Crithidia is a genus of trypanosomatidEuglenozoa. They are parasites that exclusively parasitise arthropods, mainly insects. They pass from host to host as cysts in infective faeces and typically, the parasites develop in the digestive tracts of insects and interact with the intestinal epithelium using their flagellum. They display very low host-specificity and a single parasite can infect a large range of invertebrate hosts.[3] At different points in its life-cycle, it passes through amastigote, promastigote, and epimastigote phases; the last is particularly characteristic, and similar stages in other trypanosomes are often called crithidial.

Genus of parasitic flagellate protist in the Kinetoplastea class
Not to be confused with the fungi genus Chytridium.

Crithidia luciliae (immunofluorescence pattern).
Scientific classification
Domain: Eukaryota
(unranked): Excavata
(unranked): Discoba
Superphylum: Discicristata
Phylum: Euglenozoa
Subphylum: Glycomonada
Class: Kinetoplastea
Subclass: Metakinetoplastina
Order: Trypanosomatida
Family: Trypanosomatidae
Genus: Crithidia
Léger, 1902[1]

The etymology of the genus name Crithidia derives from the Ancient Greek word κριθίδιον (krithídion), meaning “small grain of barley”.[4][5]

. . . Crithidia . . .

  • Crithidia bombi is perhaps the most well documented species and is the most prevalent parasite of bumblebees, including common species like Bombus terrestris, Bombus muscorum, and Bombus hortorum.[6][7] The parasites negatively impact reproductive fitness of Bombus queens, as they affect their ovarian development as well as early colony establishment after the queens emerge from hibernation.[8]
  • Crithidia mellificae is a parasite of the bee.
  • Crithidia brevicula might incorporate species of the genus Wallaceina (Wallaceina brevicula, W. inconstans, W. vicina, and W. podlipaevi) as suggested by molecular phylogenies based on 18S ribosomal RNA and glycosomalglyceraldehyde-3-phosphatedehydrogenase sequences.[9]
  • Other species include C. fasciculata, C. deanei, C. desouzai, C. oncopelti, C. guilhermei and C. luciliae.
  • C. deanei is atypical of the Crithidia genus, and it has been argued not a member of the Crithidia at all. It is not typical of trypanosomatids because of its unusual shape and it harbours endosymbiotic bacteria.[10]C. luciliae is the substrate for the antinuclear antibody test used to diagnose lupus and other autoimmune disorders

These parasites may be at least partially responsible for declining wild bumble bee populations. They cause the bumble bees to lose their ability to distinguish between flowers that contain nectar and those that don’t. They make many mistakes by visiting nectar scarce flowers and in so doing, slowly starve to death. Commercially bred bumble bees are used in greenhouses to pollinate plants, for example tomatoes, and these bumble bees typically harbor the parasite, while wild bumble bees do not. It is believed that the commercial bumble bees transmitted the parasite to wild populations in some cases. They escape from the greenhouses through vents; a simple mesh could help prevent this.[11]

  1. Léger, Louis. 1902. Sur un flagellé parasite de l’Anopheles maculipennis. Compt. Rend. Soc. Biol., 54: 354-356, .
  2. “Crithidia – Overview – Encyclopedia of Life”. Retrieved 18 August 2016.
  3. Boulanger; et al. (2001). “Immune response of Drosophila melanogaster to infection of the flagellate parasite Crithidia spp”. Insect Biochemistry and Molecular Biology. 31 (2): 129–37. doi:10.1016/S0965-1748(00)00096-5. PMID 11164335.
  4. Bailly, Anatole (1981-01-01). Abrégé du dictionnaire grec français. Paris: Hachette. ISBN 978-2010035289. OCLC 461974285.
  5. Bailly, Anatole. “Greek-french dictionary online”. Retrieved April 14, 2020.
  6. Runckel, Charles; DeRisi, Joseph; Flenniken, Michelle L. (2014-04-17). “A Draft Genome of the Honey Bee Trypanosomatid Parasite Crithidia mellificae. PLOS ONE. 9 (4): e95057. Bibcode:2014PLoSO…995057R. doi:10.1371/journal.pone.0095057. PMC 3990616. PMID 24743507.
  7. Baer, B. and P. Schmid-Hempel (2001). “Unexpected consequences of polyandry for parasitism and fitness in the bumblebee, Bombus terrestris“. Evolution. 55 (8): 1639–1643. doi:10.1554/0014-3820(2001)055[1639:ucopfp];2. PMID 11580023.
  8. Erler, Silvio; Popp, Mario; Wolf, Stephan; Lattorff, H. Michael G. (2012-05-01). “Sex, horizontal transmission, and multiple hosts prevent local adaptation of Crithidia bombi, a parasite of bumblebees (Bombus spp.)”. Ecology and Evolution. 2 (5): 930–940. doi:10.1002/ece3.250. ISSN 2045-7758. PMC 3399159. PMID 22837838.
  9. Kostygov, Alexei Yu.; Grybchuk-Ieremenko, Anastasiia; Malysheva, Marina N.; Frolov, Alexander O.; Yurchenko, Vyacheslav (2014-09-01). “Molecular revision of the genus Wallaceina. Protist. 165 (5): 594–604. doi:10.1016/j.protis.2014.07.001. ISSN 1434-4610. PMID 25113831.
  10. Camargo; et al. (1992). “Ribosomal DNA restriction analysis and synthetic oligonucleotide probing in the identification of genera of lower trypanosomatids”. The Journal of Parasitology. 78 (1): 40–8. doi:10.2307/3283683. JSTOR 3283683. PMID 1310733.
  11. Colla, Sheila R.; Otterstatter, Michael C.; Gegear, Robert J.; Thomson, James D. (2006-05-01). “Plight of the bumble bee: Pathogen spillover from commercial to wild populations”. Biological Conservation. 129 (4): 461–467. doi:10.1016/j.biocon.2005.11.013.

. . . Crithidia . . .

This article is issued from web site Wikipedia. The original article may be a bit shortened or modified. Some links may have been modified. The text is licensed under “Creative Commons – Attribution – Sharealike” [1] and some of the text can also be licensed under the terms of the “GNU Free Documentation License” [2]. Additional terms may apply for the media files. By using this site, you agree to our Legal pages . Web links: [1] [2]

. . . Crithidia . . .

Previous post To Kpalime
Next post Petralica