Whipworm
Encyclopedia
The human tapworm is a roundworm, which causes trichuriasis
when it infects a human large intestine
. The name whipworm refers to the shape of the worm; they look like whip
s with wider "handles" at the posterior end.
. This is the location of growth and molting. The infective larva
e penetrate the villi and continue to develop in the small intestine. The young worms move to the cecum
and penetrate the mucosa and there they complete development to adult worms in the large intestine
. The life cycle from time of ingestion of eggs to development of mature worms takes approximately three months. During this time, there may be limited signs of infection in stool samples due to lack of egg production and shedding. The female T. trichiura begin to lay eggs after three months of maturity. Worms can live up to five years, during which time females can lay up to 20,000 eggs per day.
Recent studies using genome-wide scan revealed two quantitative trait loci on chromosome 9 and chromosome 18 may be responsible for genetic predisposition or susceptibility to infection of T. trichiura by some individuals.
and to a lesser degree, in Africa
and South America
. Within the United States
, infection is rare overall but may be common in the rural Southeast where 2.2 million people are thought to be infected. Poor hygiene is associated with trichuriasis
as well as the consumption of shaded moist soil, or food that may have been fecally contaminated. Children are especially vulnerable to infection due to their high exposure risk. Eggs are infective about 2–3 weeks after they are deposited in the soil under proper conditions of warmth and moisture, hence its tropical distribution.
and mates with nearby worms. The females can grow to 50 mm (2 inches) long. Neither the male nor the female has much of a visible tail past the anus.
Whipworm commonly infects patients also infected with Giardia
, Entamoeba histolytica
, Ascaris lumbricoides
, and hookworm
s.
Mechanical damage to the mucosa may occur as well as toxic or inflammatory damage to the intestines of the host.
can be diagnosed when T. trichiura eggs are detected in stool examination. Eggs will appear barrel-shaped, unembryonated, having bipolar plugs and a smooth shell. Rectal prolapse can be diagnosed easily using defecating proctogram
and is one of many methods for imaging the parasitic infection. Sigmoidoscopy show characteristic white bodies of adult hanging from inflamed mucosa (coconut cake rectum).
is 90% effective in the first dose, and albendazole
may also be offered as an anti-parasitic agent. Adding iron to the bloodstream helps solve the iron deficiency and rectal prolapse.
Infection can be avoided by proper disposal of human feces, avoiding fecal contamination of food, not eating dirt
, and avoiding crops fertilized with night soil
. Simple and effective proper hygiene such as washing hands and food is recommended for control.
Whipworms develop when a dog swallows whipworm eggs, passed from an infected dog. Symptoms may include diarrhea
, anemia
, and dehydration
. The dog whipworm (Trichuris vulpis) is commonly found in the U.S. It is hard to detect at times, because the numbers of eggs shed are low, and they are shed in waves. Centrifugation is the preferred method. There are several preventives available by prescription from a veterinarian to prevent dogs from getting whipworm.
The cat whipworm is a rare parasite. In Europe it is mostly represented by Trichuris campanula, and in North America it is Trichuris serrata more often. Whipworm eggs found in cats in North America must be differentiated from lungworms, and from mouse whipworm eggs just passing through.
suggests that various immunological disorders that have been observed in humans only within the last 100 years, such as Crohn's disease
, or that have become more common during that period as hygienic practices have become more widespread, may result from a lack of exposure to parasitic worm
s (also called helminths) during childhood. The use of Trichuris suis
ova (TSO, or pig whipworm eggs) by Weinstock, et al., as a therapy for treating Crohn's disease and to a lesser extent ulcerative colitis
are two examples that support this hypothesis. There is also anecdotal evidence that treatment of inflammatory bowel disease
(IBD) with TSO decreases the incidence of asthma
, allergy
, and other inflammatory disorders. Some scientific evidence suggests that the course of multiple sclerosis
may be very favorably altered by helminth infection; TSO is being studied as a treatment for this disease.
Trichuriasis
Trichuriasis is a parasitic infection primarily in the tissue of the cecum, appendix, colon and rectum that is caused by Trichuris trichiura , an intestinal parasitic nematode .-Agent :...
when it infects a human large intestine
Large intestine
The large intestine is the third-to-last part of the digestive system — — in vertebrate animals. Its function is to absorb water from the remaining indigestible food matter, and then to pass useless waste material from the body...
