Abstract:
The need for improved agricultural yield led to increased use of various pesticides, especially organophosphate chemicals because of non-persistence in the environment. Dichlorvos organophosphate pesticide (DOP) is indiscriminately used by farm workers in spite of its associated acute and chronic adverse effects on nervous system. Although, information on the adverse effects of DOP on nervous system of farm workers is well documented, information on its effects on their immune status which can be drawn from inflammatory markers is scarce. This study was designed to determine changes in inflammatory markers in DOP-exposed farm workers.
Ethical approval (UI/EC/11/0107) and informed consent were obtained as appropriate. Knowledge, attitudes, practices of farm workers towards pesticide use and associated toxicity symptoms were obtained using structured questionnaire. Farm workers (FW) consisting of 60 pesticide applicators (PA) and 60 farmers exposed to DOP for ten to fifteen years were randomly selected into this case-control study. Sixty apparently healthy adults without occupational exposure to DOP served as controls. Blood sample was collected and serum obtained by centrifugation. Serum activity of acetylcholinesterase (AChE) was determined by HPLC, differential leucocyte count was determined using thin film microscopy, serum levels of immunoglobulin E (IgE), C-reactive protein (CRP), interferon gamma (IFN-γ), interleukins (IL) 4 and 10 were determined using ELISA. Activities of myeloperoxidase, NADPH oxidase (Nox) and catalase were determined by spectrophotometry. Type-1 hypersensitivity was carried out using skin prick test with environmental allergens and neutrophil-lymphocyte ratio (NLR) was calculated. Data were analysed using ANOVA, Student’s t-test and Pearson moment correlation coefficient (PMCC) at α 0.05
Lymphocyte counts (56.0±8.0; 56.0±8.0; 56.0±4.0 against 41.0±5.0), eosinophil (2.0±1.0; 3.0±1.0; 2.0±1.0 against 1.0±0.0), levels of IgE (327.4±169.3; 320.7±171.4; 334.2±168.4 against 229.3±178.4 IU/mL), CRP (10.1±8.8; 12.6±10.4; 7.6±5.7 against 7.2±6.6 mg/L), IFN-γ (104.8±9.5; 128.4±16.8; 81.2±7.9 vs 65.1±5.6 pg/mL), IL-4 (214.1±16.3; 249.7±27.8; 178.4±16.0 against 87.2±48.3 pg/mL), activities of myeloperoxidase (12.3±9.3; 10.5±7.3; 14.1±10.8 against 7.7±5.6 U/mL), Nox (7.9±5.4; 7.3±5.7; 8.6±5.1 against 4.8±3.9 U/mL), the diameter of skin reaction to grass (3.7±0.7; 3.6±0.9; 3.7±1.0 against 3.0±0.0 mm) and mold (3.6±0.7; 3.5±0.9; 3.6±0.9 against 3.0±0.0 mm) allergens were higher in FW, PA and farmers compared with control, respectively. Serum activities of AChE (7.3±0.9; 6.6±0.9; 7.9±0.6 against 9.4±1.0 IU/mL), neutrophil count (41.0±8.0; 40.0±7.0; 41.0±10.0 vs 57.0±6.0), catalase (2.9±1.4; 2.5±1.1; 3.3±1.6 against 4.2±2.1 U/mg protein) and NLR (0.8±0.0; 0.8±0.0; 0.8±0.0 against 1.4±0.0) were lower in FW, PA and farmers compared with control, respectively. However, significant decreases in serum activities of AChE (6.6±0.9 vs 7.9±0.6 IU/mL), myeloperoxidase (10.5±7.3 against 14.1±10.8 U/mL) and catalase (2.5±1.1 against 3.3±1.6 U/mg protein) but significantly raised counts of monocyte (2.0±1.0 against 1.0±0.0) and eosinophil (3.0±1.0 vs 2.0±1.0), serum levels of CRP (12.6±10.4 against 7.6±5.7 mg/L), IFN-γ (128.4±16.8 against 81.2±7.9 pg/mL), IL-4 (249.7±27.8 vs 178.4±16.0 pg/mL) and IL-10 (116.4±9.9 vs 91.1±11.1 pg/mL) were found in PA compared with farmers.
Long term exposure to dichlorvos organophosphate pesticide increases most of the inflammatory markers in farm workers especially among pesticide applicators.
