Anopheles stephensi larvae – the main mosquito vector for malaria in India – are now “abundantly present” in locations across Africa, said researchers at the Radboud University Medical Center in the Netherlands and Ethiopia’s Armauer Hansen Research Institute. Vectors are living organisms that can transmit infectious pathogens between humans or animals to people.
This species of mosquito only appeared in Africa a few years ago. This invasive insect is now “abundantly present” in water containers in Ethiopian cities – and highly susceptible to local strains of malaria, the researchers said.
Malaria, which is transmitted by the bite of the female Anopheles mosquito, is a preventable and treatable disease – but 409,000 people died in 2019.
The researchers studied whether mosquitoes would pose a health risk by spreading local malaria parasites.
“To our surprise, the Asian mosquito proved to be even more susceptible to local malaria parasites than our colony of mosquitoes in Ethiopia. This mosquito appears to be an extremely efficient spreader of the two main species of malaria,” said Teun Bousema, professor of epidemiology of tropical infectious diseases at Radboud University Medical Center in Nijmegen, in a statement.
“We must target mosquito larvae in places where they now occur and prevent mosquitoes from spreading over long distances, for example, through airports and seaports. If that fails, the risk of urban malaria will increase in large parts of Africa, ”study author Fitsam Tadesse, a doctoral student in the medical microbiology department at Radboud University Medical Center, said.
The study’s findings were “significant,” said Jo Lines, professor of malaria control and vector biology at the London School of Hygiene and Tropical Medicine.
“When these things come in, people say, ‘It’s just a mosquito, and we’re going to worry about it when it’s a vector,'” Lines, who was not involved in the study, told CNN.
“What I mean is that you can get rid of it when you’re young, if you wait until it’s well established, to realize that it’s really causing disease outbreaks … Sorry, it’s too late. All you can do is manage the problem, “he added.
Previous examples of mosquitoes that were once regional “going global”, such as the Asian tiger mosquito, which is now “in the process of invading northern Europe”, should serve as a warning that rapid action is needed to tackle the problem said Lines.
“I think we need a greater sense of urgency about this, on a continental scale, than we currently need,” he said. “If we wait now until we know more, it will be too late to get rid of him. This will no longer be a foothold that you may want to get rid of, it will be one of the mosquitoes native to much of East Africa. ”
Lines warned that if Anopheles stephensi spreads to African cities, the consequences will be severe.
“The city center has so far been the only malaria refuge in parts of Africa,” he said. “But in the future, if Anopheles stephensi establishes itself, it will no longer be the case.”