A British company breeding mosquitoes whose offspring cannot spread malaria is set to start releasing the insects into Djibouti City by the end of the year.
Genetically-engineered male mosquitoes hatched in boxes placed around the east African capital will produce female babies with genes that cause them to die before they reach adulthood. Only female mosquitoes bite and spread disease.
The scheme is designed to slash the numbers of mosquitoes in order to reduce cases of malaria, which currently infects up to 10 per cent of the country a year.
Malaria is among the world’s biggest killers of children under five.
“So much has been achieved with existing tools,” like bed nets and insecticide spraying, says Neil Morrison, chief strategy officer at Oxitec, the British biotech company which produces the altered mosquitoes. “But progress is stalling” as resistance is being built up.
As global funding to fight malaria reduces, thanks to cuts by the US, UK and a number of other nations, Morrison adds: “We just need to get a bit smarter in terms of how we think about controlling mosquitoes”.
A piece of code is inserted into the genetic material of the mosquitoes at a research facility in the UK, before the “friendly” mosquitoes are transported to a “mosquito factory” in Djibouti, Morrison explains. A chemical antidote is then given to the mosquitoes to “switch off” the code, allowing them to survive and breed within that “factory”.
Once a breeding colony is established, male eggs containing the code that will stop their female offspring surviving and therefore spreading malaria are hatched into the environment.
“They just add water and close the lid. And over the next few days our friendly male mosquitoes develop and then emerge from the box to look for local females,” Morrison says.
The boxes could be placed on lamp posts, outside shops or in people’s front yards – the company is still testing where they are most likely to survive in the hot, humid environment. This helps drives down the number of biting mosquitoes in the local area as the gene causing female mosquitoes to die before reaching maturity spreads.
Thousands of genetically-modified adult mosquitoes were already released onto the streets of the city last year as part of a pilot.
Djibouti had been close to eliminating malaria when a species of mosquito called Anopheles stephensi, generally found in Asia and the Middle East, appeared in the country for the first time. Cases of malaria skyrocketed from around 30 cases in 2012 to more than 70,000 in 2020.
The scale of the deaths, “impacted public health and impacted the economy, that impacts schools, that impacts everything,” Colonel Dr. Abdoulilah Ahmed Abdi, health advisor to the President of Djibouti says.
The mosquito species – never seen in Africa before the last decade – has since spread through the continent to Kenya, Sudan, Ethiopia, and even as far as Nigeria.
