Worms are parasitic, soft-bodied organisms that can infect humans and animals. Parasitic worms fall into several different classes and include flukes, roundworm, and tapeworm.
Worms are parasites that live within a host organism (human or animal) for the purpose of obtaining food. This relationship causes harm to the host, and, with severe cases of infection, can be fatal. The term worms commonly refers to intestinal worms, although worms can infect other organs and the bloodstream. Intestinal worms are helminths and fall into three classes: cestodes (tapeworms), nematodes (roundworms), and trematodes (flukes).
Tapeworms have a ribbon-like body composed of a scolex, which attaches the worm to the intestinal wall, and a long chain of progressively developing proglottids. Proglottids at the tail end of the worm contain eggs. Tapeworms can have 3–4,000 proglottids and be several meters long. Tapeworms that infect humans include Taenia saginata, Taenia solium, Hymenolepsis nana, and Diphyllobothrium latum. Tapeworms live in the small intestine and absorb food from the intestinal contents.
The complex life cycles of cestodes differ with each genus and involve two or three different hosts. In general, one host (the intermediate host) ingests eggs that develop into a larval stage. A second host (the definitive host) ingests the larva, which develop into adult worms in the intestine. Humans can become infected with tapeworm by eating raw or inadequately cooked, contaminated fish, pork, or beef. Humans can serve as both intermediate and definitive hosts for certain cestodes. Although humans can experience severe disease when serving as an intermediate host, they may show few signs of disease when harboring adult tapeworms.
Intestinal nematodes, or roundworms, are the most worm-like of all the helminths and resemble the earthworm. Nematodes have a mouth with either three lips or teeth (hookworms), a complete digestive tract, and separate sexes. Nematodes can range from a few millimeters to over one meter long. Roundworms that can infect humans include Trichuris trichiura (whipworm), Enterobius vermicularis (pinworm), Capillaria philippinensis, Trichostrongylus species, Ascaris lumbricoides, Ancylostoma duodenale (hookworm), Necator americanus (hookworm), and Strongyloides stercoralis. Infection occurs following contact (ingestion or skin) with contaminated soil. Pinworms are not uncommon in children and are easily spread to other family members.
There are five stages (four larval and one adult) in the life cycle of the roundworm. Each genus has a unique life cycle that can be classified into one of three patterns. A person becomes infected by ingesting eggs or larva or through skin penetration by larva. Once ingested, depending upon the genus, eggs may either develop into adult worms in the intestines, or a larval stage may gain access to the bloodstream, enter the lungs, be swallowed, and then develop into adult worms in the intestines. For certain genera, larva penetrate the skin, arrive at the lungs via the bloodstream, are swallowed, and become mature worms in the intestines. Eggs are passed out in the stool, or with pinworms, the female lays eggs on the skin surrounding the anal opening.
Trematodes, or flukes, are flat, leaf-shaped, and range in length from a few millimeters to 75 millimeters. Intestinal flukes are primarily found in the Asian continent. Intestinal flukes that can infect humans are Fasciolopsis buski, Heterophyes heterophyes, Metagonimus yokogawai, Echinostoma species, and Nanophyetus salmincola.
The life cycles of all flukes involve freshwater snails as an intermediate host. Flukes are contracted by ingestion of eggs or encysted (encased) larva from contaminated water, raw water plants (water chestnuts, water bamboo shoots, etc.), or raw or inadequately cooked fish or snails. The eggs or larva mature into adult worms in the intestines.
Causes & symptoms
Infection by worms is caused by the ingestion of or skin contact with helminth eggs or larva, as described above.
Symptoms of helminth infections vary depending upon the genera and number of worms involved. Infection with adult tapeworms often causes no symptoms, however, some patients may experience diarrhea , abdominal pain, anemia , and/or vitamin B12 deficiency. Roundworm infection often causes no symptoms but some patients may experience abdominal pain, diarrhea, growth retardation, anemia, and bloody, mucusy stools. Pinworms cause irritated, itchy skin surrounding the anal opening. Itching may be more severe at night and interfere with sleep. Mild infection with flukes may cause no symptoms, but heavy infections can cause diarrhea, abdominal pain, and profuse stools containing undigested food.
