title: Competitive virus assay method for titration of noncytopathogenic bovine viral diarrhea viruses (END⁺ and END⁻ viruses).
abstract: A new, reliable and secure virus assay method, named the competitive virus assay (CVA) method, has been established for the titration of bovine viral diarrhea viruses (BVDVs) that either show the exaltation of Newcastle disease virus (END) phenomenon or heterologous interference phenomenon (but not the END phenomenon). This method is based on the principle of (1) homologous interference between BVDVs, by using BVDV RK13/E(-) or BVDV RK13/E(+) strains as competitor virus, and (2) END phenomenon and heterologous interference, by using attenuated Newcastle disease virus (NDV) TCND strain as challenge virus. In titration of BVDV END(+) and BVDV END(-) viruses, no significant difference in estimated virus titer was observed between CVA and conventional methods. CVA method demonstrated comparable levels of sensitivity and accuracy as conventional END and interference methods, which require the use of a velogenic Miyadera strain of NDV and vesicular stomatitis virus (VSV), both of which are agents of high-risk diseases. As such, the CVA method is a safer alternative, with increased bio-safety and bio-containment, through avoidance of virulent strains that are commonly employed with conventional methods.
authors.affiliation: Department of Basic Science, School of Veterinary Nursing and Technology, Faculty of Veterinary Science, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino, Tokyo 180-8602, Japan.
authors.forename: Mahmod
authors.initials: M
authors.lastname: Muhsen
authors.forename: Kota
authors.initials: K
authors.lastname: Ohi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Aoki
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Ikeda
authors.forename: Akio
authors.initials: A
authors.lastname: Fukusho
mesh_terms: D000818:Animals; D002417:Cattle; D001908:Diarrhea Viruses, Bovine Viral / Q000302:isolation & purification*; D012680:Sensitivity and Specificity; D014762:Viral Interference; D019562:Viral Load / Q000379:methods*