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Head Lice Biology and Treatment Options

Head Lice (Pediculus humanus capitis) are a common parasite found in human hair. School-age children from age 3-10 are often the most effected by outbreaks of lice infestations because of their sustained proximity and propensity for sharing hats, combs and clothing. Non-prescription sales of head lice products and related school expenditures in the United States alone cost consumers an estimated $350 million yearly.^[1] The two most successful conventional pyrethrum-based pediculicides are Rid^©[2] and Nix^©[3], averaging sales of more than $10 million each annually.

Users and researchers, however, have long reported that head lice are becoming drug-resistant and conventional pediculicides are losing their effectiveness. This is because if even only one in a thousand head lice survive a round of treatments, that one will have a natural resistance to the pediculicide and therefore a survival advantage, undoubtedly passing that advantage on to future generations. Since the life expectancy of a head louse is only about 30 days and they are capable of laying between 1-10 eggs per day[4], it doesn't take long for enough generations of selection with this advantage to create strains of head lice highly resistant to the treatment. Description. So just what ARE these annoying little pests? Head lice are small, six-legged, wingless insects about the size of a flea or sesame seed which feed solely on human blood. They have sharp little claws that are perfectly evolved for what they do best—crawling along and clinging tenaciously to the hair shaft in between meals.

Drug Resistant Head Lice Are a Head-Scratcher For Doctors WCSH6.com 7/26/2007 Play Video

Pets. Thankfully, head lice do not thrive on pets. And contrary to popular belief, they cannot jump, fly or magically transport from one host to the next...

Nits. Nits (the eggs of the adult head louse) are small, yellowish-white or brown, oval-shaped eggs that are glued by the louse to the side of a hair shaft at an angle. Head lice usually live for approximately 4 weeks on their hosts and a female louse in that time can lay as many as 100 nits. Nits will hatch whether or not the hair they are on is attached to the head so it is important to not share combs. Once laid, it takes about 7-10 days for a nit to hatch, and another 7-10 days for the female to mature and begin laying her own eggs.

Food Supply. Since the only place head lice can get a blood meal is on your head, if you apply an effective repellent you essentially cut off their only supply of food. Without a regular blood meal lice starve to death in 24-48 hours. Therefore your house cleans itself in 2-3 days and you don't have to worry any more about vacuuming, running everything through the drier, etc.

Study: Lice Can Resist Leading Medical Cure

Researchers reach the same conclusion as parents: Repeated use on U.S. children appears to have weakened the treatment.

By Lisa M. Krieger
SAN JOSE MERCURY NEWS

Confirming the suspicions of many frustrated parents, Harvard University public health experts have proven that pesky head lice have grown resistant to chemical treatment.

A new study shows roughly a 90 percent survival rate among a population of 209 lice plucked from the heads of U.S. kids and placed inside petri dishes containing the chemical permethrin, the active ingredient in "Nix", the leading treatment for louse infestations. All children in the study had been treated previously with the chemical.

By comparison, the chemical killed 66 to 67 lice harvested from the heads of kids living in the remote Malaysian town of Sabah, Borneo, who were never before exposed to the chemical. One louse apparently escaped.

"It is evident that lice infesting (chemically exposed) U.S. children are less susceptible than are lice infesting untreated Sabahan children," according to Richard J. Pollack and his research team, who published their findings in the September issue of the Archives of Pediatric and Adolescent Medicine. "The frequency of resistance seems to have increased."

Every year, an estimated 6 million American kids are infested with the wingless, six-legged crawlers on their scalps. Most school districts have a "no-nit" policy which prohibits kids from attending class if they carry eggs or live creatures.

The general prevalence of resistance to permethrin has not been determined, the Harvard team cautioned. The resistant lice were found in two random samples of children from Cambridge, Mass., and Boise, Idaho—but this does not mean that all, or even most lice in the United States are resistant.

For that reason, permethrin and related chemicals called pyrethrins remain the treatment of choice for newly identified infestations, Pollack said.

"If live lice persist following such treatments, then one may consider that these lice may be resistant," Pollack wrote, "and further treatment may be warranted with . . . other insecticides."

Increasingly, parents swap horror stories of "super lice" that refuse to respond to treatment, despite diligent shampooing, nit-picking, and cleaning. It can cost a family $60 or more to treat a single infestation.

In desperation, some turn to home remedies like mayonnaise, olive oil, or margarine. An Iowa girl suffered severe burns when her mother doused her head with gasoline. An Oklahoma girl became severely ill after her hair was soaked in agricultural-strength insecticide.

But experts at the Centers for Disease Control and Prevention in Atlanta, as well as most pediatricians and the manufacturers of de-lousing chemicals, have insisted that there is no definitive evidence of "super lice" in the United States—although such bugs have been identified in other nations.

Insecticides do not cause mutations that lead to resistance, according to the Harvard scientists. But in Darwinian fashion, bugs that survive exposure to the chemical because of some ability to avoid, detoxify, or eliminate the toxin are able to endure—while the weaklings succumb. This leads to the emergence of a more resilient strain.

Like antibiotic-resistant bacteria, lice seem to have discovered new and more efficient ways to elude destruction.

