Advances in the application of recombinant herpesvirus-vectored vaccines in animal disease control

Recombinant herpesvirus vectors have emerged as highly potent platforms for next-generation vaccine development, distinguished by their genomic capacity and their unique ability to elicit durable, long-lasting immunity through persistent latent infections. In this review, we trace the evolutionary trajectory of herpesvirus vector engineering-transitioning from traditional homologous recombination to advanced bacterial artificial chromosome (BAC) systems and precise, scarless CRISPR/Cas9 gene editing. We comprehensively evaluate the rational design of classical animal herpesvirus vectors, including pseudorabies virus (PRV), herpesvirus of turkeys (HVT), and feline herpesvirus type 1 (FHV-1). Specifically, we highlight their distinct advantages in molecular attenuation, the optimization of non-essential insertion loci, and the application of tissue-specific promoters for multiplexed antigen presentation. Furthermore, we discuss the strategic deployment of multivalent herpesvirus vaccines within the "One Health" framework, emphasizing their critical role in simplifying immunization protocols and interrupting the transmission chains of zoonotic diseases. Finally, we address the prevailing translational bottlenecks, including scalable manufacturing challenges and stringent regulatory frameworks regarding environmental release, providing perspectives on how continuous biotechnological innovations will empower herpesvirus vectors to serve as formidable prophylactic tools against emerging and re-emerging infectious diseases.