Helminths: Commonly known as parasitic worms, this group includes the ACANTHOCEPHALA; NEMATODA; and PLATYHELMINTHS. Some authors consider certain species of LEECHES that can become temporarily parasitic as helminths.Helminthiasis: Infestation with parasitic worms of the helminth class.Helminthiasis, Animal: Infestation of animals with parasitic worms of the helminth class. The infestation may be experimental or veterinary.Therapy with Helminths: The treatment of immune system diseases by deliberate infestation with helminths. This therapy is partly based on the HYGIENE HYPOTHESIS which states that the absence of parasites increases immune dysregulation because of the lack of stimulation of REGULATORY T-CELLS.Intestinal Diseases, Parasitic: Infections of the INTESTINES with PARASITES, commonly involving PARASITIC WORMS. Infections with roundworms (NEMATODE INFECTIONS) and tapeworms (CESTODE INFECTIONS) are also known as HELMINTHIASIS.Trichuris: A genus of nematode worms comprising the whipworms.Antibodies, Helminth: Immunoglobulins produced in a response to HELMINTH ANTIGENS.Antigens, Helminth: Any part or derivative of a helminth that elicits an immune reaction. The most commonly seen helminth antigens are those of the schistosomes.Ancylostomatoidea: A superfamily of nematode parasitic hookworms consisting of four genera: ANCYLOSTOMA; NECATOR; Bunostomum; and Uncinaria. ANCYLOSTOMA and NECATOR occur in humans and other mammals. Bunostomum is common in ruminants and Uncinaria in wolves, foxes, and dogs.Anthelmintics: Agents destructive to parasitic worms. They are used therapeutically in the treatment of HELMINTHIASIS in man and animal.Helminth Proteins: Proteins found in any species of helminth.Nematospiroides dubius: A species of intestinal nematode parasites which occur most commonly in mice. Infection is by ingesting larvae. This particular species is used extensively in immunological research.Strongylida Infections: Infections with nematodes of the order STRONGYLIDA.Nematode Infections: Infections by nematodes, general or unspecified.Cestoda: A subclass of segmented worms comprising the tapeworms.Parasite Egg Count: Determination of parasite eggs in feces.Albendazole: A benzimidazole broad-spectrum anthelmintic structurally related to MEBENDAZOLE that is effective against many diseases. (From Martindale, The Extra Pharmacopoeia, 30th ed, p38)Schistosoma mansoni: A species of trematode blood flukes of the family Schistosomatidae. It is common in the Nile delta. The intermediate host is the planorbid snail. This parasite causes schistosomiasis mansoni and intestinal bilharziasis.Protozoan Infections: Infections with unicellular organisms formerly members of the subkingdom Protozoa.Filarioidea: A superfamily of nematodes of the suborder SPIRURINA. Its organisms possess a filiform body and a mouth surrounded by papillae.Schistosoma: A genus of trematode flukes belonging to the family Schistosomatidae. There are over a dozen species. These parasites are found in man and other mammals. Snails are the intermediate hosts.Cestode Infections: Infections with true tapeworms of the helminth subclass CESTODA.Filariasis: Infections with nematodes of the superfamily FILARIOIDEA. The presence of living worms in the body is mainly asymptomatic but the death of adult worms leads to granulomatous inflammation and permanent fibrosis. Organisms of the genus Elaeophora infect wild elk and domestic sheep causing ischemic necrosis of the brain, blindness, and dermatosis of the face.Nippostrongylus: A genus of intestinal nematode parasites belonging to the superfamily HELIGMOSOMATOIDEA, which commonly occurs in rats but has been experimentally transmitted to other rodents and rabbits. Infection is usually through the skin.Schistosomiasis: Infection with flukes (trematodes) of the genus SCHISTOSOMA. Three species produce the most frequent clinical diseases: SCHISTOSOMA HAEMATOBIUM (endemic in Africa and the Middle East), SCHISTOSOMA MANSONI (in Egypt, northern and southern Africa, some West Indies islands, northern 2/3 of South America), and SCHISTOSOMA JAPONICUM (in Japan, China, the Philippines, Celebes, Thailand, Laos). S. mansoni is often seen in Puerto Ricans living in the