One side effect of worm infestation that is presently being studied for potential applications in treating atopy (a type of inherited allergic response) is the release of certain anti-inflammatory chemicals in the body. These chemicals, called cytokines, may prove to be useful in preventing atopy.
The patient will be questioned about travel and ingestion of high-risk foods. Worms are diagnosed by microscopic examination of stool samples to identify eggs and adult worms. Three samples may be taken: two from normal bowel movements and one following the use of a laxative. Pinworms are diagnosed using the "Scotch tape" method in which a piece of tape is applied to the skin surrounding the anal opening. Pinworm eggs, and occasionally an adult worm, adhere to the tape and are identified by microscopic examination.
Although alternative remedies may help treat worms, the patient should consult a physician to obtain an accurate diagnosis and appropriate antihelmintic medication.
Dietary modifications help to rid a person of worm infection. Processed foods and foods that contain sugar, white flour, and milk products should be avoided. The diet should be comprised of 25% fat, 25% protein, and 50% complex carbohydrates. At least two tablespoons of unprocessed sesame, safflower, canola, or flax oil should be taken daily.
Herbals that may kill and expel worms include:
- aloe (Aloe vera )
- ash (Fraxinus americana ) bark ashes
- bayberry (Myrica cerifera ) bark tea
- black walnut bark
- Brassica oleracea decoction
- butternut root bark
- citrin (Garcinia cambogia ) extract
- clove (Eugenia caryophyllus )
- cranberry powder
- erba ruggine (Ceterach officinarum )
- fennel (Foeniculum officinale )
- garlic (Allium sativum )
- Chenopodium ambrosioides
- ginger (Zingiber officinale )
- goldenseal (Hydrastis canadensis )
- lemon (Citrus limon )
- male fern
- orange (Citrus sinensis ) peel
- onion (Allium cepa )
- palmarosa (Cymbopogon martinii )
- pinkroot (Spigelia )
- pumpkin (Cucurbita pepo ) seeds
- Punica granatum bark infusion
- sage (Salvia officinalis )
- wood betony (Stachys officinalis ) tea
- wormwood (Artemisia absinthium ) tincture
Chinese herbal medicines
Roundworms are treated with the herbs Chuan Lian Gen Pi (Cortex meliae radicis ) and Bing Lang (Semen arecae ) and the patent medicines Wu Mei Wan (Mume Pill) and Qu Hui Wan (Dispel Roundworms Pill). Pinworms are treated with the herbs Ku Lian Gen Pi (Cortex meliae radicis ) and Shi Jun Zi (Fructus quisqualis ). Flukes are treated with the herbs Bing Lang (Semen arecae ) and a mixture of Bing Lang (Semen arecae ), Da Huang (Radix et rhizoma rhei ), and Qian Niu Zi (Semen pharbitidis ). Hookworm is treated with the herbs Lei Wan (Sclerotium omphaliae ) and a combination of Guan Zhong (Rhizoma dryopteris crassirhizomae ), Ku Lian Gen Pi (Cortex meliae radicis ), Tu Jing Jie (Herba chenopodii ambrosioidis ), and Zi Su Ye (Folium perillae ).
Other alternative remedies
Other remedies for intestinal worms include:
- Acupuncture . Acupuncture may be used as an adjunct to other treatments to relieve pain and regulate the Spleen and Stomach.
- Ayurveda. Ayurvedic remedies for pinworms include eating one-quarter teaspoon twice daily with water of the herbal mixture: vidanga (5 parts), shardunika (2 parts), and trikatu (one eighth part). Also, the patient may take one-half teaspoon triphala in warm water each night.
- Homeopathy. The most common remedy for pinworms is wormseed (Cina ). Pinworms associated with other conditions are treated with stinging nettle (Urtica urens ) for hives , Mexican grass (Sabadilla ) for hay fever , cat thyme (Teucrium ) for polyps, pinkroot (Spigelia ) for heart palpitations or facial pain, and krameria (Ratanhia ) for rectal fissures.
Intestinal worm infection is treated with medications, many of which are effective with one oral dose. Helminth infections are treated with albendazole (Albenza), levamisole (Ergamisol), mebendazole (Vermox), praziquantel (Biltricide), pyrantel (Antiminth, Ascarel, Pin-X), or thiabendazole (Mintezol).
