Fig. 1: Ferrets are highly susceptible to bat H9N2.
a Ferrets (n = 15) were inoculated with 104.8 TCID50 of bat H9N2 IAV per animal. At 1 dpi, direct contact animals (n = 3) were co-housed. Donor ferrets euthanized at 6 dpi are indicated. Viral shedding was measured by nasal lavage. Dashed line indicates detection limit. b Organs collected from euthanized ferrets (n = 6) at 6 dpi with bat H9N2 were tested by RT-qPCR to determine viral genome copies. Dashed line indicates detection limit. Data are mean ± SD. c Changes in body weight relative to 0 dpi of bat H9N2-infected (n = 15) and contact (n = 3) ferrets were monitored throughout the course of the experiment. d Changes from the baseline body temperatures of donor and naïve contact ferrets were monitored from 0 to 14 dpi. e Ferret serum antibody titers in an IAV NP-specific ELISA at the indicated time points (0 dpi n = 18, 6 dpi n = 6, 21 dpi n = 12). Dashed lines indicates threshold between 45% and 50% inhibition. Mean antibody titers are indicated. Note that one ferret showed weak reactivity in the pre-experimental NP-ELISA, but was included in the study because of its low seropositivity, which could be due to a previously unrecognized IAV infection or an unspecific ELISA reactivity. There was no indication of H9N2 serology prior to inoculation. f Ferret neutralizing antibody titers (n = 18) against bat H9N2 and chicken H9N2. g Histopathologic findings with detection of viral antigen in the nasal mucosa of bat H9N2-infected ferrets (n = 6, panels 1–3) at 6 dpi or mock-infected ferret (n = 1, panels 4 and 5). Acute severe rhinitis with diffuse necrosis of the olfactory epithelium (arrow) and infiltrating neutrophils (asterisk) (1). Intralesional viral antigen (NP) is abundant in degenerated and desquamated epithelial cells (arrowhead) (2). The inset (3) is a higher magnification of the center of the image (2). No pathology was observed in the mock-infected ferret (4, 5). Representative images are shown. Scale bar, 100 µm (main panels), 25 µm (inset). Source data are provided as a Source Data file.
