Rotifers ingest oocysts of Cryptosporidium parvum

Six genera of rotifers including Philodina, Monostyla, Epiphanes, Euchlanis , Brachionus, and Asplanchna were exposed to oocysts of Cryptosporidium par vum cleaned of fecal debris. Unstained oocysts and those stained with fluor escein-conjugated monoclonal antibody were added to suspensions of viable r otifers and were examined by phase-contrast, differential interference cont rast, and fluorescence microscopy. Rotifers of all six genera were observed ingesting oocysts. A maximum of 25 oocysts was observed in the stomachs of Euchlanis and Brachionus. Euchlanis and Epiphanes were observed excreting boluses containing up to eight oocysts. It was not determined whether rotif ers digested or otherwise rendered occysts nonviable.