Issue 1 “Pest Management is People Management” August 2007
BACK-TO-SCHOOL ISSUE: FIND OUT ABOUT HEAD LICE!
In the US, there are between 6 to 12 million cases of head lice each year, most commonly among children three to twelve years of age.
"lousiness", is one of the most prevalent communicable conditions in the country.
DON’T PANIC! IT CAN HAPPEN TO ANYONE!
Many families with young children have at least one encounter with the head louse, Pediculus capitis. Head lice can infest people of all ages, but children are prone to infestations because
they play in close contact, share hats, headphones, combs and brushes, sleeping bags, stuffed animals, and clothing. In fact,
saliva may create an itchy irritation. A first case of head lice
the problem of head lice can be so rampant among preschool
may not result in itching for four to six weeks. Once
and school-aged children that often schools work in conjunction
sensitized, subsequent infestations may cause itching almost
with many families to control an infestation.
Head lice (Pediculosis capitis) are not a sign of uncleanliness
Head lice usually survive for less than two days away from
and do not vector disease organisms. The most common
the scalp, at normal room temperature. Eggs cannot hatch at
symptoms are itching and sleeplessness. Scratching can lead to
an ambient temperature lower than that near the scalp.
secondary bacterial skin infection. Head lice cases can result in
Laundering and drying clothing and bedding at 130oF will kill
extreme anxiety, embarrassment, unnecessary days lost from
school and pesticide exposure. Millions of dollars are spent on remedies annually.
Head lice are not found on animals or household pets, and are
Back-to-school time seems to be when lice are most commonly
transmitted, resulting in widespread infestations by December
and January. With September being National Head Lice
Checking for Head Lice…
Prevention Month, we are encouraging parents, teachers, and
Periodic inspections and early detection of individual lice, are
childcare professionals to be aware of this “lousy pest” and know how to manage it.
far easier to deal with than advanced infestations. During the early fall months (August to November) children Head lice Facts: The adult louse is 2 to 3 mm long;
should be inspected weekly by parents.
color varies. The female lives for 3 to 4 weeks and lays
approximately 10 eggs (nits) a day. The eggs are firmly
An adult louse can move six to 30 cm per minute. They are
attached to the hair shaft close to the scalp. Viable nits are
hard to see and very difficult to remove. Nits are easier to
camouflaged with pigment to match the hair color of the
spot, especially at the nape of the neck or behind the ears.
infested person. They are most easily seen at the hairline at the
Unhatched eggs will be within 1 cm of the scalp. In general,
back of the neck. Empty egg casings are easier to see,
nits found more than 1 cm from the scalp are unlikely to be
appearing white against the hair.
viable. In warmer climates however, viable nits can occur farther from the scalp.
Eggs are incubated by body heat and hatch in 10 to 14 days.
Generally, around 30% of school children with nits will also
After hatch, nymphs leave the shell casing grow for about nine
have adult lice. Screening for nits alone is not an accurate
to twelve days before reaching the adult stage. If left untreated,
way of predicting which children will become infested.
the life cycle may repeat every three weeks.
Results from one research study found that only 18% of children with nits alone converted to an active infestation.
Lice feed by injecting small amounts of saliva and removing
tiny amounts of blood from the scalp every few hours. The
The presence of active lice in a child’s head is the only
given that lice-related itching usually leads to excoriation of
definitive indication of an infestation that should trigger a
head treatment. If an active infestation is noted, the child’s
parent or guardian should be notified immediately.
If repeated treatments fail, some physicians will prescribe
Treatment options may be suggested. Other members of the
higher levels of permethrin (5%), Lindane or malathion, or
family should inspect each other along with children who
even scabies treatments (e.g. crotamiton, sulfamethoxazole,
regularly sleep-over or share hair apparel (hair clips, head-
trimethoprim, ivermectin, etc.). These may be extremely
sets, hats, etc.). Parents and school nurses should be
hazardous to children, despite being FDA approved.
encouraged to recheck the student’s head for lice after
treatments have occurred if the child is still symptomatic or
Ulesfia (benzyl alcohol) is a relatively new prescriptive treatment for head lice on children 6 months or older. Risks are minimal compared to some of the alternatives, The American Academy of Pediatrics and the and the product has proven to be extremely effective. National Association of School Nurses
When using a head louse shampoo, minimize body exposure
(www.nasn.org/Default.aspx?tabid=237) discourage
by confining the insecticide to the head hair. Wash the
“no nit” policies in schools. There is no need to send
infested person's hair in a basin or sink so insecticide residues
students home.
do not reach other parts of the body. The person applying the
treatment should wear rubber gloves. Never apply an
Controlling Nits and Adult Lice…
insecticide to anyone who has open cuts, scratches, or
Due to the short time period that head lice can survive off the
inflammations, and never use these materials on infants
head, transmission may occur most commonly with head-to-
without consulting a doctor. In all cases, follow label
head contact which should be avoided. To further reduce
directions completely and carefully.
potential for transmission, discourage sharing of combs,
brushes, headbands, barrettes, pillows, hats, scarves, coats,
With pyrethrin and permethrin shampoos, lice should die
backpacks or other objects that may come in contact with the
within 10 to 30 minutes after treatment. If you find live lice
head. Where possible, place hats, scarves and coats on hooks
after 30 minutes, resistance may be occurring and you should
or in separate lockers or cubbies to avoid contact. If hooks
are shared or clustered, have children place their coats and
hats in sealed plastic bags, especially if head lice are present.
Never resort to dangerous practices such as applying general use insecticides, or materials such as kerosene!
Manual removal of nits close to the head is always
recommended. Fine-toothed "nit combs" are helpful.
Special combs are needed for louse removal and will be
Combing and brushing hair damages lice and eggs
effective in eradicating head lice infestations only if used
significantly. Use of a hair dryer further injures adults,
diligently each day for up to two weeks.
Combing is critical to controlling head lice because 20 to 30% of lice can still be alive after shampooing.
1. Comb and divide hair into sections, use a metal fine
toothed louse comb to remove nits and lice. After
What needs to be done in the home? Once an
combing each section dip the comb in a container of
infestation is detected, all clothes should be washed in hot
hot soapy water to remove lice and nits.
soapy water. Pillowcases, sheets, blankets and other bedding
2. Repeat until all the sections of hair have been
material should also be washed and placed in the clothes dryer
on the "high heat" cycle to kill the lice and their eggs. Any
3. Clean nit removal comb, clips, brushes, headphones,
non-washable items should be dry cleaned or sealed in plastic
bags and placed in the freezer at 50F or lower for 10 hours or
more. Vacuuming the home will remove shed hair and nits.
Unfortunately, there are no independent studies indicating the
benefits of nit removal aids or occlusive substances including
Continue weekly head checks of the whole family.
"petrolatum shampoos". Other occlusive substances have
been suggested (mayonnaise, tub margarine, herbal oils, olive
To find out about YOUR school’s policy and
oil) but benefits have not been demonstrated.
procedures for children discovered with lice, check
Head lice shampoos contain insecticides and if they are
not used properly can be very hazardous. Most treatments
for lice are shampoos left on the head for no more than 10
minutes. Most will not kill eggs, so a second treatment is
Information taken from:
Pollack, Richard J. August 2000. Harvard School of Public Health.
Green, T. A., and D. H. Gouge, eds. 2010. School IPM 2015: A Strategic
Removing nits close to the head is usually included in the
Plan for Integrated Pest Management in Schools in the United States.
treatment instructions. Most products warn against using the
products on broken skin which is practically impossible
2 http://www.headlice.org/
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