Highly Pathogenic Avian Influenza Virus Infection in Feral Raccoons, Japan
Figure 2. Neuraminidase (NA) inhibition by virus neutralization (VN)–positive raccoon serum samples. Each of the N1 to N9 viruses, consisting of A/whooper swan/Mongolia/4/05 (H5N1), A/Hong Kong/1073/99 (H9N2), A/whooper swan/Shimane/499/83 (H5N3), A/turkey/Ontario/6188/68 (H8N4), A/duck/Alberta/60/76 (H12N5), A/duck/England/56 (H11N6), A/seal/Massachusetts/1/80 (H7N7), A/duck/Ukraine/1/63 (H3N8), and A/duck/Memphis/546/74 (H11N9), was incubated with a VN-positive serum sample (A-6, B-2, or C-1) for 1 h at 37°C, and viral NA activity was then measured (6). Data are shown as percentage of activities compared with incubation with VN-negative serum samples (100%). Three independent tests were performed, and significant reduction of NA activity (p<0.05, t test with 2-tailed analysis) was observed only for N1 virus (*). HA, hemagglutinin. Error bars indicate SDs of 3 independent tests.