Genetic and biological characteristics of species A rotaviruses detected in common shrews suggest a distinct evolutionary trajectory

Abstract

Species A rotaviruses (RVAs) are important etiological agents of severe diarrhea in young children. They are also widely distributed in mammals and birds, and increasing evidence indicates the possibility of zoonotic transmission of RVA strains between animals and humans. Moreover, reassortment of the eleven segments of the RVA genome can result in rapid biological changes and may influence pathogenic properties. Here, the nearly complete genome of an RVA strain from a common shrew (Sorex araneus) was sequenced, which showed high nucleotide sequence similarity to additionally determined partial sequences from common shrew RVAs, but only very low identity (below 68%) to RVAs from other animal species and humans. New genotypes were assigned to most genome segments of the novel common shrew RVA strain KS14/269 resulting in the genome constellation G39-P[55]-I27-R26-C22-M22-A37-N26-T26-E30-H26. Phylogenetic analyses clustered the common shrew RVAs as ancestral branches of other mammalian and avian RVAs for most of the genome segments, which is in contrast to the phylogeny of the hosts. Nevertheless, conserved sequences typical for all RVAs were identified at the 5ʹ- and 3ʹ- non-coding segment termini. To explore, whether the common shrew RVA can exchange genetic material with other mammalian RVAs by reassortment, a reverse genetics system based on the simian RVA strain SA11 was used. However, no viable reassortants could be rescued by exchanging the VP4-, VP6- or VP7-encoding genome segment alone or in combinations. It can be concluded that highly divergent RVAs are present in common shrews indicating an evolution of these viruses largely separated from other mammalian and avian RVAs. The zoonotic potential of the virus seems to be low, but needs to be further analyzed in future.

Strain-Specific Interactions between the Viral Capsid Proteins VP4, VP7 and VP6 Influence Rescue of Rotavirus Reassortants by Reverse Genetics

“…In order to test the hypothesis that strain-specific interactions between the outer and intermediate capsid proteins are important for the generation of viable reassortants, all possible combinations of VP4, VP7, and VP6 should be tested using a well-established plasmid-based RG system [ 21 ]. A plasmid encoding VP4-Wa was already available [ 25 ].…”

“…Differences in the viral UTRs at the genome segment ends have been shown to limit reassortment between different rotavirus species [ 18 ], but within one rotavirus species, at least the outmost genome segment termini are highly conserved. While this could theoretically allow members of RVA to freely exchange genome segments, experiments using reverse genetics (RG) systems suggest that not all genome segments of different RVA strains can readily reassort [ 19 , 20 , 21 , 22 ]. Analyses of circulating human RVA strains also indicate that there are preferred genome constellations [ 23 ].…”

Rotaviruses in Wild Ungulates from Germany, 2019–2022

“…RVA has been identified in various wild animal species, including bats, rodents, shrews, carnivores, and ungulates [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 22 ]. In the latter group, RVA infections in wild boar, roe deer, and water deer have been described so far [ 9 , 22 , 24 ].…”

“…In domestic animals, such as pigs, cattle, horses, cats, dogs, chickens, and turkeys, rotaviruses are widely distributed, causing acute diarrhea, and chronic runting and stunting syndromes [ 2 , 3 ]. Recently, rotaviruses have also been described in wild animals, including bats, rodents, shrews, wild boars, and red foxes [ 4 , 5 , 6 , 7 , 8 , 9 , 10 ].…”

Whole Genome Sequence Analysis of a Prototype Strain of the Novel Putative Rotavirus Species L

“…Recently, rotaviruses with low sequence identities to other mammalian and avian rotaviruses have been detected in common shrews ( Sorex ananeus ) from Germany [ 9 ]. Some of these virus strains could be classified into a divergent evolutionary branch within RVA [ 18 ]. Other strains were putatively grouped into a proposed species designated as RVK, which is most closely related to RVC, or another proposed species designated as RVL, which is most closely related to RVH [ 9 ].…”