Update of cases of acute hepatitis E confirmed by the National Centre of Microbiology (Spain, 2004-2011)

Hepatitis E Virus in Industrialized Countries: The Silent Threat

Hepatitis E virus (HEV) is the main cause of acute viral hepatitis worldwide. Its presence in developing countries has been documented for decades. Developed countries were supposed to be virus-free and initially only imported cases were detected in those areas. However, sporadic and autochthonous cases of HEV infection have been identified and studies reveal that the virus is worldwide spread. Chronic hepatitis and multiple extrahepatic manifestations have also been associated with HEV. We review the data from European countries, where human, animal, and environmental data have been collected since the 90s. In Europe, autochthonous HEV strains were first detected in the late 90s and early 2000s. Since then, serological data have shown that the virus infects quite frequently the European population and that some species, such as pigs, wild boars, and deer, are reservoirs. HEV strains can be isolated from environmental samples and reach the food chain, as shown by the detection of the virus in mussels and in contaminated pork products as sausages or meat. All these data highlight the need of studies directed to control the sources of HEV to protect immunocompromised individuals that seem the weakest link of the HEV epidemiology in industrialized regions.

Hepatitis E virus co-infection in HIV-infected patients in Foggia and Naples in southern Italy

BACKGROUND

Hepatitis E virus (HEV) infection represents an emerging infection in developed countries and is thought to be a zoonotic infection. It has recently been described as a new causative agent of acute and chronic hepatitis in immunosuppressed subjects, including HIV-infected patients. The aim of this study was to assess the sero-virological prevalence of HEV in HIV patients and in the general population as control group.

METHODS

A prospective and observational cohort study was carried out in two hospitals in southern Italy. The seroprevalence of HEV was determined in a cohort of 959 subjects, 509 (53%) of whom were HIV-positive patients and 450 were from the general population. Serum samples were tested for anti-HEV antibodies; repeatedly positive results were confirmed by a Western blot assay. In positive patients HEV RNA and genotypes were also determined.

RESULTS

A total of 46 (4.8%) of the 959 serum samples examined were reactive to anti-HEV Ig and confirmed by Western blotting. The prevalence of HEV antibodies (IgG and/or IgM) was 2.7% in the control group and 6.7% in HIV-infected patients. Anti-HEV IgM was found in 6/46 (13.0%) of the anti-HEV Ig-positive serum samples, in 5/34 HIV patients and in 1/12 of the general population. No HIV-infected patient presented chronic hepatitis with HEV infection alone.

CONCLUSIONS

This study indicates a higher circulation of HEV in HIV-infected patients, whereas a low prevalence of HEV antibodies in the general Italian population was shown. Chronic hepatitis with HEV alone was absent, while it was present in subjects with HIV-HEV, co-infected with hepatitis B virus (HBV) and/or hepatitis C virus (HCV).

Autochthonous Hepatitis E Virus Infection in Europe: A Matter of Concern for Public Health?

Human hepatitis E virus (HHEV) is the proposed name for a diverse group of RNA viruses from the family Hepeviridae that cause acute hepatitis among humans. Waterborne strains are regularly imported into Europe by international travelers, and virus transmission of zoonotic strains via contaminated aliments is involved in autochthonous cases. Therefore, in Europe, hepatitis E displays a unique dual character, having features of both imported and autochthonous infections. Environmental involvement of waterborne and zoonotic diseases puts alimentary safety at risk. In addition, it may lead to serious health problems derived from persistent infection among patients with immune impairment due to organ transplant, cancer, or human immunodeficiency virus infection. Although the European health authorities know at present that HHEV represents a problem worthy of consideration, the actual incidence of the disease in Europe is unknown, and attempts to ascertain the prevalence of the infection is hampered by unresolved technical issues. In order to determine the burden of hepatitis E in Europe, the World Health Organization Regional Office and the European Centre for Disease Prevention and Control should pay specific attention to hepatitis E, and research efforts in the continent should be transnational and collaborative. Development of a specific European network for hepatitis E would help to achieve these goals.

Light and Darkness: Prevalence of Hepatitis E Virus Infection among the General Population

Human hepatitis E virus (HHEV) spreads early in life among the population in areas endemic for genotype 1 and infects mainly adults in areas endemic for genotype 3, where it would be responsible for about 10% of cases of suspected acute viral hepatitis of unknown etiology and for a number of subclinical, unrecognized infections. The overall prevalence of antibody to HHEV is high in most of the former areas and low in most of the later ones, but wide regional differences have been recorded in both cases. "Hot spots" of HHEV infection would exist for both types of strains in particular regions or among particular populations of the world. Studies on pork derivatives, shellfish bivalves, and vegetables for HHEV contamination at the sale point need to be extended for evaluating the impact of the agent on food safety, and the meaning of the finding of HHEV genotype 1 genomes in urban sewage from developed countries should be established through active surveillance. Consensus about technical issues in regard to anti-HEV testing would improve the knowledge of the HHEV epidemiology. Studies in particular regions and populations, and introduction of molecular diagnosis in the clinical setting as a routine tool, would also be required.