Acute immunotoxicity studies of monocrotophos in rats

This study was conducted to evalute acute immunotoxic effect of monocrotophos, an organophosphate insecticides, in rats. Thirty male albino rats were devided randomly in to five groups consisting of six animals each. Single oral dose was administered to each animal of groups I, II, III, IV and V, respectively, with zero, one twentieth (1/20), one tenth (1/10), one fifth (1/5) and half (1/2) of LD₅₀ of monocrotophos (18 mg/kg). Severe clinical symptoms including salivation, lacrimation, tremors, convulsions and diarrhoea in a few rats of group IV and V were observed. Two rats of group V died on 3^rd and 5^th day, respectively. A decrease in toull erythrocyte and leukocyte count was reported in the groups of higher doses. Immunological parameters such as delayed hypersensitivity and haemagglutination titres indicated a suppression in both cellular and humoral immune response in group IV and V, however, no change was found in group II and III.