Methods for the detection of viruses in bovine serum.

An evaluation of selected commonly used procedures for the recovery of endogenous viral contaminants in bovine serum was undertaken. Low speen centrifugation (25,000 x g) was found to be efficient for the recovery of bovine herpesvirus type 1 (BHV-1) and parainfluenza virus type 3(PI-3) in bovine serum. Decreased infectivity titers were obtained when parainfluenza virus type 3, and to a lesser extent bovine herpes virus type 1, were concentrated using high speed centrifugation (100,000 x g) for extended time periods. In neither case could infectious virus be recovered from serum containing sufficient titers of homologous neutralizing antibody, although electron microscopy examination revealed the presence of the viruses previously added. In the presence of homologous antibody, virus particles appeared to have a diffuse, poorly defined outer membrane. Neutralizing antibody titers to bovine herpesvirus type 1 and outer membrane. Neutralizing antibody titers to bovine herpesvirus type 1 and parainfluenza virus types were found in fetal, calf, and adult bovine sera. The prevalence and magnitude of the antibody titers to these viruses increased with the age of the animals examined.