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

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

PREPARATION OF CONJUGATE FOR USE IN AN ELISA FOR HUMORAL IMMUNE RESPONSE AGAINST EGG DROP SYNDROME VIRUS IN LAYER CHICKS

An indirect enzyme-linked immunosorbent assay (ELISA) was performed for the detection of antibodies against Egg Drop Syndrome (EDS) virus. Virus identification was done through haemaggluti- nation inhibition (HI) test using known antisera. Antichicken immunoglobulins were raised in goats and purified by ammonium sulphate precipitation technique. These goat-antichicken immunoglobulins were conjugated with horseradish peroxidase. Twenty-seven serum samples were collected from a layers flock vaccinated against EDS and specific antibodies were determined by using a horseradish conjugate