Crithidia fasciculata

Crithidia fasciculata is a species of parasitic excavates. "C. fasciculata", like other species of "Crithidia" have a single host life cycle with insect host, in the case of "C. fasciculata" this is the mosquito. "C. fasciculata" have low host species specificity and can infect many species of mosquito.
Life cycle.
"C. fasciculata" is found in two morphologically different life cycle stages - the free swimming choanomastigote form, which has a long external flagellum for motility, and the attached, immotile, amastigote form in the mosquito gut. Amastigotes excreted in the faeces contaminate the mosquito habitat; contamination of flowers during nectar feeding is common.
Transmission of "C fasciculata" primarily occurs when amastigotes, washed into standing water, are ingested by mosquito larvae. The amastigotes are typically found in the rectum of a larva. Each molt of the larva results in loss of infection, but it is generally quickly re-acquired from the environment by ingestion of more amastigotes. When the fourth instar larva pupates the amastigote infection is maintained in the gut through metamorphosis giving rise to an infected adult mosquito.
Role in research.
"C. fasciculata" is an example of a non-human infective trypanosomatid and is related to several human parasites, including "Trypanosoma brucei" (which causes African trypanosomiasis) and "Leishmania" spp. (which cause Leishmaniasis). "C. fasciculata" parasitizes several species of insects and has been widely used to test new therapeutic strategies against parasitic infections. "C. fasciculata" is often used as a model organism in research into trypanosomatid biology that may then be applied to understanding the biology of the human infective species.
As is typical of the trypanosomatids, but unlike many other protists, "C. fasciculata" possess one mitochondrion. The mitochondrial DNA is found in a single structure, the kinetoplast, at the base of the single flagellum. As is common with parasitic species "C. fasciculata" requires a high nutrient content broth (including heme and folic acid) in which to grow under laboratory conditions.