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Parasitic worms or helminths are a division of eukaroytic parasites that, unlike external parasites such as lice and fleas, live inside their host.^[1] They are worm-like organisms that live and feed off living hosts, receiving nourishment and protection while disrupting their hosts' nutrient absorption, causing weakness and disease. Those that live inside the digestive tract are called intestinal parasites. They can live inside humans as well as other animals. Image File history File links Merge-arrow. ... Image File history File links Question_book-3. ... A parasite is an organism that lives in or on the living tissue of a host organism at the expense of it. ... Suborders Anoplura (sucking lice) Rhyncophthirina Ischnocera (avian lice) Amblycera (chewing lice) Lice (singular: louse) (order Phthiraptera) are an order of over 3000 species of wingless parasitic insects. ... Adam had em. ... Domains and Kingdoms Nanobes Acytota Cytota Bacteria Neomura Archaea Eukaryota Bikonta Apusozoa Rhizaria Excavata Archaeplastida Rhodophyta Glaucophyta Plantae Heterokontophyta Haptophyta Cryptophyta Alveolata Unikonta Amoebozoa Opisthokonta Choanozoa Fungi Animalia An ericoid mycorrhizal fungus Life on Earth redirects here. ... Nutrition is interpreted as the study of the organic process by which an organism assimilates and uses food and liquids for normal functioning, growth and maintenance and to maintain the balance between health and disease. ... A nutrient is a substance used in an organisms metabolism which must be taken in from the environment. ... This article is about the medical term. ... For the Physics term GUT, please refer to Grand unification theory The gastrointestinal or digestive tract, also referred to as the GI tract or the alimentary canal or the gut, is the system of organs within multicellular animals which takes in food, digests it to extract energy and nutrients, and... Intestinal parasites are parasites that populate the gastro-intestinal tract. ...

Helminthology is the study of parasitic worms and their effect on their hosts. Helminthology is the study of parasitic worms and their effect on their hosts. ...

Parasitic worms are categorized into three groups: cestodes, nematodes, and trematodes. Orders Subclass Cestodaria Amphilinidea Gyrocotylidea Subclass Eucestoda Aporidea Caryophyllidea Cyclophyllidea Diphyllidea Lecanicephalidea Litobothridea Nippotaeniidea Proteocephalidea Pseudophyllidea Spathebothriidea Tetraphyllidea Trypanorhyncha In biology, Cestoda is the class of parasitic flatworms, called cestodes or tapeworms, that live in the digestive tract of vertebrates as adults and often in the bodies of various animals... Classes Adenophora    Subclass Enoplia    Subclass Chromadoria Secernentea    Subclass Rhabditia    Subclass Spiruria    Subclass Diplogasteria The roundworms (Phylum Nematoda) are one of the most common phyla of animals, with over 20,000 different described species. ... Subclasses Aspidogastrea Digenea The Trematoda is a class within the phylum Platyhelminthes, which contains two groups of parasitic worms. ...

Hookworms attached to the intestinal mucosa

The scolex, or head, of Taenia solium

Two pinworms, captured on emergence from the anus

These are the principal morphologic differences of the different families of helminths: Image File history File links Download high-resolution version (1796x1200, 168 KB)Ancylostoma caninum, a type of hookworm, attached to the intestinal mucosa. ... Image File history File links Download high-resolution version (1796x1200, 168 KB)Ancylostoma caninum, a type of hookworm, attached to the intestinal mucosa. ... Species Species N. americanus and A. duodenale The hookworm is a parasitic nematode worm that lives in the small intestine of its host, which may be a mammal such as a dog, cat, or human. ... The mucous membranes (or mucosae; singular: mucosa) are linings of mostly endodermal origin, covered in epithelium, and are involved in absorption and secretion. ... Tenia solium, a parasitic cestode worm, showing its scolex. ... Tenia solium, a parasitic cestode worm, showing its scolex. ... Orders Subclass Cestodaria Amphilinidea Gyrocotylidea Subclass Eucestoda Aporidea Caryophyllidea Cyclophyllidea Diphyllidea Lecanicephalidea Litobothridea Nippotaeniidea Proteocephalidea Pseudophyllidea Spathebothriidea Tetraphyllidea Trypanorhyncha In biology, Cestoda is the class of parasitic flatworms, called tapeworms, that live in the digestive tracts of vertebrates as adults and often in the bodies of various animals as juveniles. ... Stained proglottid. ... threadworms (Edna and Phylis), mm markings This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ... threadworms (Edna and Phylis), mm markings This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ... The pinworm (Genus Enterobius) is a parasitic roundworm of the phylum Nematoda. ...

