Head Lice

Description

The adult head louse resembles a miniature ant that appears flat when viewed from the side through a strong magnifying glass. Head lice have a head, thorax and abdomenwith six legs, but their two front legs are very large in order to grab onto the hair shafts. Head lice are tan to greyish-white in color.

Life cycle

Lice eggs on the hair very close to the scalp are the primary sign of an active infestation. The female louse glues her eggs, sometimes called "nits", which look like tiny white beads, to hair shafts very close to the scalp. Eggs are very small, about the size of a period in normal printing. Eggs may appear yellowish, brownish or greyish, but almost always lighter colored. Eggs normally undergo a 7-9 day incubation before hatching as a baby nymph. Classically, a louse egg does not become a "nit" until after it has completed its incubation stage, thus leaving a "nit". A "nit" is either the empty shell remaining after the nynmph has departed or the dead egg that remains if incubation was not successful. Dead eggs will appear dark, or raisonlike, as they dry out. "Nits" are usually found one-half inch or more away from the scalp and are not considered a sign of an active infestation.

There are three nymph instar stages as the baby louse matures, with the louse shedding its exoskeleton at the end of each stage as it gets larger. The nymph stage typically takes 10 to 12 days.

Whether a louse is male or female is not apparent until they are nearly mature. Fertilization of eggs takes place once as the female reaches the mature stage. The female can then lay 3-7 eggs each day for the next 28 to 30 days, her normal life span.

There are three main stages in the life of a head louse: the nit, the nymph, and the adult.

Nit: Nits are head lice eggs. They are hard to see and are found firmly attached to the hair shaft. They are oval and usually yellow to white. Nits take about 1 week to hatch.
Nymph: The nit hatches into a baby louse called a nymph. It looks like an adult head louse, but is smaller. Nymphs mature into adults about 7 days after hatching. To live, the nymph must feed on blood. It metamorphoses 3 times before it reaches the adult stage.
Adult. Females lay nits (a few hundreds of eggs); they are usually larger than males. To live, adult lice need to feed on blood. If the louse falls off a person, it dies within 1-2 days.

Symptoms

The louse feeds on human blood, and the bite causes itching. Bites can become secondarily infected; scratching may break the skin and help cause this secondary infection. The most common symptom is itching of the scalp.

Head lice are normally spread by close contact but can also be spread by sharing clothes or bedding.

Treatment

Head lice can be killed by a 1% permethrin or pyrethrin lice shampoo, but the hair must be combed with a fine-toothed comb after treatment to remove the nits. In the Western world resistance to commercially available anti-lice shampoos is increasing strongly. In some countries, such as the UK, resistance is so strong that many families do not know what to do anymore. Lice can survive in bedding and clothing, so these items must be treated, sterilized, or contact with them must be avoided for two weeks, after which time any lice will have died.

One alternative to insecticidal treatments, particularly where resistance is common, is to use an electric comb. Alternating teeth carry a high voltage (though the developable current is small, and so the device safe). Fine combing causes any contact with the lice to result in their electrocution. This allows diligent combing to iradicate an infestation.

Lindane (1%), another pediculocide, is not recommended for pregnant or nursing women or for children less than 2 years old.

See also Pediculosis

Commercial Usage: Head Lice

Domain	Title
References	The Official Patient's Sourcebook on Head Lice Infestation (reference) (more reference examples)

Books	Horrid Henry's Head Lice (Laf) (reference) Rainbows, Head Lice, and Pea-Green Tile: Poems in the Voice of the Classroom Teacher (reference) Head Lice (My Health) (reference) Head Lice to Dead Lice (reference) The Lice-Buster Book: What to Do When Your Child Comes Home With Head Lice! (reference) (more book examples)

Theater & Movies	Head Lice to Dead Lice: Safe Solutions for Frantic Families (reference) (more DVD examples; more video examples)
Source: compiled by the editor from various references; see credits.

Photo Album: Head Lice

Non-Fiction Usage: Head Lice

Subject	Topic	Quote
Health		Do not mix head lice drugs. (references)
		Head lice do not live long if they fall off a person. (references)
		Many head lice medications are available at your local drug store. (references)
Human Rights	Russia	Head lice, scabies, and various skin diseases were prevalent. (references)
Source: compiled by the editor from ICON Group International, Inc.; see credits.

