Advances in gene editing strategies for viral disease resistance in pigs: Knock-out, knock-in, and overexpression approaches
Highly contagious viral pathogens—such as porcine reproductive and respiratory syndrome, classical swine fever, and African swine fever—continue to pose serious threats to the swine industry and cause major global economic losses. Conventional disease control approaches, such as vaccination and biosecurity, are limited by viral heterogeneity and immune escape mechanisms. Gene editing technologies, most notably the CRISPR/Cas9 system, offer an innovative means of introducing innate viral disease resistance or resilience in pigs. The continuous improvement of these tools can provide a sustainable strategy to enhance animal welfare and global food security and reduce reliance on traditional control measures. This review provides an overview of recent advances in the development of genetically engineered pigs with enhanced resistance to major viral diseases, focusing on targeted gene modifications using knockout, knock-in, and overexpression approaches.