Molecular identification of 13 new enterovirus types, EV79-88, EV97, and EV100-101, members of the species Human Enterovirus B.

Molecular methods have enabled the rapid identification of new enterovirus (EV) serotypes that are untypeable using existing neutralizing antisera. As a result, sequencing of the VP1 capsid gene has been developed as a surrogate for antigenic typing to distinguish enterovirus types. In this study, 17 enterovirus isolates from four countries were identified as members of 13 new types within the species Human Enterovirus B (HEV-B) by complete genome sequencing. Members of each of these new types are at least 75% identical to one another (91% amino acid identity) in VP1, but members of different types differ from one another and from other enteroviruses by at least 27% in nucleotide sequence (26% amino acid sequence difference). The complete P1 (capsid) sequences of the new types are at least 17% different from those of all other enterovirus serotypes (14.5% amino acid sequence difference), but they are highly conserved within a type (<8% amino acid sequence difference). For both VP1 and P1, the 17 isolates are monophyletic by type with respect to all other EV serotypes. The P2 and P3 sequences are closely related to those of other HEV-B viruses (>93% amino acid identity), confirming that the 17 new strains belong to HEV-B. We propose that these 17 isolates be classified as members of 13 new human enterovirus types, enteroviruses 79-88, 97, and 100-101.

Enteroviruses 76, 89, 90 and 91 represent a novel group within the species Human enterovirus A.

Molecular methods have enabled the rapid identification of new enterovirus (EV) serotypes that would have been untypable using existing neutralizing antisera. Nineteen strains of four new EV types termed EV76 (11 isolates), EV89 (two isolates), EV90 (four isolates) and EV91 (two isolates), isolated from clinical specimens from patients in France (one isolate) and Bangladesh (18 isolates), are described. Nucleotide sequences encoding the VP1 capsid protein (882-888 nt) are less than 65 % identical to the homologous sequences of the recognized human EV serotypes, but within each group the sequences are more than 78 % identical. The deduced amino acid sequences of the complete capsid (P1) region are more than 94 % identical within type but less than 76 % identical to those of the recognized serotypes. For both VP1 and P1, the 19 isolates are monophyletic by type with respect to all other EV serotypes. Using the proposed molecular typing scheme, these data support their identification as four new types within the species Human enterovirus A (HEV-A). In almost all cases, the VP1 sequences were more similar to those of some simian EVs than to the human EVs. Partial 3D sequences of all 19 isolates also clustered within HEV-A; they were monophyletic as a group, but not by type, suggesting that recombination has occurred among viruses of these four types. Partial 3D sequences were more closely related to those of simian EVs than to human viruses in HEV-A. These results suggest that the four new types may represent a new subgroup within HEV-A, in addition to the existing human and simian subgroups.

Molecular identification and characterization of two proposed new enterovirus serotypes, EV74 and EV75.

Sequencing of the gene that encodes the capsid protein VP1 has been used as a surrogate for antigenic typing in order to distinguish enterovirus serotypes; three new serotypes were identified recently by this method. In this study, 14 enterovirus isolates from six countries were characterized as members of two new types within the species Human enterovirus B, based on sequencing of the complete capsid-encoding (P1) region. Isolates within each of these two types differed significantly from one another and from all other known enterovirus serotypes on the basis of sequences that encode either VP1 alone or the entire P1 region. Members of each type were > or =77.2 % identical to one another (89.5 % amino acid identity) in VP1, but members of the two different types differed from one another and from other enteroviruses by > or =31 % in nucleotide sequence (25 % amino acid sequence difference), indicating that the two groups represent separate new candidate enterovirus types. The complete P1 sequences differed from those of all other enterovirus serotypes by > or =31 % (26 % amino acid sequence difference), but were highly conserved within a serotype (<8 % amino acid sequence difference). Phylogenetic analyses demonstrated that isolates of the same serotype were monophyletic in both VP1 and the capsid as a whole, as shown previously for other enterovirus serotypes. This paper proposes that these 14 isolates should be classified as members of two new human enterovirus types, enteroviruses 74 and 75 (EV74 and EV75).