TM/2 KIT (Organochlorines & Pyrethroids Groups)


Among pesticides, organochlorine and pyrethroid compounds are classified as insecticides, as their most relevant role is in the control of insect pests. Apart from natural compounds such as nicotine or rotenone, which have been used as insecticides for a few centuries, organochlorines represent the first important class of insecticides developed by the burgeoning chemical industry in the first half of the 20th century. Pyrethroids were developed in the 1970s, after two other major classes of insecticides, the organophosphates and the carbamates. Additional novel classes of insecticides, such as the neonicotinoids or the phenylpyrazoles, have been more recently introduced. In contrast to the organochlorine compounds, most of which have been banned in the past several years, the pyrethroids still demand a substantial share of the insecticide market.

All of the chemical insecticides are neurotoxicants, as they act by poisoning the nervous system of the target organisms (Costa et al., 2008; Casida, 2009Table 9.1). The central nervous system of insects is highly developed and not unlike that of mammals, and the peripheral nervous system, though less complex, also presents striking similarities (Costa, 2013). Thus, insecticides are mostly not species-selective with regard to targets of toxicity, and mammals, including humans, are highly sensitive to their toxic effects. This chapter will review the major aspects of the neurotoxicity of organochlorine and pyrethroid insecticides with a particular emphasis on their effects in humans, and their potential contribution to nervous system disorders.