الفهرس 
Cover Page Title in EnglishOnly 14 pages are availabe for public view
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Abstract
Egg DROP syndrome virus is of high economic importance due to its drastic negative effects on egg production in laying birds throughout the world including Egypt. The loss incurred by poultry industry due to reduced productivity, culling and cost of medicine is considered to be often greater than loss due to mortality To evaluate the current situation of infection with EDS-76virus in Egypt, a total of 35 tissue samples (kidney and oviduct) and oviduct swabs were collected from10 EDS-vaccinated layer chicken flocks raised in Menoufia, El-Behera and Gharbia governorates during the period 2014-2015. The flocks had a history of decreased egg production (15.5-17%) associated with occurrence of soft-shelled eggs. Virus isolation was attempted in 10-day-old embryonated duck eggs via allantoic sac inoculation.Five days after inoculation, the allantoic fluids were tested for the presence of hemagglutinating (HA) activity using chicken erythrocytes. Seven samples were tested positive for HA activity throughout three consecutive passages. HA titers for each isolate were 4,6,3,8,9,4 and 2 for samples 1,2,3,15,16,18 and 23 based on log2, respectively. Haemagglutination inhibition test of 7 isolates showed complete inhibition of 5 isolates (No 1,2,15,16 and 18) using EDS virus antiserum. Thus confirming the isolates as EDS -76 virus. The result revealed that HI titer of 5 isolates (1, 2, 15, 16 and 18) were 7,5,8,7 and 7 based on log2, respectively. The presence of EDS -76 virus was assessed in all HA-positive allantoic fluids by hexon gene-based conventional and real-time PCR assays. In 6 out of 7 samples, PCR was successfully applied to detect the virus DNA, meanwhile all the employed samples were tested positive for the presence of EDS-76 virus by real-time PCR assay. The SYBR green-based real-time PCR assay described in the present study was found to be more sensitive and less time consuming than conventional PCR assay for detection of EDS-76 virus genome.