Properties of an Australian isolate of bovine parvovirus type 1

Abstract

An Australian bovine parvovirus isolate (BPV 267) was found to haemagglutinate human, guinea-pig, rat and dog erythrocytes, out of a range of 16 species of erythrocyte tested. The haemagglutinating activity was generally found to be both pH and temperature dependent. The virus was found to replicate best in intestinal epithelium, macrophage and lung cells, out of 9 bovine cell types tested. Highest yields of virus were obtained by the use of selected cell strains at low-passage levels which were maintained near neutral pH under conditions of high rates of cell growth. Studies of the rates of thermal inactivation with time showed the virus to be relatively stable at 37°C, 56°C and 70°C, the incorporation of serum proteins, 1 M MgCl 2 and 2 M NaCl in the medium having no influence on stability at 56°C. The virus was resistant to the action of CHCl 3, ether and 1% trypsin, and its replication was inhibited by BUDR, this effect being reversed by thymidine. Actinomycin D was found to inhibit virus replication, but only when applied during the first 8 h post-infection. Density gradient studies showed infective virus to have a density of 1.41 g cm −; haemagglutinating non-infective virus with defective morphology having a density of 1.31 g cm −3. In addition, a proportion of morphologically-complete haemagglutinating, but non-infective virus particles was found at a density of 1.36 g cm −3. The virus proved to have a mean diameter of 22 nm.