Abstract

    A serological survey was conducted to see the prevalence of antibodies to egg drop syndrome (EDS) virus in breeders and commercial layers in Mansehra district. A total of 50 flocks including broiler breeder (30), layer breeder (10) and commercial layers (10) were surveyed from September, 2002 to March, 2003. Paired serum samples were collected at random from 20 birds in each flock at fortnight interval and screened through haemagglutination inhibition (HI) test. In broiler breeders, out of 30 flocks, 12(40%) were serologically positive for EDS. In layer breeders and commercial layers, 30 and 20% flocks were found to be seropositive, respectively. On the basis of age, maximum seroprevalence (42.85%) was observed in birds between 21-40 weeks of age. The seroprevalence was 33.33% in 1-20 weeks, 26.66% in 41-60 weeks and 25.00 % in 61 weeks and above old birds.  No specific clinical signs were observed in all three types of birds. A drop in egg production (22.555%) was observed in seropositive flocks along with misshapen soft shelled, shell-less and non-pigmented eggs. Based on these findings, the farmers were advised to vaccinate their flocks against EDS between 14-16 weeks of age using killed adjuvanted vaccines.

Key Words: Egg drop syndrome, seroprevalence, haemagglutination inhibition test.