Nanopesticides: A Boon Towards the Control of Dreadful Vectors of Lymphatic Filariasis

Abstract

Ever since insects, particularly the mosquitoes, had been discovered to mediate transmission of dreadful diseases, such as lymphatic filariasis, dengue and malaria during the late nineteenth century, it had been a continuous battle between man and these vector insects for survival of the fittest! Their mandatory involvement in disease transmission makes these tiny insects very important in the whole disease control efforts, drawing focused attention of entomologists, health workers and sanitarians worldwide. Significance of vector control in disease management was first demonstrated in case of malaria, and it is considered significantly important in the elimination and monitoring of lymphatic filariasis (LF). The human lymphatic filariasis, popularly referred to as elephantiasis, is one of the most debilitating neglected tropical diseases that continues to be a major health concern globally, in tropical and subtropical countries including India bearing almost 40% of the global disease burden. In India the disease is caused by Wuchereria bancrofti and Brugia malayi, and the third parasite B. timori is prevalent in Indonesia and the neighbouring islands. In India it is W. bancrofti which is causing over 95% infection. The key vector for this disease worldwide is Culex quinquefasciatus. Even though the disease is generally not fatal, nevertheless the kind of debilitation and incapacitation, apart from social stigmatization, lymphatic filariasis has assumed a great significance socially and economically, next only to malaria. The infection is largely controllable through medication (diethylcarbamazine @6 mg/kg body wt), yet the residual parasitic load remained uncontrolled in the vector mosquitoes in nature continues to warrant novel technologies and tools for an efficient control of vectors to achieve the target of disease elimination. The nanopesticides have recently attracted the attention of disease managers for their novel pathways to reach the target sites to bring about a kill in vectors. Nanopesticide, majorly classified as synthetic and bio-based, is an efficient system which can be applied in controlling vectors without causing concerns of environmental pollution or affecting adversely nontarget organisms. In the present context of vector control, a few examples of nanopesticides are nanopermethrin and other bio-based oil nanoemulsions. The applications of these nanopesticides can be made either as larvicidal or adulticidal formulation, based on their mode of action. The properties of the nano-formulated pesticides like specificity, target delivery and low residual pollution make it propitious for the integrated pest management strategy. Therefore, the application of the nanopesticide in comparison to the conventional pesticides can become an efficient step for the control of lymphatic filariasis vector in the Indian subcontinent.