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A pinworm infection or enterobiasis is a human parasitic disease and one of the most common parasitic worm infections (also called helminthiasis) in the developed world.〔Cook et al. 2009, p. 1515〕〔Encyclopædia Britannica.〕 It is caused by infestation of the parasitic roundworm ''Enterobius vermicularis'', commonly called the human ''pinworm''.〔WHO: ICD 2007〕 Infection usually occurs through the ingestion of pinworm eggs, either through contaminated hands, food, or less commonly, water.〔 The chief symptom is itching in the anal area.〔 The incubation time from ingestion of eggs to the first appearance of new eggs around the anus is 4 to 6 weeks.〔 Pinworms are usually considered a nuisance rather than a serious disease.〔 For this reason, enterobiasis is not classified as a neglected tropical disease unlike many other parasitic worm infections. Treatment is straightforward in uncomplicated cases; however, elimination of the parasite from a family group or institution often poses significant problems—either due to an incomplete cure or reinfection.〔 == Signs and symptoms == One third of individuals with pinworm infection are totally asymptomatic.〔 The main symptoms are pruritus ani and perineal pruritus, i.e., itching in and around the anus and around the perineum.〔Burkhart & burkhart 2005, p. 838〕〔Cook et al. 2009, p. 1516〕〔 The itching occurs mainly during the night,〔〔Caldwell 1982, p. 307.〕 and is caused by the female pinworms migrating to lay eggs around the anus.〔〔 Both the migrating females and the clumps of eggs are irritating, but the mechanisms causing the intense pruritus have not been explained.〔 The intensity of the itching varies, and it can be described as tickling, crawling sensations, or even acute pain.〔Cook 1994, p. 1160〕 The itching leads to continuously scratching the area around the anus, which can further result in tearing of the skin and complications such as secondary bacterial infections, including bacterial dermatitis (i.e., skin inflammation) and folliculitis (i.e., hair follicle inflammation).〔〔Gutiérrez 2005, p. 355.〕〔 General symptoms are insomnia (i.e., persistent difficulties to sleep) and restlessness.〔 A considerable proportion of children suffer from loss of appetite, weight loss, irritability, emotional instability, and enuresis (i.e., inability to control urination).〔 Pinworms cannot damage the skin,〔Gutiérrez 2005, p. 356.〕 and they do not normally migrate through tissues.〔 However, in women they may move onto the vulva and into the vagina, from there moving to external orifice of the uterus, and onwards to the uterine cavity, fallopian tubes, ovaries, and peritoneal cavity.〔 This can cause vulvovaginitis, i.e. an inflammation of the vulva and vagina.〔〔 This causes vaginal discharge and pruritus vulvae, i.e., itchiness of the vulva.〔 The pinworms can also enter the urethra, and presumably, they carry intestinal bacteria with them.〔 According to Gutierrez (2000), a statistically significant correlation between pinworm infection and urinary tract infections has been shown,〔 however Burkhart & Burkhart (2005) maintain that the incidence of pinworms as a cause of urinary tract infections remains unknown.〔 Incidentally, one report indicated that 36% of young girls with urinary tract infection also had pinworms.〔 Dysuria (i.e., painful urination) has been associated with pinworm infection.〔 The relationship between pinworm infestation and appendicitis has been researched, but there is a lack of clear consensus in the matter: while Gutierres (2005) maintains that there exists a consensus that pinworms do not produce the inflammatory reaction,〔 Cook (1994) states that it is controversial whether pinworms are causatively related to acute appendicitis,〔 and Burkhart & Burkhart (2004) state that pinworm infection causes symptoms of appendicitis to surface.〔 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「Enterobiasis」の詳細全文を読む スポンサード リンク
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