United States.Schistosomiasis mansoni: Schistosomiasis caused by Schistosoma mansoni. It is endemic in Africa, the Middle East, South America, and the Caribbean and affects mainly the bowel, spleen, and liver.Trematoda: Class of parasitic flukes consisting of three subclasses, Monogenea, Aspidogastrea, and Digenea. The digenetic trematodes are the only ones found in man. They are endoparasites and require two hosts to complete their life cycle.Feces: Excrement from the INTESTINES, containing unabsorbed solids, waste products, secretions, and BACTERIA of the DIGESTIVE SYSTEM.DNA, Helminth: Deoxyribonucleic acid that makes up the genetic material of helminths.Fasciola hepatica: A species of helminth commonly called the sheep liver fluke. It occurs in the biliary passages, liver, and gallbladder during various stages of development. Snails and aquatic vegetation are the intermediate hosts. Occasionally seen in man, it is most common in sheep and cattle.Trematode Infections: Infections caused by infestation with worms of the class Trematoda.Necator americanus: A common parasite of humans in the moist tropics and subtropics. These organisms attach to villi in the small intestine and suck blood causing diarrhea, anorexia, and anemia.Host-Parasite Interactions: The relationship between an invertebrate and another organism (the host), one of which lives at the expense of the other. Traditionally excluded from definition of parasites are pathogenic BACTERIA; FUNGI; VIRUSES; and PLANTS; though they may live parasitically.Soil: The unconsolidated mineral or organic matter on the surface of the earth that serves as a natural medium for the growth of land plants.Nematoda: A class of unsegmented helminths with fundamental bilateral symmetry and secondary triradiate symmetry of the oral and esophageal structures. Many species are parasites.Parasitic Diseases: Infections or infestations with parasitic organisms. They are often contracted through contact with an intermediate vector, but may occur as the result of direct exposure.Th2 Cells: Subset of helper-inducer T-lymphocytes which synthesize and secrete the interleukins IL-4, IL-5, IL-6, and IL-10. These cytokines influence B-cell development and antibody production as well as augmenting humoral responses.Trichinella spiralis: A parasite of carnivorous mammals that causes TRICHINELLOSIS. It is especially common in rats and in swine fed uncooked garbage. Human infection is initiated by the consumption of raw or insufficiently cooked pork or other meat containing the encysted larvae.Strongyloides stercoralis: A species of parasitic nematode widely distributed in tropical and subtropical countries. The females and their larvae inhabit the mucosa of the intestinal tract, where they cause ulceration and diarrhea.Hymenolepiasis: Infection with tapeworms of the genus Hymenolepis.Parasitology: The study of parasites and PARASITIC DISEASES.Taenia: A genus of large tapeworms.Necatoriasis: Infection of humans or animals with hookworms of the genus NECATOR. The resulting anemia from this condition is less severe than that from ANCYLOSTOMIASIS.Ascaris: A genus of nematodes of the superfamily ASCARIDOIDEA whose species usually inhabit the intestine.Mebendazole: A benzimidazole that acts by interfering with CARBOHYDRATE METABOLISM and inhibiting polymerization of MICROTUBULES.Strongyloidea: A superfamily of strongyles or roundworms which are parasites in the intestinal tract of equines, pigs, rodents, and primates (including man). It includes the genera Cyasthostomum, Ransomus, Globocephalus, OESOPHAGOSTOMUM, and STRONGYLUS.Genome, Helminth: The genetic complement of a helminth (HELMINTHS) as represented in its DNA.Strongyloidiasis: Infection with nematodes of the genus STRONGYLOIDES. The presence of larvae may produce pneumonitis and the presence of adult worms in the intestine could lead to moderate to severe diarrhea.Hymenolepis nana: The smallest species of TAPEWORMS. It is the only cestode that parasitizes humans without requiring an intermediate host.Antiparasitic Agents: Drugs used to treat or prevent parasitic infections.Trichinellosis: An infection with TRICHINELLA. It is caused by eating raw or undercooked meat that is