Serological Survey of Newcastle Disease in Layer Chickens in Diyala Governorate

Background : One of the most deadly diseases affecting chickens is Newcastle disease. Both the poultry industry and household village hens suffer severe losses of Diseases. Due to the free-ranging nature of domestic chickens in villages, there is a significant likelihood that they may come into touch with wild birds, which may serve as a reservoir for numerous viral infections . Aims: The current study was conducted to clarify the real evidence that the Layer chickens play important role in the epidemiology source of NDV.  Methods : Group of Layer chickens were used at 50 and150 day old for identification of the NDV. Antibody Rapid Test Kit (BIO-TEK Instruments Inc., USA) used to identify the positive cases, all positive cases by this kit were tested by Enzyme- Linked Immunosorbent Assay (ELISA) to determine the antibody titers against NDV in all study groups. Results : Current  study revealed that antibodies against NDV were detected with the mean titer of 11286.42± and 2232.391to each age groups respectively In 90 serum samples taken from hens without a history of Vaccination from five districts in the Diyala province between September and October 2023, the ELISA test was performed to look for antibodies against the Newcastle disease virus.  Post-mortem lesions in the nervous, digestive, and reproductive systems have been documented. The severe alterations has appeared in the female reproductive system, such as hemorrhagic stigmata on the ovarian follicles. Proventricular mucosal bleeding and necrotic hemorrhage areas on the mucosal surface of the gut, particularly the cercal tonsils, were found in the digestive system. Proventiculus liver, cecal tonsils, spleen, kidney, brain, and heart all underwent histopathological alterations. The ELISA test result during the study period showed high levels during and after 7 days after infection NDV .By ELISA 97% of sera were found to be positive Conclusions Infectious Newcastle Disease  virus infection was endemic inlayer chickens of Diyala Governorate regardless of the control program using commercial vaccines. It seems the maternal antibodies and vaccination did not protect chickens against NDV infection, which might indicate the virus circulation in industrial farms in the study area. Therefore, it is recommended to conduct more Serological studies for local detection of the viruses and the preparation of NDV vaccine from local isolates.