A leading Ghanaian medical entomologist has raised alarm over the emergence of insecticide-resistant mosquitoes, warning that human activities, particularly the widespread use of agricultural pesticides and poor environmental practices, are undermining efforts to control malaria and other mosquito-borne diseases.
Professor Yaw Asare Afrane of the Department of Medical Microbiology at the University of Ghana Medical School said mosquitoes are increasingly developing resistance to insecticides used in treated bed nets and indoor spraying programmes, reducing the effectiveness of some of the country’s most important malaria prevention tools.
Delivering an inaugural lecture at the University of Ghana on the theme, “Fighting the Bite: Human Activities and the Changing Landscape of Mosquito-Borne Diseases in Africa,” Prof Afrane explained that agricultural chemicals used on farms often find their way into water bodies where mosquitoes breed, exposing them to insecticides from an early stage of development.
According to him, this continuous exposure allows mosquitoes to gradually build tolerance and develop biological mechanisms that help them survive chemicals designed to kill them.
He noted that some mosquito species now produce enzymes capable of neutralising insecticides, while others develop genetic mutations that enable them to withstand repeated exposure. Some have even acquired what scientists describe as “knockdown resistance,” allowing them to recover after appearing temporarily incapacitated by insecticides.
Prof Afrane warned that the challenge is compounded by rapid mosquito reproduction, which accelerates the spread of resistant traits within populations.
Beyond insecticide resistance, he said changing mosquito behaviour and increasing human-driven environmental changes are creating ideal conditions for mosquito breeding across the country.
The researcher pointed to stagnant water in discarded tyres, clogged drains, broken containers, irrigation systems and poorly managed urban environments as major breeding grounds for mosquitoes. He stressed that many of the mosquitoes responsible for transmitting diseases are being bred within communities rather than in distant forests.
Drawing on more than two decades of research, Prof Afrane said studies conducted across Ghana have consistently shown a strong connection between human activities and mosquito abundance. He cited urban agriculture, deforestation, mining activities and climate change as factors altering mosquito habitats and disease transmission patterns.
He also cautioned that rising temperatures and changing weather patterns could enable mosquitoes to expand into higher-altitude areas of Ghana that historically recorded lower mosquito populations.
Adding to the concern, Prof Afrane revealed that researchers have identified invasive mosquito species in Ghana, including Anopheles stephensi and Aedes albopictus, species associated with the transmission of malaria and other diseases such as dengue fever.
He called for urgent action to eliminate mosquito breeding sites through improved sanitation, stronger environmental management and better urban planning. He also advocated stricter enforcement of sanitation regulations by local authorities and increased investment in scientific research and mosquito-control expertise.
“We humans have created opportunities through our activities for mosquitoes to breed around us, bite us and cause disease. If we reverse these activities, then we can eliminate mosquito-borne diseases around us,” he said.
Chairing the lecture, Professor Nana Aba Appiah Amfo, Vice-Chancellor of the University of Ghana, underscored the role of human activities in driving mosquito-borne diseases, noting that urban farming, environmental degradation, poor drainage systems and pollution continue to increase public health risks.
She urged citizens to take greater responsibility for maintaining clean surroundings, especially as the rainy season creates more stagnant water and breeding sites for mosquitoes across the country.
Prof Appiah Amfo also commended Prof Afrane for his extensive contributions to malaria research and disease-control policies in Ghana and across Africa.
