A serological investigation was undertaken on flooks with depressed egg production. This syndrome is characterized either by a failure to attain predicted production targets or by a fall in egg, numbers. The depression in production could reach over 30%. It might or might not return to normal. For a short period the eggs produced in some flocks were smaller, lose, colour, have poor egg shell strength and many soft shelled eggs are laid. Also, some flocks were suffering form mild respiratory symptoms and increase in mortality with decrease in feed intake. The results revealed that no obvious correlation was found between antibody to adenovirus, (BDS76 and CELO), (BDS76 and CELO), infectious bronchitis virus (I.B.V), infectious laryngotracheitis virus (I. L. T. V.), avain encephalomyelitis virus (A. E. V.), Newcastle disease virus (N. D. V.), reovirus or infectious bursal disease virus (I. B. D. V.) and this syndrome.
The ELISA results of turkey rhinotracheitis (TRT), showed only and positive cases out of 38
samples from four flocks, while three gave high positive results. When the same serum samples were examined by Ornithobacterium thinotracheale (ORT) ELISA 23 of 38 serum
samples were positive to ORT and 11 serum samples + and only 3 serum samples were
negative. These results indicate that ORT might be the cause of this. syndrome. This is the first
serological evidence of its presence in Egypt. There was a high correlation between results of
immunocomb IgG and HI for ND virus antibody titers for all serum samples tested. Immunocomb IgG proved very sensitive in detecting antibodies against IB, IBD, when it was compared with AGPT.