Effects of topical exposure to a mixture of chlorpyrifos, cypermethrin and captan on the hematological and immunological systems in male Wistar rats.

Most Thai orchid farmers heavily used pesticide mixtures, and were shown to have various hematologic/immunologic alterations. The present study investigated the effect of exposure of male Wistar rats to a mixture of three pesticides (chlorpyrifos, cypermethrin and captan) that are most often used by the farmers. Three groups of 10 rats were dermally exposed to three different doses (high, middle and low) for 28 consecutive days. The rats showed significant changes in body, liver, kidneys and adrenals weights. Significant changes were observed in various biological parameters including hematotoxicity (increased leukocyte and platelet counts, percent neutrophil, decreased RBC count, percent lymphocyte and eosinophil), hepatotoxicity (increased serum AST, decreased serum ALP, cholesterol, triglyceride, serum protein and albumin), and immunotoxicity (decrease in numbers of NK cells, decrease splenic proliferative response to LPS, and increase in serum IgG). These results confirm the potential health danger of exposure to these pesticide mixtures in orchid farmers.

Effect of pesticide exposure on immunological, hematological and biochemical parameters in thai orchid farmers- a cross-sectional study.

Various studies have found that many Thai orchid farmers used excessive amounts of pesticides without proper protective gear, but no toxicological study has been made. This cross-sectional study aimed to evaluate the immunological, hematological and biochemical statuses of these farmers. Sixty four orchid farmers and 60 controls were studied. Plasma cholinesterase activity, the percentage and absolute number of B lymphocytes (CD19+) were significantly lower in the farmers group (3966.32±1165.48 U/L, 11.61±4.09% and 312.26±164.83 cells/mm3, respectively) as compared to those of controls (5048.85±1139.40 U/L, 14.32±4.23%, 420.34±195.18 cells/mm3, respectively). There was a statistically significant higher level of serum IgE among the orchid farmers (0.031±0.011 mg/dL vs. 0.018±0.007 mg/dL) but not IgG, IgA and IgM, levels. Serum lysozyme level, lymphocyte proliferative responses to mitogens, hematological parameters and kidney function test, were not significantly different between the two groups. The liver function profiles showed significantly lower levels of albumin and serum protein in the farmer group. Thus frequent pesticide exposure resulted in subtle changes of some biological parameters. These changes, though may not be clinically significant, strongly indicated that caution in handing pesticides by these farmers is warranted.