ISOLATION OF EGG DROP SYNDROME VIRUS AND ITS MOLECULAR CHARACTERIZATION USING SODIUM DODECYL SULPHATE POLYACRYLAMIDE GEL ELECTROPHORESIS

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

Abstract   

    Six isolates of egg drop syndrome (EDS) virus were recovered from five different outbreaks of EDS in commercial laying hens in and around Faisalabad. The aberrant eggs were fed to the susceptible laying hens for experimental induction of infection. The samples from infected birds (egg washing, cloacal swabs, oviducts and spleens) were collected, processed and inoculated into 11-day old duck embryos. The presence of virus in harvested allanto-amniotic fluid was monitored by spot and microhaemagglutination tests and confirmed by haemagglutination inhibition and agar gel precipitation tests. The EDS virus grew well in duck embryos and agglutinated only avian but not mammalian red blood cells. These isolates were purified through velocity density gradient centrifugation. Protein concentration was determined through Lowry method and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) was conducted by loading 300 µg protein concentration on 12.5% gel using discontinuous buffer system. All the six isolates showed 13 polypeptides, which were identical to those described in the referral EDS-76 virus (strain-127). The molecular weights of the polypeptides ranged from 6.5 KDa to 126 KDa.

Key words: Egg drop syndrome, haemagglutination, sodium dodecyl sulphate polyacrylamide gel electrophoresis