. The name whipworm refers to the shape of the worm; they look like whip
Whip
A whip is a tool traditionally used by humans to exert control over animals or other people, through pain compliance or fear of pain, although in some activities whips can be used without use of pain, such as an additional pressure aid in dressage...
s with wider "handles" at the posterior end.
Life cycle
The female T. trichiura produces 2,000–10,000 single celled eggs per day. Eggs are deposited from human feces to soil where, after two to three weeks, they become embryonated and enter the “infective” stage. These embryonated infective eggs are ingested and hatch in the human small intestineSmall intestine
The small intestine is the part of the gastrointestinal tract following the stomach and followed by the large intestine, and is where much of the digestion and absorption of food takes place. In invertebrates such as worms, the terms "gastrointestinal tract" and "large intestine" are often used to...
. This is the location of growth and molting. The infective larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e penetrate the villi and continue to develop in the small intestine. The young worms move to the cecum
Cecum
The cecum or caecum is a pouch, connecting the ileum with the ascending colon of the large intestine. It is separated from the ileum by the ileocecal valve or Bauhin's valve, and is considered to be the beginning of the large intestine. It is also separated from the colon by the cecocolic...
and penetrate the mucosa and there they complete development to adult worms in the large intestine
Large intestine
The large intestine is the third-to-last part of the digestive system — — in vertebrate animals. Its function is to absorb water from the remaining indigestible food matter, and then to pass useless waste material from the body...
. The life cycle from time of ingestion of eggs to development of mature worms takes approximately three months. During this time, there may be limited signs of infection in stool samples due to lack of egg production and shedding. The female T. trichiura begin to lay eggs after three months of maturity. Worms can live up to five years, during which time females can lay up to 20,000 eggs per day.
Recent studies using genome-wide scan revealed two quantitative trait loci on chromosome 9 and chromosome 18 may be responsible for genetic predisposition or susceptibility to infection of T. trichiura by some individuals.
Morphology
Trichuris trichiura has a narrow anterior esophageal end and shorter and thicker posterior anus. These pinkish-white worms are threaded through the mucosa. They attach to the host through their slender anterior end and feed on tissue secretions instead of blood. Females are larger than males; approximately 35–50 mm long compared to 30–45 mm. The females have a bluntly round posterior end compared to their male counterparts with a coiled posterior end. Their characteristic eggs are barrel-shaped, brown, and have bipolar protuberances.Epidemiology
There is a worldwide distribution of Trichuris trichiura, with an estimated 1 billion human infections. However, it is chiefly tropical, especially in AsiaAsia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
and to a lesser degree, in Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
and South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
. Within the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, infection is rare overall but may be common in the rural Southeast where 2.2 million people are thought to be infected. Poor hygiene is associated with trichuriasis
Trichuriasis
Trichuriasis is a parasitic infection primarily in the tissue of the cecum, appendix, colon and rectum that is caused by Trichuris trichiura , an intestinal parasitic nematode .-Agent :...
as well as the consumption of shaded moist soil, or food that may have been fecally contaminated. Children are especially vulnerable to infection due to their high exposure risk. Eggs are infective about 2–3 weeks after they are deposited in the soil under proper conditions of warmth and moisture, hence its tropical distribution.
Infection
Infection occurs through ingestion of eggs (which are usually found in dry goods such as beans, rice, and various grains) and is more common in warmer areas. The eggs hatch in the small intestine, and then move into the wall of the small intestine and develop. On reaching adulthood, the thinner end (the front of the worm) burrows into the large intestine and the thicker end hangs into the lumenLumen (anatomy)
A lumen in biology is the inside space of a tubular structure, such as an artery or intestine...
and mates with nearby worms. The females can grow to 50 mm (2 inches) long. Neither the male nor the female has much of a visible tail past the anus.
Whipworm commonly infects patients also infected with Giardia
Giardia
Giardia is a genus of anaerobic flagellated protozoan parasites of the phylum Metamonada in the supergroup "Excavata" that colonise and reproduce in the small intestines of several vertebrates, causing giardiasis, commonly known as Beaver fever...
, Entamoeba histolytica
Entamoeba histolytica
Entamoeba histolytica is an anaerobic parasitic protozoan, part of the genus Entamoeba. Predominantly infecting humans and other primates, E. histolytica is estimated to infect about 50 million people worldwide...
