HISTORY It’s the call that none of us expect, yet every parent dreads....The school nurse calls to tell you that she has found head lice on your child and that the child is to be sent home. The stereotypes surrounding head lice are humiliating and it is so much work to eradicate them from the home. It also brings up many questions. Where did these little things come from and why are they so hard to extinguish? If we take a look into their history, we may find some answers. It is evident from discoveries from the earliest of times that Pediculus capitis, or head lice, have withstood the test of time. Lice have always been commonplace and has not discriminated between the destitute and royalty. Interestingly enough, head lice have helped researchers learn about early man. It has been hypothesized that Columbus brought the louse to the Americas. But newer findings are pointing the finger at the Vikings as the guilty party. (Scribe, 2011) There are three known strains of head lice, types A, B and C. “Type A is found worldwide, type B in the Americas, Europe and Australia, and type C is rare, known only in Nepal and Ethiopia. Since type B is abundant in North and Central America — accounting for more than half the cases of lice that appear there — researchers had speculated type A originated from Europe and type B from the Americas.” (Choi, 2008) Realizing there were multiple strains of the critter, and then narrowing each strain down to specific regions, made unearthing other details of human history possible. Typhus, which is specific to type A head lice, was widespread in the Americas prior to Columbus’ finding of the New World. Mummies excavated in Peru and dated to 100 AD were found to have head lice in their long, braided locks. When DNA studies were conducted on the insects, the findings were to be those of the clade A strain. This was a significant discovery because there was finally scientific proof that this specific organism plagued the Americas almost 500 years prior to the arrival of Columbus. Because of the overwhelming abundance on living humans, it was previously believed that it was the type B strain that had been in the Americas since the New World was populated with people upon Columbus’ discovery. “This definitely goes against the grain of conventional thought that all diseases were transmitted from the Old World to the New World at the time of Columbus.” (Choi, 2008) This finding has also led to speculation that typhus is a New World disease where it was previously thought to have originated in the Old World. Now that Columbus has been proven innocent of introducing head lice to the Americas, scientists are looking to prove that the Vikings may have been the responsible party during the Middle Ages. Several other possibilities of how the Americas were originally occupied by the Native American Indians are being researched using head lice to tell the story. The louse cannot live more than a few hours separate from its host, therefore their histories must be very similar. Although we have learned that head lice have had humans itching for several millennia, there is not evidence of treatment prior to the 1800’s. A nit comb made from bone was found and dated to the frontier days. It is housed at the Wisconsin Historical Museum and was discovered in early 1930’s Fort Crawford. “It has long been known that Fort Crawford was not the healthiest of environments, but served as an enclosed parasite heaven for diseases not limited to lice, but typhus, dysentery, malaria, and cholera. The close quarters of the Fort provided more than adequate modes of transmission, providing a more than hospitable habitat for lice to thrive.” (HelloLife, 2010)
BIOLOGY
Head lice are specific to humans. They feed from human blood and cannot survive long if separated from its host. Pediculus humanus capitis, also known as the head louse, is of the order Psocodea. (Prevention, 2010) It is an ectoparasite is an insect which lives on the skin, but does not enter the body of its host. The creature feeds several times daily on the host’s blood and remains close to the scalp so as to maintain its body temperature.
Head lice have three stages of life which are egg, nymph, and adult. The eggs are called nits. They are hard to see and when laid by the adult female, are bonded, close to the scalp hair shaft. The nits vary in color from yellow, to brown or white. Eggs are under a millimeter in length and mature in six to ten days. Viable nits are usually located closes to the scalp (within six millimeters of the scalp).
The egg hatches and releases a nymph. The casting becomes more visible and is often mistaken for hairspray or dandruff flakes. The nymph is very small and barely visible. The nymph will molt three times over approximately a week. The result of the third molting is an adult louse.
The adult head louse can be compared to a sesame seed in size. They have six legs each with a claw at the end which is used to grasp the hair follicles. They vary in color from tan to grayish or white. They have the ability to camouflage themselves for darker haired hosts. Females can lay up to eight nits per day and are usually bigger than males. Adults live roughly thirty days and feed on human blood several times each day. If they are unable to feed on a host, they will die within one or two days. They cannot feed on any species other than a human host. (Prevention, 2010)

