TY - JOUR T1 - The adherent cylindrical nit structure and its chemical denaturation in vitro: an assessment with therapeutic implications for head lice JF - Archives of Pediatric and Adolescent Medicine Y1 - 1998 DO - doi:10.1001/archpedi.152.7.711 A1 - Burkhart,Craig N. A1 - Craig G. Burkhart A1 - Pchalek,I. A1 - Arbogast,J. SP - 711 EP - 712 KW - animals KW - Lice Infestations/therapy KW - Ovum/drug effects KW - Pediculus KW - Research Support, Non-U.S. Gov't AB -

Pediculus humanus capitis is the insect responsible for head lice. During the female louse's 30-day lifespan, she lays approximately 10 eggs per day and attaches each of them with a gluelike, waterproof substance to human hair, 1 mm from the scalp. Larvae emerge 8 to 10 days later from these nits, or eggs, which remain firmly attached to hair.No topical agent has been shown to be 100% ovicidal.1 The existence of any nits, a major aspect of lice infestations, signifies the potential that this contagious malady may still be present. Many schools, therefore, adhere to a "no-nit" policy before children can reenter the classroom after infestation, thereby imposing prolonged absenteeism. Insecticides fail to kill all nits and larvae because they act on the insects' central nervous systems, which are not fully developed in the first 4 days of the insects' existence. Several products, namely, Clear lice egg remover gel (Care Technologies, Greenwich, Conn), Step 2 (Genderm, Lincolnshire, Ill), and a 50/50 mixture of vinegar and water, have been suggested as beneficial in nit removal. However, no clinical benefit has been documented in the medical literature.2

CY - UNITED STATES VL - 152 SN - 1072-4710 UR - https://jamanetwork.com/journals/jamapediatrics/article-abstract/189651 IS - 7 N1 - LR: 20041117; JID: 9422751; ppublish ER - TY - JOUR T1 - School nurses' perceptions of and experiences with head lice JF - Journal of School Health Y1 - 1999 DO - https://doi.org/10.1111/j.1746-1561.1999.tb04174.x A1 - Price,J. H. A1 - Burkhart,Craig N. A1 - Craig G. Burkhart A1 - Islam,R. SP - 153 EP - 158 KW - adult KW - Analysis of Variance KW - animals KW - Attitude of Health Personnel KW - child KW - Child, Preschool KW - humans KW - Lice Infestations/nursing/prevention & control KW - Middle Aged KW - Organizational Policy KW - Pediculus KW - Research Support, Non-U.S. Gov't KW - scalp dermatoses KW - School Nursing KW - Self Efficacy KW - U.S.A. AB -

Researchers examined school nurses' perceptions of head lice, perceived self-efficacy in dealing with head lice, and personal experience in reducing head lice problems. Survey data from a two-wave mailing from 382 school nurses found most nurses supported a "no-nit" rule of forced absenteeism of any child with nits in their hair (60%). They perceived OTC treatments for head lice as very effective in killing adult lice (66%), and 9% perceived them as not effective. Nurses had a high efficacy expectation regarding their ability to control head lice (63%), and they had high outcome expectations regarding the results of their work with students and families of students (66%). Most nurses received their information about head lice from professional journals (76%) and professional conferences/conventions (62%).

VL - 69 UR - https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1746-1561.1999.tb04174.x IS - 4 ER - TY - JOUR T1 - Molecular composition of the louse sheath JF - Journal of Parasitology Y1 - 1999 A1 - Burkhart,Craig N. A1 - Stankiewicz,B. A. A1 - Pchalek,I. A1 - Kruge,M. A. A1 - Craig G. Burkhart SP - 559 EP - 561 KW - Amino Acids KW - animals KW - Fatty Acids/analysis KW - Insect proteins KW - Mass Fragmentography KW - Pediculus KW - Research Support, Non-U.S. Gov't AB -

Flash pyrolysis-gas chromatography/mass spectrometry was used to assess the chemical composition of the head louse's nit sheath. The pyrolyzate of the female insect's secretions, which form a cement-like cylinder holding the egg onto the hair, is dominated by amino acid derivatives and fatty acids. No chitin-specific compounds were detected in the sheath. These results, contrary to previous reports, show that the polymeric complex of the sheath is composed of proteinaceous moieties, possibly cross-linked to aliphatic components. This study constitutes the first chemical characterization of the pyrolysis products of insect (louse) glue and unequivocally confirms that louse sheaths are not chitinous, as suggested by earlier histochemical studies. Development of agents that might loosen nits from the hair shaft is dependent on research that addresses the chemical composition of the nit sheath.

