Sequencing of 'untypable' enteroviruses reveals two new types, EV-77 and EV-78, within human enterovirus type B and substitutions in the BC loop of the VP1 protein for known types.
The N-terminal part of VP1 was sequenced for 43 enterovirus isolates that could not initially be neutralized with LBM pools or in-house antisera. Most isolates were found to belong to human enterovirus type A (HEV-A) and HEV-B (18 isolates of each). All HEV-A isolates could be typed by sequencing, with CV (coxsackievirus)-A16 and EV (enterovirus)-71 being dominant (nine and seven isolates, respectively). These types thus seem to have diverged more from their prototypes than the other types. Among the HEV-B isolates, E-18 dominated with five isolates that became typable after filtration. The virus type obtained by molecular typing was verified for 28 of the other patient isolates by neutralization using high-titre monovalent antisera or LBM pools. Twenty-two of the other 30 'untypable' isolates had substitutions in the VP1 protein within or close to the BC loop. Two closely related HEV-B isolates diverged by 19.4 % from E-15, the most similar prototype. Two non-neutralizable HEV-C isolates split off from the CV-A13/CV-A18 branch, from which they diverged by 15.7-18.2 %. Three of the six non-neutralizable isolates, W553-130/99, W543-122/99 and W137-126/99, diverged by >24.2 % from the most similar prototype in the compared region. The complete VP1 was therefore sequenced and found to diverge by >29 % from all prototypes and by >28 % from each other. Strains similar to W553-130/99 that have been identified in the USA are tentatively designated EV-74. The two other isolates fulfil the molecular criterion for being new types. Since strains designated EV-75 and EV-76 have been identified in the USA, we have proposed the tentative designations EV-77 and EV-78 for these two new members of HEV-B.
Norder
Helene
H
Swedish Institute for Infectious Disease Control, S-171 82 Solna, Sweden.
Bjerregaard
Lotte
L
Swedish Institute for Infectious Disease Control, S-171 82 Solna, Sweden.
Magnius
Lars
L
Swedish Institute for Infectious Disease Control, S-171 82 Solna, Sweden.
Lina
Bruno
B
Centre National de Reference des Enterovirus, Lyon, France.
Aymard
Michèle
M
Centre National de Reference des Enterovirus, Lyon, France.
Chomel
Jean-Jacques
JJ
Centre National de Reference des Enterovirus, Lyon, France.
D000328:Adult; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D002675:Child, Preschool; D029822:Enterovirus B, Human / Q000737:chemistry / Q000145:classification / Q000235:genetics*; D004769:Enterovirus Infections / Q000821:virology*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008969:Molecular Sequence Data; D009500:Neutralization Tests; D016415:Sequence Alignment; D012722:Sewage / Q000821:virology
D012722:Sewage