Isolation of Cowdria ruminantium by means of Percoll density gradient centrifugation and detection by an enzyme-linked immunosorbent assay.

The isolation of Cowdria ruminantium by means of Percoll density gradient centrifugation permits the recovery of partially purified viable populations of the organism possessing distinctly different densities. These conclusions are based upon results of analyses of density fractions by intravenous inoculation into sheep, protein determination, electron microscopy and enzyme-linked immunosorbent assay. Morphological differences were observed in the density fractions obtained from infected brain tissue and Amblyomma hebraeum nymphae.