FIG 6.
The impact of serotype-dependent competition on transmission. Within a litter, one in three to four pups (index mice) were challenged IN at 4–7 days of age with (A) an even mixture of six capsule-switch constructs or (B) a single capsule-switch construct. Four days later, all pups in the litter were inoculated IN with influenza A virus. Transmission to contact pups was assessed in URT lavages 5–6 days after virus inoculation. For experiments using the mixed strain inoculum, the proportion of each serotype in index and contact mice at the time of sacrifice was determined by colony immunoblotting, with individual colonized mice from three litters shown in A. Each bar denotes a single mouse. For pups challenged with single capsule-switch constructs, the transmission rate is shown with differences compared to T423F or T42 strains using the Fisher’s Exact Test.