Modern Translations: Head Lice

Language		Translations for "head lice"; alternative meanings/domain in parentheses.
Japanese Kanji		� �虱 (head louse). (various references)

Japanese Katakana		あたましらみ (head louse). (various references)

Pig Latin		eadhay icelay
Source: compiled by the editor from various translation references.

Anagrams: Head Lice

Scrabble® Enable2K-Verified Anagrams
	Words within the letters "a-c-d-e-e-h-i-l"
	-1 letter: leached.
	-2 letters: aedile, ceiled, chelae, chield, childe, decile, hailed, halide, healed, heiled, heliac, leched, lichee.
	-3 letters: ached, ailed, alcid, chela, chide, chiel, child, chile, clade, decal, deice, eched, edile, elide, haled, halid, ideal, ileac, laced, laich, leach, leech.
	-4 letters: aced, ache, acid, aide, alec, alee, cade, cadi, caid, cede, cedi, ceil, chad, chia, chid, clad, dace, dahl, dale, deal, deil, dele, deli, dhal, dial, dice, diel, each, eche, eide, elhi, hade, haed, hail, hale, head, heal, heed, heel, heil, held, hide, hied, hila, iced, idea, idle, ilea, lace, lade, laic, laid, lead, lech, lice, lich, lied.
	-5 letters: ace, aid, ail, ale, cad, cee, cel, chi, dah, dal, dee, del, die, edh, eel, eld, had, hae, hic, hid, hie, ice, ich, lac, lad, lea, led, lee, lei, lid, lie.
	Words containing the letters "a-c-d-e-e-h-i-l"
	+2 letters: alchemized, chandelier.
	+3 letters: chandeliers, chandleries, channelized, diencephala, hexadecimal, psychedelia.
	+4 letters: candlefishes, chalcedonies, chalcogenide, chandeliered, cheerleading, dechlorinate, decipherable, diencephalic, diencephalon, hexadecimals, mischanneled, psychedelias.
	+5 letters: candlelighted, candlelighter, cephaloridine, chalcogenides, dechlorinated, dechlorinates, diencephalons, dischargeable, mischannelled, technicalized, tetrachloride.
Source: compiled by the editor from various references; see credits. SCRABBLE® is a registered trademark. All intellectual property rights in and to the game are owned in the U.S.A and Canada by Hasbro Inc., and throughout the rest of the world by J.W. Spear & Sons Limited of Maidenhead, Berkshire, England, a subsidiary of Mattel Inc. Mattel and Spear are not affiliated with Hasbro.

Alternative Orthography: Head Lice

Hexadecimal (or equivalents, 770AD-1900s) (references)

48 65 61 64 4C 69 63 65

Leonardo da Vinci (1452-1519; backwards) (references)

Binary Code (1918-1938, probably earlier) (references)

01001000 01100101 01100001 01100100 00100000 01001100 01101001 01100011 01100101

HTML Code (1990) (references)

&#72 &#101 &#97 &#100 &#32 &#76 &#105 &#99 &#101

ISO 10646 (1991-1993) (references)

0048 0065 0061 0064 004C 0069 0063 0065

Encryption (beginner's substitution cypher): (references)

Thumbnail	Description & Credit
	EIS officer screening person for head lice.Credit: CDC.
Source: compiled by the editor from various references; see credits.

Head Lice

Definition: Head Lice

Head Lice

Noun

Synonym: Head Lice

Specialty Definition: Head lice

Description

Life cycle

Symptoms

Treatment

Crosswords: Head Lice

Commercial Usage: Head Lice

References

Books

Theater & Movies

Photo Album: Head Lice

Non-Fiction Usage: Head Lice

Health

Human Rights

Russia

Modern Translations: Head Lice

Japanese Kanji

Japanese Katakana

Pig Latin

Anagrams: Head Lice

Scrabble® Enable2K-Verified Anagrams

Alternative Orthography: Head Lice

48 65 61 64 4C 69 63 65

01001000 01100101 01100001 01100100 00100000 01001100 01101001 01100011 01100101

&#72 &#101 &#97 &#100 &#32 &#76 &#105 &#99 &#101

0048 0065 0061 0064 004C 0069 0063 0065

42716770246756971

INDEX