One of the most effective ways to combat this pest is for affected populations to use mosquito nets that have been treated with an insecticide. This offers both a physical and chemical deterrent against these powerful carriers of disease.
Some of these mosquito nets, which are known as ‘long-lasting’, are the result of very advanced research. These next-generation products are far from just fabric soaked in an insecticide solution, and are capable of releasing insecticide in a controlled and gradual manner over a longer period (at least three years). They can also handle being washed more regularly, without the insecticide on the surface of the fibres being washed away.
As research progresses, new insecticide molecules are being used. These are increasingly difficult to incorporate into mosquito nets and to analyse. Indeed, the most commonly used insecticides belong to the pyrethroid family, which mosquitoes have become increasingly resistant to. Their resistance to pyrethroids, but also to other groups of insecticides in recent times, has triggered a real race against the clock, requiring close collaboration between stakeholders in the different research areas involved. The Walloon Agricultural Research Centre (CRA-W) is one such player. It specialises in the chemical characterisation of treated mosquito nets, and is currently conducting research on the physical and chemical properties of these new products. More specifically, these studies focus on the development, validation and standardisation of gas chromatography and high-performance liquid chromatography analysis methods as a means of identifying and quantifying new active substances in treated mosquito nets. The stability of the products over time, and when exposed to heat, the homogeneity of the treatment, the release characteristics of the active substance on the surface, its resistance to washing and the persistence of the active substance are also being studied.
In order to overcome the increased resistance of mosquitoes to insecticides, increasingly complex molecules must be used. These are, as a result, increasingly difficult to analyse as well. The CRA-W is recognised as a benchmark laboratory in this area, and an expert in the development of methods of analysis and physical and chemical properties that are essential to the development of new mosquito nets, as well as the validation of their performance when used in the field.
