M. Numan and M. Siddique

Department of Veterinary Microbiology, University of Agriculture,Faisalabad, 38040, Pakistan 

Abstract

    A survey based on collection of serum samples for the determination of prevalence of avian influenza (AI) in non-vaccinated layer flocks was carried out in an area of Punjab having complaints similar to those represented by AI. Paired serum sampling was done from 14 non-vaccinated flocks against any subtype of AI virus (AIV). A total of 204 serum samples were collected (148 soon after exhibiting signs and symptoms and 56 after three weeks interval from positive farms for AIV antibodies) from 14 commercial layer farms. Haemagglutination Inhibition (HI) test was performed for the determination of serum antibodies against AIV. The results showed that out of 14 sampled farms, three farms had antibodies against only H7 subtype, two farms had antibodies against H9 and two farms showed antibodies against both subtypes, H7 and H9, while remaining 7 farms were negative for antibodies to AI. Furthermore, out of these positive farms only one farm was found seroconverted for H7 subtype.

Key words: Avian influenza, haemagglutination inhibition, seroconversion.