A new study in Malaria Journal, led by the Johns Hopkins Center for Communication Programs and U.S. President’s Malaria Initiative (PMI), warns that Africa’s malaria fight faces a fresh challenge – and it’s not just biologic.
The rise of Anopheles stephensi, an invasive mosquito spreading across African cities, is forcing experts to rethink how human behavior and community trust shape disease control.
“People’s everyday choices – how they store water, how they manage pooled or standing water around homes, how they respond to feeling ill with fever – will determine whether An. stephensi becomes a continent-wide menace or a challenge contained through collective action,” says Gabrielle Hunter, who co-led the research while at CCP.
“Raising awareness early could help prevent this mosquito from establishing a foothold. Without that, measures that could help prevent outbreaks risk being ignored.”
An. stephensi, which is primarily found in Asia, is now being found in parts of Africa. These mosquitoes can carry malaria – a disease that killed nearly 600,000 people in 2023.
Unlike most malaria mosquitoes endemic to Africa, this invasive mosquito breeds in artificial water-holding containers – water tanks, barrels, cisterns, tires, and materials at construction sites – making it well-suited to thrive in dense, urban environments.
Across malaria-endemic countries in Africa, rural areas have been the focus of many malaria prevention programs.
It is important, the researchers said, to increase malaria risk perception in areas where transmission has historically been low (including cities), and tailor social and behavior change interventions to higher-risk groups, including mobile populations and those with occupational risk.
“Early and meaningful partnerships with communities is critical for building trust and increasing the acceptance of interventions,” Hunter says.
The CCP researchers conducted a scoping review to identify what is known about social and behavioral factors that affect mosquito control. This review sought to inform evidence-based, social and behavior change considerations and guidance for responding to An. stephensi in Africa by synthesizing information currently available and leveraging lessons from controlling other mosquito species.
They examined more than 3,300 studies on prevention behaviors such as sleeping under insecticide-treated nets, acceptance of indoor spraying, seeking treatment for fever, and managing mosquito breeding sites through larval source management. Only two of them focused specifically on behavior change efforts for control of An. stephensi. Most behavior change research instead came from studies on other malaria or container-breeding mosquito species, highlighting how little social science evidence currently exists related to this particular mosquito.
“Despite its potential impact, social and behavioral research specific to An. stephensi in Africa remains extremely limited,” Hunter says. “The review calls for timely studies to identify the water storage behaviors that may favor An. stephensi breeding in different city settings, understand how people perceive the new threat and pinpoint which populations are most exposed.”
The review also found that in urban or historically low-malaria areas, people tend to underestimate their risk of malaria. That low perception leads to inconsistent use of bed nets, hesitation to accept indoor residual spraying and delays in seeking medical care when fever strikes. New communication campaigns are needed, she says, for high-risk groups such as construction workers, migrants, and urban residents living with unreliable water infrastructure.
Community trust emerged as a recurring theme, especially when it comes to the application of larvicides in homes and community areas to kill mosquito larvae. When people clearly understand malaria prevention interventions – who is carrying them out and why – acceptance rates rise dramatically. Programs that hire and train locals to apply larvicides or promote preventive behaviors are far more successful than those led entirely by outsiders.
The review also shows the importance of clear, detailed instructions. For example, simply telling households to “cover their water containers” isn’t enough, she says.
The effectiveness depends on the type and fit of the lid. Flimsy or loose covers can make the problem worse. Successful larval source management programs give residents practical guidance on how to identify the water storage containers that favor An. stephensi breeding, how often to clean or treat them and what kinds of lids work best.
The authors note that as new malaria control tools emerge – from genetic modification of mosquitoes to spatial repellents to mass drug administration – community acceptance will be crucial. Without trust and engagement, even the most advanced technologies risk rejection or misuse.
The World Health Organization has already sounded the alarm on An. stephensi, urging African countries to increase surveillance, improve public awareness and coordinate across sectors to prevent its spread.
“Social and behavioural considerations for responding to Anopheles stephensi in Africa: a scoping review,” was written by Gabrielle C. Hunter, Jayme Hughes, Sarah Zohdy, Melissa Yoshimizu, Shelby Cash, Leticia Emi Ebihara, Bridget Higginbotham and April Monroe.
