As we start a new year, I would like to take the opportunity of looking back at our accomplishments in 2018. Our work spans the full range of activities needed to develop novel genetic control tools for malaria control and bring them to the field, and good progress was made on all fronts.
First, Andrea Crisanti’s lab published a paper demonstrating for the first time that a genetic construct, introduced at low frequency into a lab population, can spread through the population over successive generations and cause it to crash. This success was the result of careful attention to the problem of resistance, and devising ways to avoid it, and demonstrated the power of gene drive to control mosquito populations.
Second, our success will depend on us getting regulatory authorization to test our constructs in the field. We believe that the first modified mosquitoes to be released in Africa should not contain a driving construct, and that an appropriately cautious approach calls for initial studies using non-driving strains. To that end, we have developed a male-sterile construct which has been imported by Abdoulaye Diabate’s lab into Burkina Faso and crossed into a locally-derived genetic background. This past year we obtained regulatory authorization from the National Biosafety Agency in Burkina Faso to conduct a small-scale release of this strain, the first of its kind in Africa, and we hope to make the releases in 2019. At a broader level, it is vitally important that the various regulatory authorities remain open to considering future applications to release gene drive constructs. At the Convention on Biological Diversity (CBD) meeting in November in Egypt there was an effort by some campaign organisations to have a blanket moratorium on such releases, and it was gratifying to see the overwhelming majority of countries reject that idea, and the positive result of the negotiation being a text emphasising the need for case-by-case assessment of any particular proposal on its own merits and risks.
Third, ecological studies are also critical to our success, as the most common question we get from our various stakeholders is about the ecological consequences of reducing populations of our target species, Anopheles gambiae and relatives of the species complex. The consensus expert opinion of ecologists who know these species is that they are not “keystone” species and reducing their population is unlikely to have ramifying effects on the wider ecosystem. Indeed, in some parts of East Africa bednets have been successful in dramatically reducing their numbers, and there have not been reports of obvious ecological consequences. Reinforcing this idea, John Mumford’s group published an important review of the ecology of An. gambiae mosquitoes, which concluded that there is unlikely to be a predator that specifically relies on them for food. To further explore this issue, we have this past year started field studies in Ghana to understand who eats whom in the relevant ecological communities.
Fourth, project success will depend on there being sufficient capacity on the African continent to implement properly. To that end, we have been building a new insectary facility at the Uganda Virus Research Institute, installed new offices at the Institut de Recherche en Sciences de la Santé (IRSS) campus in Burkina Faso, and published a clutch of papers on “facility readiness” [1, 2, 3 & 4]. And, for the second time, we have run a 3-day short course on gene drive for malaria control in collaboration with the Pan African Mosquito Control Association (PAMCA), as a side activity to their annual meeting. This is a key component of engaging and training the next generation of researchers, which itself will be essential to the success of our project.