ABSTRACT
Pestiviruses are enveloped single-chain ribonucleic acid viruses with a positive polarity. Pestiviruses include the viruses of classical swine fever (hog cholera), Border disease of sheep, mucosal disease of cattle, and isolates obtained from wild animals, such as red deer (Cervus elaphus). Among ruminants, pestiviruses have developed a remarkable strategy for assuring their persistence. Through epigenetic transmission, they lead to the birth of asymptomatic carrier animals harbouring non-cytopathic variants, which become immunotolerant to the strain of virus present. The presence of a small number of asymptomatic carriers enables the virus to circulate within a herd by horizontal transmission, leading to the birth of a new generation of asymptomatic carriers.
Subject(s)
Carrier State/veterinary , Pestivirus , Ruminants , Togaviridae Infections/veterinary , Animals , Border Disease/microbiology , Bovine Virus Diarrhea-Mucosal Disease/microbiology , Carrier State/microbiology , Cattle , Classical Swine Fever/microbiology , Deer , Pestivirus/physiology , Sheep , Swine , Togaviridae Infections/microbiologyABSTRACT
An enzyme-linked immunosorbent assay (ELISA), using monoclonal antibodies for capture and detection, was developed for detecting bovine viral diarrhoea virus (BVDV) antigens in blood samples. The test was evaluated using 761 field samples of known status (viraemic or not). When an appropriate cut-off value was chosen, the sensitivity, specificity, and predictive values of the assay were 100%, higher than the values obtained by classical virus isolation. Correlation with the latter technique exceeded 90%. The ELISA is a good candidate for replacing virus isolation as a reference method for BVDV antigen detection in persistently infected carriers. A method based on the mean of the standard deviation ratio can be used to choose the cut-off value in order to optimise reproducibility.
Subject(s)
Antigens, Viral/blood , Bovine Virus Diarrhea-Mucosal Disease/diagnosis , Carrier State/veterinary , Diarrhea Viruses, Bovine Viral/isolation & purification , Enzyme-Linked Immunosorbent Assay/veterinary , Animals , Bovine Virus Diarrhea-Mucosal Disease/epidemiology , Carrier State/diagnosis , Carrier State/epidemiology , Cattle , Diarrhea Viruses, Bovine Viral/immunology , Evaluation Studies as Topic , Predictive Value of Tests , Sensitivity and Specificity , Viremia/diagnosis , Viremia/epidemiology , Viremia/veterinaryABSTRACT
Detection of cattle persistently infected with bovine viral diarrhoea virus (BVDV) is crucial to controlling mucosal disease. A sandwich enzyme-linked immunosorbent assay (ELISA) using monoclonal antibodies raised against the 48-kDa glycoprotein and the 120/80-kDa protein was developed for detecting antigens in leucocytes of 3 persistently BVDV-infected calves. The test is simple, sensitive and rapid. Moreover the same ELISA was able to recognise Belgian field isolates of BVDV. These results show that the test can be applied in the field.
Subject(s)
Antigens, Viral/blood , Diarrhea Viruses, Bovine Viral/isolation & purification , Enzyme-Linked Immunosorbent Assay/veterinary , Animals , Antibodies, Monoclonal/immunology , Antibody Specificity , Binding, Competitive , Bovine Virus Diarrhea-Mucosal Disease/diagnosis , Cattle , Cells, Cultured , Enzyme-Linked Immunosorbent Assay/methodsABSTRACT
Twenty-one monoclonal antibodies (MAbs) directed against the NY-1 and the Osloss-c strains of bovine viral diarrhoea virus were produced and characterized by indirect immunofluorescence assay, radioimmunoprecipitation and neutralization tests. Fourteen MAbs directed against the NY-1 strain recognized the gp48 and showed a weak neutralizing activity in the presence of goat anti-mouse immunoglobulin serum.