Diseases caused in humans by helminth infection include ascariasis, dracunculiasis, elephantiasis, hookworm, lymphatic filariasis, onchocerciasis, schistosomiasis, and trichuriasis. In zoology, a hermaphrodite is a species that contains both male and female sexual organs at some point during their lives. ... A genus of trematodes, Schistosoma spp. ... Binomial name Ascaris lumbricoides Linnaeus, 1758 Ascariasis is a human disease caused by the parasitic roundworm Ascaris lumbricoides. ... Dracunculiasis, more commonly known as Guinea worm disease (GWD), is an infection caused by the parasite Dracunculus medinensis (also known as Guinea worm). Dracunculus comes from the Latin little dragon. // The life cycle of Dracunculus medinensis. ... Elephantiasis (Greek ελεφαντίασις, from ελέφαντας, the elephant) is a disease that is characterized by the thickening of the skin and underlying tissues, especially in the legs and genitals. ... Species Species N. americanus and A. duodenale The hookworm is a parasitic nematode worm that lives in the small intestine of its host, which may be a mammal such as a dog, cat, or human. ... Lymphatic filariasis is parasitic infection of the lymphatic circulation which may result in the deforming disease known as elephantiasis. ... Binomial name Onchocerca volvulus Bickel 1982 Onchocerciasis (pronounced ) or river blindness is the worlds second leading infectious cause of blindness. ... Schistosomiasis or bilharzia is a parasitic disease caused by several species of flatworm. ... Life cycle of Trichuris trichiura. ...

Reproduction

Parasitic worms are sequential hermaphrodites and reproduce depending on the species of worm, either with the presence of a male and female worm, joining sperm and eggs, producing fertile eggs, such as hookworms, or by breaking off segments that contain both male and female sex organs that are able to produce fertile eggs without the presence of a male or female. (e.g., tapeworms) For other uses, see Hermaphrodite (disambiguation). ... For other uses, see Sperm (disambiguation). ... For the video-related acronym, see OVA. A human ovum An ovum (or loosely, egg or egg cell) is a female sex cell or gamete. ... This article is about the biological unit. ...

All worm offspring are passed on through poorly-cooked meat, especially pork, wild fish, and beef, contaminated water, feces, mosquitoes, and, in general, areas of poor hygiene and food regulation standards such as parts of Africa, Central and South America, and Asia. However, it is estimated that 40 million Americans are infected with the most common roundworm, the pinworm. Medical experts theorize that widespread intestinal parasite infestation is leading to the rise of colon cancer in the United States. For other uses, see Meat (disambiguation). ... For other uses, see Pork (disambiguation). ... For other uses, see Fish (disambiguation). ... For other uses, see Beef (disambiguation). ... Horse feces Feces, faeces, or fæces (see spelling differences) is a waste product from an animals digestive tract expelled through the anus (or cloaca) during defecation. ... For other uses, see Mosquito (disambiguation). ... Hygiene refers to practices associated with ensuring good health and cleanliness. ... For other uses, see Central America (disambiguation). ...

Worm eggs or larvae or even adults enter the human body through the mouth, anus, nose, or skin, with most species attaching themselves to the intestinal tract. With the presence of digestive enzymes, worm egg shells are dissolved, releasing a brand-new worm; unlike its egg shell, the parasitic worm is protected from the body's powerful digestive enzymes by producing a protective keratin layer. In most birds and reptiles, an egg (Latin ovum) is the zygote, resulting from fertilization of the ovum. ... A larval insect A larva (Latin; plural larvae) is a juvenile form of animal with indirect development, undergoing metamorphosis (for example, insects or amphibians). ... For other uses, see Species (disambiguation). ... In anatomy, the intestine is the segment of the alimentary canal extending from the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine. ... Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... Not to be confused with kerogen or carotene. ...

Immune response

The immune response to worm infection in humans is a Th1 response in the majority of cases. This results in inflammation of the gut, and results in cyst-like structures forming around the egg deposits throughout the body. The host's lymphatic system is also heavily taxed the longer helminths propagate, which excrete toxins after feeding. These toxins are released into the intestines to be absorbed by the host's bloodstream. This phenomena makes the host susceptible to more common diseases such as seasonal viruses and bacterial infection. Antigen presentation stimulates T cells to become either cytotoxic CD8+ cells or helper CD4+ cells. ... An abscess on the skin, showing the redness and swelling characteristic of inflammation. ...

References

1. ^ Maizels RM, Yazdanbakhsh M (2003). "Immune regulation by helminth parasites: cellular and molecular mechanisms". Nat. Rev. Immunol. 3 (9): 733–44. doi:10.1038/nri1183. PMID 12949497. 

s A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ...

External links

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