| disease | Trichuriasis |
| alias | Trichuriasis |
Trichuriasis is one of the common intestinal parasitic diseases, often coexisting with the distribution of roundworms but more prevalent in warm and humid climates. The World Health Organization has estimated that the global number of whipworm infections ranges between 500 to 1,000 million. In China, whipworm infections are more common in the south than in the north, with infection rates in Taiwan reaching as high as 60–90%. Children have higher infection rates than adults. The adult worms primarily reside in the human cecum. Mild cases often present with no symptoms, while severe cases may manifest with abdominal pain, diarrhea, hematochezia, rectal prolapse, anemia, and cutaneous pruritus.
bubble_chart Pathogen
The adult worm has a morphology that is thin at the front and thick at the back, resembling a horsewhip in shape. The male worm measures 30–45 mm in length, with a distinctly enlarged posterior section that is mostly coiled and has a copulatory spicule at the end. This copulatory spicule is concealed within a retractable spicule sheath, the tip of which is bulb-shaped and surrounded by numerous small spines. The female worm measures 35–50 mm in length, with a bluntly rounded posterior end. The genital opening is located at the anterior end of the thickened portion of the body and is also surrounded by many small spines. The digestive system consists of a mouth and a slender pharyngeal tube, which is surrounded externally by a bacillary band. The bacillary band is composed of a single row of bacillary cells. Bacillary cells are active secretory cells, each with an opening into the lumen of the pharyngeal tube, suggesting the presence of an intracellular transport system that moves substances into the pharyngeal lumen. Although the exact function of the bacillary band is not fully understood, some researchers have found that bacillary cells exhibit protease and esterase activity, capable of secreting enzymes that digest host cells. In fact, the bacillary band itself constitutes a group of pharyngeal glands in the whipworm. The pharyngeal tube connects to the intestine, and the anus is located at the posterior end of the worm.
The eggs are spindle-shaped, measuring (50–54) × (22–23) μm, with a transparent nodule at each end of the longitudinal axis. The eggshell is thick, composed of a lipid layer and a chitinous layer. The outer protein membrane is stained brownish-yellow by bile pigments, while the inner layer is transparent and forms the true shell. The egg contains a granular ovum. At the time of excretion from the human body, the cells inside the eggshell have not yet divided. A female worm lays approximately 1,000–7,000 eggs per day. The eggs are excreted in the patient's feces and, under suitable environmental conditions of temperature and humidity, develop into infective-stage eggs within 3–5 weeks. When humans ingest food or water contaminated with these eggs, the infective-stage eggs hatch into larvae in the small intestine. The larvae then migrate to the large intestine, where they develop into adult worms. Adult worms typically reside in the cecum and appendix, though they may occasionally inhabit other parts of the large intestine. The head of the worm can burrow into the mucosal surface or submucosal layer, absorbing nutrients from the intestinal mucosa, while the thickened posterior portion often remains free in the intestinal lumen. The time from ingestion of infective-stage eggs to egg-laying by adult worms is 1–3 months. Adult worms can survive in the human body for up to about 5 years.bubble_chart Pathological Changes
The adult worm inserts its slender anterior segment into the intestinal mucosa or even the submucosal layer, absorbing nutrients from tissues and blood. Due to the stimulation of secretions, the intestinal mucosal tissue exhibits grade I inflammation or punctate hemorrhage, and epithelial cell degeneration and necrosis can also be observed. In a few patients, intestinal wall inflammation, cell proliferation, and thickening of the intestinal wall lead to the formation of granulomas. Some scholars used 51Cr to observe and found that each whipworm causes the host to lose approximately 0.005 ml of blood per day. Therefore, most patients do not develop symptoms of anemia. In cases of grade III infection (i.e., when the number of Chinese Taxillus Herb worms exceeds 800), chronic blood loss caused by whipworms can lead to iron-deficiency anemia. Additionally, immunological studies indicate that the human body can develop a certain level of immunity after whipworm infection. Animal experiments suggest that the bacillary band of the whipworm is the primary source of functional antigens.
Mild, grade II infections are common clinically but usually show no significant symptoms. Occasionally, there may be right lower abdominal pain, nausea, vomiting, and low-grade fever. Grade III infections are more common in children and present with the following manifestations: ① Gastrointestinal: varying degrees of colon congestion, edema, diffuse bleeding spots, and ulcer formation. Patients exhibit diarrhea, bloody and purulent stools, tenesmus, and rectal prolapse. Some patients show symptoms of chronic appendicitis. ② Hematological: blood tests reveal increased eosinophils and iron-deficiency anemia. Severe anemia can lead to cardiac enlargement. ③ Neurological: frequent dizziness and lightheadedness. Rarely, symptoms of meningitis may occur. Abdominal palpation often reveals significant tenderness in the right lower abdomen.
The detection of whipworm eggs in feces is the basis for diagnosis. Examination methods include: direct saline smear method; saturated saline flotation method; water sedimentation method. To determine the degree of infection, the quantitative plate-glycerol glass counting method (modified Kato-Katz technique) can be used. During sigmoidoscopy or fiberoptic colonoscopy, the worms can be seen attached to the intestinal mucosa, with mucus visible around the worms. The mucosa shows grade I congestion and is prone to bleeding. Colonoscopy can also serve as a means of differential diagnosis to rule out other intestinal diseases. X-ray barium enema examination, using the double-contrast barium-air technique, can reveal the translucent outline of the worms coated with barium.
(1) Mebendazole: 100mg, twice daily for three to four days as a course of treatment, with an egg-negative conversion rate of 73.7% to 96.4% and few side effects.
(2) Albendazole: The main component is albendazole. The oral dose for children over two years old and adults is 400mg, administered at draught. The egg-negative conversion rate is 71.7%. This medication has few side effects, occasionally causing headache or gastrointestinal discomfort, which usually resolves on its own within 48 hours. It is not suitable for children under one year old or pregnant women.
(3) Chinese medicinals treatment: Areca Seed decoction. Take 80–100g of Areca Seed, add 500ml of water, soak for 12 hours, then decoct until reduced to 100–200ml. The night before taking the medication, administer 20–30g of magnesium sulfate. The next morning, take the Areca Seed decoction in divided doses. If no bowel movement occurs within 3 hours after taking the medication, administer magnesium sulfate once more.
(4) Oxygen therapy for deworming: Two hours after breakfast, slowly (over 30 minutes) inject 500ml of oxygen via the rectum. After 45 minutes, administer magnesium sulfate orally once. On the second and third days, inject 750ml and 1000ml of oxygen, respectively, following the same method. After oxygen injection, gently massage the patient’s lower right abdomen and have the patient lie supine for an hour. This therapy has no side effects.
Promote harmless treatment measures for feces, strengthen fecal management, pay attention to environmental hygiene, personal hygiene, and protect water sources.
It is important to differentiate and distinguish from ascariasis, hookworm disease, and amoebic dysentery. Although the whipworm of pigs and humans are indistinguishable in appearance, they can be differentiated by the different number of chromosomes in their somatic cells.
