RSV infection is responsible for a significant number of respiratory diseases in infants and morbidity in elderly populations. The cotton rat (S. hispidus) is susceptible to non-adapted human RSV. Animals are infected by intranasal inoculation with RSV-A2. This non-lethal model has been used to successfully test RSV vaccine and therapeutic candidates leading to IND and clinical development.

Model kinetics indicate peak viral burden at day 4 or 5 post challenge followed by recovery through day 7. The best indicator of efficacy is viral load at the peak of infection and lung viremia is an indicator of morbidity.