New hepatitis E virus genotype in camels, the Middle East

Abstract

In a molecular epidemiology study of hepatitis E virus (HEV) in dromedaries in Dubai, United Arab Emirates, HEV was detected in fecal samples from 3 camels. Complete genome sequencing of 2 strains showed >20% overall nucleotide difference to known HEVs. Comparative genomic and phylogenetic analyses revealed a previously unrecognized HEV genotype.

Figure 1

Predicted genomic organization of hepatitis E virus (HEV) from dromedary camel (DcHEV) and other HEVs, considering the reading frame of open reading frame (ORF) 1 as frame 1.

Figure 2

Phylogenetic analyses of open reading frame (ORF) 1 (A), ORF2 (B), ORF3 (C), and ORF1/ORF2 proteins, excluding the hypervariable region (HVR) (D) of hepatitis E virus (HEV) from dromedary camels (DcHEV). The trees were constructed by using Bayesian methods of phylogenetic reconstruction (www.fifthdimension.jp/products/mrbayes5d/), and ProtTest-suggested JTT+I+G+F, MtMam+I+G+F, HIVw+I+G+F, and JTT+I+G+F (http://darwin.uvigo.es/software/prottest.html) are the optimal substitution models for ORF1, ORF2, ORF3, and concatenated ORF1/ORF2 excluding HVR, respectively. For this analysis we included amino acid positions 1698, 660, 113, and 2282 in ORF1, ORF2, ORF3 and concatenated ORF1/ORF2 excluding HVR, respectively. For ORF2 and concatenated ORF1/ORF2 excluding HVR, the scale bars indicate the estimated number of substitutions per 50 aa. For ORF1 and ORF3, the scale bars indicate the estimated number of substitutions per 20 aa. Boldface indicates the 2 strains of DcHEV with complete genomes sequenced in this study.