Djibouti looks to genetically engineered mosquitoes to quell urban malaria wave

The first batch of genetically engineered non-biting mosquitoes will be released in Djibouti on Thursday in an attempt to stop the spread of an invasive species that threatens to swamp African cities and set back years of progress on tackling malaria.

The genetically modified Anopheles stephensi mosquitoes, developed by Oxitec, a US biotechnology company using technology spun out of the UK’s Oxford university, are engineered so that their female progeny die. Only female mosquitoes bite.

Similar technology was used in 2022 to combat dengue-carrying mosquitoes in São Paulo, Brazil, where it suppressed 96 per cent of dengue mosquitoes, according to a peer-reviewed journal.

Djibouti’s government is desperate to stop the spread of Anopheles stephensi, an invasive species of mosquito, which arrived in the east African port city a decade ago from the Indian subcontinent. Unlike other species, which thrive in rural settings and bite at night, stephensi does better in cities, bites in the daytime and is resistant to insecticides.

Djibouti, a mostly urban country of 1.1mn people, had been on the verge of eliminating malaria in 2012, when it recorded just 27 cases. But since the arrival of stephensi, which probably came in by cargo ship, cases have ballooned. In 2020, 70,000 people, roughly 1 in 15 of the population, contracted malaria, with 190 deaths.

Dr Abdoulilah Ahmed Abdi, health adviser to the president, said the government’s objective was to “urgently reverse malaria transmission in Djibouti, which has spiked over the past decade”. Djibouti, he said, could act as a blueprint for other nations; stephensi has already spread to countries including Ethiopia and Kenya and as far afield as Lagos, the huge commercial capital of Nigeria on Africa’s west coast.

Malaria killed 620,000 people worldwide in 2022, most of them in Africa. Unlike in the countryside, where bed nets and insect spray are effective against the disease, these remedies are of little use against the daytime biter stephensi. Urban populations, many never exposed to malaria, have little resistance to the disease.

In the past, African governments have been wary of genetically modified organisms, particularly plants and seeds. But Grey Frandsen, chief executive of Oxitec, told the Financial Times that Djibouti had embraced the technology after seeing it safely deployed in Brazil, Panama and the Cayman Islands, where billions of genetically modified mosquitoes had been released.

Unlike a rival “gene drive” technology, which was designed to spread and persist in the environment as modified insects outbred competitors, he said, Oxitec’s mosquitoes were “self-limiting” and would eventually die out.

Uganda’s President Yoweri Museveni had committed $5mn of state funds to combat malaria through Oxitec’s technology, he said.

“Decades of progress in the race to eradicate malaria are at risk as mosquitoes are adapting and outsmarting human interventions,” Frandsen added.

This will be the first time genetically modified mosquitoes have been released in east Africa and only the second time in the continent as a whole. In 2019, genetically engineered mosquitoes were deployed in Burkina Faso in an early-stage trial.