Table 1.
Morbidity, seroconversion, and respiratory viral replication of ferrets inoculated with wild bird avian influenza viruses H1N9 and H6N1.
Figure 1.
Nasal shedding and direct contact transmission of wild bird influenza viruses in ferrets.
Seven ferrets were intranasally inoculated with 5×105 PFUs of either H6N1 (A) or H1N9 (B) and nasal washes were collected and titered on MDCK cells (days post-inoculation portion of graph). Three naïve ferrets were paired with three of the inoculated ferrets 24 hours post inoculation for each virus group (days post-direct contact portion); nasal washes were collected titered on MDCK cells. Both H6N1 and H1N9 demonstrated replication in the upper respiratory tract of the ferrets, however, viral shedding was consistently greater in magnitude and duration for H1N9. H1N9 demonstrated direct contact transmission, but H6N1 did not transmit to direct contact ferrets.
Figure 2.
Histopathologic lesions and influenza antigen localization in ferrets inoculated with wild bird influenza viruses.
A) Nasal turbinates of ferrets inoculated with H6N1 or H1N9 demonstrated moderate submucosal inflammation (asterisk) (H1N9, d3pi). B) There is widespread strong intranuclear and some intracytoplasmic positive immunoreactivity for the nucleoprotein of influenza A on immunohistochemistry in ferrets inoculated with H6N1 or H1N9 on day 3 pi (H1N9, d3pi). C) Epithelial damage in the lung was early for ferrets inoculated with H1N9, with necrosis in the bronchioles (arrow) and inflammation (asterisks) within and around bronchioles on day 2 pi. D and E) There was evidence of early repair with regeneration of bronchiolar epithelium (arrow) and persistence of inflammation (asterisks) on day 3 pi for ferrets inoculated with H6N1 and H1N9 (H1N9, d3pi). The arrow highlights the stretched and plump bronchiolar epithelial cells, indicating regeneration. F) Presence of influenza antigen was confirmed in ferrets inoculated with H6N1 and H1N9 by strong positive intranuclear staining of bronchiolar epithelial cells with immunohistochemistry on day 3 pi (H6N1, d3pi). G) Inflammation around larger airways in the lung was also present in ferrets inoculated with H6N1 and H1N9, with prominent periglandular bronchial inflammation (asterisk) (H6N1, d7pi). H) There was strong positive intranuclear staining for the nucleoprotein of influenza in the peribronchial glandular epithelial cells on immunohistochemistry on day 3 pi in ferrets inoculated with H6N1 and H1N9 (H1N9, d3pi).
Table 2.
Presence of influenza virus in ferret organs by virus isolation in ECEs for ferrets infected with wild bird avian influenza viruses H6N1 and H1N9.
Table 3.
Comparison of critical amino acids involved in receptor specificity of influenza hemagglutinin.
Table 4.
Agglutination of erythrocytes from different animal species by human and avian influenza viruses.
Figure 3.
Glycan binding analysis of wild bird avian or human influenza viruses.
Influenza viruses were propagated in Madin-Darby kidney cells, purified on a 25% sucrose cushion by ultracentrifugation, and labeled with Alexa488 before being applied to the microarray. The data was organized based on Neu5GC, α2,3 SA, α2,6 SA and α2,8 SA glycan structures and represented by different color schemes. Glycan microarray binding analysis was performed by Core H of the Consortium for Functional Glycomics. A) A/Ruddy Turnstone/DE/1171/02 (H1N9), B) A/Ruddy Turnstone/DE/892/02 (H6N1), C) A/Pennsylvania/08/2008 (H1N1).