Full genome analysis of bovine astrovirus from fecal samples of cattle in Japan: identification of possible interspecies transmission of bovine astrovirus

Abstract

A viral metagenomics approach was used to investigate fecal samples of Japanese calves with and without diarrhea. Of the different viral pathogens detected, read counts gave nearly complete astrovirus-related RNA sequences in 15 of the 146 fecal samples collected in three distinct areas (Hokkaido, Ishikawa, and Kagoshima Prefectures) between 2009 and 2015. Due to the lack of genetic information about bovine astroviruses (BoAstVs) in Japan, these sequences were analyzed in this study. Nine of the 15 Japanese BoAstVs were closely related to Chinese BoAstVs and clustered into a lineage (tentatively named lineage 1) in all phylogenetic trees. Three of 15 strains were phylogenetically separate from lineage 1, showing low sequence identities, and clustered instead with an American strain isolated from cattle with respiratory disease (tentatively named lineage 2). Interestingly, two of 15 strains clustered with lineage 1 in the open reading frame (ORF)1a and ORF1b regions, while they clustered with lineage 2 in the ORF2 region. Remarkably, one of 15 strains exhibited low amino acid sequence similarity to other BoAstVs and was clustered separately with porcine astrovirus type 5 in all trees, and ovine astrovirus in the ORF2 region, suggesting past interspecies transmission.

Neurologic Clinical Signs in Cattle With Astrovirus‐Associated Encephalitis

“…One study noted that the presence of astroviruses was strongly associated with the presence of group A rotaviruses and postulated that age may protect against clinical disease after infection with astroviruses as is known for rotaviruses . The genetic sequences identified in astroviruses from fecal samples did not correspond to those of neurotropic astroviruses, indicating a different tissue tropism . Only 3 animals in our study had altered fecal consistency (cow #s 1, 2, and 9), and this finding might also be explained by indigestion or excitement.…”

“…Astroviruses are an important cause of diarrhea in humans and also have been isolated from fecal samples of cattle in Europe and Asia . A link between diarrhea and the presence of astroviruses was not established in these studies.…”

Genome analysis of canine astroviruses reveals genetic heterogeneity and suggests possible inter-species transmission

“…It remains to be established whether strain HUN/2012/8 is actually a canine virus, or it is the result of inter-species transmission from an unidentified animal source. Although AstVs are regarded as viruses with a robust host-species restriction, several pieces of evidences in mammals (including humans) indicate that the host species barrier may be permeable in some occasions, and that heterologous viruses may stably adapt to the new host (Finkbeiner et al, 2008(Finkbeiner et al, , 2009Nagai et al, 2015). Moreover, occasional transmission of AstVs is thought to have occurred between avian and mammalian species in both directions (Sun et al, 2014;Pankovics et al, 2015).…”

Whole genome sequences of Japanese porcine species C rotaviruses reveal a high diversity of genotypes of individual genes and will contribute to a comprehensive, generally accepted classification system

“…The cDNA library was constructed using NEBNext® Ultra™ RNA Library Prep Kit for Illumina® version 2.0 (New England Biolabs, Ipswich, MA, USA) as described previously (Nagai et al, 2015). After assessing the library quality and quantity, the libraries were loaded onto a MiSeq cartridge (MiSeq Reagent Kit V2 (300 cycles); Illumina, San Diego, CA, USA).…”