FIG 3.

hRSV strains Long and A2 can replicate throughout the respiratory tract of ferrets after i.n. inoculation. Ferrets were infected via the i.n. route with hRSV Long or A2 virus and tissues collected on day 5 or 9 p.i. Levels of vRNA for the viral N gene were determined in tissue homogenates by real-time quantitative RT-PCR assay. (A) Diagrammatic representation of virus spread (indicated by an asterisk) throughout the respiratory tract: 1, turbinates; 2, oropharynx; 3, trachea; 4, left cranial lobe; 5, left caudal lobe; 6, right caudal lobe; 7, middle lobe; 8, right cranial lobe. Figure adapted from reference 37. (B) Virus load in different tissues from the respiratory tract of ferrets. Results for individual animals are shown (n = 4/group), and the horizontal line represents the median value. The dotted line indicates the limit of detection. Titers for each tissue were compared between virus strains using the Mann-Whitney U test.