Hepatitis E: the current state of play

Abstract

The hepatitis E virus (HEV) is a major cause of acute hepatitis globally. Genotypes 1 and 2 (G1 and G2) are obligate human pathogens transmitted faeco-orally, leading to epidemics in developing countries. In contrast, genotypes 3 and 4 (G3 and G4) have a wider host range, including humans, but are primarily porcine viruses and are transmitted from animals to humans as a food-borne zoonosis when meat from an infected animal is consumed. HEV is increasingly recognised as a problem in developed countries, including countries in Europe. G3 HEV is now the most common cause of acute viral hepatitis in the UK and cases continue to rise. The majority of these infections are acquired within the UK and thought to be from insufficiently cooked meat, predominantly processed pork meat. Previously thought to only cause self-limiting disease, HEV infection can persist in immunosuppressed patients, which may lead to chronic hepatitis and the rapid development of cirrhosis. Of particular interest to the transfusion community has been the possibility of transfusion-transmitted HEV, which has been reported from countries classically considered HEV-endemic but also non-endemic countries in Europe and Japan. This has prompted some countries to introduce screening for HEV in blood donations.

Current hepatitis E virus seroprevalence in Swiss blood donors and apparent decline from 1997 to 2016

“…In many European countries similarly high seroprevalence differences have been recorded; for example, 25%–86.4% in France and 21%–27% in the Netherlands [19,20,27,28]. Interestingly, the French Jura, a region directly adjacent to the west of Switzerland, has reported a similar seroprevalence to the one in our report [20].…”

“…It has been suggested that these large regional variations may be a consequence of the consumption of a regional delicacy of traditional raw dry-cured pork sausage containing raw pork liver (e.g. mortadella di fegato crudo ) [19,31]. It remains to be seen whether the variation in Switzerland can be explained by these dietary differences.…”

“…In recent years, a number of published data have indicated a wide variation in HEV seroprevalence in Europe, ranging from 1.9% in Switzerland to 86.4% in France [19,20]. The reason for this wide variation is not entirely clear, but it could be a consequence of many factors, such as eating habits, differences in food production, age of the tested population, country or region of residence or sex.…”

Retrospectively seroprevalence study on anti‐HEV‐IgG antibody in patients with chronic hepatitis or liver cirrhosis in a Chinese teaching hospital

“…Chronic liver diseases include hepatitis caused by the hepatitis B virus (HBV), hepatitis C virus (HCV), alcohol, autoimmune, fat, all of which can progress to cirrhosis, and various factors involving genetic background, hormones, environmental agents, drugs, and viral co‐infection have been proposed as triggers for the histological development . Hepatitis E virus (HEV) infection has been suggested as one of the contributing factors . The viral hepatitis caused by HEV infection is generally considered to be a self‐limiting acute course and the majority of the patients are healed within 6 weeks after onset .…”

Hepatitis E virus infection in Thai blood donors

“…In several countries, inadvertent HEV transmission to blood recipients was associated with blood donation from healthy donors who may have acquired zoonotic foodborne HEV infection . Reports of such blood‐borne HEV transmission has increased the awareness of potential risks from HEV in donated blood and blood components.…”