In treating tapeworm infestations, it is important to completely eliminate the head and neck regions of the tapeworm, as the entire worm can regenerate from these parts.
Medications are very effective in eliminating helminth infections; however, reinfection is always a possibility. Some types of worms appear to trigger changes in the human immune system that make reinfection easier. Patients should be retested following treatment to ensure that the infection has been eliminated. Complications of severe untreated infections include anemia, growth retardation, malnourishment, intestinal blockage, rectal prolapse (when the rectum extrudes out of the anal opening), and death.
Most intestinal worm infections may be prevented by properly washing the hands after using the bathroom, washing skin after contact with soil, wearing shoes outside, and eating thoroughly cooked fish, meats (including meat from wild game), and freshwater plants. A number of cases of worm infections caused by eating raw salmon and crayfish were reported in North America in 2003; in addition, there was an outbreak of trichinellosis in Saskatchewan in 2000 that was traced to infected bear meat.
Skin penetration by larva may be reduced by eating foods rich in vitamin A including squash, carrots, sweet potatoes, yams, and greens.
People who live on farms, or have dogs or cats as house pets, should have their animals checked by a veterinarian on a regular basis and have them dewormed if necessary.
The Centers for Disease Control and Prevention (CDC) recommends that people traveling abroad should wash their hands with soap and water before handling food; should wash and peel all raw vegetables and fruits before eating; and should drink only bottled or boiled water, or carbonated drinks in cans or bottles.
As of late 2003, researchers in developing countries are working on a vaccine for pigs to help control worms transmitted by pigs to humans; however, the vaccine is not likely to be available for several years.
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Pearson, Richard D. Parasitic Diseases: Helminths. Textbook of Gastroenterology, 3rd edition. Edited by Tadataka Yamada et al. Philadelphia: Lippincott Williams & Wilkins, 1999.
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Kumaran, A. M., P. D'Souza, A. Agarwal, et al. "Geraniol, the Putative Anthelmintic Principle of Cymbopogon martinii." Phytotherapy Research 17 (September 2003): 957.
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Rebecca J. Frey, PhD
"Worms." Gale Encyclopedia of Alternative Medicine. . Encyclopedia.com. (April 26, 2017). http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/worms-0
"Worms." Gale Encyclopedia of Alternative Medicine. . Retrieved April 26, 2017 from Encyclopedia.com: http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/worms-0
Worms (vôrms), city (1994 pop. 79,155), Rhineland-Palatinate, SW Germany, on the Rhine River. It is an industrial city and a leading wine trade center. Manufactures include leather goods, textiles, electrical appliances, paints, ceramics, chemicals, and machinery. One of the most venerable historic centers of Europe, Worms was originally a Celtic settlement called Borbetomagus. It was captured and fortified by the Romans under Drusus in 14 BC and was known as Civitas Vangionum. It became the capital of the first kingdom of Burgundy in the 5th cent.; much of the Nibelungenlied is set in Worms at the Burgundian court. The city was an early episcopal see, and its bishops ruled some territory on the right bank of the Rhine as princes of the Holy Roman Empire until 1803, when the bishopric was secularized and passed to Hesse-Darmstadt. The city itself, however, early escaped episcopal control; in 1156, it was created a free imperial city. Numerous important meetings, including about 100 imperial diets, were held there. The best known of these meetings were the episcopal synod of 1076, which declared Pope Gregory VII deposed; the conference that led in 1122 to the Concordat of Worms; the diet of 1495 (see Maximilian I, emperor); and the diet of 1521 (see Worms, Diet of). The City suffered heavy damage in the Thirty Years War (1618–48). It was annexed by France in 1797 and passed to Hesse-Darmstadt at the Congress of Vienna (1814–15). Worms was occupied (1918–30) by French troops after World War I. The city was more than half destroyed in World War II, but was reconstructed after 1945. Worms had one of the oldest Jewish settlements in Germany. Its Romanesque-Gothic synagogue, founded in 1034, was destroyed by the Nazis in 1938 but was rebuilt after the war and reopened in 1961. Of note is the city's Romanesque cathedral (11th–12th cent.). Near Worms is the Liebfrauenkirche (13th–15th cent.), a church surrounded by vineyards, which gave its name to the area's noted white wine, Liebfraumilch.
