Project Number: 3625-32000-095-00
Project Type: Appropriated

Start Date: Oct 01, 2007
End Date: Sep 30, 2009

Objective:
Objective 1: Identify host-pathogen interactions and environmental factors that lead to bovine adenovirus associated respiratory disease. Subobjective 1.1: Identify and isolate bovine adenoviruses field strains that are virulent in cattle. Subobjective 1.2: Determine the pathogenesis of bovine adenovirus associated with respiratory disease. Subobjective 1.3: Determine the pathogenesis of bovine adenovirus and bovine viral diarrhea (BVD) co-infections.

Approach:
Nasal secretions from field cases of bovine respiratory disease and lung tissue from diagnostic laboratories where adenovirus has been indicated histologically will be processed for virus isolation. Virus isolates will be identified and characterized. Adenovirus will be characterized by hexon PCR, restriction fragment length polymorphism analysis, and hexon DNA sequence analysis. Calves will be inoculated with adenoviruses associated with clinical disease to determine pathogenicity. Sera samples collected from feedlot cattle will be used to determine prevalence and importance of these isolates. Where mixed viral infections are found in association with respiratory disease, pathogenesis studies will be done in calves using virus combinations reflective of isolation frequency. Calf inoculations will be done to ascertain whether adenovirus predispose to nasopharyngeal colonization and/or establishment of bovine pneumonia by Mannheimia haemolytica. BSL-Exempt; Recertified 10/13/07; IBC-0209. BSL-Exempt; Recertified 4/19/08; IBC-0277.