Porcine Coronaviruses

Abstract

Transmissible gastroenteritis virus (TGEV), porcine epidemic diarrhoea virus (PEDV), and porcine deltacoronavirus (PDCoV) are enteropathogenic coronaviruses (CoVs) of swine. TGEV appearance in 1946 preceded identification of PEDV (1971) and PDCoV (2009) that are considered as emerging CoVs. A spike deletion mutant of TGEV associated with respiratory tract infection in piglets appeared in 1984 in pigs in Belgium and was designated porcine respiratory coronavirus (PRCV). PRCV is considered non-pathogenic because the infection is very mild or subclinical. Since PRCV emergence and rapid spread, most pigs have become immune to both PRCV and TGEV, which has significantly reduced the clinical and economic importance of TGEV. In contrast, PDCoV and PEDV are currently expanding their geographic distribution, and there are reports on the circulation of TGEV-PEDV recombinants that cause a disease clinically indistinguishable from that associated with the parent viruses. TGEV, PEDV and PDCoV cause acute gastroenteritis in pigs (most severe in neonatal piglets) and matches in their clinical signs and pathogenesis. Necrosis of the infected intestinal epithelial cells causes villous atrophy and malabsorptive diarrhoea. Profuse diarrhoea frequently combined with vomiting results in dehydration, which can lead to the death of piglets. Strong immune responses following natural infection protect against subsequent homologous challenge; however, these viruses display no cross-protection. Adoption of advance biosecurity measures and effective vaccines control and prevent the occurrence of diseases due to these porcine-associated CoVs. Recombination and reversion to virulence are the risks associated with generally highly effective attenuated vaccines necessitating further research on alternative vaccines to ensure their safe application in the field.

Evidence for SARS-CoV-2 Infection of Animal Hosts

“…Some CoVs are endemic in domestic animals in different countries [ 5 ]. The most common members of CoVs infecting animals are infectious bronchitis virus (IBV; γ-CoV) in chickens [ 6 ]; porcine transmissible gastroenteritis coronavirus (TGEV; α-CoV) [ 7 ], porcine hemagglutinating encephalomyelitis coronavirus (HEV; β-CoV) [ 8 ] and porcine epidemic diarrhea coronavirus (PEDV; β-CoV) [ 9 ] in swine; bovine CoV (BCoV, β-CoV) in cattle [ 10 ]; canine enteric coronavirus (CECoV; α-CoV) [ 11 ] and canine respiratory coronavirus (CRCoV; β-CoV) [ 12 ] in dogs; feline coronavirus (FCoV; α-CoV) in cats [ 13 ]; and murine hepatitis virus (MHV; β-CoV) in mice [ 14 ] ( Table 1 ).…”

SARS-CoV-2 spike protein predicted to form complexes with host receptor protein orthologues from a broad range of mammals

“…Coronaviruses, including SARS-CoV-2, are major multi-host pathogens and can infect a wide range of non-human animals 3 – 5 . SARS-CoV-2 is a member of the Betacoronavirus genus, which includes viruses that infect economically important livestock, including cows 6 and pigs 7 , together with mice 8 , rats 9 , rabbits 10 , and wildlife, such as antelope and giraffe 11 . Severe acute respiratory syndrome coronavirus (SARS-CoV), the betacoronavirus that caused the 2002–2004 SARS outbreak 12 , likely jumped to humans from its original bat host via civets.…”

Hallmarks ofAlpha- andBetacoronavirusnon-structural protein 7+8 complexes

“…COVID-19 caused major perturbations of historical dimensions in politics, economics and healthcare. Moreover, coronaviruses are important, widespread animal pathogens as illustrated by feline intestine peritonitis virus (FIPV) causing a severe and often fatal disease in cats [ 7 ] or porcine coronaviruses [ 8 ], such as transmissible-gastroenteritis virus (TGEV) or porcine epidemic diarrhea virus (PEDV), the latter causing massive outbreaks and economic losses in swine industry.…”