Anopholes quadriannulatus, so full with its blood meal that a droplet of excess blood had been extruded from the abdomen’s distal tip. As a member of the A. gambiae species complex, A. quadriannulatus is a known vector for disease malaria.Credit: CDC/ James Gathany
In Dielmo, on the banks of the Nema stream in Senegal, childhood was once marred by the relentless grip of malaria.
Close to the Gambian border, and 280km southeast of the Senegalese capital Dakar, villagers in Dielmo typically grow millet, peanuts, mango, and cashews, and tend livestock. Most live in thatched mud-walled houses. Children endured an average of 23 fever episodes by their fourth year, and 43 by their 10th birthday.
However, thanks to widescale interventions including long-lasting insecticide-treated nets, improved antimalarial drugs, and rapid diagnostic tests, the children of Dielmo are now almost free of malaria.
Research and eventual pay-off
The turnaround can be traced to 1989 when Dielmo became part of a long-term research project. At this time all villagers had at some stage had malaria and about 95% of the children were infected by mosquitoes that were present all year.
A research station and dispensary were built in 1990. For the first 25 years, health workers and scientists tracked villagers’ health status daily, noting all fever episodes and running regular clinical, parasitological and immunological tests. They surveyed the presence of parasites four times a year and monitored malaria transmission monthly by collecting mosquitoes at night.
A study in eClinical Medicine, the most recent of more than 200 papers featuring Dielmo data, outlines the lives of youngsters in the village before interventions. Four (3,6%) of the 111 Dielmo children monitored for more than a decade suffered through 100 bouts of malaria by their 15th birthday, and one experienced 110 such events by age 24.
“Until 2008, when long-lasting insecticidal nets (LLINs) were deployed, our only intervention was to provide prompt and effective treatment for clinical malaria attacks and other diseases,” says project leader Jean-Francois Trape of the Malarialogy and Medical Zoology Laboratory of Institut de Recherche pour le Dévelopement (IRD) in Dakar.
He says malaria treatment has changed over the years in response to increasing drug resistance, but since 2006, artemisinin plus amodiaquine are first-line approaches. Insecticide-treated nets (ITNs) were introduced in 2008.
By 2015, efforts paid off. When asked to describe the lives of village children today, compared to the 1990s, Trape says: “Free from malaria. We built a school in the village in 1991. No-one was going to school before that, and only two adults could read and write. Today, all children can. Several of those born in the first years of the project now have university degrees.”
The Dielmo Project continues through funding from IRD in France and the Pasteur Institute of Dakar in Sénégal, now with a greater focus on diseases other than malaria that the 400 villagers might have.
Addressing the future
Trape and co-authors call for increased domestic and international commitment and funding to scale up malaria control and prevention interventions. To him, Dielmo’s long term data remains a stark reminder that, for many, childhood can be “an endless history of malaria fever episodes”.
According to the 2023 United Nations Inter-agency Group for Child Mortality Estimation (UN IGME) Report, in Senegal, malaria caused 3% of all deaths of children under five, compared with other West African countries, such as Niger and Benin, where the percentage rises to 25%.
A review paper in the Elite Journal of Nursing and Health Sciences shows malaria increases the risk of preterm births, low birth weight, and newborn deaths.
Eshetu Engeda of the University of Gondar, Ethiopia, who led a 2023 scoping review in Disability and Rehabilitation, called on policy makers to better fund disability screening and rehabilitation services in areas where malaria is rampant.
Vaccines
Roll-out of the recently approved RTS,S/AS01E and R21/Matrix-M vaccines across 15 African countries to children over five months old will be pivotal in the battle against malaria, and boosts optimism that it could be eradicated, says DeAnna Friedman-Klabanoff from the University of Maryland School of Medicine Centre for Vaccine Development and Global Health.
With colleagues in Ghana, Friedman-Klabanoff took stock of recent developments in malaria prevention in children, in Current Opinions in Pediatrics. “As we advance, it is critical to continuously monitor the effectiveness of these vaccines and adapt our strategies in response to new challenges and epidemiological shifts in malaria cases and fatalities,” she adds.
Physician-scientist, Floriano Amimo of the Faculty of Medicine at Eduardo Mondlane University, Mozambique says vaccines, could make “a game-changing contribution to improving child survival and health on the continent. This is even more significant given the multitude of complex threats to progress towards global goals, including rising antimalarial drug resistance, frequent and more intense disasters and other shocks. These disrupt disease control,” he notes in BMC Medicine.
Amimo is however concerned that these efforts will be hampered by “the chronic difficulties that traditionally reduce the value of public health interventions and programmes, and have undermined the control and elimination of other vaccine-preventable diseases in Africa.”
This includes issues such as the delivery cost of vaccines, the vaccine allocation framework and governments’over-reliance on funding agencies to pay for vaccines, without allocating enough in their national budget to healthcare.
“If core issues can be tackled, progress is possible. Otherwise, Africa will continue to lag in eliminating malaria,” says Amimo, who believes a continent-wide assessment program is essential to overcoming disease-specific and systemwide hurdles.
