Changes

Tests that detect anti-BVDV antibody include the serum neutralisation test, and an ELISA³⁴. The serum neutralisation test depends on the ability of antibodies in the serum to neutralise BVD virus and thereby prevent infection of cell culture. The test takes four to seven days to obtain a result and requires cell culture facilities and an experienced observer. The ELISA detects anti-BVDV antibody when it binds to a specifica viral antigen. The test is completed within one day and is simple to perform. Because antibody against BVDV is prevalent in most cattle populations, a single serologic test is not usually sufficient for diagnosis. Therefore, an increase in antibody titre between paired serum samples must be more than four-fold to confirm recent infection³⁹.

Tests that detect anti-BVDV antibody include the serum neutralisation test, and an ELISA³⁴. The serum neutralisation test depends on the ability of antibodies in the serum to neutralise BVD virus and thereby prevent infection of cell culture. The test takes four to seven days to obtain a result and requires cell culture facilities and an experienced observer. The ELISA detects anti-BVDV antibody when it binds to a specifica viral antigen. The test is completed within one day and is simple to perform. Because antibody against BVDV is prevalent in most cattle populations, a single serologic test is not usually sufficient for diagnosis. Therefore, an increase in antibody titre between paired serum samples must be more than four-fold to confirm recent infection³⁹.

 

Isolation of BVDV from blood, nasal swab specimens, or tissues confirms active infection. Identification of persistent infection requires detection of virus in clinical specimens obtained at least 3 wk apart. At necropsy, tissues of choice for viral isolation include spleen, lymph node, and ulcerated segments of the GI tract.

 

 

 

. Isolation of BVDV from blood, nasal swab specimens, or tissues confirms active infection. Identification of persistent infection requires detection of virus in clinical specimens obtained at least 3 wk apart. At necropsy, tissues of choice for viral isolation include spleen, lymph node, and ulcerated segments of the GI tract.

Alternatives to viral isolation include antigen-capture ELISA from blood or serum, immunohistochemistry to detect viral protein in frozen or fixed tissues, PCR to detect viral RNA in clinical specimens, and PCR or in situ hybridization to detect viral RNA in fresh or fixed tissues. Differentiation of viral genotypes usually is done by PCR or PCR followed by nucleic acid sequencing. Monoclonal antibody binding assays and nucleic acid hybridization assays also differentiate viral genotypes.

Alternatives to viral isolation include antigen-capture ELISA from blood or serum, immunohistochemistry to detect viral protein in frozen or fixed tissues, PCR to detect viral RNA in clinical specimens, and PCR or in situ hybridization to detect viral RNA in fresh or fixed tissues. Differentiation of viral genotypes usually is done by PCR or PCR followed by nucleic acid sequencing. Monoclonal antibody binding assays and nucleic acid hybridization assays also differentiate viral genotypes.