Chronic pesticide poisoning from persistent low-dose exposures in Ecuadorean floriculture workers: toward validating a low-cost test battery

Abstract

Chronic pesticide poisoning is difficult to detect. We sought to develop a low-cost test battery for settings such as Ecuador’s floriculture industry. First we had to develop a case definition; as with all occupational diseases a case had to have both sufficient effective dose and associated health effects. For the former, using canonical discriminant analysis, we found that adding measures of protection and overall environmental stressors to occupational category and duration of exposure was useful. For the latter, factor analysis suggested three distinct manifestations of pesticide poisoning. We then determined sensitivity and specificity of various combinations of symptoms and simple neurotoxicity tests from the Pentox questionnaire, and found that doing so increased sensitivity and specificity compared to use of acethylcholinesterase alone – the current screening standard. While sensitivity and specificity varied with different case definitions, our results support the development of a low-cost test battery for screening in such settings.

Keywords:

• Pesticide poisoning
• Chronic exposure
• Neurobehavioural Evaluation System (NES2)
• Biomarker indices of toxicity
• Ecuador
• Floriculture validity of acetylcholine esterase
• Environmental stressors

This study was funded by the International Development Center (Canada), Centro de Estudios y Asesoría en Salud (Ecuador), and the Universidad Andina Simón Bolívar (Quito, Ecuador).

We also wish to thank the Canada Research Council for funding Dr. Yassi's Chair. We are grateful for the contributions to project design plus sample collection and laboratory work provided by CEAS in Ecuador; and specifically Arturo Campaña, Orlando Felicita and María de Lourdes Larrea for their enormous contributions. We also acknowledge the work of Gustavo Teran and his BIODILAB Laboratory System for the clinical blood sample processing. We are grateful to the faculty and staff at the Univerity of British Columbia, for their assistance including Jerry Spiegel, Karen Lockhart, Michael Lathuilliere, Nadine Straka, and Arnaldo Sanchez who played a particularly enourmous role in helping to revise the manuscript for final submission. Finally, we thank the workers who participated in this study for their willingness to contribute to research that will strengthen world knowledge and ultimately improve environmental and occupational health in the agro-industry.

Disclosures: The authors declare no conflict of interest.