African scientists are confident that the limited environmental release of genetically engineered (GE) sterile mosquitoes — the first-ever in Africa — could set the continent on a path to possibly eradicating malaria.
Burkina Faso authorities last week approved the release of GE mosquitoes in their country in a bid to eliminate malaria. Authorities there have been looking forward to the first release of the mosquitoes for a while now as it seeks alternative means to deal with the disease. Malaria is a big issue in Burkina Faso, where more than two-thirds of all children are hospitalized for malaria before turning age five. A 2015 World Health Organization ranking of the prevalence rate of the disease in 88 countries placed Burkina Faso second to only Mali.
The mosquito-borne disease annually sickens 200 million with headaches, vomiting, chills and extreme fever and eventually kills about 400,000 people. Most of its victims are women and children. More than 70 percent of malaria deaths occur in children under five years, according to World Health Organization statistics, with about 300,000 children dying from malaria in 2015. Some 90 percent of the world’s reported cases and fatalities occur in sub-Saharan Africa.
Throughout the world, various methods have been used to reduce the spread of mosquitoes and malaria over the last century, including insecticide sprays, treated nets and anti-malarial drugs. A lot of progress has been made, but the pace has been slow and mosquitoes, as well as malaria-causing parasites, have repeatedly developed resistance to the control methods.
Now the concept of controlling mosquitoes through the release of male mosquitoes genetically engineered to be sterile is taking shape. The idea is that wild females will mate with the sterile males, which would reduce the overall population. Though the sterile male approach to managing insect pest populations is not new, genetic engineering appears to be a more efficient and effective method of producing the large numbers of sterile males needed to achieve effective controls.
In Africa, the sterile mosquito project is being run by Target Malaria, an international not-for-profit consortium led by scientists at the Imperial College in London who are working to develop and share technology for long term malaria control.
“This decision is a milestone as it is the first approval for field release of genetically modified mosquitoes in Africa and the first for malaria vectors anywhere,” a statement from Target Malaria explained. However, the project is still in its early stage of field research. The mosquitoes to be released in Burkina Faso will not persist for more than a few weeks in the environment and are not intended to reduce the incidence of malaria or reduce the population of malaria transmitting mosquitoes.
“The knowledge and experience from this study will serve to inform the development of our next phases of the project towards a sustainable vector control intervention for malaria,” the statement said. “The purpose of the small-scale release is to collect scientific data on longevity and dispersal of the released mosquitoes and will serve to build capacity and operational experience amongst our teams.”
Abdoulaye Diabate, the lead researcher in Burkina Faso, clarified in a statement to STAT news that “these mosquitoes, unlike their ‘gene drive’ counterparts, are not intended to have a lasting impact on the insect population. They have something called a ‘sterile male’ mutation — none of the male mosquitoes that will be released will be able to have offspring.”
If this process proves successful, the stage will be set for more elaborate trials that will see the release of GE mosquitoes that really will help control the population.
Dr. Umar Traore, head of the Biosafety Laboratory at the National Biosafety Agency in Burkina Faso, told the Alliance for Science in an earlier interview that Burkina Faso wants to use biotechnology to stop further deaths from malaria. He is confident the public will embrace that approach.
“For the genetically modified mosquitoes, we are trying to fight malaria. We will control the vector. Malaria is killing a lot of children under five and so it’s really an important issue. Most of the time, if you have a pregnant woman who is infected by malaria, you have to choose between the baby and the mother, so it’s something really important and so there won’t be any problem for those technologies to be released into the country,” he said.
Traore gave additional insight into how the project will work, explaining, “The mosquitoes are genetically modified to control the mosquito population to fight against malaria. So now they are going into controlled release. They release on specific sites to see how it works for competitiveness [with wild males seeking to mate with wild females] and other properties.”
He confirmed that the recently approved sterile mosquito release is just an experimental step that won’t control the insects, but will offer good data to work with going forward. “It is not the final product… but they will get that data that can be used for the final product to be released,” he explained.
Prof. Kwabena Mante Bosompem, director of Africa’s leading biomedical research institute, the Noguchi Memorial Institute for Medical Research at the University of Ghana, has also backed the plan to use biotechnology to fight malaria. He noted that genetic engineering is a powerful method to help stop the spread of the disease, and said the technology provides at least two options.
“The mosquitoes are the ones taking the pathogens from one person to the other,” he told the Alliance for Science in an interview. “And so if you can reduce the mosquito population, you naturally will reduce the risk of infection because there will be fewer mosquitoes to bite [people]. The other method is where you genetically engineer mosquitoes so that they are no longer effective in carrying and transmitting the parasite.”
Bosompem said the public can rest assured that the processes leading to the release of such GE products prioritize safety, so there is nothing to fear. “There is a whole process of assessment, evaluation, risk assessment. The scientists would have done rigorous work to be sure that it is fit for the purpose so that any risk of failure or disaster is as minimal as possible. Otherwise, there will be no release… it is important for the public to understand this. There should be no fears,” he explained.
It could take at least five years before researchers are ready to release the GE mosquitoes that will actually help control malaria in Africa. It’s a broad process that goes beyond the laboratory to focus as well on community engagement. But once it’s under way, a lot of progress could be made in stopping the needless deaths and suffering caused by malaria, particularly in Africa.