"Worms." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. (April 26, 2017). http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/worms
"Worms." The Columbia Encyclopedia, 6th ed.. . Retrieved April 26, 2017 from Encyclopedia.com: http://www.encyclopedia.com/reference/encyclopedias-almanacs-transcripts-and-maps/worms
See also 430. ZOOLOGY .
- the branch of zoology that studies worms, especially parasitic worms. —helminthologist , n. —helminthologic, helminthologieal , adj.
- an abnormal fear of being infested with worms.
- an abnormal fear of worms.
- a study of worms.
- the breeding and raising of silk worms for the production of silk. —sericulturist , n. —sericultural , adj.
- taeniacide, teniacide
- an agent or preparation for killing tapeworms. —taeniacidal, teniacidal , adj.
- Rare. helminthology. —vermeologist , n.
- a substance for killing worms, especially intestinal worms, in animals or humans. Cf. vermifuge.
- motion similar to that of a worm. See also 282. MOTION ; 305. ORNAMENTATION .
- a drug for expelling worms from the intestinal tract. Cf. vermicide . —vermifuge , adj.
- the state or process of being infested with worms or vermin.
- an abnormal fear of worms.
"Worms." -Ologies and -Isms. . Encyclopedia.com. (April 26, 2017). http://www.encyclopedia.com/education/dictionaries-thesauruses-pictures-and-press-releases/worms
"Worms." -Ologies and -Isms. . Retrieved April 26, 2017 from Encyclopedia.com: http://www.encyclopedia.com/education/dictionaries-thesauruses-pictures-and-press-releases/worms
Worms are invertebrate (in-VER-te-bret) animals, which means they lack spinal columns (backbones). Worms can cause certain types of parasitic infestation* in humans.
- * infestation
- occurs when parasites are living on or in the body tissues of a human or other host.
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Diseases and conditions caused by worms are as varied as the types of worms that cause them. Worms that act as parasites* come in thousands of different species, including roundworms, tapeworms, flatworms, flukes, and leeches. The worms may be microscopic, or they may be as long as 9 meters (almost 30 feet).
- * parasites
- are creatures that live in and feed on the bodies of other organisms.
Some worms cause painful and deforming conditions, while others are barely noticed by the host. Some worm infestations clear up after a short time, while others cause long-term problems that affect many different body organs and may even cause death. Common garden earthworms do not cause human illness.
Frequent hand-washing, good hygiene, good sanitary conditions, and clean water can help prevent worm infections. Prompt diagnosis and treatment by a doctor can help clear up worm infestations.
The World Health Organization’s Division of Control of Tropical Diseases posts many fact sheets about worm infections at its website. http://www.who.int/ctd/html/intest.html
The U.S. National Institute of Allergy and Infectious Diseases posts a fact sheet about parasitic roundworm diseases at its website. http://www.niaid.nih.gov/factsheets/roundwor.htm
"Worms." Complete Human Diseases and Conditions. . Encyclopedia.com. (April 26, 2017). http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/worms
"Worms." Complete Human Diseases and Conditions. . Retrieved April 26, 2017 from Encyclopedia.com: http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/worms
"Worms." World Encyclopedia. . Encyclopedia.com. (April 26, 2017). http://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/worms
"Worms." World Encyclopedia. . Retrieved April 26, 2017 from Encyclopedia.com: http://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/worms
"Worms." The Oxford Dictionary of Phrase and Fable. . Encyclopedia.com. (April 26, 2017). http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/worms
"Worms." The Oxford Dictionary of Phrase and Fable. . Retrieved April 26, 2017 from Encyclopedia.com: http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/worms
"worms." A Dictionary of Zoology. . Encyclopedia.com. (April 26, 2017). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/worms
"worms." A Dictionary of Zoology. . Retrieved April 26, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/worms
"Worms." Oxford Dictionary of Rhymes. . Encyclopedia.com. (April 26, 2017). http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/worms-0
"Worms." Oxford Dictionary of Rhymes. . Retrieved April 26, 2017 from Encyclopedia.com: http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/worms-0