Trichuris trichiura
المؤلف:
Patricia M. Tille, PhD, MLS(ASCP)
المصدر:
Bailey & Scotts Diagnostic Microbiology
الجزء والصفحة:
13th Edition , p662-663
2025-10-26
51
GENERAL CHARACTERISTICS
Trichuris trichiura, whipworm, has a worldwide distribution. Unlike other intestinal nematodes discussed in this chapter, there is no tissue migration phase within the life cycle of T. trichiura.
EPIDEMIOLOGY
Trichuris trichiura is typically found in moist, warm cli mates around the world. Infections are relatively common in Asia, Africa, and South America, with some cases identified in the southeastern United States. Often the nematode is identified in co-infections along with A. lumbricoides.
Poor hygiene is associated with increased transmission, especially in children. Humans are infected by ingestion of the eggs. Larvae are released in the intestine where they mature into adult worms. Eggs are then passed in the feces and deposited in the soil. The eggs require a warm, moist environment for embryonation in order to become infective to another host.
PATHOGENESIS AND SPECTRUM OF DISEASE
Pathogenesis and severity of the disease are closely related to the worm burden. The lack of symptoms is related to the life cycle that does not include a tissue migration stage, as is seen in other nematode infections. Infections range from mild, very low worm burden, to severe infections with bleeding and weight loss in heavy worm infestations. The characteristic whiplike worm buries its threadlike anterior into the intestinal mucosa and feeds on tissue secretions, causing an inflammatory reaction and peripheral eosinophilia. See Table 1 for a summarized detail of associated diseases.
Table1. Pathogenesis and Spectrum of Associated Diseases
Table1. Pathogenesis and Spectrum of Disease—cont’d
LABORATORY DIAGNOSIS
Diagnosis is typically from the identification of eggs and rarely the adult worm within the feces. An adult female may produce up to 20,000 eggs per day. However, during the lengthy development of mature worms within the intestine, there may be no shedding of eggs for up to 3 months. Eggs appear as brown barrel-shaped structures. They are unembryonated and contain a thick wall with hyaline polar plugs at each end (Figure 1). The adult female worm ranges in size from 35 to 50 mm and demonstrates a gradually increasing width from anterior to posterior, with a straight end (Figure 2). The adult male ranges in size from 30 to 45 mm and demonstrates the same broadening morphology with a coiled posterior end.
Fig1. Trichuris trichiura egg. Note the clearly evident polar hyaline plugs. (Courtesy Dr. Henry Travers, Sioux Falls, S.D.)
Fig2. Adult female Trichuris trichiura. (Courtesy Dr. Henry Travers, Sioux Falls, S.D.)
THERAPY
Therapy may or may not be indicated, dependent on the nutritional status of the host, the length of infection, and the level of worm burden. Anthelmintics such as albendazole are recommended when necessary.
PREVENTION
Prevention includes practicing proper hygiene and sanitation as well as the disposal of dirt or soil contaminated with feces.
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