Porcine coronaviruses: transmission, pathogenesis and vaccine development

Abstract

Porcine enteric coronaviruses (CoVs) cause severe disease in the porcine herds worldwide, leading to important economic losses. The complexity of known porcine coronaviruses (CoVs) has considerably increased. To the classical transmissible gastroenteritis virus (TGEV) known since 1946, its deletion mutant with an exclusive respiratory tropism, the porcine respiratory CoV (PRCV), and the porcine epidemic diarrhea virus (PEDV), we have to add several emerging CoVs. Among them, the swine enteric CoV (SeCoV) a novel recombinant virus with the backbone of TGEV and the spike (S) protein from PEDV, and the porcine delta CoV (PDCoV) identified for the first time in 2012 have recently emerged. Although SeCoV has been reported for the first time in January 2016 in Italy, similar recombinant CoVs were soon later (February 2016) described in Germany and Denmark (2016). These viruses were already present in swine samples as early as in 2009. This augmented complexity of porcine CoVs has complicated the diagnostic of this family of viruses.