title: Experimental infection of sheep with Neospora caninum oocysts.
abstract: The purpose of the present study was to investigate the potential of Neospora caninum oocysts to infect sheep and determine whether N. caninum DNA could be detected by polymerase chain reaction (PCR) assay in blood and brain of sheep after oocyst inoculation. Six ewes were inoculated per os with 10(4) N. caninum oocysts, whereas 2 ewes served as uninoculated controls. All sheep were bled weekly for 7 wk after inoculation. Blood was analyzed for the presence of N. caninum DNA by 2 different PCR assays, as well as for the presence of antibodies to recombinant and native N. caninum antigens. Neospora caninum DNA was detected in 2 sheep as early as 7 days after oocyst inoculation (DAOI). All 6 sheep were PCR positive by 32 days and remained positive until the end of the study at 49 DAOI. Aside from 1 ewe, all sheep inoculated with N. caninum oocysts contained detectable N. caninum DNA in the brain tissue collected at 49 DAOI. Unlike with PCR, no lesion or parasite was detected by immunohistochemistry. Antibodies were detected by enzyme-linked immunosorbent assay, Neospora agglutination test, or immunoblotting to either native or recombinant N. caninum antigens in sheep inoculated with oocysts.
authors.affiliation: Parasite Biology, Epidemiology and Systematics Laboratory, Animal and Natural Resources Institute, Agricultural Research Service, United States Department of Agriculture, Beltsville, Maryland 20705, USA.
authors.forename: Ryan
authors.initials: R
authors.lastname: O'Handley
authors.forename: Susan
authors.initials: S
authors.lastname: Liddell
authors.forename: Carolyn
authors.initials: C
authors.lastname: Parker
authors.forename: Mark C
authors.initials: MC
authors.lastname: Jenkins
authors.forename: J P
authors.initials: JP
authors.lastname: Dubey
mesh_terms: D000372:Agglutination Tests / Q000662:veterinary; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood*; D001921:Brain / Q000469:parasitology; D003048:Coccidiosis / Q000276:immunology / Q000662:veterinary*; D016054:DNA, Protozoan / Q000032:analysis / Q000097:blood; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005260:Female; D015151:Immunoblotting / Q000662:veterinary; D018688:Neospora / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012756:Sheep; D012757:Sheep Diseases / Q000276:immunology* / Q000469:parasitology
chemical_list: D000913:Antibodies, Protozoan; D016054:DNA, Protozoan