Fig. 1: Aerosol inoculation of C57BL/6J mice with H5N1 results in dose-dependent mortality and virus replication.

a Experimental schedule. Mice (N = 14) were inoculated with A/Bovine/Ohio/B24osu-342/2024 (BoV342, green) or A/Vietnam/1203/2004 (VN1203, blue) at 10² (circle), 10³ (square), or 10⁴ TCID₅₀ (triangle), via aerosols. Uninfected animals are shown in gray circles. Oral swabs were taken every two days (N = 6), and necropsies were scheduled on day 3 and day 6 post exposure (N = 4). One group per dose of virus was observed for survival up to day 28 post exposure (N = 6). Image created using Biorender. b All animals in the survival groups received a transponder, and activity was monitored up to D10 post inoculation. Activity in inches traveled was totaled per 6 h, shown is median (N = 6). Arrow indicates time of virus exposure via aerosols. c Relative weight compared to day 0 post exposure. Shown is median with 95% confidence interval (CI), weights of all groups were compared to weights of control animals on same day post exposure. d Survival post virus exposure (N = 6). Survival comparison was done against high dose group per virus. e Shedding profile of infectious virus in oral swabs. Individual values shown, bar graph shows minimum to maximum, with middle line displaying median (N = 6). Seronegative animal is shown as a diamond shape (VN1203, dose 10²). For each day, amount of shedding was compared between BoV342 and VN1203 animals that received the same dose of virus. f Infectious virus titer in brain, nasal turbinate, and lung tissues at day 3 and either day 5 (BoV342) or day 6 (VN1203) post exposure. Individual values shown, bar graph shows minimum to maximum, with middle line displaying median (N = 4). For each day, amount of shedding was compared between BoV342 and VN1203 animals that received the same dose of virus. For statistical analysis in (c), (e), and (f), first a one-way ANOVA (f), two-way ANOVA (c), or mixed-effect analysis (e) was performed. If significantly different, groups of interests were compared using a Mann–Whitney test. Survival was compared via Kaplan–Meier analysis. *p-value < 0.05; **p-value < 0.01; ***p-value < 0.001.