Ascaris lumbricoides: A species of parasitic nematode that is the largest found in the human intestine. Its distribution is worldwide, but it is more prevalent in areas of poor sanitation. Human infection with A. lumbricoides is acquired by swallowing fully embryonated eggs from contaminated soil.Ascaris: A genus of nematodes of the superfamily ASCARIDOIDEA whose species usually inhabit the intestine.Ascariasis: Infection by nematodes of the genus ASCARIS. Ingestion of infective eggs causes diarrhea and pneumonitis. Its distribution is more prevalent in areas of poor sanitation and where human feces are used for fertilizer.Trichuris: A genus of nematode worms comprising the whipworms.Helminthiasis: Infestation with parasitic worms of the helminth class.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.Trichuriasis: Infection with nematodes of the genus TRICHURIS, formerly called Trichocephalus.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.Hookworm Infections: Infection of humans or animals with hookworms other than those caused by the genus Ancylostoma or Necator, for which the specific terms ANCYLOSTOMIASIS and NECATORIASIS are available.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.Anthelmintics: Agents destructive to parasitic worms. They are used therapeutically in the treatment of HELMINTHIASIS in man and animal.Parasite Egg Count: Determination of parasite eggs in feces.Mebendazole: A benzimidazole that acts by interfering with CARBOHYDRATE METABOLISM and inhibiting polymerization of MICROTUBULES.Albendazole: A benzimidazole broad-spectrum anthelmintic structurally related to MEBENDAZOLE that is effective against many diseases. (From Martindale, The Extra Pharmacopoeia, 30th ed, p38)Antinematodal Agents: Substances used in the treatment or control of nematode infestations. They are used also in veterinary practice.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.Protozoan Infections: Infections with unicellular organisms formerly members of the subkingdom Protozoa.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.Nematode Infections: Infections by nematodes, general or unspecified.Feces: Excrement from the INTESTINES, containing unabsorbed solids, waste products, secretions, and BACTERIA of the DIGESTIVE SYSTEM.Pyrantel Pamoate: Broad spectrum antinematodal anthelmintic used also in veterinary medicine.Toilet Facilities: Facilities provided for human excretion, often with accompanying handwashing facilities.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.EcuadorAntigens, Helminth: Any part or derivative of a helminth that elicits an immune reaction. The most commonly seen helminth antigens are those of the schistosomes.Thiabendazole: 2-Substituted benzimidazole first introduced in 1962. It is active against a variety of nematodes and is the drug of choice for STRONGYLOIDIASIS. It has CENTRAL NERVOUS SYSTEM side effects and hepatototoxic potential. (From Smith and Reynard, Textbook of Pharmacology, 1992, p919)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.Antibodies, Helminth: Immunoglobulins produced in a response to HELMINTH ANTIGENS.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.Nematoda: A class of unsegmented helminths with fundamental bilateral symmetry and secondary triradiate symmetry of the oral and esophageal structures. Many species are parasites.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.Levamisole: An antihelminthic drug that has been tried experimentally in rheumatic disorders where it apparently restores the immune response by increasing macrophage chemotaxis and T-lymphocyte function. Paradoxically, this immune enhancement appears to be beneficial in rheumatoid arthritis where dermatitis, leukopenia, and thrombocytopenia, and nausea and vomiting have been reported as side effects. (From Smith and Reynard, Textbook of Pharmacology, 1991, p435-6)Sanitation: The development and establishment of environmental conditions favorable to the health of the public.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.Helminth Proteins: Proteins found in any species of helminth.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.Toxocara: A genus of ascarid nematodes commonly parasitic in the intestines of cats and dogs.Parasitology: The study of parasites and PARASITIC DISEASES.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.DNA, Helminth: Deoxyribonucleic acid that makes up the genetic material of helminths.Ancylostomiasis: Infection of humans or animals with hookworms of the genus ANCYLOSTOMA. Characteristics include anemia, dyspepsia, eosinophilia, and abdominal swelling.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)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.Rural Health: The status of health in rural populations.Giardiasis: An infection of the SMALL INTESTINE caused by the flagellated protozoan GIARDIA LAMBLIA. It is spread via contaminated food and water and by direct person-to-person contact.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.Ethiopia: An independent state in eastern Africa. Ethiopia is located in the Horn of Africa and is bordered on the north and northeast by Eritrea, on the east by Djibouti and Somalia, on the south by Kenya, and on the west and southwest by Sudan. Its capital is Addis Ababa.Giardia lamblia: A species of parasitic EUKARYOTES that attaches itself to the intestinal mucosa and feeds on mucous secretions. The organism is roughly pear-shaped and motility is somewhat erratic, with a slow oscillation about the long axis.Rural Population: The inhabitants of rural areas or of small towns classified as rural.Immunoglobulin E: An immunoglobulin associated with MAST CELLS. Overexpression has been associated with allergic hypersensitivity (HYPERSENSITIVITY, IMMEDIATE).BrazilKenya: A republic in eastern Africa, south of ETHIOPIA, west of SOMALIA with TANZANIA to its south, and coastline on the Indian Ocean. Its capital is Nairobi.Cameroon: A republic in central Africa lying east of CHAD and the CENTRAL AFRICAN REPUBLIC and west of NIGERIA. The capital is Yaounde.