An improved hemagglutination test for study of canine parvovirus

Optimal conditions for hemagglutination (HA) by canine parvovirus (CPV) strains were investigated using several buffers. Porcine erythrocytes often agglutinated spontaneously in phosphate-buffered salt solution, isotonic saline solution or barbitone-complement-fixation buffer. Results were reproducible when borate-buffered saline (BBS) was used as the diluent for antigen, and "virus adjusting diluent" (VAD), containing 0.15 M NaCl and 0.3 M phosphate was used as the diluent for erythrocytes. Highest HA titers were obtained at pH 6.0 using BBS and VAD. Specific HA with CPV was observed not only at 4 degrees C but at 37 degrees C, and erythrocytes from horse, shrew mouse, hamster, cat, sheep and dog, as well as pig and African green monkey were agglutinated by CPV using the improved method.