Whipworm, or trichuriasis, is caused by an infestation of the helminth (parasitic worm) Trichuris trichiura. This roundworm infects human hosts and reproduces within the large intestine. Transmission of this parasite occurs when infective eggs are passed via the feces and contaminate food and soil. Humans ingest contaminated food or soil to become infected. Light infestations often cause no symptoms, or mild symptoms, while heavy infestations can cause more serious complications including anemia, rectal prolapse, appendicitis, and colitis.
Treatment for whipworm involves anti-parasitic medication containing either mebendazole or albendazole. In addition, treatment may be necessary for accompanying symptoms. Whipworm is a worldwide infection that is prevalent in tropical, densely populated countries, especially in regions with poor sanitation methods. Both adults and children can become infected, although children tend to have a higher infection rate. Whipworm can be prevented by avoiding consumption of contaminated foods, maintaining high sanitation practices, and washing hands after working or playing in soil.
Whipworm infection is a parasitic infection caused by ingestion of the whipworm, or roundworm, Trichuris trichiura. The life cycle of T. trichiura involves a human host for the maturation of worms and the production of eggs. Humans become infested after ingesting food or soil contaminated with embryonated (containing an embryo) whipworm eggs. The eggs hatch and mature in the small intestine before migrating to the large intestine. Here, the worms attach to the intestine walls, reach about 4 inches in length, and become sexually mature. The worms mate and two to three months after entering the body, females produce up to 20,000 eggs a day. These eggs pass out of the body with the feces and remain in moist, dark conditions until they are ingested by a new host. Without extremes in temperatures, the eggs can remain viable in soil for years.
In cases where infestation is low, that is, fewer than 100 worms, people usually suffer no symptoms, but some may experience flatulence, abdominal pain, constipation, or diarrhea. If heavily infested, symptoms include weight loss, abdominal pain, nausea, bloody stools, and diarrhea. In severe cases, gastrointestinal problems, anemia, and even rectal prolapse, where the rectum protrudes outside of the body, may occur. The disease is diagnosed when a stool ova and parasite exam reveals the presence of T. trichiura or their eggs.
Whipworm occurs worldwide. According to the Centers for Disease Control and Prevention (CDC), this parasitic worm is the third most common roundworm to infect humans. The CDC estimates the prevalence of whipworm at approximately 800 million people worldwide. However, the majority of whipworm infections occur in regions with dense populations and a tropical climate. Poor sanitation levels also increase the likelihood of the disease. Whipworm is most common in areas of Southeast Asia, the Caribbean, and Central and South America. Although whipworm infestations can occur in the United States, Japan, Western Europe, or Australasia, it is not common.
Children are at the greatest risk of infection. This is generally thought to be a result of infrequent handwashing and their penchant for playing in soil. As soil may be contaminated with whipworm, failure to wash hands thoroughly before contact with the mouth or food increases their chance of infection.
As most cases of whipworm tend to be asymptomatic, and treatment usually involves removing the worms. This is achieved through administration of medication containing either mebendazole, which is recommended by the CDC, or albendazole. For symptomatic cases, supportive treatment may be necessary in addition to the anti-parasitic medication. In some cases in which large blood loss occurs, there is a risk of anemia developing. Therefore, iron supplements may be necessary to prevent an iron deficiency.
WORDS TO KNOW
HELMINTH: A representative of various phyla of worm-like animals.
HOST: Organism that serves as the habitat for a parasite, or possibly for a symbiont. A host may provide nutrition to the parasite or symbiont, or simply a place in which to live.
OVA: Mature female sex cells produced in the ovaries. (Singular: ovum.)
Whipworm infection is prevented by avoiding contact with contaminated soil and contaminated food. This may involve wearing protective clothing while working in potentially contaminated soil, or washing hands thoroughly after touching soil. Food can be washed and cooked to remove parasites. In addition, crude sanitation, such as the collection of human feces for disposal or for use as fertilizer, is a common way for the infection to spread. Therefore, improved sanitation methods will decrease the likelihood of infections spreading.
Whipworm infections are most likely to occur in developing countries, or countries with dense populations, tropical weather, or poor sanitation methods. In economically depressed countries, 95% of children with protein deficiency and anemia also have whipworm infection. It is in these same countries that medical infrastructure is often limited and seldom able to deliver the repeated anti-helminth medication that successful treatment whipworm infection requires.
Another issue related to whipworm infections involves the potential complications that can arise following heavy whipworm infestations. Anemia, a complication that results in a low transfer of oxygen to body tissues, directly affects tissue development. As children are commonly infected, this complication could affect their growth and overall health. Girls with whipworm infection are particularly vulnerable to anemia caused by whipworm infestation, as they experience additional blood loss with menstruation and often begin childbearing at a relatively young age in countries where whipworm is endemic.
The World Health Organization has identified several key strategies in reducing whipworm infestation in people living in developing countries. Rather than reduce the number of whipworm infections in people (the old strategy), health authorities now work to reduce the number of worms residing in each person. This strategy recognizes the fact that re-infection will probably occur, and focuses on lessening the severity of the disease. Drugs are also now delivered to schools and other long-standing facilities, where minimally trained local citizens can administer them. This strategy is showing more success in delivering repeated treatments than relying on mobile medical teams.
Mandell, G.L., J.E. Bennett, and R. Dolin. Principles and Practice of Infectious Diseases. vol. 2. Philadelphia, PA: Elsevier, 2005.
Centers for Disease Control (CDC). “Trichuriasis.” July 27, 2004 <http://www.dpd.cdc.gov/DPDx/HTML/Trichuriasis.htm> (accessed March 9, 2007).
National Institute of Allergy and Infectious Diseases. “Parasitic Roundworm Diseases.” March 8, 2005 <http://www.niaid.nih.gov/factsheets/roundwor.htm> (accessed March 9, 2007).