and is resistant to insecticides. Anopheles stephensi has spread across East and West Africa, Arabia and South Asia, threatening over 100 million people in Africa alone.

Anopheles stephensi mosquitoes pose a significant threat to urban communities in Djibouti, and the Djibouti Friendly™ Mosquito Program is working with urgency to develop a solution to this growing challenge not just for Djibouti, but the region as a whole.

The Djibouti Friendly™ Mosquito Program has been working with local communities for over 18 months in preparation for these releases. Community members have assisted with mosquito surveillance by hosting mosquito traps in their homes, and we have previously carried out mark-release-recapture exercises with wild An. stephensi mosquitoes in the same neighbourhoods. Throughout this period our community engagement activities have been led by the local health not-for-profit Association Mutualis. Mutualis have been working hand-in-hand with local communities in Djibouti City since 2022 to inform them about the Djibouti Friendly™ Mosquito Program’s activities.

Local community health leaders have been at the forefront of this engagement work, having been trained by Association Mutualis on the Program and its aims. In previous mark-release-recapture exercises with wild mosquitoes, community members themselves have assisted in conducting these releases – demonstrating the deep trust and strong relationships between the Djibouti Friendly™ Mosquito Program and local communities.

We use genetics to provide two useful traits in our insects. A self-limiting gene allows us to release male-only adult mosquitoes into the environment, which mate with local invasive female mosquitoes, and the self-limiting gene prevents female offspring from surviving. With sustained releases of self-limiting male mosquitoes, the number of pest females in the population is reduced, and the local invasive mosquito population declines. Our insects also carry a fluorescent marker gene which, when collected from traps from the field and viewed under special filters, allows us to distinguish the self-limiting insects from local invasive counterparts, this improves efficiency and aids monitoring.

Friendly™ mosquitoes carry a self-limiting gene that is only active in females, therefore preventing females from surviving; males are not affected by this gene, so can survive as normal. This gene blocks the female mosquito’s cells from carrying out normal cellular processes and from producing many of the other proteins required for normal mosquito development. This stops the female larvae from developing to adults. 

We release only Friendly™ male mosquitoes, which are not capable of biting (only female mosquitoes bite). The self-limiting gene we insert in Friendly™ mosquitoes prevents biting females from surviving.

All Oxitec mosquitoes are produced in our dedicated facility in Djibouti City. Only in this facility are female Friendly™ mosquitoes kept, alongside males, for the purpose of producing non-biting male Friendly™ Anopheles stephensi for deployment in communities.

Yes - because self-limiting mosquitoes work by finding and mating with invasive females, the suppression effect is highly targeted to this species of mosquito. This specificity leaves non-target species, such as beneficial insects like bees and butterflies, unharmed. As the self-limiting genes dilutes from the environment in just a few generations, there is no long-lasting presence or effect once treatment has been stopped.

Yes, Oxitec mosquitoes have been determined to be safe and to pose no threat to humans or the environment by multiple regulatory agencies, including both the EPA and the FDA in the US, as well as in Brazil where we have conducted numerous successful field demonstrations. These releases in Djibouti have been approved by the Ministry of Environment and Sustainable Development following a comparable risk assessment.

Oxitec’s technology has been independently reviewed by hundreds of scientists around the world and has been the subject of more than 100 peer-reviewed studies, which are by definition independent scientific reviews. The list of Oxitec’s peer-reviewed publications is available on the company’s website: https://www.oxitec.com/en/our-technology#publications

We haven’t yet published specifically on the Anopheles stephensi Oxitec mosquitoes. Because these mosquitoes use the same proteins used by Oxitec in other insects, the peer-reviewed papers published on the safety and efficacy of other Oxitec insects are also relevant. 

These include: 

Spinner SAM, et al. (2022) New self-sexing Aedes aegypti strain eliminates barriers to scalable and sustainable vector control for governments and communities in dengue-prone environments. Frontiers in Bioengineering and Biotechnology 10.

OPEN ACCESS: https://www.frontiersin.org/articles/10.3389/fbioe.2022.975786

Gorman K, et al. (2016) Short-term suppression of Aedes aegypti using genetic control does not facilitate Aedes albopictus. Pest Management Science 72(3):618-28. doi: 10.1002/ps.4151.

OPEN ACCESS: http://onlinelibrary.wiley.com/doi/10.1002/ps.4151/epdf

Carvalho DO, et al. (2015) Suppression of a field population of Aedes aegypti in Brazil by sustained release of transgenic male mosquitoes. PLoS Negl Trop Dis 9(7): e0003864.

OPEN ACCESS: http://www.plosntds.org/article/fetchObject.action?uri=info:doi/10.1371/journal.pntd.0003864&representation=PDF

Harris AF, et al. (2012) Successful suppression of a field mosquito population by release of engineered male mosquitoes. Nature Biotech. 30:828-830

PAYWALL: http://www.nature.com/nbt/journal/v30/n9/full/nbt.2350.html

Publications describing our work with Anopheles stephensi mosquitoes are currently in draft.

Oxitec’s Friendly™ solution has been tried and tested successfully over more than a decade around the world. Our Friendly™ Aedes aegypti mosquitoes are now being scaled across Brazil and used by local governments, businesses and households to reduce populations of Aedes aegypti mosquitoes which transmit dengue, Zika and chikungunya. Pilot studies in Brazil have shown that Friendly™ Aedes aegypti mosquitoes suppress dengue-spreading mosquitoes by more than 95%. Approximately 1 billion Oxitec mosquitoes have been released over 10 years in 4 countries across 3 continents. No adverse effect on environmental or human health has ever been documented.