1. Bugs that May Affect Children in the Pre-school Environment
David N. Gaines, Ph.D.
Public Health Entomologist
Virginia Department of Health
Division of Environmental Epidemiology

2. How to deal with Head Lice on Children in a Pre-School Setting
Photo by Gilles San Martin

3. Head Lice Environment
Head lice evolved to live on human heads and cannot survive in any other environment, on any other part of the human body, or any other animal.
The environment on a head provides the perfect combination of warmth, humidity, food (blood), and a matrix (hair) to live on.
The feet (claws) of a head louse are best adapted to crawling rapidly along and through hair.
Head lice will die if separated from the human head for more than a day, so they avoid leaving the head if possible.

4. How Head Lice Spread
Head lice are most commonly spread from person to person by direct and prolonged head to head contact.
It is much less common for head lice to be spread from inanimate objects to a person. When head lice are spread on objects it is usually by:
Head gear (hats, scarves, hair ties, barrettes, head phones, brushes, combs), or by:
Other items that have been in recent, prolonged contact with infested hair (coat collars, couch cushions, pillows, stuffed toys, carpet).

5. Head Lice on Children
Head lice infestations are more common on young children than adults because children have a much higher degree of physical, interpersonal contact.
Girls are more predisposed to head lice than boys because girls are more likely have direct prolonged head to head contact , and share things like hats, hair ties, combs, and clothing.
African Americans are less likely than other races to get a head louse infestation due to the structure of their hair.

6. Head Lice on Children
Head lice infestations are not related to a child’s level of cleanliness or hygiene .
Infestations are primarily due to a child’s unfortunate contact with another carrier of lice.
As head lice can spread quickly in a kindergarten / pre-school setting, it is important to be vigilant for children with signs of an infestation and resolve the problem before it spreads .

7. Head Lice Biology and Life Cycle
Adult female head lice lay eggs (nits) on a strand of hair right next to the scalp.
Eggs are firmly glued to the hair.
By the time eggs hatch 8 – 9 days later, the hair has grown out about ¼ inch from the scalp.
Eggs (nits) found on hair more than ¼ inch from the scalp are empty egg shells (have already hatched).

8. Head Lice Biology and Life Cycle
Nymph stage lice hatch out of the eggs and molt through three progressively larger nymph stages.
Nymph 1 2 3
Adult
Male
Female
CDC Public Health Image Library
About days after hatching from eggs, nymph stage lice become adults.

9. Head Lice Biology and Life Cycle
Adult lice measure from 1/16” to 1/8” (inch) in length.
Photo by Eran Finkle
Louse on Q-tip
Adult Female
Adult Male
Photo by Gilles San Martin
Photo by Gilles San Martin
Mated adult females live for about 30 days, can lay up to six eggs a day, and must have a blood meal each day.

10. Beginning a Head Louse Infestation
A head louse infestation cannot be started by a single louse unless that louse is a mated female.
A child infested with a single mated female would probably not begin to notice the infestation until about days after the louse climbed aboard.
By that time, there would be at least 12 to 24 nymph stage lice feeding on the scalp as well as the adult female.
The initial signs of a head louse infestation are a tickling or itchy feeling in the scalp and difficulty sleeping (head lice are more active at night).

11. Other Signs of a Head Louse Infestation
Nits (eggs) visible in hair.
Nymph and adult lice scurrying around.
As head lice are small and move through the hair very quickly, a magnifying glass and strong light will be needed to observe them.

12. Other Signs of a Head Louse Infestation
Head lice can be found anywhere in the hair as well as on eyebrows, but are most often observed in the hair behind the ears, on the back of the head, and in hair at the neck-line.
Observing active lice and new nits requires using a lamp, magnifying glass, and comb to look through hair to the scalp level.

13. Transmission Prevention
Prevent head to head contact among children during play.
Prevent the sharing of head gear, combs, hats, clothing, beds, pillows, or couches, among children.
Vacuum any carpet, or sofa cushions that have come into contact with an infested child’s head.
Launder any clothing, blankets, sheets or pillow cases that have been used by an infested child (wash in hot water and dry on high heat on a daily basis) .
Disinfect any combs, brushes, or hair ware used on an infested child (in hot water [130°F] for 5-10 minutes) .

