- Diseases, Disorders & Conditions
The Clinical Manifestations And Health Implications Of Enterobiasis And Cestodiasis In General
Enterobiasis Is Caused by Enterobis vermicularis
Enterobiasis (Oxyuriasis)- Thread Worm, Pinworm, Seatworm
Enterobiasis is caused by Enterobis vermicularis (also known as Oxyuris vermicularis), the adults of which inhabit the large intestine, especially the caecum, rectum and anal canal. The infection occurs worldwide and is seen more in children.
The female is 8 to 13 mm long and has the thickness of a thread. The male is 2 to 5 mm long. The egg which contains a well-formed larva when passed, is plano-convex, 20 X 50u in size, and is infective when laid.
Life cycle: The gravid female comes out of the anus to lay eggs in the perianal and perineal skin, usually during sleep. Intense itching results in scratching and the ova contaminate fingers of the host. These are swallowed accidentally by the same host or may be spread to others. The ova hatch in the intestine and the larvase migrate to the colon to mature. Lifespan is 4 to 6 weeks. This infection can perpetuate itself in the same host for considerable periods.
Enterobis vermicularis In The Small Intestine
Clinical Presentations Of Enterobiasis
The patient may complain of passing pinworms in stools. Symptoms are produced by the adult female which migrates to lay eggs. It results in perianal pruritus and excoriation due to scratching. In females, severe pruritus vulvae and mild vulvitis may develop. Children may suffer from nocturnal enuresis, insomnia and allergic manifestations.
Diagnosis: The condition can be diagnosed by observing the worms in the perianal region while the child is asleep or on the surface of the feces. Ova can be demonstrated by examining a scotch-tape swab prepared from the perianal skin. A cellophane tape is applied to the uncleaned parianal region in the morning, with the sticky side up, to collect the ova. After removal it is placed on a clean glass slide, sticky side down with a drop of toluene over the slide, and examined under the low power of the microscope to detect the eggs. In heavy infections, material collected by digital examination of the rectum shows the ova.
Course: The infection is self limiting if auto-infection is prevented, otherwise it persists for long periods due to re-infection. Members of the same household get cross-infection and therefore the parasite can be eradicated from the household only if all affected persons are treated simultaneously.
Treatment: Piperazine citrate given orally as tablets or syrup in a daily dose of 50 mg/Kg body weight for seven days clears the infection. Single dose treatment with either mebendazole 200mg orally or pyrantel pamoate 10 mg/Kg is also effective.
Morphology Of The Tapeworm
General Considerations In Cestodiasis (tapeworm Infection)
Cestodes or tapeworms are segmented flat ribbon-like hermaphrodite worms that inhabit the small intestines of men or animals. The head (Scolex) is at the anterior end and the body (strobila) is made up of segments. The head is small in size and it is provided with suckers which help the worm to attach to the intestinal mucosa. The scolex contains hooklets in some species. The body consists of a short neck and a chain of successive segments (proglottides). Every proglottide is a complete hermaphrodite unit. The proglottides are formed near the head as the worm grows. The segments near the head are immature, the intermediate ones are mature with fully developed gonads and the distal ones are gravid, filled by the uterus containing numerous eggs. Cross-fertilization occurs between adjacent segments.
Tapeworms have no body cavity or digestive tract. Nutrients are absorbed by the surface. They require 2 or 3 hosts for completion of their lifecycle. More than 30 species have been found to affect man but only six of them are common. These are Taenia solium, T. saginata, T. echinococcus, Diphyllobothrium latum, Hymenolepis nana and H. diminutum.
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