title: Detection of Neospora caninum in semen of bulls.
abstract: In cattle, transplacental infection is the main route of Neospora caninum transmission, but postnatal transmission by the oral uptake of sporozoite-containing oocysts shed by dogs may also be possible. Other routes of horizontal transmission, such as the venereal route, have not been investigated. In this study, we evaluated the presence of N. caninum DNA by a nested-PCR in fresh non-extended semen and frozen extended semen straws of five Holstein-Friesian bulls with naturally-acquired neosporosis. The infection status was assessed by an immunofluorescent antibody test (IFAT) and confirmed by immunoblotting (IB). Because of inhibitory components of semen, a protocol was developed to purify N. caninum DNA from bovine semen. Sporadically, N. caninum DNA was detected in non-extended fresh semen samples and frozen extended semen straws of the five seropositive bulls. In all positive samples, specific DNA was consistently found in the cell fraction of semen and not in seminal plasma. The parasite mean load in positive fresh semen samples determined by a real-time PCR was low oscillating between 1 and 2.8 parasites/ml of semen (maximum parasite load detected in one sample was 7.5 parasites/ml of semen). In parallel, another three similar but uninfected bulls acted as controls and no N. caninum DNA was amplified in any of their fresh and straw semen samples assayed. Whether venereal transmission plays a role in the spread of bovine neosporosis needs to be determined.
authors.affiliation: Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain. luis.ortega@vet.ucm.es
authors.forename: Luis Miguel
authors.initials: LM
authors.lastname: Ortega-Mora
authors.forename: Ignacio
authors.initials: I
authors.lastname: Ferre
authors.forename: Itziar
authors.initials: I
authors.lastname: del-Pozo
authors.forename: Andrea
authors.initials: A
authors.lastname: Caetano-da-Silva
authors.forename: Esther
authors.initials: E
authors.lastname: Collantes-Fernández
authors.forename: Javier
authors.initials: J
authors.lastname: Regidor-Cerrillo
authors.forename: Carlos
authors.initials: C
authors.lastname: Ugarte-Garagalza
authors.forename: Gorka
authors.initials: G
authors.lastname: Aduriz
mesh_terms: D000818:Animals; D002417:Cattle; D003048:Coccidiosis / Q000635:transmission / Q000662:veterinary*; D016054:DNA, Protozoan / Q000032:analysis; D019084:Fluorescent Antibody Technique, Indirect / Q000662:veterinary; D008297:Male; D018688:Neospora / Q000235:genetics / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary; D012661:Semen / Q000469:parasitology*; D012749:Sexually Transmitted Diseases / Q000469:parasitology / Q000635:transmission / Q000662:veterinary*
chemical_list: D016054:DNA, Protozoan