Bluetongue Virus Detection Using Microspheres Conjugated with Monoclonal Antibodies against Group-Specific Protein Vp7 by Flow Virometry

— Bluetongue is a reemerging transmissive infectious disease that threatens all countries with intensive livestock production. In cattle, bluetongue may either lead to lethality or be asymptomatic with a long-lasting viremic phase, which makes development of high-sensitivity bluetongue virus detection methods an important task. Methods of virus particle detection based on immunofluorescence assay in bluetongue-infected Vero cells, sandwich enzyme immunoassay and flow virometry have been developed using high-affinity monoclonal antibodies against VP7 (viral protein 7). High analytical sensitivity of the method (10 –0.25 TCID 50 /mL (tissue cytopathogenic dose)) was demonstrated in a flow cytometry assay. The ability to rapidly and efficiently detect virus particles in the biological fluids obtained from animals by flow virometry was demonstrated in a model system in which BTV was measured in cattle blood serum. The detection sensitivity was 10 0.75 TCID 50 /mL.