Submitted to: International Symposium on Avian Influenza
Publication Type: Abstract Only
Publication Acceptance Date: January 30, 2009
Publication Date: April 5, 2009
Citation: Avellaneda, G.E., Sylte, M.J., Lee, C., Suarez, D.L. 2009. A heterologous neuraminidase subtype strategy for the differentiation of vaccinated and infected animals (DIVA) strategy for avian influenza virus using a more flexible neuraminidase inhibition test in chickens [abstract]. 7th International Symposium on Avian Influenza, April 5-8, 2009, Athens, Georgia. p. 58. Technical Abstract: The option of vaccinating poultry against avian influenza (AI) as a control tool is gaining greater acceptance by the government and poultry industry world-wide. One reservation about vaccination with killed whole virus vaccines is the loss of the ability to use serologic surveillance to identify infected flocks with the commonly available diagnostic tests. There has been considerable effort to develop a reliable test for the differentiation of infected from vaccinated animals (DIVA). The heterologous neuraminidase (hNA) subtype DIVA approach has been used with some success in the field with an accompanying ad-hoc serological test. The traditional neuraminidase inhibition (NI) test can be used for all nine neuraminidase (NA) subtypes, but it is time consuming and it is not designed to screen large numbers of samples nor determine a NA antibody titers. In this study, a quantitative NI test using fluorescent substrate as an NA substrate for NI testing in a heterologous neuraminidase DIVA strategy. Serum NI activity was determined in chickens given different vaccines encoding different H5 and NA subtypes and challenged with high pathogenic avian influenza (HPAI) H5N2 virus. Prior to challenge, the NI DIVA test clearly differentiated chickens receiving different vaccine antigens (e.g., N8 or N9) and no antibody was seen in the control birds. Two weeks post-challenge, 100% of the vaccinated birds had significant levels of N2 NI activity, activity that was not interfered with by the presence of vaccine-induced NI activity against N8 or N9. These results provided additional information that the hNA DIVA strategy is a rapid and sensitive approach for chickens.