Fig 3. Intranasal 2009 H1N1 infection in mother ferrets leads to severe disease and virus transmission to breastfeeding infants.

Schematic of nursing-mothers intranasally inoculated with the Cal/07 strain of 2009 H1N1 influenza (10⁵ EID₅₀) and housed with their feeding infants (A). Temperature (B) and weights (C) were recorded daily for mothers and infants post-inoculation. Grey lines indicate mock inoculated mothers. Survival of mothers and infants post-mother-inoculation (D). Live viral loads were quantified by MDCK titration of nasal wash (NW) (E) and infant lung (F) homogenates collected throughout the infection course (infants that had reached cut-off or succumbed to illness). * indicates a p-value less than 0.05 determined by ANOVA comparing H1N1 inoculated to mock controls. Error bars indicate +/- SD. Data was collected from three independent litter inoculations/infections (3 inoculated/infected mothers, 16 infants, and 3 mock inoculated/infected mothers) and results show the mean or are a representative of the inoculations/infections.