Detection of Cryptosporidium parvum oocysts in bovine feces by monoclonal antibody capture enzyme-linked immunosorbent assay

Abstract

A monoclonal antibody enzyme-linked immunosorbent assay (ELISA) was developed to detect Cryptosporidium parvum oocysts in bovine feces. Fecal oocysts were concentrated by centrifugation through formalin-ethyl acetate solution and captured with monoclonal antibody 18.280.2 reactive with C. parvum oocysts. Captured oocysts were detected with goat anti-oocyst serum, following the addition of a peroxidase conjugate of rabbit anti-goat immunoglobulin and O-phenylenediamine substrate. The assay was specific for Cryptosporidium sp. oocysts and did not detect oocysts of Eimeria auburniensis, Eimeria bovis, Eimeria ellipsoidalis, or Eimeria zuernii. Assay sensitivity allowed detection of 3 x 105 oocysts per ml of feces, compared with 1 x 106 oocysts per ml detected by examination of acid-fast-stained fecal smears and 1 x 103 oocysts per ml detected by indirect immunofluorescence. The capture ELISA was suitable for diagnostic analysis of bovine fecal samples and for assessment of oocyst shedding in experimentally infected calves. This assay may also prove useful for diagnostic assessment of humans in which cryptosporidiosis is suspected.