Hidden Viruses: Unveiling Animals' Virome with Cutting Edge Molecular Techniques

Viruses constitute the most abundant and genetically diverse biological entities on Earth, infecting hosts across all domains of life and exerting profound influences on ecosystems, evolution, and human health. Although viral diseases have been recognized for centuries, systematic virus identification began only in the late nineteenth century. In recent decades, the emergence and reemergence of high-impact pathogens including Ebola virus, pandemic H1N1 influenza, Zika virus, and SARS-CoV-2 have underscored the urgent need for more comprehensive and sensitive approaches to viral surveillance and detection. Conventional diagnostic methods such as electron microscopy, serology, and cell culture have been foundational to virology; however, their limitations particularly the inability to culture many viruses have restricted a full understanding of viral diversity. Advances in molecular virology, especially the advent of next-generation sequencing technologies, have transformed the field. Metagenomics, a culture-independent, high-throughput sequencing approach, enables direct characterization of viral genomes from complex biological and environmental samples. This approach has revolutionized virology by facilitating the discovery of previously unknown viruses and enabling deeper insights into the virome, defined as the complete viral community associated with a host or environment. This review synthesizes recent developments in viral metagenomics and highlights the critical role of virome research in elucidating viral ecology, improving outbreak preparedness, anticipating emerging viral threats, and exploring the potential of viruses for therapeutic and biotechnological applications.