The name Sapelovirus is derived from Simian, Avian and Porcine Entero-Like viruses.

The three sapelovirus species may be distinguished by i) different host species; and ii) sequence diversity. For example in the VP1 gene there is less than 50% amino acid identity between the species (Table 1; Fig. 1). The simian sapeloviruses (which probably belong to three [sero]types) have probably undergone some complicated recombination events as can be seen from a comparison of sequences in different genome regions (Figs. 1 and 2).

The complete genome sequences of three entero-like viruses have been determined, porcine enterovirus 8 (PEV-8) (formerly classified within the enterovirus species Porcine enterovirus A), simian virus 2 (SV2) (an unassigned member of the genus Enterovirus) and an unclassified duck picornavirus (DPV)(Krumbholtz et al., 2002; Oberste et al., 2003; Tseng and Tsai, 2007). These three viruses are related to each other (clustering together phylogenetically) (Figs. 3 and 4) and broadly resemble the enteroviruses. However, they are distinct for a number of reasons: i) they are all predicted to share a type IV (hepatitis C virus-like) internal ribosome entry site (IRES) (Hellen and de Breyne, 2007); ii) possess a Leader polypeptide; and iii) have very divergent 2A, 2B and 3A sequences such that cannot be directly compared with the same enterovirus proteins. Genetic distances from the enteroviruses in the P1^cap, 2C, 3C^pro and 3D^pol regions are large (31-37%; 35-45%, 39-52%, 52-58%, respectively). Thus they have been assigned to a novel genus, Sapelovirus.

In 2011, two new sapeloviruses were discovered in California sea lions and tentatively named California sea lion sapelovirus 1 and 2 (Li et al., 2011).

A partial sequence of a murine sapelovirus has recently been reported (Phan et al., unpublished).

Genome organisation:

Porcine sapelovirus & simian sapelovirus:

VPg+5’UTR^IRES-IV[L/1A-1B-1C-1D/2A^pro?-2B-2C/3A-3B^VPg-3C^pro-3D^pol]3’UTR-poly(A)

Avian sapelovirus:

VPg+5’UTR^IRES-IV[L^pro?/1A-1B-1C-1D/2A-2B-2C/3A-3B^VPg-3C^pro-3D^pol]3’UTR-poly(A)

Hellen, C.U. and de Breyne, S. (2007). A distinct group of hepacivirus/pestivirus-like internal ribosomal entry sites in members of diverse picornavirus genera: evidence for modular exchange of functional noncoding RNA elements by recombination. J. Virol. 81: 5850-5863.

Kaku, Y., Sarai, A. and Murakami, Y. (2001). Genetic reclassification of porcine enteroviruses. J. Gen. Virol. 82: 417-424.

Krumbholz, A., Dauber, M., Henke, A., Birch-Hirschfeld, E., Knowles, N.J., Stelzner, A. and Zell, R. (2002). Sequencing of porcine enterovirus groups II and III reveals unique features of both virus groups. J. Virol. 76: 5813-5821.

Li, L., Shan, T., Wang, C., Côté, C., Kolman, J., Onions, D., Gulland, F.M.D. and Delwart, E. (2011). The fecal viral flora of California sea lions. JVI Accepts, published online ahead of print on 27 July 2011; doi:10.1128/JVI.05026-11.

Oberste, M.S., Maher, K. and Pallansch, M.A. (2003). Genomic evidence that simian virus 2 and six other simian picornaviruses represent a new genus in Picornaviridae. Virology 314: 283-293.

Tseng, C.-H. and Tsai, H.-J. (2007). Sequence analysis of a duck picornavirus isolate indicates that it together with porcine enterovirus type 8 and simian picornavirus type 2 should be assigned to a new picornavirus genus. Virus Res 129: 104-114.