Induced sero-conversion in heifers with a field strain of bovine pestivirus--a comparison of methods and doses
| Autor: | L. G. Cook, T. M. Jessep, I. R. Littlejohns |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
Veterinary medicine
General Veterinary Serial dilution Strain (chemistry) Inoculation animal diseases Infectious dose Pestivirus Cattle Diseases General Medicine Biology biology.organism_classification Antibodies Viral Virology Togaviridae Infections Carrier State Herd Animals Nasal administration Cattle Female Immunization Viremia |
| Zdroj: | Australian veterinary journal. 67(11) |
| ISSN: | 0005-0423 |
| Popis: | SUMMARY Losses from pestivirus infection in a closed herd of cattle occurred over several years. In order to prevent further losses, controlled exposure of non-pregnant heifers to pestivirus from viraemic carrier animals was undertaken. Two initial experiments were conducted using either intra-nasal EDTA blood or field contact. Subsequently, other yearling heifers were inoculated with various dilutions of serum using subcutaneous, conjunctival and intra-nasal routes. Effective doses were determined. Neither inoculation nor contact infection produced any clinical illness. The highest dilutions of serum at which sero-conversion occurred were conjunctival, undiluted; intranasal, 10-1 and subcutaneous 10-5. With the subcutaneous route all heifers sero-converted at 10-3. The results for the subcutaneous inoculations showed that the 50% infectious dose for cattle was not distinguishable from that determined in cell culture. Inoculation with a field strain of pestivirus in freeze-thawed serum has effectively and safely induced sero-conversion in heifers. Inoculation of all cattle at risk is considered necessary because no secondary transmission from inoculated heifers was observed. |
| Databáze: | OpenAIRE |
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