Elsevier

Virus Research

Volume 183, 21 April 2014, Pages 75-80
Virus Research

Molecular typing and characterization of a new serotype of human enterovirus (EV-B111) identified in China

https://doi.org/10.1016/j.virusres.2014.01.002Get rights and content

Highlights

  • A new enterovirus serotype (EV-B111) was discovered and characterized in China.

  • The virus (strain Q0011) was isolated from a stool sample from a patient with acute flaccid paralysis in 2000.

  • The complete genome of the newly discovered enterovirus serotype (EV-B111) was sequenced and analyzed.

  • Low positive rate and titer of neutralizing antibody against EV-B111 were found in the Tibet region of China.

  • The extent of transmission and the exposure of the population to this new EV are very limited.

Abstract

Molecular methods, based on sequencing the region encoding the complete VP1 or P1 protein, have enabled the rapid identification of new enterovirus serotypes. In the present study, the complete genome of a newly discovered enterovirus serotype, strain Q0011/XZ/CHN/2000 (hereafter referred to as Q0011), was sequenced and analyzed. The virus, isolated from a stool sample from a patient with acute flaccid paralysis in the Tibet region of China in 2000, was characterized by amplicon sequencing and comparison to a GenBank database of enterovirus nucleotide sequences. The nucleotide sequence encoding the complete VP1 capsid protein is most closely related to the sequences of viruses within the species enterovirus B (EV-B), but is less than 72.1% identical to the homologous sequences of the recognized human enterovirus serotypes, with the greatest homology to EV-B101 and echovirus 32. Moreover, the deduced amino acid sequence of the complete VP1 region is less than 84.7% identical to those of the recognized serotypes, suggesting that the strain is a new serotype of enterovirus within EV-B. The virus was characterized as a new enterovirus type, named EV-B111, by the Picornaviridae Study Group of the International Committee on Taxonomy of Viruses. Low positive rate and titer of neutralizing antibody against EV-B111 were found in the Tibet region of China. Nearly 50% of children ≤5 years had no neutralizing antibody against EV-B111. So the extent of transmission and the exposure of the population to this new EV are very limited. This is the first identification of a new serotype of human enterovirus in China, and strain Q0011 was designated the prototype strain of EV-B111.

Introduction

Currently, human enteroviruses (EVs) are classified into 4 species: EV-A, EV-B, EV-C, and EV-D (Knowles et al., 2011). The species EV-B comprises 60 serotypes: coxsackievirus group B (CVB: serotypes 1–6), coxsackievirus group A (CVA: serotype 9), echovirus (serotypes 1–7, 9, 11–21, 24–27, 29–33), EV-B69, and recently identified novel EV serotypes to be designated EV-B73–B75 (Norder et al., 2002, Oberste et al., 2001, Oberste et al., 2004b), EV-B77–B88 (Norder et al., 2003, Oberste et al., 2007, Sun et al., 2013, Tao et al., 2013), EV-B93 (Junttila et al., 2007), EV-B97–B98 (Oberste et al., 2007, Smura et al., 2007, Yamashita et al., 2010), EV-B100–B101 (Oberste et al., 2007), EV-B106–B107 (Yamashita et al., 2010), EV-B110 (Harvala et al., 2011), and simian enterovirus SA5.

The viruses in species EV-B belong to the genus Enterovirus in the family Picornaviridae and order Picornavirales. Picornaviruses are small, non-enveloped human EVs comprising 60 copies each of the capsid proteins VP4, VP2, VP3, and VP1, which enclose a positive-sense, single-stranded RNA genome. The viral RNA contains a long open reading frame flanked by a 5′-untranslated region (UTR) and a 3′-UTR.

In this study, we describe a newly discovered EV serotype within species EV-B, which was named EV-B111 by the Picornaviridae Study Group of the International Committee on Taxonomy of Viruses (ICTV) (www.picornastudygroup.com). The virus was isolated from a patient with acute flaccid paralysis (AFP) during virological surveillance supporting global polio eradication in China in 2000. To the best of our knowledge, EV-B111 has not been reported elsewhere, and its pathogenic role, disease association, and global occurrence are unknown. The aim of this study was to characterize the newly discovered serotype EV-B111.

Section snippets

Clinical specimens

The newly discovered EV serotype (EV-B111, strain Q0011/XZ/CHN/2000, hereafter referred to as Q0011) was isolated from a stool sample collected from a 2-year-old girl who presented with AFP on September 2000 in Lhasa City (population: ∼474,500) of the Tibet Autonomous Region, China, during the course of poliovirus surveillance activities in support of the global polio eradication initiative. Epidemiological data was collected prospectively by the attending physician using an anonymous standard

Neutralization typing and molecular typing of the Tibetan isolate Q0011

The Tibetan isolate was primarily characterized using a standard pool of EV typing antisera (RIVM, the Netherlands) distributed by the World Health Organization. The isolate was not neutralized by any of the pools (data not shown). Based on the absence of neutralization using antisera against polioviruses, echoviruses, and coxsackieviruses, the isolate was tentatively identified as an ‘untypeable’ non-polio EV.

The complete VP1 region (876 nucleotides) of the ‘untypeable’ non-polio EV was

Discussion

Both the neutralization test and molecular typing method (VP1 region sequencing and database comparison) are important for EV serotyping. The neutralization test is previously considered to be the gold standard, and the molecular typing is the new gold standard because the VP1 region sequences of EVs correlate well with antigenically defined serotypes, such as those determined by the neutralization test (Norder et al., 2001, Oberste et al., 1999b, Oberste et al., 2000), and all new types

Acknowledgements

This study was supported by the National Natural Science Foundation of China (project nos. 30900063, 81101303 and 81373049), and the National Key Technology R&D Program of China (project no. 2013ZX10004-202).

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  • 1

    These authors contributed equally to this work.

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