Biology:Cercaria
A cercaria (plural cercariae) is a larval form of the trematode class of parasites. It develops within the germinal cells of the sporocyst or redia.[1] A cercaria has a tapering head with large penetration glands.[2] It may or may not have a long swimming "tail", depending on the species.[1] The motile cercaria finds and settles in a host where it will become either an adult, or a mesocercaria, or a metacercaria, according to species.
Cercarial infection in water environments by non-human schistosome species causes dermatologic burden to nearby swimmers, fishermen and farmers. The cycle as mentioned above, starts with egg distribution whether fecal in route or from the nostril of a duck or goose.[3]: 157–159 Miracidia infect snail reservoirs and form successive sporocysts. Released cercariae travel and infect nearby non-human mammals or birds, depending on species, or accidental hosts such as humans. This dead-end infection and host allergic reaction has been referred to as cercarial dermatitis or "swimmer's itch".[4][5] Dermatitis can also be seen following exposure to the cercariae of schistosome species that cause patent infections in humans (schistosomiasis) in endemic areas.[6]
Among fish, infection beneath the scale bedding by cercariae of other trematode species can result in black spot disease.[7][8] This is an example of an encysted form, or metacercaria. For some trematode species, cercarial encystment takes place on aquatic plants (e.g. in the liver fluke Fasciola gigantica[9] and the intestinal fluke Fasciolopsis buski[10]).
The term Cercaria is also used as a genus name in descriptions of species when only the larval form is known.[11]
Rotifers (Rotaria rotatoria) produce a chemical, Schistosome Paralysis Factor, that suppresses cercaria swimming and reduces infections.[12]
References
- ↑ 1.0 1.1 "Glossary". VPTH 603 Veterinary Parasitology. University of Pennsylvania School of Veterinary Medicine. http://cal.vet.upenn.edu/projects/parasit06/website/glossary.htm.
- ↑ "Schistosoma". Australian Society for Parasitology. http://parasite.org.au/para-site/text/schistosoma-text.html.
- ↑ Horák, P.; Kolářová, L.; Adema, C.M. (2002). "Biology of the Schistosome Genus Trichobilharzia". Advances in Parasitology 52: 155-233. doi:10.1016/S0065-308X(02)52012-1. ISSN 0065-308X.
- ↑ ((National Center for Emerging and Zoonotic Infectious Diseases, Division of Parasitic Diseases and Malaria)) (10 May 2019). "Cercarial Dermatitis". U.S. Centers for Disease Control and Prevention. https://www.cdc.gov/dpdx/cercarialdermatitis/index.html.
- ↑ "About Swimmer's Itch". U.S. Centers for Disease Control and Prevention. 10 September 2024. https://www.cdc.gov/swimmers-itch/about/index.html.
- ↑ Kolářová, L.; Horák, P.; Skírnisson, K.; Marečková, H.; Doenhoff, M. (2012). "Cercarial Dermatitis, a Neglected Allergic Disease". Clinical Reviews in Allergy & Immunology 45 (1): 63-74. doi:10.1007/s12016-012-8334-y.
- ↑ Pyzer, Gord (8 January 2018). "The Real Truth About Black Spot Disease, and How It Affects Fish". https://www.outdoorcanada.ca/black-spot-disease/.
- ↑ Meyers, Theodore; Burton, Tamara; Bentz, Collette; Ferguson, Jayde; Stewart, Davis; Starkey, Norman (July 2019). "Black Spot Disease (Neascus and Heterphyids)". DISEASES OF WILD AND CULTURED FISHES IN ALASKA. Fish Pathology Laboratories, Alaska Department of Fish and Game. pp. 78-79. OCLC 1104329201. https://www.adfg.alaska.gov/static/species/disease/pdfs/fishdiseases/black_spot_disease.pdf. Retrieved 21 December 2024.
- ↑ Carmona, Marcus (2013). "Fasciola gigantica". in Mulcrone, Renee. https://animaldiversity.org/accounts/Fasciola_gigantica/.
- ↑ Greiner, Lindsey (2011). "Fasciolopsis buski". https://animaldiversity.org/accounts/Fasciolopsis_buski/.
- ↑ "Cercaria Müller, 1773". WoRMS. World Register of Marine Species. 2023. http://www.marinespecies.org/aphia.php?p=taxdetails&id=728666.
- ↑ Gao, Jiarong; Yang, Ning; Lewis, Fred A.; Yau, Peter; Collins, James J.; Sweedler, Jonathan V.; Newmark, Phillip A. (2019). Khosla, Chaitan. ed. "A rotifer-derived paralytic compound prevents transmission of schistosomiasis to a mammalian host". PLOS Biology 17 (10). doi:10.1371/journal.pbio.3000485. ISSN 1545-7885. PMID 31622335.
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