, Ascaris lumbricoides
Ascaris lumbricoides
Ascaris lumbricoides is the giant roundworm of humans, belonging to the phylum Nematoda. An ascarid nematode, it is responsible for the disease ascariasis in humans, and it is the largest and most common parasitic worm in humans. One-sixth of the human population is estimated to be infected by this...
, and hookworm
Hookworm
The hookworm is a parasitic nematode that lives in the small intestine of its host, which may be a mammal such as a dog, cat, or human. Two species of hookworms commonly infect humans, Ancylostoma duodenale and Necator americanus. A. duodenale predominates in the Middle East, North Africa, India...
s.
Symptoms and pathology
- Light infestations (<100 worms) are frequently asymptomatic.
- Heavy infestations may have bloody diarrheaDiarrheaDiarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
. - Long-standing blood loss may lead to iron-deficiency anemiaAnemiaAnemia is a decrease in number of red blood cells or less than the normal quantity of hemoglobin in the blood. However, it can include decreased oxygen-binding ability of each hemoglobin molecule due to deformity or lack in numerical development as in some other types of hemoglobin...
. - Rectal prolapseRectal prolapseRectal prolapse normally describes a medical condition wherein the walls of the rectum protrude through the anus and hence become visible outside the body.-Types:There are three chief conditions which come under the title rectal prolapse:...
is possible in severe cases. - Vitamin AVitamin AVitamin A is a vitamin that is needed by the retina of the eye in the form of a specific metabolite, the light-absorbing molecule retinal, that is necessary for both low-light and color vision...
deficiency may also result due to infection.
Mechanical damage to the mucosa may occur as well as toxic or inflammatory damage to the intestines of the host.
Diagnosis
TrichuriasisTrichuriasis
Trichuriasis is a parasitic infection primarily in the tissue of the cecum, appendix, colon and rectum that is caused by Trichuris trichiura , an intestinal parasitic nematode .-Agent :...
can be diagnosed when T. trichiura eggs are detected in stool examination. Eggs will appear barrel-shaped, unembryonated, having bipolar plugs and a smooth shell. Rectal prolapse can be diagnosed easily using defecating proctogram
Defecating proctogram
The defecating proctogram or defecography is an imaging study performed by a radiologist in which the mechanics of a patient's defecation are visualized in real time using a fluoroscope.-History:...
and is one of many methods for imaging the parasitic infection. Sigmoidoscopy show characteristic white bodies of adult hanging from inflamed mucosa (coconut cake rectum).
Treatment and control
MebendazoleMebendazole
Mebendazole or MBZ is a benzimidazole drug developed by Janssen Pharmaceutica and marketed as Vermox, Ovex, Antiox, and Pripsen...
is 90% effective in the first dose, and albendazole
Albendazole
Albendazole, marketed as Albenza, Eskazole, Zentel and Andazol, is a member of the benzimidazole compounds used as a drug indicated for the treatment of a variety of worm infestations. Although this use is widespread in the United States, the U.S. Food and Drug Administration has not approved...
may also be offered as an anti-parasitic agent. Adding iron to the bloodstream helps solve the iron deficiency and rectal prolapse.
Infection can be avoided by proper disposal of human feces, avoiding fecal contamination of food, not eating dirt
Geophagy
Geophagy is the practice of eating earthy or soil-like substances such as clay, and chalk. It exists in animals in the wild and also in humans, most often in rural or preindustrial societies among children and pregnant women...
, and avoiding crops fertilized with night soil
Night soil
Night soil is a euphemism for human excrement collected at night from cesspools, privies, etc. and sometimes used as a fertilizer. Night soil is produced as a result of a waste management system in areas without community infrastructure such as a sewage treatment facility, or individual septic...
. Simple and effective proper hygiene such as washing hands and food is recommended for control.
Dog and cat whipworms
Diarrhea
Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
, anemia
Anemia
Anemia is a decrease in number of red blood cells or less than the normal quantity of hemoglobin in the blood. However, it can include decreased oxygen-binding ability of each hemoglobin molecule due to deformity or lack in numerical development as in some other types of hemoglobin...
, and dehydration
Dehydration
In physiology and medicine, dehydration is defined as the excessive loss of body fluid. It is literally the removal of water from an object; however, in physiological terms, it entails a deficiency of fluid within an organism...
. The dog whipworm (Trichuris vulpis) is commonly found in the U.S. It is hard to detect at times, because the numbers of eggs shed are low, and they are shed in waves. Centrifugation is the preferred method. There are several preventives available by prescription from a veterinarian to prevent dogs from getting whipworm.
