Crithidia is a genus of parasites that exist primarily in the intestines of invertebrates. See genus (mathematics) for the use of the term in mathematics. ... A parasite is an organism that lives in or on the living tissue of a host organism at the expense of that host. ... Invertebrate is a term coined by Chevalier de Lamarck to describe any animal without a backbone or vertebra, like insects, squids and worms. ...

These flagellate protozoa are classified as kinetoplastids. The primary primarily host for crithidia are arthropods, especially insects, and they live the intestine. They pass from host to host as cysts in feces. Parasitic excavate (Giardia lamblia) Green alga (Chlamydomonas) Flagellates are cells with one or more whip-like organelles called flagella. ... Protozoa (in Greek protos = first and zoon = animal) are single-celled creatures with nuclei that show some characteristics usually associated with animals, most notably mobility and heterotrophy. ... Families Bodonidae Trypanosomatidae The kinetoplastids are a group of flagellate protozoa, including a number of parasites responsible for serious diseases in humans and other animals, as well as various forms found in soil and aquatic environments. ... Subphyla and Classes Subphylum Trilobitomorpha Trilobita - Trilobites (extinct) Subphylum Chelicerata Arachnida - Spiders, Scorpions, etc. ... Classes & Orders Subclass: Apterygota Orders Archaeognatha (Bristletails) Thysanura (Silverfish) Monura - extinct Subclass: Pterygota Orders Ephemeroptera (mayflies) Odonata (dragonflies and damselflies) Diaphanopteroidea - extinct Palaeodictyoptera - extinct Megasecoptera - extinct Archodonata - extinct Infraclass: Neoptera Orders Blattodea (cockroaches) Isoptera (termites) Mantodea (mantids) Dermaptera (earwigs) Plecoptera (stoneflies) Orthoptera (grasshoppers, etc) Phasmatodea (walking sticks) Embioptera (webspinners) Zoraptera... The intestine is the portion 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. ... A cyst is a closed sac having a distinct membrane and developing abnormally in a cavity or structure of the body. ... Rabbit feces are usually 0. ...

Though it changes shape throughout its life cycle, its characteristic shape is fusiform (spindle shaped).

These parasites can be passed to humans via insect hosts, and are respsonsible for a number of diseases. These include Chagas disease and African sleeping sickness spread by the tsetse fly. Sleeping sickness or African trypanosomiasis is a parasitic disease in humans. ... Binomial name Glossina morsitans The tsetse fly, Glossina morsitans, is a fly (order Diptera) that eats blood from animals, including humans. ...