Chlorophyll derivative activated with sunlight for malaria vector control: a small-scale field study

Abstract Background Malaria is a life-threatening infectious disease transmitted through the bite of the Anopheles mosquito; hence, it could be prevented by a proper vector control. To date, this could be achieved by controlling adult mosquitoes using synthetic chemicals such as DDT for indoor residual spraying (IRS) and pyrethroid-treated bed nets. These approaches possess potential toxicities; therefore, a new ecologically safe technology for vector control was developed in this study. Methods Small-scale field studies were performed in the swamp with anopheline larvae from different sub-saharan countries, such as Sudan, Uganda and Ethiopia. Photodynamic control of anopheles larvae was employed using a chlorophyll derivative, pheophorbide-a (Ph-a) as a photosensitizer and sunlight as a light source. This could interrupt the life cycle of the Anopheles mosquitoes from the larval stage, which induces the interruption of the malaria disease cycle. Results Ph-a accumulates in the larval body and upon sunlight exposure, it induces oxidative stress, which causes 85 to 100% larval death 24 hours after treatment with Ph-a. This photosensitizer’s effect persisted up to 21 days in the new generations in the same breeding site (residual effect). It is a target selective formula that has shown no effect on the other beneficial organisms in the breeding site. Conclusions This technique was found to be both effective and highly selective. It achieved a high mortality rate of mosquito larvae, while maintaining the highest levels of human safety and environmental friendliness.