According to Harvard's Pollack and his team, lice that are resistant to permethrin at low doses are also resistant to the chemical at high doses—strongly suggesting that prescription formulations of permethrin at high (3 percent to 5 percent) concentrations are unwarranted.

Further Information:

Head Lice: Information and Frequently Asked Questions
A Statement by Dr. Richard J. Pollack, Ph.D., Harvard School of Public Health.

Head Lice Description and Biology
University of Maine Pest and Disease Management Lab

Citizen Petition Seeking to Ban the Use of Lindane as a Treatment for Lice and Scabies
Samuel S. Epstein, M.D., Cancer Prevention Coalition

Head Lice; University of Main Pest Management Lab Fact Sheet.

Permethrin - Identification, toxicity, use, water pollution potential, ecological toxicity and regulatory information. National Pesticide Telecommunications Network Pesticides Database.

Pesticide Action Network North America; Pesticide Registration (PR) Notice 94-6, Environmental Protection Agency.

^[1]Jones KN, English JC III. Review of Common Therapeutic Options in the United States for the Treatment of Pediculosis capitis. Clin Infect Dis. 2003; 36 (11):1355-1361.

^[2]Rid^© Active Ingredients: Piperonyl butoxide (4%) Pyrethrum extract (equivalent to 0.33% pyrethrins)

^[3]Nix^© Active Ingredient: Permethrin 1%

^[4]Downs, Anthony M. R., Managing Head Lice in an Era of Increasing Resistance to Insecticides. American Journal of Clinical Dermatology; 2004, Vol. 5 Issue 3, p169-177.

Bibliography^*:

Arnos, Kathy (1998). Head Lice Treatments Can Be Hazardous to Your Child's Health. LILIPOH; Fall 98, Vol. 4 Issue 16, p25.

Bailey, Anita M, Prociv, Paul. Persistent Head Lice Following Multiple Treatments: Evidence for Insecticide Resistance in Pediculus humanus capitis. Australasian Journal of Dermatology; Nov 2000, Vol. 41 Issue 4, p250-254.

Burgess, Ian F. Human Lice and Their Control. Annual Review of Entomology; 2004, Vol. 49 Issue 1, p457-481.

Burkhart CG; Burkhart CN, Clinical Evidence of Lice Resistance to Over-the-Counter Products. Journal of Cutaneous Medicine and Surgery. [J Cutan Med Surg] 2000 Oct; Vol. 4 (4), pp. 199-201.

Burkhart CN; Burkhart CG. Head Lice: Scientific Assessment of the Nit Sheath With Clinical Ramifications and Therapeutic Options. Journal Of The American Academy Of Dermatology [J Am Acad Dermatol] 2005 Jul; Vol. 53 (1), pp. 129-33.

Callahan, Richard D. The Kings of France and England Were Thwarted in 1528 - by a Louse. Military History; Feb 2005, Vol. 21 Issue 6, p18-23.

Cestari, I.M.; Sarti, S.J.; Waib, C.M.; Branco, A.C. Jr. Evaluation of the potential insecticide activity of Tagetes minuta (Asteraceae) essential oil against the head lice Pediculus humanus capitis (Phthiraptera: Pediculidae). Neotropical entomology, 2004 Nov-Dec, v. 33, no. 6, p. 805-807.

Downs AM; Stafford KA. (1999) Head lice: prevalence in schoolchildren and insecticide resistance. Coles GC Department of Dermatology, Bristol Royal Infirmary, Bristol, UK BS2 8HW. Parasitology today. 1999 Jan; Vol. 15 (1), pp. 1-4.

Downs, Anthony M. R.; Oxley, Jonathan. Head Lice Infestations in Different Ethnic Groups. International Journal of Dermatology, Mar 2001, Vol. 40 Issue 3, p237.

Downs, Anthony M. R. Managing Head Lice in an Era of Increasing Resistance to Insecticides. American Journal of Clinical Dermatology; 2004, Vol. 5 Issue 3, p169-177.

Fedarko, Kevin. A Lousy, Nit-Picking Epidemic. Time; 01/12/98, Vol. 151 Issue 1, p73.

Flinders, David C. & De Schweinitz, Peter, (2004) Pediculosis and Scabies. American Family Physician, 69(2), 341-348. Retrieved October 4, 2005 from American Family Physician web site at www.aafp.org/afp.

Gao, Jian-Rong; Yoon, Kyong Sup; Lee, Si Hyeock; Takano-Lee, Miwako; Edman, John D.; Meinking, Terri L.; Taplin, David; Clark, J. Marshall, (2003) Increased frequency of the T929I and L932F mutations associated with knockdown resistance in permethrin-resistant populations of the human head louse, Pediculus capitis, from California, Florida, and Texas. Pesticide Biochemistry & Physiology, Nov 2003, Vol. 77 Issue 3, p115, 10p; DOI: 10.1016/j.pestbp.2003.08.003; (AN 11040413).

Gray, Bev. (Sep 2005) An Itchy Start: Heading Off Head Lice. Alive: Canadian Journal of Health & Nutrition, Issue 275, p74-75, 2p.

