The Health Studies Branch (HSB) is responsible for responding to domestic and international requests for assistance with suspected and known environmental-associated public health threats as well as pursuing original environmental research. The HSB employs personnel with a wide variety of educational backgrounds and professional training including epidemiology, medicine, toxicology, statistics, and other environmental public health-related disciplines. This wide range of expertise is necessary to address the broad scope of potential environmental health threats. HSB scientists conduct studies on environmental exposures. Recent examples include the following: mercury exposure in children living in large urban areas, exposure to brevetoxins and microcystins arising from harmful algal blooms, and occupational exposures to pesticides. This article will present a brief description of an ongoing study of insecticide exposure and paraoxonase-1 (PON-1) genotype in banana plantation workers in Chinandega, Nicaragua. We will then discuss the enzyme PON-1 and its potential role in organophosphate insecticide metabolism and toxicity.Keywords PON-1 . OrganophosphateInvestigators: Health Studies branch, division of Environmental Health/Health Effects, in the National Center for Environmental HealthThe Health Studies Branch (HSB) is responsible for responding to domestic and international requests for assistance with suspected and known environmental-associated public health threats as well as pursuing original environmental research. The HSB employs personnel with a wide variety of educational backgrounds and professional training including epidemiology, medicine, toxicology, statistics, and other environmental public health-related disciplines. This wide range of expertise is necessary to address the broad scope of potential environmental health threats. HSB scientists conduct studies on environmental exposures. Recent examples include the following: mercury exposure in children living in large urban areas [1,2], exposure to brevetoxins and microcystins arising from harmful algal blooms [3], and occupational exposures to pesticides. This article will present a brief description of an ongoing study of insecticide exposure and paraoxonase-1 (PON-1) genotype in banana plantation workers in Chinandega, Nicaragua. We will then discuss the enzyme PON-1 and its potential role in organophosphate (OP) insecticide metabolism and toxicity.Current CDC Activity: PON-1 and Chlorpyrifos Exposure Among Agricultural Workers Paraoxonase-1, a serum enzyme closely associated with high-density lipoprotein (HDL), plays a role in lipid and OP metabolism. Various mutations in the PON-1 gene are known to determine the efficacy of OP metabolism by PON-1. Animal studies show that PON-1 genotype and the rate of OP metabolism play a major role in determining resistance to the acute toxicity of OPs [4]. However, the

ObjectiveTo describe the results of the evaluation of the PAILD active surveillance system and lessons learned for similar surveillance efforts in a resource-limited setting.