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Head lice infestation (also known as pediculosis capitis, nits, or cooties〔(【引用サイトリンク】url=http://dictionary.reference.com/browse/cootie )〕) is the infection of the head hair and scalp by the head louse (''Pediculus humanus capitis'').〔 Itching from lice bites is common.〔 During a person's first infection, the itch may not develop for up to six weeks.〔 If a person is infected again, symptoms may begin much more quickly.〔 The itch may cause problems with sleeping.〔 Generally, however, it is not a serious condition.〔 While head lice appear to spread some other diseases in Africa, they do not appear to do so in Europe or North America.〔 Head lice are spread by direct contact with the hair of someone who is infected.〔 The cause of head lice infestations are not related to cleanliness.〔 Other animals, such as cats and dogs, do not play a role in transmission.〔 Head lice feed only on human blood and are only able to survive on human head hair.〔 When adults, they are about 2 to 3 mm long. When not attached to a human, they are unable to live beyond three days.〔 Humans can also become infected with two other lice – the body louse and the crab louse. To make the diagnosis, live lice must be found.〔 Using a comb can help with detection.〔 Empty eggshells (known as nits) are not sufficient for the diagnosis.〔 Possible treatments include: combing the hair frequently with a fine tooth comb or shaving the head completely. A number of topical medications are also effective, including malathion, ivermectin, and dimeticone.〔 Dimeticone, which is a silicone oil, is often preferred due to the low risk of side effects.〔 Pyrethroids such as permethrin have been commonly used; however, have become less effective due to increasing resistance. There is little evidence for alternative medicines. Head-lice infestations are common, especially in children. In Europe, they infect between 1 and 20% of different groups of people.〔 In the United States, between 6 to 12 million children are infected a year.〔 They occur more often in girls than boys.〔 It has been suggested that historically, head lice infection were beneficial, as they protected against the more dangerous body louse. Infestations may cause stigmatization of the infected individual.〔 ==Signs and symptoms== Head lice are generally uncomfortable, but typically do not constitute a serious condition.〔 The most common symptom is itching of the head, which normally worsens 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. Swelling of the local lymph nodes and fever are rare. Itching may cause skin breakdown and uncommonly result in a bacteria infection.〔 In Ethiopia, head lice appear to be able to spread louse-born epidemic typhus and ''Bartonella quintana''.〔 In Europe, the head lice do not appear to carry these infections.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Head lice infestation」の詳細全文を読む スポンサード リンク
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