The online version of this article (doi:10.1186/s12985-017-0809-2) contains supplementary material, which is available to authorized users.
Echovirus 6 (E6) infections are associated with aseptic meningitis and acute flaccid paralysis (AFP). But some infections, sometimes most of them, are asymptomatic. The mechanism of E6 virulence is unknown. Analyses of the molecular evolution of asymptomatic E6 may help understand why the infections show different manifestations.
Ninety-six stool samples of healthy children in Yunnan, China were collected and two E6 strains were isolated from them. The whole genomes of these two E6 strains were sequenced, and their molecular evolution was analyzed.
The results showed that the two E6 strains may be derived from KJ7724XX strains, which were predominant in AFP patients in Shangdong in 2011. The evolution was accelerated when the two E6 strains formed, although no positive selection site was found. The 11 exclusive mutations on which selection force significantly changed were found in the 2C, 3AB and 3C genes.
There are some E6 strains which did not cause the disease in the children of Yunnan. These E6 strains maybe come from a recombinant E6 strain which was associated with the outbreak of AFP in Shangdong in 2011. However, some new mutations were found in the 2C, 3AB and 3C genes of these asymptomatic strains, and these mutations may be constraint by the natural selection and could be potentially responsible for clinical presentations.
Additional file 1: Figure S1. Polygenetic tree based on the VP1 sequences of EVs. The tree includes nearly all of the E6 strains found in China by 2016. The black circles indicate the strains that we found, and the black triangles indicate the closest strains to them. Figure S2. Similarity plot and bootscanning analysis queried by K843. (a) The similarity plot between K843 and other EVs. (b) The bootscanning analysis for K843. The analyses were conducted via Simplot v3.5.1 using a sliding window of 400 nucleotides moving in steps of 20 nucleotides. (PDF 919 kb)12985_2017_809_MOESM1_ESM.pdf
Khetsuriani N, Lamonte-Fowlkes A, Oberst S, Pallansch MA, Centers for Disease C, Prevention. Enterovirus surveillance--United States, 1970-2005. MMWR Surveill Summ. 2006;55:1–20. PubMed
Pallansch M, Roos R. Enteroviruses: polioviruses, coxsackieviruses, echoviruses, and newer enteroviruses. In: Knipe D, Howley P, editors. Fields virology. 5th ed. Philadelphia: Lippincott, Williams & Wilkins; 2007. p. 839–93.
WHO. WHO polio laboratory manual. 4th ed. Geneva: World Health Organization; 2004.
Nei M, Kumar S. Molecular evolutionary genetics. New York: Oxford University Press; 2000.
Yang Z. Computational molecular evolution. Oxford: Oxford University Press; 2006. CrossRef
Centers for Disease C, Prevention. Nonpolio enterovirus and human parechovirus surveillance --- United States, 2006-2008. MMWR Morb Mortal Wkly Rep. 2010;59:1577–80.
Wang H, Tao Z, Li Y, Lin X, Yoshida H, Song L, Zhang Y, Wang S, Cui N, Xu W, et al. Environmental surveillance of human enteroviruses in Shandong Province, China, 2008 to 2012: serotypes, temporal fluctuation, and molecular epidemiology. Appl Environ Microbiol. 2014;80:4683–91. CrossRefPubMedPubMedCentral
Jia QJ, Chen XY, Li Z, Xu JJ, Xu ZG, Duan ZL, Wen JS. Comparative genomic analysis of Enterovirus 71 revealed six new potential neurovirulence-associated sites. Biomed Environ Sci. 2016;29:767–72. PubMed
- Molecular evolution of two asymptomatic echovirus 6 strains that constitute a novel branch of recently epidemic echovirus 6 in China
- BioMed Central
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