Developmental neurotoxicity of succeeding generations of insecticides

Abstract

Insecticides are by design toxic. They must be toxic to effectively kill target species of insects. Unfortunately, they also have off-target toxic effects that can harm other species, including humans. Developmental neurotoxicity is one of the most prominent off-target toxic risks of insecticides. Over the past seven decades several classes of insecticides have been developed, each with their own mechanisms of effect and toxic side effects. This review covers the developmental neurotoxicity of the succeeding generations of insecticides including organochlorines, organophosphates, pyrethroids, carbamates and neonicotinoids. The goal of new insecticide development is to more effectively kill target species with fewer toxic side effects on non-target species. From the experience with the developmental neurotoxicity caused by the generations of insecticides developed in the past advice is offered how to proceed with future insecticide development to decrease neurotoxic risk.

Sex-Specific Neurotoxic Effects of Organophosphate Pesticides Across the Life Course

“…Prenatal OP exposure has been associated with a variety of adverse effects on neurobehavioral development in infants and children such as changes in body length and abnormal neonatal reflexes [33,34], poorer mental development [35,36], cognitive impairments [37–39], attention problems [40,41], and other effects reviewed elsewhere [42–44]. Yet, limited epidemiological evidence exists in support of sexually dimorphic responses to developmental OP exposure because most studies adjust for sex (e.g.…”

“…In stark contrast with epidemiological and in vitro studies, sex-specific effects of gestational or early developmental OP exposure are commonly reported in rodent studies (see [42] for a thorough review on developmental neurotoxicity of insecticides to date). While CPF is the most studied OP, sex-dependent effects in rodents have also been reported after exposure to other OPs including diazinon (DZ), dichlorvos, malathion, methyl parathion, and parathion (see Table 2 for a summary of sex-dependent effects in these less commonly studied OPs, as sex-dependent effects of CPF have been reviewed elsewhere [42,64]).…”

“…While CPF is the most studied OP, sex-dependent effects in rodents have also been reported after exposure to other OPs including diazinon (DZ), dichlorvos, malathion, methyl parathion, and parathion (see Table 2 for a summary of sex-dependent effects in these less commonly studied OPs, as sex-dependent effects of CPF have been reviewed elsewhere [42,64]). In general, most of the studies we will discuss employ the following dosing regimen: administration via subcutaneous injection to the dam or neonate over a short period (usually 4 days), where the dose is below the threshold for overt cholinergic toxicity.…”

Children’s low-level pesticide exposure and associations with autism and ADHD: a review

“…Several important and comprehensive reviews have been published that examine various relationships between pesticides and neurodevelopmental effects. [2][3][4][5][6][7] Most of the reviews include studies that assess additional or non-specific outcomes such as developmental or cognitive delays. One review is specific only to the organophosphate (OP) insecticide chlorpyrifos and is the most comprehensive review of this particular insecticide to date.…”

Gas chromatography/negative chemical ionization mass spectrometry of transfluthrin in rat plasma and brain

“…They are widely used in insect sprays, wood preservation, lice treatment, veterinary medicine, mosquito control, and against malaria . However, the increasing production and application of pyrethroids has led to frequent human exposures by inhalation, skin absorption and ingestion via entry into the food chain and the ecosystem …”