- Ribeiroia
Ribeiroia is a genus of
parasite in the classTrematoda , phylumPlatyhelminthes . Three species of "Ribeiroia" are currently recognized: "R. ondatrae" in the Americas, "R. marini" in the Caribbean, and "R. congolensis" in Africa.The
adult form lives in the intestines of greater than 40 species of birds and at least several species of mammals. Its eggs pass out in its host's faeces, and hatch intomiracidia if the faeces falls into water.The
miracidium swims about until it finds a freshwatersnail of the familyPlanorbidae . In the snail the miracidium develops into aredia which producescercaria e. The cercariae exit from the snail and penetrate the developinglimb bud s of a metamorphosingfrog tadpole , usually the hind limb buds, andencyst there as metacercariae. As a result the affected limbs can develop wrongly, leading to various malformations such as extra limbs, missing limbs, skin webbings, and bony triangles.cite journal | last = Johnson | first =P. T. J. | coauthors =Lunde, K. B. Haight, R. W. Bowerman, J.; Blaustein, A. R. | title ="Ribeiroia ondatrae" (Trematoda: Digenea) infection induces severe limb malformations in western toads ("Bufo boreas") | journal =Canadian Journal of Zoology | volume =79 | issue =3 | pages =370–379 | date =Mar 2001 | doi =10.1139/cjz-79-3-370 | accessdate =] [cite journal | last =Schotthoefer | first =Anna M | coauthors = Koehler, Anson V; Meteyer, Carol U; Cole, Rebecca A | title =Influence of "Ribeiroia ondatrae" (Trematoda: Digenea) infection on limb development and survival of northern leopard frogs ("Rana pipiens"): Effects of host stage and parasite-exposure level | journal =Canadian Journal of Zoology | volume =81 | issue =7 | pages =1144–1153 | date = Jul 2003 | doi =10.1139/z03-099 | accessdate =]In laboratory experiments, "Ribeiroia" also causes elevated mortality (up to 60%) in developing amphibian larvae. Malformed frogs may survive and mature, but the deformity makes the frog slower, and more easily caught by the parasite's definitive host (birds or mammals), whose
gut digests the frog, releasing the parasite, which grows to adulthood in the predator's gut.References
Johnson, P. T. J., K. B. Lunde, E. G. Ritchie, and A. E. Launer. 1999. The Effect of Trematode Infection on Amphibian Limb Development and Survivorship. Science 284: 802-804
External links
*http://www.blackwell-synergy.com/links/doi/10.1111%2Fj.1523-1739.2003.00217.x
*http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=126596
*http://info.hartwick.edu/biology/def_frogs/
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