Submitted to: American College of Veterinary Pathologists Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/23/2003
Publication Date: 9/1/2003
Citation: MEYERHOLZ, D.K., GRUBOR, B.M., GALLUP, J.M., LEHMKUHL, H.D., ACKERMANN, M.R. LAMB AGE AFFECTS SUSCEPTIBILITY AND LESION SEVERITY IN BOVINE RESPSIRATORY SYNCYTIAL VIRUS INFECTION. AMERICAN COLLEGE OF VETERINARY PATHOLOGISTS ABSTRACTS. Vet. Pathol. 39:5, 2003, p. 633, Abstract #84.
Technical Abstract: Bovine respiratory syncytial virus (BRSV) infection is a significant cause of respiratory disease in cattle and sheep. The purpose of this study was to evaluate the effect of age on the severity of BRSV infection in lambs. In this study, two groups of commercial lambs (3-5 days old or 12-weeks old) were infected intranasally and intratracheally with BRSV inoculum. Each group of lambs was randomly placed in time points (3, 6-7, and 14 days post inoculation [PI]) for evaluation. Evaluation of disease severity was assessed by gross and microscopic examination, and BRSV antigen was detected by immunohistochemistry. At 6-7 days PI, the neonatal lambs grossly had multifocal consolidation (3-5 mm) in all lung lobes. Microscopically, infected bronchiolar epithelium had segmental necrosis with intraluminal neutrophils and cell debris. Remaining areas of bronchiolar epithelium was proliferative with frequent mitotic figures. Older lambs had minimal to no lesions. Immunohistochemistry for BRSV antigen intensity and distribution showed increased staining in the neonatal tissue compared to the older lambs. Our results suggest neonatal lambs are more susceptible to BRSV infection and exhibit more severe gross and microscopic lesions than young adults.