Objectives. Farm workers chronically exposed to low levels of pesticides seldom show signs and symptoms of clinical significance. This study investigates subclinical morbidity patterns among male farm workers in a desert country. Methods. Migrant-established farm workers (N = 226) were compared with referents (N = 226) and with new farm workers (N = 92) who had just entered the country to work on farms. Acetylcholinesterase was measured, the aiming test and digit symbol test were applied, and a morbidity profile was collected with a questionnaire. Results. The erythrocyte acetylcholinesterase activity and hemoglobin-adjusted erythrocyte acetylcholinesterase activity were significantly depleted in the established farm workers. The results of the aiming and digit symbol tests were also significantly lower for the established farm workers. For the morbidity profile, irritated conjunctiva (47.3%), watery eyes (52.2%), blurred vision (63.3%), dizziness (55.2%), headache (63.7%), muscular pain (61.1%), and weakness (76.6%) were reported by established farm workers in statistically significantly higher number than by the referents and new farm workers. Conclusions. Morbidity patterns, such as the health complaints and objective parameters suggested in this study, would be suitable as criteria for identifying farm workers most at risk from pesticide toxicity and as criteria for initiating measures to control and reduce exposure.

Aiming test Erythrocyte acetylcholinesterase Organophosphates Digit symbol test Hemoglobin-adjusted erythrocyte cholinesterase

visual impairment agricultural worker Agricultural Workers human clinical feature neurologic disease controlled study priority journal health status morbidity erythrocyte level muscle weakness desert neuromuscular function conjunctiva disease vertigo headache myalgia male occupational exposure pesticide questionnaire Article human experiment acetylcholinesterase hemoglobin normal human medical geography disease incidence