Figure. . Phylogenetic tree of hepatitis E virus (HEV) open reading frame (ORF) 1 sequences, including HEV infections, the Netherlands, 2000–2011. Phylogenetic relation of a 306-bp ORF1 region was calculated by using maximum-likelihood, Kimura 2-parameter analysis with bootstrapping (n = 1,000). HEV sequences originating in the Netherlands are indicated as NL with year of isolation and isolate number (GenBank accession nos. JQ015399–JQ015448). Boldface indicates virus strains of chronic HEV-infected solid organ transplant recipients identified in this study. Scale bar indicates number of nucleotide substitutions per site. HTX, heart transplant; NTX, kidney transplant; LTX, liver transplant; lungTX, lung transplant.