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Pathogenesis and epidemiology of border disease
Annales De Recherches Veterinaires. Annals of Veterinary Research
|January 1, 1987
Summary
Border disease virus (BDV) infection in pregnant sheep causes fetal death or congenital defects like tremors and hairy fleeces in lambs. Persistently infected sheep are key to BDV epidemiology, with cattle also posing a risk.
Area of Science:
- Veterinary Virology
- Sheep and Cattle Infectious Diseases
- Epidemiology
Background:
- Border disease virus (BDV) infection poses significant risks to susceptible pregnant sheep.
- Infection can lead to fetal death (resorption, mummification, stillbirths) or congenital abnormalities in lambs, termed 'hairy-shaker' lambs.
- Persistently infected sheep act as the primary reservoir and disseminators of BDV, crucial for flock epidemiology.
Purpose of the Study:
- To review the pathogenesis of BDV infection in sheep.
- To investigate the role of persistently infected sheep and cattle in BDV epidemiology.
- To assess antigenic relationships between cattle pestiviruses (BVD) and BD viruses for vaccine development.
Main Methods:
- Review of existing literature on BDV pathogenesis and epidemiology.
- Analysis of antigenic relationships among Scottish isolates of cattle pestiviruses and BD viruses.
- Evaluation of potential vaccine efficacy based on viral strain identification.
Main Results:
- BDV readily crosses the placenta, causing severe fetal outcomes or congenital defects in lambs.
- Persistently infected sheep and cattle (1-3% prevalence) are significant sources of BDV transmission.
- Two antigenically distinct strains of BD virus have been identified, impacting vaccine strategies.
Conclusions:
- An effective BDV vaccine for sheep must protect against both identified strains.
- A cattle vaccine should ideally incorporate both strains to prevent BDV transmission from cattle to sheep.
- Understanding persistent infections is critical for controlling BDV spread in sheep flocks.