|Pandarrangga, Putri - University Of Georgia|
|Brown, Corrie - University Of Georgia|
|Haddas, Ruth - Kimron Veterinary Institute|
|Rehmani, Shafqat - University Of Veterinary And Animal Sciences|
|Susta, Leonardo - University Of Guelph|
Submitted to: Veterinary Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/3/2016
Publication Date: 7/1/2016
Publication URL: http://handle.nal.usda.gov/10113/62695
Citation: Pandarrangga, P., Brown, C.C., Miller, P.J., Haddas, R., Rehmani, S.F., Afonso, C.L., Susta, L. 2016. Pathogenesis of new strains of Newcastle disease virus from Israel and Pakistan. Veterinary Pathology. 53(4)792-796. doi:10.1177/0300985815622972.
Interpretive Summary: Newcastle disease is a disease of poultry that is caused by virulent strains of Newcastle disease virus (NDV). If birds do not have sufficient antibodies from vaccination, they will die from the disease. The NDV strains change their genetic makeup as they pass from bird to bird over time. Our laboratory has identified two strains of NDV, one from Pakistan and another from Israel, that have changed so much that when their genetic makeup is compared to other NDV strains, they form new groups called sub-genotypes. The new subgenotypes VIIi and XIIIb are from Israel and Pakistan, respectively. Both viruses have three or more basic amino acids in their fusion cleavage site, which means that they are virulent and able to cause high levels of mortality in susceptible birds. In addition, these NDV strains caused severe gross lesions in all of the organs important for an immune response (thymus, bursa, spleen, Peyer’s patch, etc.). Both viruses replicated to very high amounts (titers) in chickens before causing the death of the animals, which increased the amount of virus in the environment. No novel gross lesions were observed with these two viruses. This is the first report of gross and histopathic lesions with these two new sub-genotypes.
Technical Abstract: In the past few years, Newcastle disease virus (NDV) strains with epizootic characteristics belonging to subgenotypes VIIi and XIIIb emerged in the Middle East and Asia. In this study, 2 NDV strains—1 representative of subgenotype VIIi isolated in Israel (Kvuzat/13) and 1 representative of subgenotype XIIIb isolated in Pakistan (Karachi/07)—were characterized by intracerebral pathogenicity index and detailed clinicopathologic assessment. The intracerebral pathogenicity index values for Kvuzat/13 and Karachi/07 were 1.89 and 1.85, respectively, classifying these strains as virulent by international standards. In 4-week-old White Leghorn chickens, both strains caused 100% mortality within 4 (Kvuzat/13) and 5 (Karachi/07) days postinfection. Histopathology and immunohistochemistry for NDV nucleoprotein showed that both strains had wide systemic distribution, especially targeting lymphoid organs and mucosa-associated lymphoid tissues in the respiratory and intestinal tracts. Results of the animal experiment confirm that both Kvuzat/13 and Karachi/07 are highly virulent and behaved as velogenic viscerotropic NDV strains.