FLORIDA TICKS & MITES
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HUMAN HEAD LICE Pediculosis
The presence of head lice is a medical issue and should be diagnosed and treated by a
physician. Typically, a physician will prescribe a louse control shampoo or similar product. Also,
a fine-toothed comb may be used to help remove lice and some nits from hairs. It is important to note that the
label directions of any louse control product should be strictly followed. Reports of concerned or panicked parents
applying such products daily or at higher than label-directed dosages have occurred. Such misuse of these products
is potentially unsafe for the lice-infested person; much like taking a higher dose of medication than recommended
by a physician is unsafe. A pest management professional can do nothing
to help in dealing with this insect. The premises do not require treatment. Noninfested family members
should not share combs, brushes, hats, towels or bedding with an infested person until that person’s louse
infestation has been eliminated. Use hot water and detergent to wash bedding, clothing, towels, etc. that have been
in contact with an infested person. Combs and brushes can be boiled for a minute or so in water and then washed
thoroughly with soap and water.
Information supplied by Wikapedia ...
(also known as head lice infestation, "nits" and cooties)
is a human medical condition caused by the colonization of the
hair and skin by the parasitic insect Pediculus humanus capitis—the
head louse.
Typically, only the head or scalp of the host is infested. Head lice feed on human blood
(hematophagy), and itching from lice bites is a common symptom of this
Treatment typically includes application of topical insecticides such as a pyrethrin or permethrin, although a variety of herbal remedies are also common.
Lice infestation in general is known as pediculosis, and occurs in many mammalian and bird
The term pediculosis capitis, or simply "pediculosis", is sometimes used to refer to the specific human
pediculosis due to P. humanus capitis (i.e., head-louse infestation). Humans
are hosts for two other lice as well — the body louse and the crab louse.
Head-lice infestation is widely endemic, especially in children. It is a cause of some concern in public health,
although, unlike human body lice, head lice are not carriers of other infectious diseases.
Signs and symptoms:
The most common symptom of infestation is pruritus (itching) on the head which normally intensifies 3 to
4 weeks after the initial infestation. The bite reaction
is very mild and it can be rarely seen between the hairs. Bites can be seen, especially in the neck of
long-haired individuals when the hair is pushed aside. In rare cases, the itch scratch cycle can lead to
secondary infection with impetigo and pyoderma. Swelling of the
local lymph nodes and fever are rare. Head lice are not known to
transmit any pathogenic microorganisms.
Head lice are generally spread through direct head-to-head contact with an infested person; transmission
by sharing bedding or clothing such as headwear is much less common.
Body lice are spread through direct contact with the body, clothing or other personal items of a person
already carrying lice. Pubic lice are most often spread by intimate contact with an infested person. Head lice
occur on the head hair, body lice on the clothing, and pubic lice mainly on the hair near the groin. Human lice do
not occur on pets or other animals.
Lice do not have wings and cannot jump[citation
From each egg or "nit" may hatch one nymph that will grow and develop to the adult
Full-grown lice are found to be the size of a sesame seed. Lice feed on blood 1-8 times each day by piercing the
skin with their tiny needle-like mouthparts.
Lice cannot burrow into the skin.
Head lice and body lice (Pediculus humanus) are similar in
appearance, although the head lice is often smaller.
Pubic lice (Pthirus pubis), on the other hand, are
quite distinctive. They have shorter bodies and pincer-like claws, and are colloquially known as
Head lice (Pediculus
humanus capitis) are not known to be vectors of diseases, unlike body lice (Pediculus
humanus humanus), which are known vectors of epidemic or louse-borne
typhus (Rickettsia prowazeki), trench
fever (Rochalimaea quintana) and louse-borne relapsing
fever (Borrellia recurrentis)[citation
The condition is diagnosed by the presence of lice or eggs in the hair, which is facilitated by using a
magnifying glass or running a comb through the child's hair. In questionable cases, a child can be referred to a
health professional. However, the condition is overdiagnosed, with extinct infestations being mistaken for active
ones. As a result, lice-killing treatments are more often used on noninfested than infested children.
The use of a louse comb is the most effective way to detect living lice.
In cases of children with dirty, long and/or curly/frizzy hair, an alternative method of diagnosis is
examination by parting the hair at 2 cm intervals to look for moving lice near the scalp. With both
methods, special attention should be paid to the area near the ears and the nape of the neck. The examiner
should examine the scalp for at least 5 minutes. The use
of a magnifying glass to examine the material collected between the teeth of the comb could prevent
The presence of nits alone, however, is not an accurate indicator of an active head louse infestation. Children
with nits on their hair have a 35-40% chance of also being infested with living lice and eggs.
If lice are detected, the entire family needs to be checked (especially children up to the age of 13 years)
with a louse comb, and only those who are infested with living lice should be treated. As long as no living
lice are detected, the child should be considered negative for head louse infestation. Accordingly, a child
should be treated with a pediculicide ONLY when living lice are detected on his/her hair (not because he/she
has louse eggs/nits on the hair and not because the scalp is itchy).