14. Prevention – School “No-Nit” Policies
School “no-nit” policies are controversial.
Visible nits in hair is not evidence of an active louse infestation, and the absence of visible nits does not mean there are no head lice present.
Some public health advocacy groups say that “no-nit” policies have not reduced louse infestation rates, and have disrupted student attendance and education.
Due to this disagreement, no-nit policies are instituted by some state or local school boards, but not by others.
More studies are needed to understand the cost/benefit analysis of no-nit policies.

15. Chemical Treatments – Commercial Remedies
Pyrethrum (Pyrethrins) Shampoos - Kill nymph and adult lice, but have no effect on eggs.
Re-treatment is necessary in 9 days to kill the nymphs that hatch out of unaffected eggs.
Pyrethrins have negligible toxicity to people, but allergy to this product could be a concern for some people.
Some lice may be resistant to pyrethrum treatments.

16. Chemical Treatments – Commercial Remedies
Permethrin Lotion 1% (Nix) - Kills nymph and adult lice and has residual activity, but has no effect on eggs.
Re-treatment in 9 days is necessary to kill the nymphs that hatch out of unaffected eggs.
Permethrin has very low toxicity to people, but is not recommended for use on children under 2.
Some lice may be resistant to permethrin treatments.
Use of shampoos with conditioners in the week after treatment may reduce residual treatment effectiveness (use baby shampoo only).

17. Chemical Treatments – Commercial Remedies
Benzyl Alcohol Lotion 5% (Ulesfia lotion) - Kills nymph and adult lice, but has no effect on eggs.
Re-treatment is necessary in 9 days to kill the nymphs that hatch out of unaffected eggs.
Benzyl alcohol is non-toxic and may be used on babies as young as 6 months old, but caution is required in use due to potential for eye irritation, or for skin irritation in sensitive people.

18. Chemical Treatments – Commercial Remedies
Malathion Lotion 0.5% (Ovide) - Kills eggs, nymphs and adult lice and has residual activity.
Re-treatment is recommended in 9 days to kill any lice or eggs that may have escaped treatment.
Malathion can be toxic to people and may cause irritation to eyes and skin, and is not recommended for use on children under 6.
Use of shampoos with conditioners in the week after treatment may reduce residual treatment effectiveness (use baby shampoo only).

19. Chemical Treatments – Commercial Remedies
When using chemical treatments, strict adherence to label instructions is essential for maximum efficacy and to minimize the risk of toxic reactions!
Nit and Lice Combing and Removal
As there is potential for treatment failure due to louse resistance to some insecticide products, combining topical chemical treatments with nit and lice combing activities is advisable.

20. Nit and Lice Combing and Removal
Combing all nits and lice out of hair can be done instead of chemical treatments, or as a supplement to improve the efficacy of chemical treatments.
If used in place of pesticide treatments, it must be done very thoroughly and frequently (should be done at no more than two-day intervals for several weeks).
A thorough removal of all nits may be necessary in school districts that have no-nit policies.
A white vinegar rinse (30 to 60 minutes) - Loosens glue on eggs, and facilitates egg removal by nit comb.

21. Non Toxic Treatments – Nit and Louse Removal
Some nit and louse combs may be better than others (some recommend combs made by Lice Out™ or LiceMeister™ ).
Lice Out™ Gel - When applied to hair, it gums up and slows the movement of nymphs and adult lice so they can be easily combed out.
A thorough combing out of nits and lice may require up to an hour or more of time – depending on child’s hair length.
Hair is parted into four sections and each section is worked methodically with the comb from one end to the other.

22. Home Remedies – Oil Based Treatment
The “oil based treatment” is a popular home remedy that is said to suffocate lice and eggs.
Although popular, the oil treatment’s efficacy has not been tested in a controlled study.
Oil or mayonnaise is worked into hair, oiled hair is covered with a shower cap; shower cap/oily hair is briefly heated with hair dryer; oil is left in place for at least 30 minutes.
Hair is combed out with nit comb and then shampooed several times to remove remaining oil.