Parasitology: The study of parasites and PARASITIC DISEASES.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.Parasitic Diseases, Animal: Infections or infestations with parasitic organisms. The infestation may be experimental or veterinary.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.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.Cestoda: A subclass of segmented worms comprising the tapeworms.Coccidia: A subclass of protozoans commonly parasitic in the epithelial cells of the intestinal tract but also found in the liver and other organs. Its organisms are found in both vertebrates and higher invertebrates and comprise two orders: EIMERIIDA and EUCOCCIDIIDA.Veterinary Medicine: The medical science concerned with the prevention, diagnosis, and treatment of diseases in animals.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.Protozoan Infections: Infections with unicellular organisms formerly members of the subkingdom Protozoa.Food Parasitology: The presence of parasites in food and food products. For the presence of bacteria, viruses, and fungi in food, FOOD MICROBIOLOGY is available.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.Eukaryota: One of the three domains of life (the others being BACTERIA and ARCHAEA), also called Eukarya. These are organisms whose cells are enclosed in membranes and possess a nucleus. They comprise almost all multicellular and many unicellular organisms, and are traditionally divided into groups (sometimes called kingdoms) including ANIMALS; PLANTS; FUNGI; and various algae and other taxa that were previously part of the old kingdom Protista.Feces: Excrement from the INTESTINES, containing unabsorbed solids, waste products, secretions, and BACTERIA of the DIGESTIVE SYSTEM.Quality Control: A system for verifying and maintaining a desired level of quality in a product or process by careful planning, use of proper equipment, continued inspection, and corrective action as required. (Random House Unabridged Dictionary, 2d ed)Sensitivity and Specificity: Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)