Thus, our current study had a few objectives: (1) Can we model RSV/Spn pneumonia in a large infant animal species that can be improved in future studies; (2) can we successfully dually infect lambs and do we get enhanced disease; (3) can we use the model to gain insights into mechanisms that enhance morbidity over the single pathogen control groups; and (4) can we use infant lambs to study Spn pathogenesis? Here, SPN is linked to susceptibility to pneumonia measurement.