Low‐level exposures to organophosphorus esters and peripheral nerve function

Abstract

This review evaluates the epidemiological and clinical evidence linking low-level and prolonged exposures to organophosphorus esters, used as insecticides or nerve agents, to peripheral nerve dysfunction. The clinical effects of large doses of these chemicals-including the cholinergic syndrome, the intermediate syndrome, and the delayed polyneuropathy-are all well established and are summarized. Based on these clinical observations and experimental studies, dose-effect relationships indicate that peripheral neuropathy always develops after cholinergic toxicity. However, several studies have suggested that this relationship may be different after low-level prolonged exposures, as, for instance, those experienced by Gulf War veterans and British sheep farmers, thereby leading to the development of peripheral neuropathy without preceding cholinergic toxicity. A critical assessment of these studies, involving subjects with either current or past exposures, indicates that changes in peripheral nerve function were mild, inconsistent, and unexplained and that most studies lack exposure data. Suggestions made about individual hypersusceptibility to delayed polyneuropathy lack support. It is concluded that there is no evidence of peripheral nerve dysfunction caused by low-level prolonged exposures to organophosphate insecticides or nerve agents.

Health symptoms related to pesticide exposure and agricultural tasks among rice farmers from northern Thailand

“…Another possibility is that our farmers were exposed to low levels of pesticides and that these levels were not high enough to produce other symptoms. Indeed, several studies on low-level exposure to AChE have reported mild, inconsistent, and unexplained changes of the peripheral nerve system [7,33,34]. Acute poisoning is well defined in terms of threshold, but low-level effects shade into range of non-specific symptoms [7].…”

Pesticide degradation in water using atmospheric air cold plasma

“…Pesticide pollution has been recognized as an important global issue with scientists and environmental agencies tackling the problem with the development of more biocompatible pesticides which aim to minimise the side effects on the non-target species. However, even low levels of pesticides in drinking water may result in toxicity, with increased risk due to bio-accumulation and potential long term chronic effects [3,4]. In many cases, the environmental fate of pesticides is poorly understood, which is further complicated with the introduction of new ingredients in pesticide formulations [5].…”

Loss of neuropathy target esterase in mice links organophosphate exposure to hyperactivity

“…There are also delayed effects for a subset of organophosphates. In humans, delayed chronic neurotoxic syndromes from exposure to individual organophosphates or combinations of agents have been reported for Gulf War veterans and chronically exposed individuals [3][4][5][6][7][8][9] . The most common and best understood delayed syndrome is organophosphate-induced delayed neuropathy (OPIDN).…”