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Emerson SU, Nguyen HT, Torian U, Mather K, Firth AE.Emerson SU, et al. Among authors: firth ae.J Gen Virol. 2013 Jul;94(Pt 7):1468-1476. doi: 10.1099/vir.0.051870-0. Epub 2013 Mar 20.J Gen Virol. 2013.PMID: 23515023Free PMC article.