Histopathology and Immunology Studies of Broiler Obtained La Sota Strain of Newcastle Disease Vaccine that Being Challenged with the Velogenic Indonesian Strain Newcastle Disease Virus (VND/Tasik/M13/2009)

Abstract

Newcastle Disease (ND) is a highly contagious and very virulent avian disease in all age of poultry. The aims of this study were to investigate the protective level of antibody, clinical signs, histopathology, and immunohistochemistry analyses of selected internal organs of broiler which obtained La Sota Strain of ND Vaccine and then being challenged with local strain of velogenic ND virus. Eighty birds used and divided into 4 groups @ 20 birds. The treatment birds were vaccinated with live and killed ND vaccine on 4th days old. Two groups were challenged at 25th days of age intramuscularly with 104 EID50 /0.1 ml/bird of velogenic virulent ND virus. Sera were collected at 1, 18, 22, 28, 30, and 32 days of age. Three birds from each group were examined for protective antibody level using Hemaglutination inhibition (HI) test and enzyme-linked immunosorbent assay (ELISA) at 3, 5, and 7 days post inoculation with virulent ND virus. The HI test result at 28th and 32nd days old showed that antibody level of birds obtained vaccination and followed by virus challenging were higher than those the vaccinated birds but not be challenged. The unvaccinated group showed clinical signs such as anorexia, sleepy, weakness, greenish diarrhea, and death on 3rd days onward after infection. Histopathological lesions indicated hyperemia, haemorrhages, hyperplasia, mononuclear cells infiltration, oedema, and necrosis of proventriculus and intestines. Neuronal necrosis, gliosis, vasculitis, perivascular infiltration with mononuclear cells, and endothelial hypertrophy were also observed in the brain. Immunohistochemically, ND virus antigen was detected in the endothelial cells of brain, lung, kidney, and cryptae of duodenum, but negative immunoreactivities in proventriculus. All unvaccinated birds and then challenged with ND virus were died within 7 days post challenge.