Provided are newly identified pneumoviruses that can infect mammals, including dogs cats and potentially humans. Isolated polynucleotides and proteins of the viruses, as well as the isolated viruses themselves are provided. The invention includes compositions and methods for detecting the viruses, methods and compositions for prophylaxis and/or therapy of disease signs that are positively correlated with the presence of the viruses, and isolated cells comprising the viruses. Intact virions, viral proteins, and fragments thereof are also provided.