pretiosa (Bowerman and Johnson 2003), such abnormalities appear to be relatively rare and generally associated with the trematode Ribeiroia
ondatrae (Sessions and others 1999; Johnson and others 2001; Stopper and others 2002).
In a study of Ribeiroia
ondatrae, cercariae were consumed by Hydra spp.
As parasites of the genus Ribeiroia
, which also can cause deformities in amphibians (Johnson et al.
Pieter Johnson of the University of Colorado Boulder and colleagues studied field data from hundreds of California ponds and found that communities with high species diversity had only about 20 percent as much transmission of the trematode parasite Ribeiroia
ondatrae, and suffered roughly half as much disease as communities with low diversity.
Johnson and colleagues visited hundreds of ponds in California, recording the types of amphibians living there as well as the number of snails infected by the pathogen Ribeiroia
Algunos factores que han sido reconocidos como causantes de malformaciones son: parasitos, como el helminto trematodo Ribeiroia
ondatrae (Johnson et al.
Analysis of a subsample did not demonstrate any evidence of infection with the parasite Ribeiroia
Recent research has linked the infection of a flatworm parasite called Ribeiroia
ondatrae to amphibian malformations," says Larsen.
Johnson discovered that bodies of water with higher frequencies of abnormal frogs also teem with a trematode--or wormlike parasite (organism that lives on or inside another organism)--called Ribeiroia
Schotthoefer (UIUC, Urbana) reported that infection with the larval trematode Ribeiroia
ondatrae could be responsible for limb malfomations in tadpoles and could explain the observed increase in the frequency of these malformations within natural frog populations.
2003) reported an increased prevalence of parasite-induced malformations by the trematode Ribeiroia
from 1946 to 2002.
In the April 30 SCIENCE, they finger Ribeiroia
as the villain in ponds in Santa Clara County, Calif.