Start Date: Aug 07, 2013
End Date: Jan 02, 2014
Pathogenesis studies will be conducted at SEPRL on specific pathogen free (SPF) chickens and other avian species to characterize the clinical disease observed from vaccine and virulent Newcastle Disease Virus (NDV) strains, relating histopathological data (tissue tropism) back to epidemiological data. Some of the viruses will be obtained from diagnostic materials (swabs) from wild birds procured from a wildlife specialist from the pathology department that has a permit to collect such samples. Wild birds species listed on the APHIS permit, again procured by the wildlife specialist, may be included in these studies. Birds will be infected by dropping virus into the eye, a natural route of infection using a technique that has been employed at SEPRL over the last 12 years allowing us to compare differences over time. Clinical observations will be recorded over for two weeks and birds will be euthanized for sampling at defined days post inoculation. Birds dying from infection will be included in sampling. Tissues will be collected into 10% formalin for processing, sectioning and staining for histopathology, in situ hybridization (ISH) with a NDV matrix gene riboprobe to detect NDV mRNA, and immunohistochemistry (IHC) with an NDV anti-peptide serum to detect expressed NDV nucleoprotein (N). Other riboprobes may also be used. Seroconversion detected in blood samples collected on days 10 and 14 and/or virus isolated from oral and cloacal swabs collected at each sampling will confirm infection in sampled birds that display no clinical signs of disease. Selected tissues may also be processed separately for virus isolation or for RNA isolation. Epidemiological information on the viruses obtained, including vaccine virus strains, will be correlated with the characterization of the virus and the clinical disease and tissue tropism observed.