Several lines of investigation have indicated a role for eosinophilic leukocytes in limiting virus infectivity and promoting virion clearance. We have established a respiratory virus infection model with pneumonia virus of mice (PVM; family Paramyxoviridae), a natural mouse pathogen that replicates the more severe forms of human disease elicited by the phylogenetically related respiratory syncytial virus (RSV). In this chapter, we present a rapid and highly reproducible dual-standard curve qRT-PCR based method for quantitative detection of PVM replication in mouse lung tissue. We have used this assay to evaluate eosinophil-mediated antiviral host defense in mouse models of cytokine and antigen-driven eosinophilic inflammation.