Emergence of porcine epidemic diarrhea virus in southern Germany

Abstract

BackgroundOver the last years, porcine epidemic diarrhea virus (PEDV) has caused devastating enteric diseases in the US and several countries in Asia, while outbreaks in Europe have only been reported sporadically since the 1980s. At present, only insufficient information is available on currently circulating PEDV strains in Europe and their impact on the European swine industry. In this case report, we present epidemic outbreaks of porcine epidemic diarrhea in three farms in South-Western Germany.Case presentationEpidemic outbreaks of diarrhea affecting pigs of all age groups were reported in three farms, one fattening farm and two piglet producing farms, in South-Western Germany between May and November 2014. In the fattening farm yellowish, watery diarrhea without evidence of mucus or blood was associated with a massive reduction of feed consumption. Severity of clinical signs and mortality in young suckling pigs varied significantly between the two affected sow farms. While mortality in suckling piglets reached almost 70 % in one sow herd, no increase in suckling piglet mortality was observed in the second sow farm. In all three cases, PEDV was confirmed in feces and small intestines by RT-qPCR. Phylogenetic analyses based on full-length PEDV genomes revealed high identity among strains from all three herds. Moreover, the German strains showed very high nucleotide identity (99.4 %) with a variant of PEDV (OH851) that was isolated in the United States in January 2014. This strain with insertions and deletions in the S-gene (so called INDEL strains) was reported to show lower virulence. Slightly lower identities were found with other strains from the US and Asia.ConclusionPhylogenetic information on the distribution of PEDV strains in Europe is severely lacking. In this case report we demonstrate that acute outbreaks of PEDV occurred in southern Germany in 2014. Current strains were clearly different from isolates found in the 1980s and were closely related to a PEDV variant found in the US in 2014. Moreover, the present case report indicates that variant strains of PEDV, containing insertions and deletions in the S gene, which were reported to be of lower virulence, might be able to cause high mortality in suckling piglets.

Porcine epidemic diarrhoea virus with a recombinant S gene detected in Hungary, 2016

“…In France, an outbreak caused by an S INDEL strain was reported in 2015 by Grasland and Bigault. Similar cases affecting mostly fattening pigs with mild diarrhoea were reported from Belgium (Theuns et al, 2015), Germany (Stadler et al, 2015), Austria (Steinrigl et al, 2015), Portugal (Mesquita et al, 2015), Slovenia (Toplak et al, 2016) and Italy (Bertasio et al, 2016), while in Ukraine a highly pathogenic virus caused an outbreak with nearly 100% mortality rate among piglets under 10 days of age (Dastjerdi et al, 2015). In Hungary, the first PED outbreak was reported in 1977 by Benyeda et al, and the last PEDV-positive pigs were found in 2009, although there is no report describing that case (EFSA AHAW Panel, 2014).…”

First Detection and Clinical Presentation of Porcine Epidemic Diarrhea Virus (Pedv) in Serbia

“…Shortly after its fi rst detection, in 2014, a novel PEDV variant strain OH851 (called INDEL strains) was isolated in the USA, which was associated with the milder disease symptoms and low mortality in suckling piglets [13,14]. After the emergence of PED in the USA, sequence analyses revealed high nucleotide identity between North American and Asian PEDV strains suggesting a common ancestor for PEDV in both continents [15].…”

Porcine epidemic diarrhea virus: current insights

“…57,85 Possible recombination events might contribute to a rapid evolution of US strains. 57 Recently, OH851-like strains have been detected in South Korea 56 and Japan 81 in Asia, and Germany, 15,16 Italy, 17 the Netherlands, 18 Belgium, 19 France, 20 Portugal, 22 Slovenia, 21 and Austria 21 in Europe. A novel variant TC-PC22A (GenBank accession number KM392224), which has a large deletion (197-aa) in the N-terminal portion of the S protein, was recently isolated in the United States.…”

“…15,20,21,56,57,81 However, severe cases associated with OH851-like strains were reported in Germany, where mortality in suckling piglets reached almost 70% in one of two sow farms, and in Portugal (mortality rate was not given). 16,22 A comparison experiment on the pathogenesis of three US prototype strains and one OH851-like variant reported recently by Chen et al 100 demonstrated that the OH851-like variant had significantly diminished clinical signs, virus shedding in feces, gross or histopathological lesions in small intestines, and immunohistochemistry (IHC) scores in ileum compared to three US prototype isolates. …”

“…Genotype Ia contains classical strains, including the prototype strain CV777 and historical vaccine strains, and genotype Ib includes some variants such as OH851-like isolates from the People's Republic of China, the United States, South Korea, Europe, and Austria. 16,[19][20][21]56,57 Genotype II contains historical isolates in South Korea, and currently prevalent global field isolates. Genotype IIa was a recently prevalent genotype in the People's Republic of China, 58,59 Taiwan, [60][61][62] South Korea, 55,63 and the United States.…”