Protection of Chinese painted quails (Coturnix chinensis) against a highly pathogenic H5N1 avian influenza virus strain after vaccination

Chinese painted quails immunized with a single dose (6 μg HA) of inactivated H5N1 (clade 1) influenza vaccine NIBRG-14 and challenged with 100 LD₅₀ of the heterologous A/Swan/Nagybaracska/01/06(H5N1) (clade 2.2) strain were protected, whereas unvaccinated quails died after challenge. No viral antigens or RNA were detected in cloacal swabs from immunized animals. Sera obtained post-immunization gave low titres in serological assays against the vaccine and the challenge viruses. Our results demonstrate the protective efficacy of the NIBRG-14 strain against the challenge virus and the usefulness of these small birds in protection studies of influenza vaccines.