title: Electron Microscopic Alterations in Pediculus humanus capitis Exposed to Some Pediculicidal Plant Extracts.
abstract: Head lice, Pediculus humanus capitis, infestation is an important public health problem in Egypt. Inadequate application of topical pediculicides and the increasing resistance to the commonly used pediculicides made the urgent need for the development of new agents able to induce irreversible changes in the exposed lice leading to their mortality. The aim of the present work is to evaluate pediculicidal efficacy of some natural products such as olive oil, tea tree oil, lemon juice, and ivermectin separately in comparison with tetramethrin-piperonyl butoxide (licid), as a standard pediculicide commonly used in Egypt. The effects of these products were evaluated by direct observation using dissecting and scanning electron microscopes (SEM). Results showed that after 1 hr exposure time in vitro, absolute (100%) mortalities were recorded after exposure to 1% ivermectin and fresh concentrate lemon juice. The mortalities were decreased to 96.7% after exposure to tea tree oil. Very low percentage of mortality (23.3%) was recorded after 1 hr of exposure to extra virgin olive oil. On the other hand, the reference pediculicide (licid) revealed only mortality rate of 93.3%. On the contrary, no mortalities were recorded in the control group exposed to distilled water. By SEM examination, control lice preserved outer smooth architecture, eyes, antenna, respiratory spiracles, sensory hairs, and legs with hook-like claws. In contrast, dead lice which had been exposed to pediculicidal products showed damage of outer smooth architecture, sensory hairs, respiratory spiracles and/or clinching claws according to pediculicidal products used.
authors.affiliation: Department of Parasitology, Faculty of Medicine, Cairo University, Cairo, Egypt.
authors.forename: Dina M H El
authors.initials: DM
authors.lastname: Akkad
authors.affiliation: Department of Parasitology, Faculty of Medicine, Cairo University, Cairo, Egypt.
authors.forename: Naglaa Saad M
authors.initials: NS
authors.lastname: El-Gebaly
authors.affiliation: Department of Parasitology, Faculty of Medicine, Cairo University, Cairo, Egypt.
authors.forename: Hebat-Allah Salah A
authors.initials: HA
authors.lastname: Yousof
authors.affiliation: Department of Parasitology, Faculty of Medicine, Cairo University, Cairo, Egypt.
authors.forename: Mousa A M
authors.initials: MA
authors.lastname: Ismail
mesh_terms: D000818:Animals; D001688:Biological Products / Q000302:isolation & purification / Q000494:pharmacology*; D004353:Drug Evaluation, Preclinical; D007306:Insecticides / Q000302:isolation & purification / Q000494:pharmacology*; D008855:Microscopy, Electron, Scanning; D010374:Pediculus / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure*; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D016019:Survival Analysis
chemical_list: D001688:Biological Products; D007306:Insecticides; D010936:Plant Extracts
keywords: Pediculus humanus capitis; in vitro; pediculicide; plant extract; scanning electron microscope