Lesions in lambs experimentally infected

Abstract

An experimental model was designed to characterize lesions in the lung of lambs inoculated with bovine respiratory syncytial virus (BRSV). 25 Merino lambs of both sexes, with a live weight of 17+3 Kg, received an intratracheal inoculation of 20 m1 saline solution containing 1 . 2 6l~o 6 TCIDSOB RSV (strain NMK-7) per ml. Lambs were laughtered 1, 3, 7, 11 and 15 postinoculation days (PID), and histopathological, immunohistochemical and electron microscopic studies were performed. Results reflected a series of lesions, the most noteworthy of which were bronchiolitis obliterants with destruction of the mucociliary apparatus, the presence of syncytial cells in alveoli and a progressive interstitial reaction. BRSV antigen was detected in lung samples. These changes might be expected to decrease the efficiency of respiratory tract defence mechanisms, rendering the lung parenchyma susceptible to opportunist bacteria1 infection.