| Dissertation note |
ND is an infectious, highly contagious and widespread disease of avian species and has a considerable economic impact on poultry industry. This study is a preliminary work to understand the mode of action of the recent VVNDV isolate of the UVAS, towards the tissue tropisms of both lymphatic and non lymphatic organs. One hundred chicks purchased from the local hatchery and reared for the trial including control, however, the VVNDV strain was received from the QOL, UVAS, Lahore, Pakistan. Three trials were conducted using the challenge dose 100,000 ELD50 (Group C) and 10,000 ELD 50 as (Group B) and 1000 ELD 50 as (Group A). Five chickens were selected randomly from each group and slaughtered on daily basis, including two chicks from control. These samples were used for histopathology and immunohistochemistry (IHC) test. Conclusively, the study indicates that NDV induces early necrosis in the lymphoid tissues of infected chickens which is correlated with the severity of the disease caused by each dilution. Necrosis does not seem only to be the direct viral replication and indirect effects may lead to death of the animals, due to depletion of lymphoid organs. However, the peak hours were recorded 72 hours to 96 hours post infection in all lymphoid and non lymphoid organs irrespective of the dilution factor of the VVNDV. Immunohistochemistry is not a routine practice in diagnostic test, however, this study may lead to a roadmap in understanding the interpretation of the clinical/pathological picture and the tropism may be helpful in future to study some other aspects like failure of commercial vaccines and to control the outbreaks of NDV in the country an endemic as well as a devastating disease of the poultry industry.
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