Examination of the child’s head at regular intervals using a louse comb allows the diagnosis of louse
infestation at an early stage. Early diagnosis makes treatment easier and reduces the possibility of infesting
others. In times and areas when louse infestations are common, weekly examinations of children, especially those
4–15 yrs old, carried out by their parents will aid control. Additional examinations are necessary if the child
came in contact with infested individuals, if the child frequently scratches his/her head, or if nits suddenly
appear on the child’s hair. Keeping long hair tidy could be helpful in the prevention of infestations with head
Clothes, towels, bedding, combs and brushes, which came in contact with the infested individual, can be
disinfected either by leaving them outside for at least 2 weeks or by washing them at 60°C(140 degrees F) for 30
is because adult lice can survive only one to two days without a blood meal, and are highly dependent on human
body warmth. An
insecticidal treatment of the house and furniture is not necessary.
There is no product or method which assures 100% destruction of the eggs and hatched lice after a single
treatment. However, there are a number of treatment modalities that can be employed with varying degrees of
success. These methods include chemical treatments, natural products, combs, shaving, hot air,
and silicone-based lotions
however all effective treatments require a two-fold process of killing both the adult lice and the eggs.
Generally the eggs (nits) need to be manually picked off one by one in order to ensure all live eggs are
Lice on the hair and body are usually treated with medicated shampoos or cream rinses. Nit combs can be used to
remove lice and nits from the hair. Laundering clothes using high heat can eliminate body lice. Efforts to treat
should focus on the hair or body (or clothes), and not on the home environment.
Some lice have become resistant to certain (but not all) insecticides used in commercially available anti-louse
products. A physician or pharmacist can prescribe or suggest treatments. Empty eggs of head lice may remain
attached to the hair shaft long after the lice have been eliminated, but
rarely are adult lice seen even with an active infestation. Since there is no way to determine whether each egg
is alive or dead, chemical treatment (which may not kill the eggs) should be considered only when live
(crawling) lice are discovered in order to kill the adults. Instead, nitpicking, which is checking each hair
strand for eggs and picking off each egg, should be used to prevent the possibility of an egg hatching resulting
The number of cases of human louse infestations (or pediculosis) has increased worldwide since the mid-1960s,
reaching hundreds of millions annually.
Despite improvements in medical treatment and prevention of human diseases during the 20th century, head louse
infestation remains stubbornly prevalent. In 1997, 80% of American elementary schools reported at least one
outbreak of lice.
Lice infestation during that same period was more prevalent than chicken pox.
About 6-12 million children between the ages of 3 and 11 are treated annually for head lice in the United States
High levels of louse infestations have also been reported from all over the world including Israel, Denmark,
Sweden, U.K., France and Australia.
The number of children per family, the sharing of beds and closets, hair washing habits, local customs and
social contacts, healthcare in a particular area (e.g. school) and socioeconomic status were found to be
significant factors in head louse infestation. Girls are
2-4 times more frequently infested than boys. Children
between 4 and 13 years of age are the most frequently infested group.
In the U.S., African-American children have lower rates of infestation.
The United Kingdom's National Health Service and many
American health agencies  report that lice "prefer" clean hair because it's easier to attach eggs and to cling to
the strands; however, this is often contested.
Head lice (Pediculus humanus capitis) infestation is most frequent on children aged 3–10 and their
Females get head lice twice more often than males,
and infestation in persons of Afro-Caribbean or other black descent is rare because of hair
But these children may have nits that hatch and the live lice could be transferred by head contact to other
Because head louse infestation occurs primarily in children,
much of the effort to prevent head lice transmission has focused on school and day care settings—places where large
numbers of children come into close contact. Schools in the United States, Canada, and Australia commonly exclude infested students, and prevent
return of those students until all lice, eggs, and nits are removed.
This is the basis of the "no-nit policy". Data from a primarily American study during 1998-1999 found that
no-nit policies were present at 82% of the schools attended by children suspected of louse infestation.
A separate 1998 survey revealed that 60% of American school nurses felt that "forced absenteeism of any child
who has any nits in their hair is a good idea."
School head lice policy involves a number of issues:
- Establishing criteria to infer infestation
- Screening asymptomatic children for evidence of infestation
- Establishing the circumstances under which children will be inspected
- Immediate exclusion of infested children
- Establishing criteria to permit previously infested children to return to school (e.g., the no-nit
All of these policies are controversial. In particular, a number of health researchers and organizations object
to the required removal of nits (i.e., the no-nit policy).
Opponents to the no-nit policy point out that nits, being empty egg casings, have no clinical
Transmission can only occur via live lice or eggs. Time-consuming nit removal, therefore, has no direct effect
on transmission. This has led to the perception that the no-nit policy serves only to ease the workload of
school nurses and punish the parents of infested children.
Proponents of the no-nit policy counter that only a consistently nit-free child can be reliably shown to be
That is, the presence of nits serves as an indirect proxy for infestation status. Proponents argue that such a
proxy is necessary because lice screening is prone to false negative conclusions (i.e., failure to find lice
present on actively infested children).
For example, a 1998 Israeli study found that 76% of live lice infestations were missed by visual inspection
(as verified by subsequent combing methods).
Although lice cannot fly or jump, they are fast and agile in their native environment (i.e., clinging to hairs
near the warmth of the scalp),
and will try to avoid the light used during inspection.
Lice colonies are also sparse (often fewer than 10 lice), which can contribute to difficulty in finding live
Further, lice populations consist predominantly of immature nymphs,
which are even smaller and harder to detect than adult lice.
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