Effect of wood tar on some biochemical aspects and morphological changes of the head lice pediculus humanus capitis (Phthiraptera: Pediculidae)

Abstract

Background and Objective: The head lice, Pediculus humanus capitis is considered one of the most important parasites that attach human body and causes many diseases infestation of humans worldwide. This insect could be found between children during the warm months in developed and developing countries. This study is aimed to evaluate the insecticidal effect of wood tar oil against the adult of head Lice Pediculus humanus capitis. Materials and Methods: Adult insects were collected from school children that do not have been treated with any applications whether chemical or natural treatments. Adult insects were treated with 3, 5 and 7% of wood tar. Acetylcolinesterase, glutathione peroxidase and superoxide dismutase activities were evaluated. In addition, total soluble protein in treated insects was quantified using Bradford technique. Alterations in adult insects were evaluated using scanning electron microscope. Results: Observed data demonstrated significant effect of three concentrations 3, 5 and 7% of wood tar where the recorded mortalities were 60, 90 and 100% after 6 h, respectively. Treatments with wood tar caused inhibition in acetylcholine esterase level, it also reduces the total protein activity in treated insects. The GPX and SOD activities increased gradually in the adult of P. humanus capitis after exposure with tar concentrations. Scanning electron microscope showed several distortions of the body structure, spiracles, hairs and body segments of dead lice exposed to wood tar. Conclusion: Treatment with tar caused oxidative and morphological damages in insects. Wood tar could be a good insecticidal agent against head Lice Pediculus humanus capitis.