Detection of Cryptosporidium parvum oocysts in calf fecal samples by direct immunofluorescence assay

• Autor(a) principal: Teixeira,Weslen Fabricio Pires
• Data de Publicação: 2011
• Outros Autores: Coelho,Willian Marinho Dourado, Nunes,Cáris Maroni, Meireles,Marcelo Vasconcelos
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Revista Brasileira de Parasitologia Veterinária (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1984-29612011000400003
• topic: Direct immunofluorescence; oocysts; Cryptosporidium parvum; fecal samples; cattle

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.