Background The aim of this work was to study the prevalence and distribution of Porcine astrovirus (PAstV), Porcine
kobuvirus (PKoV), Porcine torovirus (PToV), Mammalian orthoreovirus (MRV) and Porcine mastadenovirus (PAdV) as well
as their association with widely recognized virus that cause diarrhoea in swine such as coronavirus (CoVs) and rotavi‑
rus (RVs) in diarrhoea outbreaks from Spanish swine farms. Furthermore, a selection of the viral strains was genetically
characterized.
Results PAstV, PKoV, PToV, MRV and PAdV were frequently detected. Particularly, PAstV and PKoV were detected in
almost 50% and 30% of the investigated farms, respectively, with an age-dependent distribution; PAstV was mainly
detected in postweaning and fattening pigs, while PKoV was more frequent in sucking piglets. Viral co-infections
were detected in almost half of the outbreaks, combining CoVs, RVs and the viruses studied, with a maximum of 5 dif‑
ferent viral species reported in three investigated farms. Using a next generation sequencing approach, we obtained
a total of 24 ARN viral genomes (>90% genome sequence), characterizing for frst time the full genome of circulating
strains of PAstV2, PAstV4, PAstV5 and PToV on Spanish farms. Phylogenetic analyses showed that PAstV, PKoV and PToV
from Spanish swine farms clustered together with isolates of the same viral species from neighboring pig producing
countries.
Conclusions Although further studies to evaluate the role of these enteric viruses in diarrhoea outbreaks are
required, their wide distribution and frequent association in co-infections cannot be disregard. Hence, their inclusion
into routine diagnostic panels for diarrhoea in swine should be considered.
Keywords Swine, Multiplex RT-PCR, Phylogenetic analysis, Porcine astrovirus, Porcine kobuvirus, Porcine torovirus,
Mammalian orthoreovirus, Porcine mastadenovirusThis work was supported by the program of the National Institute of Agricultural and Food Research and Technology (INIA project E-RTA2015-0003-C02-01 and E-RTA2015-0003-C02-02) of Spanish Government. H. Puente, O. Mencía-Ares, L. Pérez-Pérez, M. Cortey and H. Argüello were supported by Spanish Government (FPU17/00466, FPU16/03485, PRE2020-093762, RYC-2015-1715-4 and BEAGAL- 18-106, respectively) and M. Gómez-García by Junta de Castilla & León (LE131-18)info:eu-repo/semantics/publishedVersio