Emerging orthobunyaviruses: genomic diversity, reassortment, and expanding public health risks
Orthobunyaviruses (family Peribunyaviridae ) represent one of the most diverse groups of arboviruses, infecting humans, livestock, and wildlife worldwide. Despite their broad geographic distribution and ecological complexity, most orthobunyaviruses remain poorly characterized, with limited understanding of their genomic diversity, transmission dynamics, and pathogenic potential. While research has focused on clinically recognized viruses such as Oropouche virus (OROV), La Crosse virus (LACV), Jamestown Canyon virus (JCV), and Schmallenberg virus (SBV), numerous neglected lineages like Ilesha virus (ILEV), Bwamba virus (BWAV), and Ingwavuma virus (INGV) continue to circulate silently, particularly in Africa, Asia, and Latin America. Recent outbreaks of OROV in South America and the emergence of SBV in Europe highlight their capacity for rapid spread and significant public and animal health impact. The segmented negative-sense RNA genome of orthobunyaviruses enables reassortment, a key evolutionary mechanism that drives diversification and may generate strains with altered virulence or host range. In addition, climate change, environmental disruption, and increased human-animal-vector interactions may facilitate expansion into new regions. This review synthesizes current knowledge on taxonomy, evolution, ecology, clinical features, diagnostics, and surveillance strategies. We emphasize the importance of integrated genomic monitoring and One Health approaches to strengthen preparedness against emerging and neglected orthobunyaviruses.