EPIDEMIOLOGY AND RISK FACTORS In the United States, the most common affected groups are pre-school and elementary school children. As a result, members of their households and their care providers are also commonly affected. Head lice are not known to transmit disease; however, infections following scratching are a risk. The contraction of head lice is not relevant to socioeconomic class not is it related to cleanliness. The most likely mode of transmission is through direct contact. “The most common way to get head lice is by head-to-head contact with a person who already has head lice. Such contact can be common among children during play at school, home, and elsewhere (e.g., sports activities, playgrounds, camp, and slumber parties).” (Prevention, 2010) Other possible, although less likely ways to contract head lice is through sharing clothing or hair products worn or used by infested individuals. Lying on bedding, furniture or flooring or playing with stuffed animals which were in recent contact with an infested person are also risk factors. Girls are estimated to be more at risk than boys for head lice because of their fondness for playing with each other’s hair. Approximately six to twelve million people will become infested each year in the United States among children 3 to 11 years of age. Head lice found in the United States prefer hair strands that are round. They have claws which are especially adapted for round hairs. Hairs that are ovoid at the cross-section, such as that of African Americans are not as inviting. Head lice is prevalent in Africa, however, it is a different type of head lice which is dominant in that area of the world. That specific type is claw adapted for ovoid hairs. Although the type of head lice found in the U.S. do not prefer the ovoid hairs, does not mean that they will not infest such heads, but they are much less susceptible. (Rust, 2001)
SYMPTOMS AND DIAGNOSIS The most common symptom of head lice is itching. When insects bite, it causes an irritation in the skin which makes it itch. Itching especially at the nape of the neck and near the ears is an indicator that lice may be present.
It is not uncommon for an infestation to go unnoticed. It is difficult to see head lice as they are small and move quickly to avoid light. It may be helpful to use a magnifying glass in a well-lit area while looking for lice. When looking, look at the back of the neck and by the ears. If itching is persistent and no crawling insects are found, look on the hair follicles close to the scalp to see if any nits are visible.
If no nymphs or crawling adults are found and the only nits are further away from the scalp, it may be safe to assume that the infestation is old and inactive. However, if itching persists, it may be wise to continue onto treatment.

TREATMENT AND PREVENTION All infested persons, household members and their close contacts should be treated at the same time. It is recommended to treat a second time approximately nine days later since most medications do not affect the nits. Clothing and bedding worn or used while infested should be washed with hot water and dried for a minimum of five minutes at 128.3°F. It is suggested that furniture and floors should be vacuumed to remove any infested hairs. Hats, clothing, or grooming products should not be shared with an infested person. To treat the infested person an over-the-counter medication such as Nix may be used. Follow the instructions on the packaging carefully. If the person has hair longer than shoulder length, it may require additional medication. It is important not to use any form of conditioner in the hair prior to using pediculicides. Clean clothes need to be donned and hair is not to be washed for a day or two following treatment. Using a fine-toothed nit comb, remove nits and lice from the hair. After 8-12 hours of treatment, observe the head. If live head lice are found and they appear to be active, consult a physician for a stronger pediculicide. To prevent head lice, clothing and personal grooming items should not be shared. Children should be taught not to play with each other’s hair or to share grooming items. If one has been in contact with a person known to be infested, then measures should be taken immediately to prevent infestation.

Works Cited

Choi, C. Q. (2008, February 12). Lice Shed Light on Ancient History of Americas. Retrieved March 4, 2012, from Live Science: http://www.livescience.com/2291-lice-shed-light-ancient-history-americas.html

HelloLife. (2010, February 13). History of Head Lice Treatment. Retrieved March 21, 2012, from Hellolife.net: http://www.hellolife.net/head-lice/b/history-of-head-lice-treatment/

Prevention, C. f. (2010, November 2). Parasites - Lice - Head Lice. Retrieved March 28, 2012, from Centers for Disease Control and Prevention: http://www.cdc.gov/parasites/lice/head/biology.html

Rust, M. K. (2001, August). Pests of Homes, Structures, People, and Pets : Head Lice. Retrieved March 28, 2012, from UC IPM Online: http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7446.html

Scribe, T. (2011, May 11). Lice and Humans - An Ancient (and Itchy) History. Retrieved March 12, 2012, from The Ancient Standard: http://ancientstandard.com/2011/05/11/lice-and-humans-an-ancient-and-itchy-history/