A Novel Cardiotropic Murine Adenovirus Representing a Distinct Species of Mastadenoviruses

During cell culture isolation experiments to recover Dobrava hantavirus from a suspension of liver from a striped mouse (Apodemus agrarius), an unknown virus was coisolated. Atypically for hantaviruses, it had extensive cytopathic effects. Using a random PCR approach, it was identified as a novel murine adenovirus, MAdV-3 (for MAdV type 3). A plaque-purified virus clone was prepared and further characterized. The complete genome sequence of MAdV-3 was determined to be 30,570 bp in length. Sequence comparisons to other adenovirus species revealed highest similarity to MAdV-1, the representative of the murine adenovirus A species. However, substantial differences were found in the E1, E3, and E4 genomic regions. The phylogenetic distance of MAdV-3 amino acid sequences for pVIII, protease, polymerase, and hexon from MAdV-1 is markedly higher than 0.1 exchange per position, and, based on our cross-neutralization experiments, MAdV-3 and MAdV-1 can be regarded as different serotypes. Therefore, we propose to classify MAdV-3 as the first isolate of a novel adenovirus species, designated murine adenovirus C (MAdV-C). The novel MAdV-3 virus is not only genetically and serologically distinct from MAdV-1 but also shows a unique organ tropism in infected mice. In contrast to MAdV-1, the virus was not detectable in brain but predominantly infected heart tissue. Thus, infection of mice with cardiotropic MAdV-3 might be an interesting animal model of adenovirus-induced myocarditis.