Hepatitis E virus epidemiology in industrialized countries

Abstract

To determine the prevalence of Hepatitis E virus (HEV) in industrialized nations, we analyzed the excretion of HEV strains by the populations of Spain, France, Greece, Sweden, and the United States. Twenty of 46 (43.5%) urban sewage samples collected in Barcelona from 1994 to 2002 tested positive for HEV. We identified 15 HEV strains, which were similar to two HEV isolates previously described in Barcelona in clinical samples and to strains from diverse geographic HEV-nonendemic areas. We also identified two HEV strains in sewage samples from Washington, D.C., and Nancy, France; these samples were also positive for Hepatitis A virus. In addition, we studied the role of pigs as a reservoir for HEV and identified one new swine HEV strain. Our results suggest that HEV may be more prevalent than previously considered in industrialized countries and that variants of the virus circulate simultaneously in one region.

Figure 1

Unrooted phylogenetic tree showing the relationship over a 123-bp fragment within open reading frame 2 between representative Hepatitis E virus strains reported in this study and other isolates from genotype I (C1, China; P, Pakistan; I, India; BCN, Barcelona, Spain; and B, Burma), genotype II (M, Mexico), genotype III (US1 and US2, United States; Sw, swine; G1 and G2, Greece; It, Italy; and Au, Austria), and genotype IV (C2 and C3, China). Strains from Barcelona, Spain, Washington, D.C., United States, and Nancy, France, are in black.

Figure 2

Nucleotide alignment of the amplified fragment within ORF2 from some representative isolates in this study with other Hepatitis E virus strains. Dots indicate sequence identities.

Figure 3

Amino acid alignment from representative isolates in this study with other Hepatitis E virus strains. Amino acid sequences from BCN3–BCN8, BCN10–BCN13, and BCN16 are identical to BCN2. Dots indicate sequence identities.