The lack of detection of fox circoviruses in domestic dogs could be attributed to a combination of factors, including differences in susceptibility between wild and domestic canids and environmental factors that limit transmission. It is possible that domestic dogs have a lower susceptibility to fox circoviruses compared to wild canids, which may explain why these viruses have not been identified in dogs. Additionally, environmental circumstances, such as limited contact between domestic and wild canids, could play a role in preventing the spread of fox circoviruses to dogs. Further research is needed to fully understand the reasons behind the absence of fox circoviruses in domestic dogs.