ARS | Publication request: Experimental clinical and pathologic characterization of West African Newcastle disease viruses

Submitted to: American Association of Avian Pathologists
Publication Type: Abstract Only
Publication Acceptance Date: April 1, 2012
Publication Date: August 4, 2012
Citation: Jones, M.E., Cattoli, G., Cardenas-Garcia, S., Miller, P.J., Afonso, C.L., Brown, C.C. 2012. Experimental clinical and pathologic characterization of West African Newcastle disease viruses [abstract]. American Association of Avian Pathologists. p.22.

Technical Abstract: Newcastle disease is a very significant disease of commercial and backyard poultry in Africa, and has been reported in numerous African countries. Recent analysis of strains from West Africa has revealed the emergence of at least one novel genetic lineage that differs from the previously-characterized strains known to circulate in Southern Africa (1). Clinical signs and the ability to replicate and cause pathogenic damage in different tissues of three West African strains and one South African strain of Newcastle disease virus (NDV) were investigated through an experimental infection study. The West African viruses Burkina Faso/2415-580/2008, Nigeria/228-7/2006, and Niger/1377/2006, were compared to Goose/South Africa/08100426/2008, which was considered to be representative of Southern African NDV. Each strain was inoculated into a group of 4-week-old, specific pathogen free (SPF), white leghorn chickens via eyedrop, following the protocol for our standardized clinicopathologic assessment experiments. A fifth group was mock-inoculated, as a control. For each experimental group, euthanasia and complete post-mortem examination were performed at days 2, 5, and 10 post-infection, or earlier in the case of severe disease. For all strains, all virus-infected birds died, or were euthanized due to severity of clinical signs, by day 4 post-infection. Gross and histologic examination of all birds revealed severe necrosis of lymphoid tissues (spleen, thymus, Bursa of Fabricius, cecal tonsils), intestinal hemorrhage, and eyelid edema and hemorrhage. Immunohistochemical staining of lymphoid tissues revealed widespread viral antigen associated with lesions, in all cases. Results demonstrate that the three previously-uncharacterized West African strains are highly virulent, and highlight the importance of continued surveillance and virus characterization in Africa.