Submitted to: Journal of Parasitology
Publication Type: Research Notes
Publication Acceptance Date: 7/1/2002
Publication Date: 10/1/2002
Citation: TROUT, J.M., WALSH, E.J., FAYER, R. ROTIFERS INGEST GIARDIA CYSTS. JOURNAL OF PARASITOLOGY. 2002. Vol.88:1038-1040. Interpretive Summary: There is little information available on any organisms that may be predator of Giardia cysts under natural conditions. A class of free-living microscopic organisms called rotifers was previously shown to ingest oocysts of another protozoan, Cryptosporidium parvum. Rotifer species of six genera were tested for their ability to ingest Giardia cysts, that had been isolated from the feces of experimentally infected calves. The cysts were pre-stained with an fluorescent antibody to facilitate observation under the microscope. Five of the rotifer species ingested Giardia cysts within five minutes after cysts and rotifers were combined. The cysts were retained within the rotifer bodies through the twenty minute observation period. These results suggest rotifers could could be used as bio-controls to reduce Giardia contamination of surface waters.
Technical Abstract: Seven species of rotifers representing six genera, Epiphanes, Plationus, Philodina species A, Asplanchna, Philodina species B, Platyias, and Brachionus (brackish water species), were exposed to Giardia cysts isolated from the feces of experimentally infected holstein calves. Giardia cysts were prestained with an FITC-conjugated monoclonal antibody and mixed with viable rotifers on 3-well teflon coated microscope slides. Organisms were observed with phase-contrast, differential interference contrast, and fluorescence microscopy. Five rotifer species, Epiphanes brachionus, Plationus patulus, Bdelloid Sp1, Philodina sp., Platyias quadricornis, ingested varying numbers of cysts, which were retained within the rotifers' bodies throughout the observation period. Thus rotifers have the potential for use as a bio-control agent for reducing Giardia contamination of surface waters.