Pseudorabies virus (PRV), the causative agent of Aujeszky’s disease, is one of the most important infectious pathogens threatening the global pig industry. Like other members of alphaherpesviruses, PRV establishes a lifelong latent infection and occasionally reactivates from latency after stress stimulus in infected pigs. Latent infected pigs can then serve as the source of recurrent infection, which is one of the difficulties for PRV eradication. Virus latency refers to the retention of viral complete genomes without production of infectious progeny virus; however, following stress stimulus, the virus can be reactivated into lytic infection, which is known as the latency-reactivation cycle. Recently, several research have indicated that alphaherpesvirus latency and reactivation is regulated by a complex interplay between virus, neurons, and the immune system. However, with those limited reports, the relevant advances in PRV latency are lagging behind. Therefore, in this review we focus on the regulatory mechanisms in PRV latency via summarizing the progress of PRV itself and that of other alphaherpesviruses, which will improve our understanding in the underlying mechanism of PRV latency and help design novel therapeutic strategies to control PRV latency.

In recent years, the clinical cases of ENTV-2 infection have increased and become prevalent in several provinces of China. In this study, we reported the occurrence of ENTV-2 in one goat farm in Chongqing, southwest China. The complete genome of an emerged ENTV-2 isolate (designated as CQ2) was sequenced with 7468 bp in length. Phylogenetic analysis revealed that ENTV-2 consisted of two main lineages. Lineage 1 was composed of Chinese strains and could be subdivided into five sublineages. CQ2 and the other six recent isolates from China were clustered in sublineage 1.5; however, CQ2 was significantly different from the other six isolates. Furthermore, recombination analysis suggested that CQ2 might be a recombinant variant derived from sublineage 1.5 and sublineage 1.2 strains, with the recombination region in areas of pro and pol genes. In conclusion, we sequenced and analyzed the complete genome of a potential ENTV-2 recombinant, which may contribute to our understanding of the genetic variation and evolution of ENTV-2 in China.