Ascaris: A genus of nematodes of the superfamily ASCARIDOIDEA whose species usually inhabit the intestine.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.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.Anthelmintics: Agents destructive to parasitic worms. They are used therapeutically in the treatment of HELMINTHIASIS in man and animal.Trichuriasis: Infection with nematodes of the genus TRICHURIS, formerly called Trichocephalus.Parasite Egg Count: Determination of parasite eggs in feces.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.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.Antinematodal Agents: Substances used in the treatment or control of nematode infestations. They are used also in veterinary practice.Albendazole: A benzimidazole broad-spectrum anthelmintic structurally related to MEBENDAZOLE that is effective against many diseases. (From Martindale, The Extra Pharmacopoeia, 30th ed, p38)Helminth Proteins: Proteins found in any species of helminth.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.Mebendazole: A benzimidazole that acts by interfering with CARBOHYDRATE METABOLISM and inhibiting polymerization of MICROTUBULES.DNA, Helminth: Deoxyribonucleic acid that makes up the genetic material of helminths.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)Antibodies, Helminth: Immunoglobulins produced in a response to HELMINTH ANTIGENS.Bephenium Compounds: Analogs or derivatives of bephenium (N,N-dimethyl-N-(2-phenoxyethyl)benzenemethanaminium).Nematoda: A class of unsegmented helminths with fundamental bilateral symmetry and secondary triradiate symmetry of the oral and esophageal structures. Many species are parasites.Toilet Facilities: Facilities provided for human excretion, often with accompanying handwashing facilities.Nematode Infections: Infections by nematodes, general or unspecified.Protozoan Infections: Infections with unicellular organisms formerly members of the subkingdom Protozoa.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).Feces: Excrement from the INTESTINES, containing unabsorbed solids, waste products, secretions, and BACTERIA of the DIGESTIVE SYSTEM.Toxocara: A genus of ascarid nematodes commonly parasitic in the intestines of cats and dogs.