Journal of Biology and Nature

Bluetongue remains one of the most consequential vector-borne viral diseases of sheep. Its importance has grown as outbreaks have repeatedly breached older assumptions about climatic and geographical limits, while genomic surveillance has revealed complex patterns of serotype emergence, reassortment and transboundary spread. The emergence of bluetongue virus serotype 8 in north-western Europe in 2006, the re-emergence of serotype 8 in France, the severe serotype 3 epidemic that began in the Netherlands in 2023, and the subsequent detection of serotype 12 in Europe have together reshaped the scientific and policy understanding of bluetongue risk. This critical narrative review synthesises contemporary evidence on bluetongue virus biology, ovine disease expression, Culicoides-borne transmission, between-farm spread, diagnostic and genomic surveillance, vaccination and One Health control. The review argues that disease impact in sheep is not determined by virus presence alone. It emerges from the interaction of serotype, strain phenotype, sheep susceptibility, flock management, vector competence, climatic suitability, landscape structure, animal movements, surveillance sensitivity and the timing of vaccine deployment. Whole-genome sequencing now plays a central role in distinguishing new incursions from local persistence, detecting reassortment and interpreting unusual serotype emergence. Yet sequencing has greatest value when coupled with field epidemiology, mortality monitoring, midge surveillance and rapid vaccine decision-making. Inactivated vaccines remain the most practical emergency-control tool where matched products are available, but their protective value is constrained by serotype specificity, incomplete coverage, delayed rollout and uneven field-effectiveness data. Newer vaccine platforms offer credible opportunities for broader protection and differentiation of infected from vaccinated animals, although stronger field validation is needed. A One Health perspective is warranted despite the absence of zoonotic infection because bluetongue links climate change, livestock welfare, rural economies, wildlife interfaces, trade and ecosystem management. Future control will depend on earlier warning systems, better vector competence evidence, adaptive vaccine strategies, harmonised genomic standards and decision frameworks that translate surveillance signals into timely action for flocks and regions.