Malaria has survived bed nets, insecticides, and medicines, adapting again and again over decades. But in high-security laboratories in Tanzania, scientists are pursuing a different strategy to end the disease–one that targets the mosquito itself.
In a study published in Nature, researchers report that genetically modified mosquitoes were able to block malaria parasites taken directly from infected children, sharply reducing the insects’ ability to transmit the disease to humans.
“This is the first time a genetically modified, gene-drive–compatible mosquito strain has been developed in Africa, by African scientists, targeting malaria parasites circulating in local communities,” said Dr. Dickson Wilson Lwetoijera of the Ifakara Health Institute in Tanzania, whose team played a key role in the study.
Furthermore, the authors note that “its efficacy against field-derived parasites ensures that the findings are directly applicable to real-world transmission settings.”
Malaria remains one of the continent’s deadliest diseases, killing hundreds of thousands of people each year, most of them young children. Although insecticide-treated bed nets and indoor spraying have saved millions of lives, their effectiveness is increasingly threatened by insecticide resistance and changing environmental conditions. These pressures have driven growing interest in genetic approaches–first proposed more than a quarter century ago–that could complement existing tools.
Targeting transmission, not mosquitoes
Rather than killing mosquitoes, the researchers altered them so they are poor carriers of malaria. The team genetically modified Anopheles gambiae–Africa’s primary malaria vector–to produce two antimicrobial molecules that interfere with the malaria parasite’s development inside the insect. The molecules, originally derived from frogs and bees, act as internal barriers to infection.
For malaria to spread, the parasite must complete a complex journey inside the mosquito. After a blood meal from an infected person, the parasite develops in the gut, multiplies, and eventually reaches the salivary glands. Only then can it be transmitted to another human. The modified mosquitoes disrupted this process, slowing parasite growth and often preventing it from reaching the salivary glands altogether.
A key strength of the study is that it did not rely solely on laboratory strains of malaria. Instead, researchers used parasites taken from naturally infected children in villages in northeastern Tanzania. This is important because malaria parasites circulating in real-world settings are genetically diverse and can behave differently from laboratory strains.
Blood samples from infected children were fed to both unmodified mosquitoes and genetically modified ones under controlled laboratory conditions. The difference was striking. In ordinary mosquitoes, parasites frequently reached the salivary glands, making the insects capable of infecting humans. In the modified mosquitoes, parasites were typically stunted or delayed, and in many experiments never reached the salivary glands.
In one set of experiments, none of the modified mosquitoes had detectable parasites in tissues associated with transmission, compared with more than one-third of unmodified mosquitoes. In another, only a small fraction of modified mosquitoes showed any signs of potentially transmissible infection–and even then, parasite levels were extremely low.
A built-in transmission brake
The genetic modification had an additional effect that could further reduce malaria spread: female mosquitoes carrying the modification tended to die sooner after taking a blood meal. Because malaria parasites usually require more than a week to develop to an infectious stage, a shorter mosquito lifespan leaves fewer opportunities for transmission.
Although reduced lifespan might seem like a disadvantage, modelling studies suggest that even modest reductions in mosquito survival can have a disproportionate impact on malaria transmission.
For the approach to work beyond the laboratory, the malaria-blocking trait would need to spread through mosquito populations. To explore this, the researchers paired the modified mosquitoes with a controlled gene-drive system, which biases inheritance so that a genetic trait can be passed on to far more than the usual 50 percent of offspring.
When crossed with a helper strain providing the gene-drive machinery, the malaria-blocking trait was inherited by more than 90 percent of the next generation, suggesting it could spread efficiently through mosquito populations. Importantly, the system tested was “non-autonomous,” meaning the malaria-blocking gene and the gene-drive machinery were kept separate. This allows researchers to evaluate effectiveness and safety without creating a fully self-propagating organism.
For Africa
Much of the world’s gene-drive research has historically been based in Europe or North America. By building infrastructure in Tanzania and involving local scientists throughout the project, the researchers aimed to ensure the technology is developed with regional expertise, regulatory readiness, and community engagement.
While gene-edited mosquitoes are not yet ready for deployment, the findings provide some of the clearest evidence so far that genetic approaches could one day play a role in Africa’s long fight against malaria.
That moment could come as early as 2029.
VISUAL OF THE WEEK
The seventh United Nations Environment Assembly (UNEA-7) wrapped up with global leaders approving 11 resolutions and a Ministerial Declaration to tackle climate change, biodiversity loss, pollution, and sustainable development, while emphasising inclusive action, youth involvement, local solutions, and urgent steps for a resilient planet and communities.
QUOTE OF THE WEEK
“My mother would not be happy with the state of the planet,” Wanjira Mathai, daughter of the late Nobel Prize laureate Prof. Wangari Maathai, said in an interview with Mongabay.
RESEARCH HIGHLIGHTS
Africa Faces a Sharp Rise in Dangerous Heatwaves: Africa is heating up faster than the rest of the world, even though it produces very little of the pollution causing climate change. This study shows that extreme heatwaves–hot days and hot nights happening together–will become far more frequent, longer, and more intense as the planet warms. Heatwaves that once happened only once every 50 or 100 years could occur every few years, or even every year, especially if global temperatures rise by 3°C. Central, West, and East Africa will be hit hardest.
As populations and economies grow, more people and livelihoods will be exposed to dangerous heat. The main cause is rising temperatures driven by trapped heat in the atmosphere. Without strong climate action and adaptation, heat-related risks to health, food, and economies will grow rapidly across Africa. [Reference, Earth’s Future]
Where Did the Giraffes Go? West Africa has plenty of green vegetation, yet it has surprisingly few large animals like elephants and giraffes. Scientists now think the reason isn’t a lack of food, but a lack of salt. Animals need salt to survive, and in many parts of West Africa, plants contain very little of it. In drier regions of Africa, animals find salt by licking rocks, digging in riverbeds, or visiting natural salt pans. Many protected areas in West Africa are low in salt, forcing animals to wander into human areas in search of it, increasing conflict with people. Reference, Science newsletter. Paper in Nature]
Masculinity and Mental Health in Older Men in Sub-Saharan Africa: mental health of older men in Sub-Saharan Africa is often overlooked. As men age, many struggle with poverty, poor health, and the loss of traditional roles as providers, leaders, or strong family heads. These changes can lead to sadness, stress, loneliness, or shame, especially because cultural expectations often encourage men to appear strong and avoid talking about emotional problems.
Many older men express distress through physical pain or spiritual concerns rather than discussing depression, and they often seek help from family members, religious leaders, or traditional healers instead of clinics. The review finds that research and services rarely focus on older men’s specific needs and calls for culturally sensitive, gender-aware mental health support that respects local traditions and realities. [Reference, Sociology Compass]
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