The cat whipworm is a rare parasite. In Europe it is mostly represented by Trichuris campanula, and in North America it is Trichuris serrata more often. Whipworm eggs found in cats in North America must be differentiated from lungworms, and from mouse whipworm eggs just passing through.
Whipworm as a therapeutic agent for IBD and other inflammatory disorders
The hygiene hypothesisHygiene hypothesis
In medicine, the Hygiene Hypothesis states that a lack of early childhood exposure to infectious agents, symbiotic microorganisms , and parasites increases susceptibility to allergic diseases by suppressing natural development of the immune system...
suggests that various immunological disorders that have been observed in humans only within the last 100 years, such as Crohn's disease
Crohn's disease
Crohn's disease, also known as regional enteritis, is a type of inflammatory bowel disease that may affect any part of the gastrointestinal tract from mouth to anus, causing a wide variety of symptoms...
, or that have become more common during that period as hygienic practices have become more widespread, may result from a lack of exposure to parasitic worm
Parasitic worm
Parasitic worms or helminths are a division of eukaryoticparasites that, unlike external parasites such as lice and fleas, live inside their host. They are worm-like organisms that live and feed off living hosts, receiving nourishment and protection while disrupting their hosts' nutrient...
s (also called helminths) during childhood. The use of Trichuris suis
Trichuris suis
Trichuris suis is a whipworm; the variations in thickness of the anterior and posterior segments give the parasite the characteristic “whip-like” appearance. Adult females measure 6 to 8 cm and adult males 3 to 4 cm. T. suis eggs are oval and yellow-brown with bipolar plugs.T...
ova (TSO, or pig whipworm eggs) by Weinstock, et al., as a therapy for treating Crohn's disease and to a lesser extent ulcerative colitis
Ulcerative colitis
Ulcerative colitis is a form of inflammatory bowel disease . Ulcerative colitis is a form of colitis, a disease of the colon , that includes characteristic ulcers, or open sores. The main symptom of active disease is usually constant diarrhea mixed with blood, of gradual onset...
are two examples that support this hypothesis. There is also anecdotal evidence that treatment of inflammatory bowel disease
Inflammatory bowel disease
In medicine, inflammatory bowel disease is a group of inflammatory conditions of the colon and small intestine. The major types of IBD are Crohn's disease and ulcerative colitis.-Classification:...
(IBD) with TSO decreases the incidence of asthma
Asthma
Asthma is the common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath...
, allergy
Allergy
An Allergy is a hypersensitivity disorder of the immune system. Allergic reactions occur when a person's immune system reacts to normally harmless substances in the environment. A substance that causes a reaction is called an allergen. These reactions are acquired, predictable, and rapid...
, and other inflammatory disorders. Some scientific evidence suggests that the course of multiple sclerosis
Multiple sclerosis
Multiple sclerosis is an inflammatory disease in which the fatty myelin sheaths around the axons of the brain and spinal cord are damaged, leading to demyelination and scarring as well as a broad spectrum of signs and symptoms...
may be very favorably altered by helminth infection; TSO is being studied as a treatment for this disease.
See also
- Human parasitic diseasesHuman parasitic diseasesThis is a list of topics related to human parasitic diseases. See also the categories shown below.-Diseases:*Acanthamoeba keratitis*Amoebiasis*Ascariasis*Babesiosis*Balantidiasis*Baylisascariasis*Chagas disease*Clonorchiasis*Cochliomyia*Cryptosporidiosis...
- Helminthic therapyHelminthic therapyHelminthic therapy, a type of immunotherapy, is the treatment of autoimmune diseases and immune disorders by means of deliberate infestation with a helminth or with the ova of a helminth. Helminths are parasitic worms such as hookworms and whipworms....
- List of parasites (human)
- WormWormThe term worm refers to an obsolete taxon used by Carolus Linnaeus and Jean-Baptiste Lamarck for all non-arthropod invertebrate animals, and stems from the Old English word wyrm. Currently it is used to describe many different distantly-related animals that typically have a long cylindrical...
External links
- Man finds extreme healing eating parasitic worms, By Elizabeth Cohen, CNN Senior Medical CorrespondentDecember 9, 2010
- Potential Disease Treatment: Swallow Some Worms
- Globe and Mail: Sometimes having worms is good
- BBC article mentions the Iceman had Whipworm
- Video of Live Trichuris trichiura "Whip Worm"