Pediculus as Vector Geetanjali Mishra Associate Professor Department of Zoology University of Lucknow Lucknow HUMAN LOUSE: (Pediculus humanus captis carporis) Class: Insecta Division: Exopterygota Order: Anoplura Family: Pediculidae They occur all over the world. They have been associated with man since ancient times. External feature: It is a small (3-3.5mm long), with elongate and dorsoventrally flattened body. Mouth part are sucking type. Head are small and eyes are reduced. Claws on the legs are meant for clinging to hairs on host’s body. Antennae are small, 5-6 jointed. Wings are lacking and wing pads are present. Abdomen of male are narrower and pointed than the female and terminates into a curved hook like clasper, which works as a sheath, aedeagus. Abdomen of female is relatively broad, nearly rounded apically with a prominent niche or genital pouch. Head louse is smaller than the body louse. Life Cycle: The lice breed throughout the year. The female lays eggs or nits, singly, glued to the hair. Average 100 eggs are laid by the head louse and 300 eggs by the body louse. The eggs are oval and elongated with a perforated covering of the eggs, the operculum. The egg hatch within 8 days and the nymphs eclose by pushing the operculum of the eggs. Nymphs start feeding soon after then eclosion and there are three nymphal stages. Nymphal period lasts for 16 days (15-16). The adults survive for 30-40 days. The life cycle is completed at about a month and their arev10-12 generations in a year. Economic Importance: Both the nymphs and adults bite and suck the blood of the host. Head louse preferred to bite on the back of head and neck and body louse at the place in close contact with clothing. They inject irritating substance during feeding, which produces roseate elevated papules accompanied by severe itching. Repeated bites induce a condition of local pigmentation of the skin, known as “Vagaband’s Disease”. In severe infestation, called pediculosis, pigmentation, discolouration, hardening and even ulceration in the skin may take place. They are known to be biological vectors of relapsing fever, typhus fever, and trench fever. Control Measure: i. Maintenance of cleanliness and personal hygienic condition will reduce the chance the egg laying and thus increase in number. ii. The clothing of infected persons should be treated in boiling water which would cause dead of eggs, nymphs, etc. iii. Liberal application of 2% carbolic acid, mediker etc. will kill the stage. iv. The treatment should be repeated in ten days to destroy newly hatcted lice. v. In case of severe infestation, cutting the hair short and shaving them off completely is also adviced. References Jawaid Ahsan, Sinha, S. P. 2008. A Handbook of Economic Zoology. S. Chand Group Publ. Khan, A.A. (Editor), 2007. Encyclopedia of Economic Zoology. 2 vols. Anmol Publications Pvt. Ltd. (April 1, 2007) Shukla, G.S. & Upadhyay, V.B. Economic zoology. Rastogi Publs. 2005. 487 pages. Nigam, H.C. 2006. ModernTrends in Biology & Economic Zoology. Vishal Publ. Co. 444+xii pages. A B (a) Pediculus, and (b) Phthirius pubis E 100-200 7- 8 da ys Pediculus A 5-7 days N3 .