Isolation and characterization of a novel cervid adenovirus from white-tailed deer (Odocoileus virginianus) fawns in a captive herd

A novel adenovirus, CeAdV1, was isolated from buffy coat and nasal swab samples collected from two captive white-tailed deer (Odocoileus virginianus) fawns. The isolation was an incidental finding in the course of screening animals for use in a research study on an unrelated pathogen. In the screening process, virus isolation was performed on both nasal swabs and buffy coat samples and cytopathic effect was observed. Electron microscopy revealed viral particles with the shape and morphology of an adenovirus. Next generation sequencing followed by phylogenetic analysis classified this virus to the Mastadenovirus genus. Its sequence was genetically distinct from all other recognized species in this genus, with only 76% sequence identity to its closest genetic match, bovine adenovirus 3 (BAdV3). The virus could be propagated in bovine derived cells but grew to a higher titer in cervid derived cells. Inoculation of white-tailed deer fawns with the isolated virus resulted in pyrexia, depletion of thymus tissue and mild respiratory disease. Comparative serology performed using convalescent sera revealed distinct antigenic differences between the novel cervid adenovirus and BAdV3. A retrospective serological survey of the captive deer herd indicated that this virus had been circulating in the herd for at least 14 years with no report of clinical disease. A survey of serum collected from free ranging mule deer residing in Nevada revealed high serum titers against this novel adenovirus.