The use of synthetic pyrethroids as an insecticide in households has surpassed the other pesticides like organophosphates because of its likely to be safer for humans. This study was designed and executed to find out the toxic effects of allethrin (a synthetic pyrethroid) when they are overused or have an accidental oral exposure in humans or animals. For this purpose, 60 BALB/c mice were randomly divided into four equal groups. Group A served as a control group. Groups B, C and D were given allethrin @ 0.5, 1 and 1.5 g/kg BW, respectively orally on the 14^th day of the experiment. Animals were monitored twice daily for clinical signs and mortalities. Randomly selected five mice from each group were euthanized humanly at 21^st and 42^nd day of the experiment to collect blood/serum for determination of immunological parameters. Clinical signs such as hair coat roughness, alopecia, conjunctival hyperemia, salivation, frequent defecation and nervous signs like tremors and convulsions were observed. The highest mortality (53.3%) was recorded in group D (1.5 g/kg BW) followed by group C (1 g/kg BW) and group B (0.5 g/kg BW) with 46.6% and 26.7% mortalities, respectively. The absolute weight of the spleen and thymus was significantly (P<0.05) decreased in all treated groups at 21^st and 42^nd day of the experiment. Total antibody titer against SRBCs at the 14^th and 28^th day of experiment decreased significantly (P<0.05) in treated groups. At 29^th day, the lymphoproliferative response to tetanus toxoid at 24 and 48 h of time was significantly decreased in all the treatment groups as compared to control group. It is concluded that exposure to the allethrin can lead to immunosuppression by inducing pathological alterations in immune organs.

To Cite This Article: Gul ST, Khan A, Saleemi MK, Ahmad M, Zahoor A, Naseem MN and Hussain R, 2019. Immuno-toxicological effects of allethrin (Active ingredient in mosquito repellent coils) in BALB/c mice following oral administration. Pak Vet J, 39(2): 256-260. http://dx.doi.org/10.29261/pakvetj/2019.036