Hepatitis E: An emerging awareness of an old disease R.H. Purcell, S.U. Emerson  Journal of Hepatology  Volume 48, Issue 3, Pages 494-503 (March 2008) DOI: 10.1016/j.jhep.2007.12.008 Copyright © 2008 Terms and Conditions

Fig. 1 Geographic distribution of clinically significant hepatitis E and relative importance of hepatitis E virus (HEV) in the etiology of clinical hepatitis among adults in selected regions [25–27]. Journal of Hepatology 2008 48, 494-503DOI: (10.1016/j.jhep.2007.12.008) Copyright © 2008 Terms and Conditions

Fig. 2 The age-specific prevalence of anti-HEV also varies from region to region [29–31]. Journal of Hepatology 2008 48, 494-503DOI: (10.1016/j.jhep.2007.12.008) Copyright © 2008 Terms and Conditions

Fig. 3 Surprisingly, in the United States, the prevalence of anti-HEV is equal to or greater than the prevalence of anti-HAV in some regions, especially in states that are large producers of swine [31]. Journal of Hepatology 2008 48, 494-503DOI: (10.1016/j.jhep.2007.12.008) Copyright © 2008 Terms and Conditions

Fig. 4 Each of the four genotypes of HEV that infect humans has a distinct, and in some cases, overlapping geographic distribution. Journal of Hepatology 2008 48, 494-503DOI: (10.1016/j.jhep.2007.12.008) Copyright © 2008 Terms and Conditions

Fig. 5 HEV genotypes 3 and 4, which infect both humans and swine, have been recovered from pigs in regions that roughly parallel the distribution of these viruses in human infections. However, there are exceptions. Journal of Hepatology 2008 48, 494-503DOI: (10.1016/j.jhep.2007.12.008) Copyright © 2008 Terms and Conditions

Fig. 6 The age-related clinical attack rate of hepatitis E differs by genotype. In the famous Delhi epidemic of 1955 (presumably caused by a genotype 1 virus), the highest incidence of disease was in those 20–29 years of age [36]. Similarly, endemic disease associated with HEV genotype 1 or 2 infections in developing countries also peaks in the 20–29 year age group. In contrast, clinical hepatitis E associated with infection with genotypes 3 or 4, often in industrialized countries, peaks in those 60 years of age or older. Journal of Hepatology 2008 48, 494-503DOI: (10.1016/j.jhep.2007.12.008) Copyright © 2008 Terms and Conditions

Fig. 7 The genome of HEV consists of single-stranded, positive sense RNA with a size of 7.2kb. There are three open reading frames (ORFs) that encode the non-structural proteins, a small protein of unknown function and the capsid protein, respectively. The genome also encodes putative phosphorylation and glycosylation sites and contains a cis-reactive element (CRE). Two subgenomic RNAs were reported previously; the smaller of the two has been shown to express both ORF2 and ORF3 [7,68]. Journal of Hepatology 2008 48, 494-503DOI: (10.1016/j.jhep.2007.12.008) Copyright © 2008 Terms and Conditions