Epidemiological studies on a hairy shaker virus infected flock

A serological study of hairy shaker disease (HSD) was carried out on a group of 30 Romney two-tooth ewes and their lambs over a two year period. Although ten ewes showed seroconversion to HSD virus during pregnancy, an association between infection with HSD virus and reproductive failure was not established. Passive immunity was demonstrated in nine of 21(43%) of the lambs. The duration of passive immunity was 10-20 weeks (mean 14.9 weeks) with the half life of antibody being 18.7 days (SD=3.04). The lambs were studied serologically for 12-20 months. Infection with HSD virus was demonstrated in nine of 16 lambs (56%) with most infections occurring in the summer and autumn when they were three to eight months old.