To study the effects of ibaraki virus on preimplantation mouse embryos collected from prepubertal ICR and BALB/cByJ mice (30-40 days old) by superovulation, zona pellucida-intact (ZPI) or free (ZPF) embryos (n=774) of 4- to 8-cell and morulae were exposed to 10** (5.8) TCID50 of the viurs up to 96 hours. The embryos were examined morphologically by observing the degeneration and hatching rates, and virologically and immunologically by determining the presence of infection with the virus, in addition, the effect of washing the embryos to remove virus possibly attached to was also investigated. The ZPI 4- to 8-cell embryos and morulae exposed to the virus showed considerably higher degeneration rate than those not exposed, for 96, and for 72 to 96 hours, respectively (p0.01). The ZPF 4- to 8-cell embryos and morulae exposed to the virus showed considerably higher degeneration rates than those not exposed, throughout the whole culture hours in vitro (p0.01). The ZPI 4- to 8-cell embryos and morulae not exposed to the virus showed considerably higher rates of hatched blastocyst than those exposed (p0.01). The virus infection rates of the ZPF 4- to 8-cell embryos and morulae were significantly higher than those of the ZPI embryos according to cell culture system. The viral antigen was detected exclusively on the zona pellucida of ZPF embryos by the immunofluorescent assay. In the ZPI embryos exposed to ibaraki virus, the virus was detected in the two times-washing groups, but not in the ten times-washing groups. The results indicated that zona pellucida of murine embryos would provide an effective protection and that ten times-washing of the ZPI embryos previously exposed to the virus was effective to remove virus from the embryos

To develop more specific and sensitive diagnostic methods for infectious bovine rhinotracheitis, 7-C-2 monoclonal antibody specific to polypeptides of infectious bovine rhinotracheitis virus (IBRV) was applied in indirect immunofluorescence antibody assay (IFA), indirect immunoperoxidase assay (IPA) and radial immunodiffusion enzyme assay (RIDEA). It was found that IBRV infected in MDBK cells could be detected as early as 8 hours post infection by IFA, and that IFA was more rapid and specific to identify IBRV antigen than IPA. The diagnostic efficacy of RIDEA and SN test was studied with 88 bovine sera. It was evident that RIDEA could eliminate the false positive reaction encountered in serum neutralization (SN)test, being more rapid and sensitive than the latter. Highly significant correlation coefficiency (r= 0.76, p0.01) was evaluated between the titers of sera and the diameters of RIDEA. Tracheal membranes and sera collected from 96 slaughtered cattle with lesions in respiratory organs were examined to detect IBRV antigen and antibody by IFA, RIDEA and SN test. It was presented that positive rates were 32.3 % in IFA, 20.8 % in RIDEA and 21.9 % in SN test, and that coincidence rate between RIDEA and SN test were 100 % in positive sera and 98.7 % in negative sera. In conclusion, it was assumed that application of monoclonal antibody could improve the diagnostic efficacy of IBR by enhancing sensitivity and specificity of IPA, IFA and RIDEA