Swine coronaviruses. Part I. Porcine respiratory and neurotropic coronaviruses

Coronaviruses (CoV), exhibit high mutation rates and strong tendency to recombine. These properties enable them to easy overcome the host species barrier and adapt to new hosts. It is currently known that six CoV are able to infect pigs. Four of them, belong to the genus Alphacoronavirus - transmissible gastroenteritis coronavirus (TEGV), porcine respiratory coronavirus (PRCV), porcine epidemic diarrhea virus (PEDV) and swine acute diarrhea syndrome coronavirus (SADS-CoV). One of them belongs to the genus Betacoronavirus - porcine hemagglutinating encephalomyelitis virus, PHEV, and the last one, to the genus Deltacoronavirus (PDCoV). PHEV was one of the first identified swine CoVs and is still widespread, causing subclinical infections in pigs in several countries. PRCV, a spike deletion mutant of TGEV, is considered as non-pathogenic. Since vaccines are available only for some porcine CoVs, prevention should focus mainly on a high level of biosecurity. In view of the diversity of CoVs and the potential risk factors associated with zoonotic emergence, updating the knowledge concerning this area is essential