Fig. 6.

Transmission of SW2783 and ZZ346 influenza viruses in tree shrews and guinea pigs. Intra-species transmission of SW2783 and ZZ346 viruses in tree shrews (A, D) or guinea pigs (B, E), and inter-species transmission of SW2783 viruses between guinea pigs and tree shrews (C, F). Groups of tree shrews or guinea pigs seronegative for influenza viruses (n=3) were inoculated with 10⁵ TCID₅₀ /mL of swine SW2783 or avian ZZ346 influenza virus, respectively. The next day, for the intra-species transmission experiment, the inoculated animals were co-housed with three guinea pigs or tree shrews, and for C and F, the inoculated tree shrews were co-housed with three guinea pigs, and vice versa. After infection with the test virus, the nasal and conjunctiva swabs of tree shrews and guinea pigs were collected at the indicated dpi. Virus titers were determined by TCID₅₀ assay. Each color bar represents a value from an individual animal. The dashed black lines indicate the lower limit of detection.