infected with larvae of nematode worms TRICHINELLA genus. All members of the TRICHINELLA genus can infect human in addition to TRICHINELLA SPIRALIS, the traditional etiological agent. It is distributed throughout much of the world and is re-emerging in some parts as a public health hazard and a food safety problem.Prevalence: The total number of cases of a given disease in a specified population at a designated time. It is differentiated from INCIDENCE, which refers to the number of new cases in the population at a given time.Ancylostoma: A genus of nematode intestinal parasites that consists of several species. A. duodenale is the common hookworm in humans. A. braziliense, A. ceylonicum, and A. caninum occur primarily in cats and dogs, but all have been known to occur in humans.Parasites: Invertebrate organisms that live on or in another organism (the host), and benefit at the expense of the other. Traditionally excluded from definition of parasites are pathogenic BACTERIA; FUNGI; VIRUSES; and PLANTS; though they may live parasitically.Praziquantel: An anthelmintic used in most schistosome and many cestode infestations.Ascaris suum: A species of parasitic nematode usually found in domestic pigs and a few other animals. Human infection can also occur, presumably as result of handling pig manure, and can lead to intestinal obstruction.Coinfection: Simultaneous infection of a host organism by two or more pathogens. In virology, coinfection commonly refers to simultaneous infection of a single cell by two or more different viruses.Hymenolepis: A genus of small tapeworms of birds and mammals.Taeniasis: Infection with tapeworms of the genus Taenia.Fascioliasis: Liver disease caused by infections with parasitic flukes of the genus FASCIOLA, such as FASCIOLA HEPATICA.Spiruroidea: A superfamily of parasitic nematodes which requires one or two intermediate arthropod hosts before finally being eaten by the final host. Its organisms occur rarely in man.Immunoglobulin E: An immunoglobulin associated with MAST CELLS. Overexpression has been associated with allergic hypersensitivity (HYPERSENSITIVITY, IMMEDIATE).Cote d'Ivoire: A republic in western Africa, south of MALI and BURKINA FASO, bordered by GHANA on the east. Its administrative capital is Abidjan and Yamoussoukro has been the official capital since 1983. The country was formerly called Ivory Coast.Mansonelliasis: Infection with nematodes of the genus MANSONELLA. Symptoms include pruritus, headache, and articular swelling.Schistosoma haematobium: A species of trematode blood flukes of the family Schistosomatidae which occurs at different stages in development in veins of the pulmonary and hepatic system and finally the bladder lumen. This parasite causes urinary schistosomiasis.Echinostomiasis: Infection by flukes of the genus Echinostoma.Toxocariasis: Infection by round worms of the genus TOXOCARA, usually found in wild and domesticated cats and dogs and foxes, except for the larvae, which may produce visceral and ocular larva migrans in man.Basophils: Granular leukocytes characterized by a relatively pale-staining, lobate nucleus and cytoplasm containing coarse dark-staining granules of variable size and stainable by basic dyes.Wuchereria bancrofti: A white threadlike worm which causes elephantiasis, lymphangitis, and chyluria by interfering with the lymphatic circulation. The microfilaria are found in the circulating blood and are carried by mosquitoes.Strongyloides: A genus of parasitic nematodes widely distributed as intestinal parasites of mammals.Parasitic Diseases, Animal: Infections or infestations with parasitic organisms. The infestation may be experimental or veterinary.Antinematodal Agents: Substances used in the treatment or control of nematode infestations. They are used also in veterinary practice.Amoebozoa: A supergroup (some say phylum) of ameboid EUKARYOTES, comprising ARCHAMOEBAE; LOBOSEA; and MYCETOZOA.Schistosomiasis haematobia: A human disease caused by the infection of parasitic worms SCHISTOSOMA HAEMATOBIUM. It is endemic in AFRICA and parts of the MIDDLE EAST. Tissue damages most often occur in the URINARY TRACT, specifically the URINARY BLADDER.Neglected Diseases: Diseases that are