USAID's NTD Program
Whipworm (Trichuris trichiura or Trichocephalus trichiuris)
- Overview
- Epidemiology
- Distribution of Whipworm
- Life Cycle of T. trichiura
- Symptoms
- Diagnosis
- Treatment, Prevention, and Control
Overview
Whipworm (Trichuris trichiura [T. trichiura] or Trichocephalus trichiuris) is the third most common roundworm found in humans. The name "whipworm" refers to the shape of the worm; the worms look like whips with wider "handles" at the posterior end. Globally, nearly 800 million people are infected with whipworms, which are highly prevalent in children. Heavy infections could lead to short-term symptoms such as diarrhea and anemia and longer-term symptoms such as growth retardation and impaired cognitive development. Coinfection of whipworm with giardia, Entamoeba histolytica, Ascaris lumbricoides, and hookworm is common.
Epidemiology
Whipworm infection, known as trichuriasis, is prevalent in both temperate and tropical zones of the world. However, infections follow a clustered distribution and are more frequently found in areas with tropical weather and poor sanitation practices. Whipworm infection occurs through ingestion of whipworm eggs, which can be found in fecally contaminated dry goods, such as beans, rice, and various grains, and in crops grown in soil fertilized with sewage. Humans are infected when such produce is consumed raw or food is contaminated by handlers.
Distribution of Whipworm
| Estimated Number of Whipworm Infections (in millions) by Age Group, 2003 | |||||
|---|---|---|---|---|---|
| WHO Region | 0-4 Years |
5-9 Years |
10-14 Years |
≥15 Years |
Total |
| African | 26 | 27 | 23 | 66 | 162 |
| Americas | 10 | 12 | 12 | 86 | 100 |
| E. Mediterranean | 1 | 1 | 1 | 4 | 7 |
| South-East Asia | 18 | 20 | 19 | 90 | 147 |
| Western Pacific | 30 | 38 | 41 | 268 | 379 |
| Total | 85 | 98 | 96 | 514 | 795 |
Source: World Health Organization
Life Cycle of T. trichiura
 | |
| Source: CDC |
Step 1: Whipworm eggs are passed in the stool of an infected person.
Steps 2–4: In the soil, the eggs develop into a two-cell stage, an advanced cleavage stage and then develop into embryos. Eggs become infective in 15 to 30 days.
Step 5: Once consumed, the eggs hatch in the small intestine and move into its wall, where the larvae develop. When they reach adulthood, the thinner end burrows into the large intestine and the thicker end hangs into the lumen, where it mates with nearby worms. The females begin to lay their eggs 60 to 70 days after infection and shed between 3,000 and 20,000 eggs per day. Adults can live about 1 to 3 years, and females can grow to 50 mm (2 inches) long.
Symptoms
Trichuriasis symptoms range from asymptomatic through vague digestive tract distress for light infestations to emaciation with dry skin and diarrhea (usually mucoid and/or bloody) for heavy infestations. In children, heavy infections can lead to growth retardation. Longstanding bloody diarrhea leads to iron-deficiency anemia in many individuals. Severe cases can cause rectal prolapse. However, finger clubbing (swelling of the nails and area around the nails) is the best clinical predictor of the intensity of infection.
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| Adult whipworm Source: VCD Kampala/Uganda |
Diagnosis
Whipworm infestation is usually diagnosed by microscopic examination of stool samples to detect eggs. The Kato-Katz is the technique of choice for diagnosis and quantification of infection with T. trichiura. Adult worms may be seen in a prolapsed rectal mucosa.
Treatment, Prevention, and Control
Mebendazole and albendazole are currently the drugs of choice to treat adult whipworms. In the case of light infection, successful treatment can be achieved with a single dose of 300 mg to 500 mg of mebendazole or with a single dose of 400 mg of albendazole. For heavy whipworm infection, 200 mg of mebendazole a day for 3 successive days or albendazole at 400 mg a day for 3 successive days is recommended. In the presence of iron deficiency, comprehensive treatment should be undertaken to solve the deficiency.
Prevention and control measures for trichuriasis are similar to most of the other soil-transmitted helminthes and include:
- Availability of water for use for personal hygiene
- Sanitation and education to promote use of latrines
- Education on hand washing and washing of food
- Avoiding the use of uncomposted human feces as fertilizer
- Mass drug administration: Modern anthelminthics, such as mebendazole and albendazole, administered in a single dose are safe, relatively inexpensive, and effective for several months. The association of albendazole to ivermectine and to diethylcarbamazine in community-wide drug distribution to eliminate lymphatic filariasis in many areas also will reduce the number of eggs released in the environment and, consequently, decrease the intensity and prevalence of T. trichiura infection.
References
- Bundy D.A.P., Cooper E.S. Trichuris and trichuriasis in humans. Adv Parasitol. 28:107, 1989.
- Cooper E.S., Bundy D.A.P., MacDonald T.T., et al. Growth suppression in the Trichuris dysentery syndrome. Eur J Clin Nutr. 44:138, 1990.
- Cooper E.S., Whyte-Alleng C.A.M., Finzi-Smith J.S., et al. Intestinal nematode infections in children: The pathophysiological price paid. Parasitology. 104(suppl):S91, 1992.
- Grencis R.K., Cooper E.S. Enterobius, trichuris, capillaria, and hookworm including ancylostoma caninum. Gastroenterol Clin North Am. 25:579-97, 1996.
- World Health Organization. First WHO report on neglected tropical diseases 2010: Working to overcome the global impact of neglected tropical diseases. World Health Organization, 2010.
- World Health Organization. Prevention and control of schistosomiasis and soil transmitted helminthiasis. Report of a WHO expert committee, WHO Technical Report Series 912. World Health Organization, 2002.
- World Health Organization. Preventive Chemotherapy in Human Helminthiasis – October 2006 [PDF, 1.6MB].
- World Health Organization. Report of the WHO informal consultation on the use of praziquantel during pregnancy/lactation and albendazole/mebendazole in children under 24 months. World Health Organization, 2003.