Porcine epidemic diarrhea: A retrospect from Europe and matters of debate

Abstract

A retrospect is given on the emergence of porcine epidemic diarrhea (PED) during the early seventies in Europe. While, at first, it appeared as a disease affecting feeder pigs, fattening- and adult swine, it later also became pathogenic for neonatal and suckling pigs hereby drastically increasing its economic impact. Isolation of the causative virus revealed a new porcine coronavirus, the origin of which has never been clarified. Pathogenesis studies with the prototype strain CV777 showed severe villous atrophy in neonatal pigs and the virus-animal interactions showed many similarities with transmissible gastro-enteritis virus (TGEV), another porcine coronavirus. Disease patterns in field outbreaks showed muchvariation but, while farm related factors played a role, possible genetic variations of virus strains in Europe have not been examined and are thus unknown. CV777 in experimental pigs caused diarrheal disease and mortality rates similar to those later encountered in Asia and more recently with the "original" US strains even though genomic typing of the prototype European strain have shown that it belongs to the S-INDEL strains. In Europe, PED has become endemic during the eighties and nineties and subsequently regressed so that, after 2000, swine populations in many countries have largely become seronegative. Sporadic outbreaks have recently reappeared showing a large variety of clinical outcomes.

Development of a multiplex RT‐PCR for the detection of major diarrhoeal viruses in pig herds in China

“…As we mentioned earlier in this manuscript, TGEV is a widely accepted and well‐characterized enteric pathogen (Pensaert & Martelli, ). Of the 382 faecal samples analysed, TGEV was not detected by our multiplex RT‐PCR, which was confirmed by single TGEV RT‐PCR.…”

“…Swine enteric health is continuously challenged by viral infections that cause severe diarrhoea, high mortality in piglets and economic losses. The pathogenesis of TGEV, PEDV and PRV‐A has been extensively characterized (Pensaert & Martelli, ; Vlasova, Amimo, & Saif, ). However, several novel viruses have been found in the faeces of pigs, such as PDCoV, PKV and PSaV.…”

Attenuation of an original US porcine epidemic diarrhea virus strain PC22A via serial cell culture passage

“…Subsequently, PEDV variants, including OH851 and Iowa106 strains, sharing the same insertions and deletions in the S1 region of S protein as the "classical" PEDV strains, such as PEDV prototype CV777 strain, were reported and designated as "S INDEL" PEDV strains Wang et al, 2014). Compared with the original US PEDV (non-S INDEL) strains, some US S INDEL strains showed lower pathogenicity but could still cause severe diarrhea and death in some pig litters (Lin et al, 2015a) similar to the CV777 strain (Pensaert and Martelli, 2016).…”

Full-Length Genome Sequence of Porcine Epidemic Diarrhea Virus Strain CH/GX/2015/750A

“…PED was initially reported in British swine herds in the early 1970s (3, 4), and the prototype PEDV strain CV777 was described in 1978 (5). Since then, outbreaks of PEDV infections have been reported in multiple swine-producing countries, especially in Europe and Asia (6–10).…”