Hansen, RC. Overview: the State of Head Lice Management and Control. The American Journal of Managed Care. [Am J Manag Care] 2004 Sep; Vol. 10 (9 Suppl), pp. S260-3.

Harder, B., (August, 2005) Comb over Chemicals, Science News, 168(8).

Jones, Kimberly N., English III, Joseph C. Review of Common Therapeutic Options in the United States for the Treatment of Pediculosis Capitis. Clinical Infectious Diseases; 6/1/2003, Vol. 36 Issue 11, p1355.

Leo, N.P., Brogdon, W.G., Barker, S.C., Poudel, S.K.S., Hughes, J.M. Yang, X. The Head and Body Lice of Humans Are Genetically Distinct (Insecta: Phthiraptera, Pediculidae): Evidence From Double Infestations. Heredity: An International Journal of Genetics, 2005 July, v. 95, no. 1, p. 34-40.

McKay, Shelley J., Myths & Facts...About Head Lice. Nursing; Jun 99, Vol. 29 Issue 6, p30.

Meinking TL, (2004) Clinical update on resistance and treatment of Pediculosis capitis. (eng; includes abstract) Am J Manag Care, 2004 Sep; Vol. 10 (9 Suppl), pp. S264-8; PMID: 15515630. Retrieved Oct. 5 2005 from EBSCO’s Academic Search Elite database.

Mumcuoglu KY; Magdassi S; Miller J; Ben-Ishai F; Zentner G; Helbin V; Friger M; Kahana F; Ingber A. Repellency of Citronella for Head Lice: Double-Blind Randomized Trial of Efficacy and Safety. The Israel Medical Association journal : IMAJ. [Isr Med Assoc J] 2004 Dec; Vol. 6 (12), pp. 756-9.

National Pesticide Telecommunications Network Pesticides Database. Permethrin - Identification, toxicity, use, water pollution potential, ecological toxicity and regulatory information. http://www.pesticideinfo.org/Detail_Chemical.jsp?Rec_Id=PC35397.

Nowak, Rachel. Hair Wars. New Scientist; 12/25/2004, Vol. 184 Issue 2479/2480, p64-67.

Pennisi, Elizabeth. Louse DNA Suggests Close Contact Between Early Humans. Science; 10/8/2004, Vol. 306 Issue 5694, p210-210.

Pesticide Action Network North America URL: http://www.panna.org/ Pesticide Registration (PR) Notice 94-6, Environmental Protection Agency.

Pollack, Richard J. Head Lice: Information and Frequently Asked Questions http://www.hsph.harvard.edu/headlice.html.

Roberts, Richard J.; Burgess, Ian F. New Head-Lice Treatments: Hope or Hype? Lancet, 1/1/2005, Vol. 365 Issue 9453, p8.

Speare, R.; Thomas, G.; Cahill, C. Head Lice Are Not Found On Floors in Primary School Classrooms. Australian and New Zealand journal of public health. [Aust N Z J Public Health] 2002; Vol. 26 (3), pp. 208-11.

Speare R.; Cahill C.; Thomas G. Head Lice On Pillows, and Strategies To Make a Small Risk Even Less. International Journal of Dermatology. [Int J Dermatol] 2003 Aug; Vol. 42 (8), pp. 626-9.

Takano-Lee M; Yoon KS; Edman JD; Mullens BA; Clark JM. In Vivo and In Vitro Rearing of Pediculus Humanus Capitis (Anoplura: Pediculidae). Journal of Medical Entomology. [J Med Entomol] 2003 Sep; Vol. 40 (5), pp. 628-35.

Takano-Lee, Miwa Edman, John D. Mullens, Bradley A., Clark, John M. Transmission Potential of the Human Head Louse, Pediculus Capitis (Anoplura: Pediculidae). International Journal of Dermatology; Oct2005, Vol. 44 Issue 10, p811-816.

University of Maine Pest and Disease Management Lab, Head Lice Description and Biology, http://pmo.umext.maine.edu/factsht/headlice.htm.

Williams, Rose Marie. Health Risks and Environmental Issues; Head Lice are Not Nice, But Using Lindane is Insane. Townsend Letter for Doctors & Patients; April 2000 Issue 201, p50.

Williams, L. Keoki, Reichert, Amanda, Blake, Paul A., MacKenzie, William R., Hightower, Allen W. Lice, Nits, and School Policy. Pediatrics; May 2001, Vol. 107 Issue 5, p1011.

Yang, Y.C., Lee, H.S., Clark, J.M., Ahn, Y.J. Insecticidal Activity of Plant Essential Oils Against Pediculus humanus capitis (Anoplura: Pediculidae). Journal of Medical Entomology, 2004 July, v. 41, no. 4, p. 699-704.

Yang, Y.C.; Choi, H.Y.; Choi, W.S.; Clark, J.M.; Ahn, Y.J. Ovicidal and Adulticidal Activity of Eucalyptus Globulus Leaf Oil Terpenoids Against Pediculus humanus capitis (Anoplura: Pediculidae). Journal of Agricultural and Food Chemistry, 2004 May 5, v. 52, no. 9, p. 2507-2511.

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