The unembryonated eggs are passed with the stool . In the soil, the eggs develop into a 2-cell stage , an advanced cleavage stage, and then they embryonate ; eggs become infective in 15 to 30 days. After ingestion (soil-contaminated hands or food), the eggs hatch in the small intestine, and release larvae that mature and establish themselves as adults in the colon . The adult worms (approximately 4 cm in length) live in the cecum and ascending colon. The adult worms are fixed in that location, with the anterior portions threaded into the mucosa. The females begin to oviposit 60 to 70 days after infection. Female worms in the cecum shed between 3,000 and 20,000 eggs per day. The life span of the adults is about 1 year.
Known as the whipworm is also a soil- transmitted helminth. Ascaris and Trichuris are frequently observed as occuring together. Trichuris is also notable for its small size compared with Ascaris lumbricoides. A holomyarian, based on the arrangement of somatic muscles in cross section where cells are small, numerous and closely packed in a narrow zone.
The male worm measures 30 to 45 mm, slightly shorter than the female. The female worm is about 35 to 50 mm long. The female has a bluntly rounded posterior end. The male has a coiled posterior with a single spicule and retractile sheath.
Both worms have an attenuated anterior three-fifths traversed by a narrow esophagus resembling a string of beads. And the robust posterior two-fifths contain the intestine and a single set of reproductive organs.
The femaleworm is about35 to 50 mm The male worm measures 30 to 45 mm
Posterior part of male Trichuris trichuriaPosterior part offemale Trichuristrichuria
A female lays approximately 3000 to 10000 eggs per day. The eggs approximately measures about 50 to 54 um. It is lemon shaped with plug like translucent polar prominence. Fertilized eggs are unsegmented at oviposition and embryonic development takes place outside the host. Compared to Ascaris eggs, Trichuris eggs in soil are more susceptible to desiccation.
Eggs Eggs are lemon shaped with plug-like translucent polar prominences. 50~54um
Trichuris worm inhabit the large intestine. After copulation, the female worm lays eggs, which are passed out with feces and deposited in the soil. Under favorable conditions, the eggs develop and become embryonated within two to three weeks. If swallowed, the infective embryonated eggs go to small intestine and undergo four larval stages to become adult worm. Unlike Ascaris, there is no heart lung migration.
The anterior portion of the worm, which is embedded in the mucosa, cause petechial hemorrhages, which may predispose to amebic dysentery. The mucosa is hyperemic and edematous; enterorrhagia is common and there may even be rectal prolapse. The lumen may be filled with worms, and irritation and inflammation may lead to appendicitis or granulomas.
Infection with over 5,000 T. trichuria eggs per gram of feces are usually symptomatic. Those with more than 20,000 eggs per gram feces often develop severe diarrhea or dysenteric syndrome. Light infections, usually asymptomatic, and the presence of the parasite is discovered in stool examination. In heavily parasitized individuals, the worm may be found throughout the colon and rectum.
Heavy chronic trichuriasis are often marked by: Frequent blood-streaked diarrheal stools Abdominal pain and tenderness Nausea Vomiting Anemia Weight loss
Clinical diagnosis is possible only in heavy chronic Trichuris infection. In light infection, where symptoms are absent, laboratory diagnosis is essential.
Direct fecal smear (DFS) with a drop of saline. Kato thick smear method – highly recommended in diagnosis of trichuriases Kato-Katz technique – used for egg counting to determine cure rate (CR), egg reduction rate (ERR), and intensity of infection. Acid-ether Formalin-ether method Kato-cellophane – as well as Kato-Katz are simpler and low-cost.
Mebendazole – drug of choice for Trichuris. Albendazole – may be used as an alternative drug. Ivermectin in combination with albendazole – exhibit better cure and egg reduction rate than albendazole alone.
Egg reduction rate (ERR), cure rates (CR), re-infection rate and egg count should be determined pre and post- treatment. Contraindication for albendazole is pregnancy. Contraindication for mebendazole are hypersensitivity and early pregnancy.
Trichuris occurs in both temperate and tropical countries, but is more widely distributed in warm, moist areas of t ranges he world. Prevalence in temperate countries ranges from 20 to 30%. In tropical countries, it ranges from 60 to 85%. In the Philippines, the prevalence is from 80 to 84%.
In school surveys conducted in 2001, T. trichuria has been found to have higher infection rates than A. lumbricoides. Factors affecting transmission are the same as that of Ascariasis namely: Indiscriminate defecation of children around yards Frequent contact between fingers and soil among children at play Poor health education Poor personal and community hygiene Unhygienic behavior and eating habits.
Mass treatment may be indicated id infection rates are higher than 50% Infection in highly endemic areas may be prevented by: Treatment of infected individuals Sanitary disposal of human feces by construction of toilets Washing of hands with soap and water before meal Health education on sanitation and personal hygiene Washing and scalding of uncooked vegetables especially if night soils is used as fertilizers
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