Protection of Cattle Against Lumpy Skin Disease: II—Factors Affecting Small Scale Production of a Tissue Culture Propagated Virus Vaccine

Abstract

SUMMARY A method is described for the propagation of sheep pox virus in tissue culture of prepubertal lamb testes for use as an immunizing agent against lumpy skin disease. The virus titre obtained was apparently unaffected if cultures were used between the 3rd and 8th day after preparation. Maximum infective titres were achieved by 48 hours when inocula of high titre were used and by 8 days with inocula of low titre. Freezing and thawing of whole cultures gave satisfactory release of virus associated with cells. No loss of infectivity was demonstrated after freeze-drying and the freeze-dried vaccine was stable for long periods when stored in the dark at 4°C. and minus 20°C. When freeze-dried vaccine in either the dry or reconstituted state was stored in clear glass containers and exposed to sunlight, there was a loss of infectivity. No loss occurred when reconstituted vaccine was exposed to sunlight in amber glass containers.