Sheep border dz

Pathogen and transmission

·    Pestivirus

·    Transmission: respiratory secretions, transplacental, semen

·    When infected:

o  Non-pregnant sheep infected:

§ Shed virus for few weeks, self-recovers = TI

o  Pregnant sheep infected:

§ <60d gestation = abortion

§ 60-85d gestation = abortion or PI lamb

§ >85d gestation = PI lamb

History

·    Clinical signs?

·    Abortions?

·    Weight loss in ewes?

·    DLWG in lambs? – reduced rates

·    Fertility rates? – poor fertility

·    Have they had previous known occurrences?

·    What do they do if they find a positive?

Clinical signs

·    Mainly lambs affected – hairy little shakers

o  Small, conformational abnormalities

o  Dry, hairy fleece

o  Neurological abnormalities – muscle tremours, head bbbing, shaking

·    Abortions

·    Weight loss

Investigations

·    Clinical signs in lambs

·    PCR to identify PIs – will be persistently ag positive but ab negative

Treatment

·    No treatment

Control

·    Identify and cull PI lambs

·    Avoid buying infected animals

·    Routine screening in rams, prior to breeding

·    Natural immunity through exposure of non-pregnant animals to PO

·    No vaccination available

Impacts

·    Increased level of infectious disease in lambs

·    Reduced lamb growth

·    Reproductive losses