underfunded and have low name recognition but are major burdens in less developed countries. The World Health Organization has designated six tropical infectious diseases as being neglected in industrialized countries that are endemic in many developing countries (HELMINTHIASIS; LEPROSY; LYMPHATIC FILARIASIS; ONCHOCERCIASIS; SCHISTOSOMIASIS; and TRACHOMA).Ivermectin: A mixture of mostly avermectin H2B1a (RN 71827-03-7) with some avermectin H2B1b (RN 70209-81-3), which are macrolides from STREPTOMYCES avermitilis. It binds glutamate-gated chloride channel to cause increased permeability and hyperpolarization of nerve and muscle cells. It also interacts with other CHLORIDE CHANNELS. It is a broad spectrum antiparasitic that is active against microfilariae of ONCHOCERCA VOLVULUS but not the adult form.Hygiene: The science dealing with the establishment and maintenance of health in the individual and the group. It includes the conditions and practices conducive to health. (Webster, 3d ed)Tropical Medicine: The branch of medicine concerned with diseases, mainly of parasitic origin, common in tropical and subtropical regions.Oxyurida: An order of nematodes of the subclass SECERNENTEA. Its organisms are characterized by a single, ventral excretory gland and a relatively stout, short body.LaosMethyl Green: A tri-benzene-ammonium usually compounded with zinc chloride. It is used as a biological stain and for the dyeing and printing of textiles.Ancylostomiasis: Infection of humans or animals with hookworms of the genus ANCYLOSTOMA. Characteristics include anemia, dyspepsia, eosinophilia, and abdominal swelling.Hydrology: Science dealing with the properties, distribution, and circulation of water on and below the earth's surface, and atmosphere.Mansonella: A genus of parasitic nematodes whose organisms are distributed in Central and South America. Characteristics include a smooth cuticle and an enlarged anterior end.Interleukin-4: A soluble factor produced by activated T-LYMPHOCYTES that induces the expression of MHC CLASS II GENES and FC RECEPTORS on B-LYMPHOCYTES and causes their proliferation and differentiation. It also acts on T-lymphocytes, MAST CELLS, and several other hematopoietic lineage cells.Elephantiasis, Filarial: Parasitic infestation of the human lymphatic system by WUCHERERIA BANCROFTI or BRUGIA MALAYI. It is also called lymphatic filariasis.Platyhelminths: A phylum of acoelomate, bilaterally symmetrical flatworms, without a definite anus. It includes three classes: Cestoda, Turbellaria, and Trematoda.Mice, Inbred BALB COxyuroidea: A superfamily of parasitic nematodes consisting of several genera. ENTEROBIUS, which occurs in humans, and Oxyuris, which occurs in horses, are two of the most common. Other genera are: Skrjabinema, Passalurus, Dermatoxys, and Probstmayria.Hymenolepis diminuta: A species of tapeworm (TAPEWORMS) infecting RATS and MICE but rarely causing disease in humans. Its life cycle involves RODENTS as the definitive host and BEETLES as the intermediate host.Ascaridida: An order of nematodes of the subclass SECERNENTEA. Its organisms possess two or three pairs of dorsolateral caudal papillae.Toxocara canis: A species of parasitic nematode found in the intestine of dogs. Lesions in the brain, liver, eye, kidney, and lung are caused by migrating larvae. In humans, these larvae do not follow normal patterns and may produce visceral larva migrans (LARVA MIGRANS, VISCERAL).Pregnancy Complications, Parasitic: The co-occurrence of pregnancy and parasitic diseases. The parasitic infection may precede or follow FERTILIZATION.Onchocerciasis: Infection with nematodes of the genus ONCHOCERCA. Characteristics include the presence of firm subcutaneous nodules filled with adult worms, PRURITUS, and ocular lesions.Trichostrongyloidea: A superfamily of nematodes. Most are intestinal parasites of ruminants and accidentally in humans. This superfamily includes seven genera: DICTYOCAULUS; HAEMONCHUS; Cooperia, OSTERTAGIA; Nematodirus, TRICHOSTRONGYLUS; and Hyostrongylus.Echinostoma: A genus of intestinal flukes of the family Echinostomatidae which consists of many species. They occur in man and other vertebrates. The intermediate hosts are frequently mollusks.