Scientist takes aim at reducing mosquito resistance to insecticides
Published:Tuesday | November 7, 2023 | 12:06 AMAsha Wilks/Gleaner Writer
Dr Sheena Francis, senior lecturer and research fellow at the Natural Products Institute at The University of the West Indies (UWI), Mona, is researching countermeasures that Jamaica can employ against the growing Aedes aegypti mosquito population, which is responsible for the spread of dengue fever.
Speaking on October 26 at the Science for Today public lecture series organised by the Faculty of Science and Technology at The UWI, Francis noted how the Aedes aegypti mosquito has become highly adapted to the wet and dry seasons as well as other environmental conditions in Jamaica.
At the online event which facilitated discussions under the theme ‘Killing the Buzz: The Fight against Dengue and Other Mosquito-borne Diseases’, she further stated that because of this, mosquitoes have become the dominant vectors of dengue and were only in need of roughly a cap full of water to lay their eggs and increase their population.
According to her, the rate at which mosquitoes develop decreases with rising temperatures. This means that a mosquito’s usual development period of 14 days is sometimes shortened to nine days.
On September 23, the health ministry declared a dengue virus outbreak in the country. As of November 1, Jamaica recorded 2,763 suspected, presumed, and confirmed dengue cases. Of the cases classified, 694 were confirmed, with dengue type two continuing to be the dominant strain. At the same time, there were two confirmed at seven suspected dengue-related deaths.
“Even the insecticides that we use, the mosquitoes have become resistant to that. So, the insecticides that we’re using to control the population of mosquitoes is decreasing in its effectiveness because the mosquitoes have found a genetic modification to evade the insecticide – metabolising it at a higher rate and driving the insecticides out of their body,” Francis revealed.
She added that this situation was not unique to Jamaica but seen across the world.
“I myself conducted some studies between 2017 and 2020 and I found that we do have mosquitoes in Jamaica that have become tolerant to insecticides, showing varying range of tolerance depending on the insecticide,” the research fellow said.
As such, Francis proposed the use of local plants as insecticides.
“In a lab currently, I am looking at Jamaican plants that have a toxic effect against the mosquitoes,” she said of her ongoing studies.
She revealed that she has so far developed three distinct treatments for these plants, and that the effectiveness of each treatment varies depending on the kind of plant. For some plants, only one kind of treatment is effective; in other instances, all of the treatments are effective in killing the mosquitoes; while none of the treatments are effective for other plants.
“So, what I’m doing now in the lab is finding out what components of the plant is responsible for the toxic effect and how is it killing the mosquito,” she shared.
Francis went on to say that it is hoped that some of her findings could be presented in the near future.
Her work aims to reduce mosquitoes’ resistance to insecticides in Jamaica, therefore overriding their natural methods for survival.
She believes that more research is necessary to fully comprehend this since it could result in the creation of substances that can be used as insecticides, lower mosquito populations, and ultimately reduce mosquito-borne illnesses.