title: Detection of Cryptosporidium parvum oocysts in calf fecal samples by direct immunofluorescence assay.
abstract: The aim of this study was to produce a conjugate containing anti-Cryptosporidium parvum polyclonal antibodies and standardize a Direct Immunofluorescence Assay (DIF) for detecting C. parvum oocysts in fecal samples from calves. In order to obtain anti-C. parvum polyclonal antibodies, two New Zealand rabbits were immunized with a purified solution of C. parvum oocysts and Freund's adjuvant. Purification of the immunoglobulin G (IgG) fraction was performed by means of precipitation in ammonium sulfate and chromatography using a DEAE-cellulose column. The anti-C. parvum polyclonal antibody titer was determined by means of the enzyme-linked immunosorbent assay (ELISA). The rabbit anti-C. parvum IgG fraction was conjugated with fluorescein isothiocyanate and standardization of the DIF was performed using various dilutions of conjugate on slides positive for C. parvum oocysts. The cross-reactivity of the anti-C. parvum conjugate was tested using oocysts of Cryptosporidium serpentis, Cryptosporidium andersoni, Escherichia coli, Eimeria sp., and Candida sp. An anti-C. parvum conjugate was successfully produced, thus allowing standardization of DIF for detection of Cryptosporidium oocysts in fecal samples. Cross-reactivity of anti-C. parvum polyclonal antibodies with C. andersoni and C. serpentis was also observed.
authors.affiliation: Faculdade de Medicina Veterinária, Universidade Estadual Paulista, Araçatuba, SP, Brazil.
authors.forename: Weslen Fabricio Pires
authors.initials: WF
authors.lastname: Teixeira
authors.forename: Willian Marinho Dourado
authors.initials: WM
authors.lastname: Coelho
authors.forename: Cáris Maroni
authors.initials: CM
authors.lastname: Nunes
authors.forename: Marcelo Vasconcelos
authors.initials: MV
authors.lastname: Meireles
mesh_terms: D000818:Animals; D002417:Cattle; D016785:Cryptosporidium parvum / Q000276:immunology / Q000302:isolation & purification*; D005243:Feces / Q000469:parasitology*; D019085:Fluorescent Antibody Technique, Direct; D033661:Oocysts / Q000276:immunology; D010274:Parasitology / Q000379:methods