Viral zoonosis and human cancer: a perspective.

Zoonotic viruses, which are pathogens naturally transmitted from animals to humans, pose a significant and evolving challenge to public health. Although most known zoonotic viruses do not exhibit the persistence typically necessary for viral oncogenesis, the potential cancer-causing effects of these infections remain unclear. Persistent infection, latency, or abortive replication within susceptible but non-permissive human cells may allow some animal-origin viruses to evade immune clearance, disrupt host cell signaling, and induce genomic instability-key features of cancer development. Evidence from both in vitro and in vivo studies indicates that certain animal viruses can enter human cells, integrate their genetic material, or express oncogenic proteins, even without completing full replication. These mechanisms resemble those of established human oncoviruses and suggest that, under specific host and environmental conditions, zoonotic viruses could contribute to neoplastic transformation. Given the increasing frequency of human-animal interactions through companionship, agriculture, wildlife trade, and food production, multidisciplinary research combining virology, oncology, and epidemiology is essential. Such efforts should focus on sensitive molecular detection, mechanistic studies, and population-based investigations to better understand the long-term cancer risks associated with zoonotic viral infections and to guide effective prevention strategies.