Further Observations on a Filtrable Agent Isolated from Bovine Lumpy Skin Disease

SUMMARY: The method of estimating potency of lethal substances by determining death times was applied to the titration of the virus isolated from a case of bovine Lumpy Skin Disease. It was more reliable than that based on the occurrence of recognizable lesions in the embryo after amniotic inoculation.

The method was used to demonstrate the growth of virus in tissues other than skin epithelium, to determine the susceptibility of the virus to destruction by heat, and for the demonstration of neutralizing antibody.

Neutralizing antibody was found in convalescent bovine sera. Normal sera from a variety of animal species including bovines feebly neutralized the virus. This feeble neutralization may indicate the presence in sera of virus-inhibiting substances other than antibody or, in the case of bovines, antibody acquired as a result of inapparent infection.