Global emergence and re-emergence of Porcine epidemic diarrhea virus (PEDV), an Alphacoronavirus which causes a highly contagious enteric disease, have led to several studies addressing its variability. The aim of this study was to characterize the infection of weaned pigs with Swine enteric coronavirus (SeCoV) -a chimeric virus most likely originated from a recombination event between PEDV and Transmissible gastroenteritis virus, or its mutant Porcine respiratory coronavirus-, and two PEDV G1b variants, including a recently described recombinant PEDV-SeCoV (rPEDV-SeCoV), as well as to determine the degree of cross-protection achieved against the rPEDV-SeCoV. For this purpose, forty-eight 4-week-old weaned pigs were randomly allocated into four groups of 12 animals; piglets in groups B, C and D were orally inoculated with a PEDV variant (B and D) or SeCoV (C), while piglets in group A were mock inoculated and maintained as controls. At day 20 post-infection all groups were exposed to rPEDV-SeCoV; thus, group D was subjected to a homologous re-challenge, groups B and C to a heterologous re-challenge (PEDV/rPEDV-SeCoV and SeCoV/rPEDV-SeCoV, respectively) and group A was primary challenged (-/rPEDV-SeCoV). Clinical signs, viral shedding, microscopic lesions and specific humoral and cellular immune responses (IgG, IgA, neutralizing antibodies and IgA and IFN-γ-secreting cells) were monitored. After primo-infection all three viral strains induced an undistinguishable mild-to-moderate clinical disease with diarrhea as the main sign and villus shortening lesions in the small intestine. In homologous re-challenged pigs, no clinical signs or lesions were observed, and viral shedding was only detected in a single animal. This fact may be explained by the significant high level of rPEDV-SeCoV-specific neutralizing antibodies found in these pigs before the challenge. In contrast, prior exposition to a different PEDV G1b variant or SeCoV only provided partial cross-protection, allowing rPEDV-SeCoV replication and shedding in feces.

Rotaviruses (RVs) are a major cause of viral gastroenteritis in both animals and humans worldwide. According to the molecular and serological properties of Viral Protein 6 (VP6), RVs are classified into nine species or groups (RVA-RVD and RVF-RVJ). RVA, RVB and RVC are well-recognized as etiological agents of enteric disease on swine farms and have been identified in all countries with a relevant pork production. Contrarily, RVH has only been identified on swine farms from Japan and more recently from Brazil, USA, South Africa and Vietnam but not yet in Europe. The occurrence of RVH was investigated in 103 Spanish pig herds. Nine farms were positive and the complete nucleotide sequences were achieved for four RVH isolates. Mean nucleotide identities with the RVH sequences available in GenBak ranged between 69.4 and 93.7 %. Phylogenetically, all genomic segments of Spanish RVH isolates clustered closely with other porcine RVH strains but were distantly related to human RVH as well as bat RVH strain. Moreover, based on the available tentative genotyping system for RVH, a new genotype for VP7 was proposed. To the best of our knowledge this is the first report of RVH on swine farms in Europe including its characterization by means of complete genome sequencing.