Phylodynamic Characterization of an Ocular-Tropism Coxsackievirus A24 Variant

PLoS One. 2016 Aug 16;11(8):e0160672. doi: 10.1371/journal.pone.0160672. eCollection 2016.

Abstract

Recent phylodynamic studies have focused on using tree topology patterns to elucidate interactions among the epidemiological, evolutionary, and demographic characteristics of infectious agents. However, because studies of viral phylodynamics tend to focus on epidemic outbreaks, tree topology signatures of tissue-tropism pathogens might not be clearly identified. Therefore, this study used a novel Bayesian evolutionary approach to analyze the A24 variant of coxsackievirus (CV-A24v), an ocular-tropism agent of acute hemorrhagic conjunctivitis. Analyses of the 915-nucleotide VP1 and 690-nt 3Dpol regions of 21 strains isolated in Taiwan and worldwide during 1985-2010 revealed a clear chronological trend in both the VP1 and 3Dpol phylogenetic trees: the emergence of a single dominant cluster in each outbreak. The VP1 sequences included three genotypes: GI (prototype), GIII (isolated 1985-1999), and GIV (isolated after 2000); no VP1 sequences from GII strains have been deposited in GenBank. Another five genotypes identified in the 3Dpol region had support values >0.9. Geographic and demographic transitions among CV-A24v clusters were clearly identified by Bayes algorithm. The transmission route was mapped from India to China and then to Taiwan, and each prevalent viral population declined before new clusters emerged. Notably, the VP1 and 3Dpol genes had high nucleotide sequence similarities (94.1% and 95.2%, respectively). The lack of co-circulating lineages and narrow tissue tropism affected the CV-A24v gene pool.

MeSH terms

  • Base Sequence
  • Bayes Theorem
  • Capsid Proteins / genetics
  • Enterovirus C, Human / genetics
  • Enterovirus C, Human / physiology*
  • Evolution, Molecular
  • Genotype
  • Monte Carlo Method
  • Phylogeny*
  • Spatio-Temporal Analysis
  • Viral Tropism*

Substances

  • Capsid Proteins

Grants and funding

This study was supported by Ministry of Science and Technology, Taiwan grant no. MOST104-2320-B-037-018 (url: http://www.most.gov.tw/) to PYC; Chi-Mei Medical Center and Kaohsiung Medical University Research Foundation grant no. 103CM-KMU-06 (URL: http://devel.kmu.edu.tw/index.php/en-GB/) to PYC; Center for Infectious Disease and Cancer Research, Kaohsiung Medical University grant no. KMU-TP104E12 (URL: http://devel.kmu.edu.tw/index.php/en-GB/) to YCT; Wei Gong Memorial Hospital grant no. 105-1-001 (URL: http://www.weigong.org.tw/eng-index.html) to PHC, and Chi-Mei Foundation Medical Center grant no. CLFHR10127 (URL: http://www.chimei.org.tw/main/clh_department/79052/index.htm) to YCY. The funders had no role in the design of the study, the collection and analysis of data, the decision to publish, or the preparation of the manuscript.