In Colombia there are regions that historically have been more affected by malaria, a disease produced by a parasite of the genus Plasmodium, which can be transmitted by the bite of the feared female Anopheles mosqui. The fight against this disease has given experience and knowledge to the country’s health authorities, until now, because it seems that the transmitting mosquito may have developed resistance to insecticides.
The main malaria transmission hotspots in the country are in the Pacific region, followed by the Uraba region (lower Cauca), Alto Sinu (Antioquia and Cordoba), Amazonia and Orinoquia (central east), and the Atlantic region. But, apparently, due to climate change, its geographic expansion and population density are also increasing. This is also happening in other regions of the continent where the troublesome Anopheles mosquito lives, which makes the situation more worrying.
Colombia also contributed mosquitoes for the study
The journal Science published a study led by the Harvard T.H. Chan School of Public Health, which found that these mosquitoes are becoming increasingly difficult to eliminate because they are evolving and becoming resistant to insecticides. Such a scenario complicates the control of the disease, which has increased on the continent, where it is a real challenge because it produces more than 500,000 cases annually, mainly concentrated in the Amazon basin, highlighting Venezuela, Brazil and Colombia.
One of the co-authors of the study, Dr. Jacob Tennessen, explained to El Pais of Spain that while genomic studies of the different Anopheles living in Africa had already been carried out, in Latin America there was a gap. That motivated them to partner with researchers from Colombia, Venezuela, Brazil, but also from Peru, Guyana and French Guiana.
From all those countries, they sent Harvard researchers samples of mosquitoes captured in 16 different locations. After generating the complete genome sequence of 1,094 adult females, they confirmed that resistance to insecticides has indeed been developing. The mosquito captures in Colombia took place in the middle Atrato of Choco and in Guainia, on the border with Venezuela, explained Dr. Martha Lucia Quinones, who was in charge of that process.
This news abruptly halts the optimism of the Colombian government which, when it was just beginning, had offered the scenario of zero malaria. “We are moving toward the goal of elimination: the time has come to achieve zero malaria […]. For this, this ministry [of Health], together with the Inter-American Development Bank, the Pan American Health Organization and the [Departmental] Health Secretariats, we are working very hard on a regional initiative to reduce malaria in 12 municipalities of three departments of the country,” said at the time Mauricio Vera, head of the Endemoepidemic Diseases Group of that ministry.
Malaria also produces political fever
But the Anopheles mosquito perhaps, at that time, had already developed the resistance that today worries scientists. In fact, Dr. Quinones also told the Spanish newspaper that, from the Choco group, she had already reported its resistance to insecticides since the 1990s. “Since that time, that very localized population of Anopheles darlingi had resistance to DDT which, moreover, some time later, we saw was a cross-resistance with pyrethroids,” she said.
Last year a serious situation occurred in several municipalities of Tolima, which produced a strong clash between the departmental and national governments. By April 2025, that region in the center of the country had confirmed 58 cases of yellow fever and 23 deaths. Despite the fact that the governor, Adriana Magali Matiz, assured that more than 100,000 vaccines had been administered throughout the department.
President Petro accused her of not allocating resources to face the crisis, and the governor responded by assuring that he was lying. “I believe the statements are ill-intentioned and we regret them. From a distance it is easy to criticize the efforts being made in the territory,” she said at the time.
Returning to the Harvard T.H. Chan School of Public Health study, although it did not validate on a large scale what happens with Anopheles darlingi in real life, one of its researchers, John Bernard Dushiman, did carry out a mini experiment in French Guiana.
According to El Pais, the researcher collected some mosquitoes in a bottle, exposed them to insecticides and timed how long they took to die. “By tracking the genotypes, we indeed observed that one of these P450 genes influenced the life expectancy of the mosquitoes.” And he added that “they suspect that agricultural insecticides could be influencing this evolution.”