VL - 85 UR - https://www.jstor.org/stable/pdf/3285796.pdf IS - 3 ER - TY - JOUR T1 - Scanning electron microscopy of human head louse (Anoplura: Pediculidae) egg and its clinical ramifications JF - Journal of Medical Entomology Y1 - 1999 A1 - Burkhart,Craig N. A1 - Craig G. Burkhart A1 - Gunning,W. T. A1 - Arbogast,J. SP - 454 EP - 456 KW - animals KW - humans KW - Microscopy, Electron, Scanning KW - Ovum/ultrastructure KW - Pediculus KW - Research Support, Non-U.S. Gov't KW - scalp dermatoses AB - Pediculosis affects more elementary school students than all other communicable childhood diseases combined, excluding the common cold. The current study using scanning electron microscopy visualized operculums through which developing embryos received oxygen, as well as fracture lines within the adherent sheath by which the egg is attached to the hair. Using microscopic techniques, including freeze-fracturing, the mode of attachment of the sheath to the hair follicle was observed, in addition to the existence of several inner membranes enclosing the embryo within the egg structure. The chemical nature of the sheath is also analyzed using electron dispersive x-ray analysis. CY - UNITED STATES VL - 36 SN - 0022-2585 IS - 4 N1 - LR: 20041117; JID: 0375400; ppublish ER - TY - JOUR T1 - Scanning electron microscopy of adult head lice (Pediculus humanus capitis) with focus on clinical implications JF - Journal of Cutaneous Medicine and Surgery Y1 - 2000 DO - DOI: 10.1177/120347540000400402 A1 - Burkhart,Craig N. A1 - Craig G. Burkhart A1 - Gunning,W. T. SP - 181 EP - 185 KW - animals KW - humans KW - Microscopy, Electron, Scanning KW - Pediculus KW - Research Support, Non-U.S. Gov't AB -

BACKGROUND: The incidence of head lice infestations in North America is escalating with an estimated 12 million cases of head lice per year despite the existence of insecticidal therapies. OBJECTIVE: To evaluate certain characteristics of the human head louse, including their chitinous structure, nymphal developmental stages, legs with claw adaptations, antennae with sensory perceptions, and spiracles by which oxygen exchange occurs, for assessment of possible means to control the spread and growth of this insect. METHODS: Scanning electron-microscopic examination of head lice was performed. RESULTS: Newer treatments of head lice must acknowledge defense mechanisms that are based on anatomic structure and physiologic characteristics, details of louse transmission, and the insects' ability to 'resurrect' after sham death. CONCLUSIONS: An understanding of lice entomology is essential in the pursuit of novel means to control the lice epidemic.

CY - Canada VL - 4 SN - 1203-4754 UR - https://www.researchgate.net/publication/12100953_Scanning_electron_microscopy_of_adult_head_lice_Pediculus_humanus_capitis_with_focus_on_clinical_implications IS - 4 N1 - LR: 20041117; JID: 9614685; 1999/12/15 [received]; 2000/03/06 [accepted]; ppublish ER - TY - JOUR T1 - Head lice JF - New England Journal of Medicine Y1 - 2002 A1 - Meinking,Terri Lynn A1 - Craig G. Burkhart A1 - Burkhart,Craig N. SP - 1381 EP - 1382 KW - animals KW - humans KW - insecticide KW - Lice Infestations/drug therapy/transmission KW - Malathion KW - Pediculus KW - Research Support, Non-U.S. Gov't KW - scalp dermatoses KW - U.S.A. VL - 347 IS - 17 ER -