Age-related differences in pulmonary cytokine response to respiratory syncytial virus infection: modulation by anti-inflammatory and antiviral treatment.

Background: Respiratory syncytial virus (RSV) is the major cause of severe lower respiratory tract infection in infants and young children. Recently, RSV has also been recognized as a serious health risk in elderly individuals, but the pathogenesis of RSV infection in elderly individuals remains unknown.

Methods: Dynamics of pulmonary cytokine response (including interferon- gamma , interleukin [IL]-4, IL-10, IL-6, monocyte chemoattractant protein-1, and growth-regulated oncogene [GRO] mRNA) during acute RSV infection were investigated in young (<2 months old) and aged (>9 months old) cotton rats (Sigmodon hispidus).

Pathogenesis of human metapneumovirus lung infection in BALB/c mice and cotton rats.

Human metapneumovirus (hMPV) is a newly described member of the Paramyxoviridae family causing acute respiratory tract infections, especially in young children. We studied the pathogenesis of this viral infection in two experimental small animal models (BALB/c mice and cotton rats). Significant viral replication in the lungs of both animals was found following an intranasal challenge of 10(8) 50% tissue culture infectious doses (TCID50) and persisted for <2 and <3 weeks in the case of cotton rats and mice, respectively.