Nombuso Princess Bhembe opens a freezer in Siphofaneni, pulling out blue-lidded tubes of cows’ blood—dinner for Eswatini’s captive mosquitoes. In this unassuming national insectary, scientists are waging a quiet war against malaria, a disease that has nearly been vanquished in this nation of 1.2 million but refuses to stay gone. The country recorded just 362 confirmed cases in 2024, a fraction of the 11.6 million in neighboring Mozambique. Yet every new case sparks an urgent response: phone alerts, house-to-house visits, and immediate insecticide spraying. “Every time it becomes something new that you need to deal with,” says Nomcebo Dlamini, Eswatini’s chief malaria surveillance officer, “and develop strategies to curb or work around.”
Eswatini’s progress toward malaria elimination is one of Africa’s most promising public health stories. Once a high-burden country, it has reduced transmission to near-zero levels through rigorous surveillance, indoor spraying, and rapid response. But the final stretch is proving the hardest. Climate change is extending the malaria season into May—overlapping with the sugarcane harvest—while extreme weather creates new mosquito breeding sites. Floods turn ditches and wheelbarrows into stagnant pools, bringing vectors closer to homes. Meanwhile, economic migrants from high-transmission countries like Mozambique cross informal border routes daily, sometimes carrying the parasite in their blood.
In the northern Hhohho region, a recent case in a woman who had not traveled reignited alarm. Her illness triggered a full investigation: her neighbors were tested, homes resprayed, and potential breeding sites identified. The insecticide used lasts only three months, so timing is critical. Mosquitoes from the insectary are even placed in cones on walls to test residual effectiveness. Teams also monitor “sentinel sites,” tracking shifts in mosquito species and insecticide resistance—a growing threat as Anopheles mosquitoes adapt to changing temperatures and chemical exposure.
Another challenge lies in the shadow economy. Illegal cannabis farms, known locally as dagga, employ low-wage workers from Mozambique who often sleep outdoors without bed nets. If a worker carries the parasite and gets bitten, a single mosquito can spark a cluster of cases. Fear of authorities keeps many from seeking care, allowing silent transmission to take hold.
Still, Eswatini’s teams remain undeterred. They’ve gone from reacting to outbreaks to anticipating them, using data and on-the-ground vigilance. “It is better to take rapid action now,” Dlamini says, “than come back in a few weeks when there might be more cases.” The goal remains zero local transmission. With climate and borders working against them, their success could become a blueprint for other nations on the brink of elimination.