Enterobiasis or pinworm infection is a common, contagious, parasitic infestation found mainly in children. The disorder is spread by swallowing or inhaling the tiny eggs of the pinworm. Enterobiasis rarely causes any serious physical problems except for the main symptom, which is severe rectal itching.
The major symptom of enterobiasis is itching in the anal area. There may also be restlessness and difficulty sleeping. Secondary bacterial infections may develop in the areas that are constantly scratched and, very infrequently, the vagina may become involved in young girls. Very rarely, enterobiasis may lead to appendicitis or inflammation of the fallopian tubes in females.
Many children with enterobiasis show no symptoms (asymptomatic). In rare cases, nausea, loss of appetite, vomiting, involuntary discharge of urine at night (enuresis) or stomach pain may occur. The disorder is usually first identified when live, thin, white pinworms, (females are about 10 mm in length and males are 4-5 mm in length) are noticed in the feces.
Enterobiasis is contracted by ingesting the eggs of pinworms, which may be carried on fingernails, clothing, toys or bedding. The eggs may also be inhaled in dust. The infection may be transmitted to others by hand-to-mouth contact with contaminated food or objects.
The female worm, residing in the rectum, usually crawls out through the anus at night and deposits her eggs in the surrounding (perianal) area. The sticky, gelatinous substance in which the eggs are deposited and the movements of the female worm usually cause intense rectal itching. The adult female worm dies after laying the eggs. However, the eggs may survive for as long as three weeks. As the child scratches the area, the tiny eggs become imbedded under the fingernails. These eggs may be swallowed, continuing the parasites’ lifecycle. The parasites reach maturity in the large intestine within two to six weeks.
Enterobiasis is a common disorder affecting both sexes in equal numbers. It most frequently occurs in children during nursery school or kindergarten years. An entire classroom of children may be affected very quickly as the infection is spread from one child to the next.
In the United States, it is thought that about 10% of the general population is infested but that the number is declining.
Enterobiasis usually is self-limiting if good hygiene is followed. However, most individuals prefer some type of treatment, and the drug pyrantel pamoate is usually prescribed. One dose of pyrantel pamoate, repeated in two weeks, usually stops the infestation. Reinfestation is likely since eggs deposited as long as one week after therapy may survive, and eggs deposited before therapy may survive for up to three weeks. The entire family is usually treated. Petroleum jelly may be applied topically to relieve itching.
Treatment to prevent reinfection includes careful attention to personal hygiene, especially the washing of hands and fingernails, clothing and bed linens.
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FROM THE INTERNET
Fact Sheet: Pinworm Infection. CDC Division of Parasitic Diseases. Last reviewed August 15, 1999. 3pp.
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