Browsing by Author "Ferris, R.D"
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Item Studies with Rinderpest Virus ill Tissue Culture III. The Stability of Cultured Virus and its Use in Virus Neutralization Tests(1961) Plowright, W.; Ferris, R.D; East African Veterinary Research OrganizationThe stability of cultured rinderpest virus, in maintenance medium containing 5% normal ox serum, was studied at 4°, 37°, and 56° C. The half-life at these temperatures was calculated and the results compared with figures available for other strains of rinderpest virus in cattle tissues and for measles virus in tissue culture fluids. Data were also provided on the freezing of the same virus at _25° C and _70° C, with storage for periods of up to four months. The accuracy of replicate virus titrations, in primary or serially-cultivated calf-kidney cells, was determined. Details were given of tissue culture techniques for the detection and titration of neutralizing antibody to rinderpest virus in the sera of animal especially cattle. Box titrations of a standard ox immune serum showed that a 1 log increase in virus dose lowered the SN 50 titre of the serum by a mean 0.56 log units. The error in replicate titrations of two standard immune Hera, using different batches of calf-kidney cells as substrate, was determined. The effect of normal ox serum on rinderpest virus was investigated and the sera of over 3.000 experimental cattle were examined by a "screening" test for immunity. There were no false positives and only 0.25% of the serologically-negative cattle gave later evidence of resistance to challenge. Tissue culture techniques for the detection and titration of rinderpest neutralizing antibody are briefly compared with the methods hitherto available.Item Studies with Rinderpest Virus in Tissue Culture - A Technique for the Detection and Titration of Virulent Virus in Cattle Tissues(1962) Plowright W.; Ferris, R.DVirulent strains of rinderpest virus were isolated and titrated directly in rolled tube cultures of primary calf-kidney cells. The til1le to appearance of cytopathic changes varied from 3 to 12 days, depending on the amount of virus in the inocula, which were blood or tissue suspensions derived from injected cattle. No period of adaptation to withdraw growth was necessary. Immune serum incorporated ill the medium as late as the 2nd day p.i. completely suppressed viral cytopathogenicity, thus allowing the rapid, specific identification of isolates. Culture titres were probably somewhat lower than those which have been recorded ill cattle titrations of comparable materials, but cultural methods may be reliably applied to the laboratory diagnosis and quantitative study of virulent rinderpest injections. Two attenuated vaccine strains of virus were 1I0t cytopathogenic to calf-kidney mono layers. These findings are discussed ill the light of previously reported observations, which suggested some difficulty in the adaptation of virulent rinderpest virus to growth in monolayer culture.
