Control of swine pseudorabies in China: Opportunities and limitations

Pseudorabies (PR), also known as Aujeszky's disease (AD), is caused by pseudorabies virus (PRV) or called suid herpesvirus 1 (SuHV-1). It is an economically significant viral disease of pigs and other animals. Although the disease has been eradicated in commercial swine populations of some countries using gE-deleted vaccines and differentiating infected from vaccinated animals (DIVA) strategy, PR continues to be one of the most important diseases of pigs in many countries, particularly in regions with dense pig populations, including China. This article reviews the current situation of PR in China, including epidemiology, diagnostic assays, control strategies and challenges of the disease. PR has been endemic in most provinces of China largely due to the lack of appropriate compulsory vaccination campaigns of pigs, sufficient awareness and biosecurity measures, although gE-deleted vaccines based on the Bartha-K61 strain and regional DIVA-based eradication programs have been widely used in the past decades. Notably, since 2011, an emerging variant PRV with enhanced pathogenicity has become prevalent in vaccinated swine herds in many regions of China and the disease situation is worsening. Control and eventual eradication of PR remain a big challenge in China, and strengthened control measures based on updated DIVA strategy are urgently needed toward national eradication of PR.