Molecular Epidemiology of Hepatitis B Virus Infection in Switzerland: A Retrospective Cohort Study

Chronic hepatitis B virus (HBV) infection affects up to 7 % of the European population. Specific HBV genotypes are associated with rapid progression to end-stage liver disease and sub-optimal interferon treatment responses. Although the geographic distribution of HBV genotypes differs between regions, it has not been studied in Switzerland, which lies at the crossroads of Europe.

In a retrospective analysis of 465 HBV samples collected between 2002 and 2013, we evaluated the HBV genotype distribution and phylogenetic determinants, as well as the prevalence of serological evidence of hepatitis delta, hepatitis C and HIV infections in Switzerland. Baseline characteristics of patients were compared across their region of origin using Fisher’s exact test and ANOVA, and risk factors for HBeAg positivity were assessed using logistic regression.

The Swiss native population represented 15.7 % of HBV-infected patients living in Switzerland. In the overall population, genotype D was most prevalent (58.3 %), whereas genotype A (58.9 %) was the predominant genotype among the Swiss native population. The prevalence of patients with anti-HDV antibodies was 4.4 %. Patients of Swiss origin were most likely to be HBeAg-positive (38.1 %). HBV genotypes of patients living in Switzerland but sharing the same original region of origin were consistent with their place of birth.

The molecular epidemiology of HBV infection in Switzerland is driven by migration patterns and not by the genotype distribution of the native population. The prevalence of positive anti-HDV antibodies in our cohort was very low.

Below:  Regions of origin of HBV infected individuals in comparison to the general population in Switzerland. Left bar: distribution of regions of origin of the study population. Right bar: regions of origin of the overall population of Switzerland. *Data from Swiss Federal office for statistics [16]

Below:  Hepatitis B virus genotypes by region of origin. The bars represent the frequency of the different HBV genotypes by regions of origin

Full article at: http://goo.gl/5h3N31

By: Cédric Hirzel^1*, Gilles Wandeler¹, Marta Owczarek³, Meri Gorgievski-Hrisoho³, Jean-Francois Dufour², Nasser Semmo² and Samuel Zürcher³

¹Department of Infectious Diseases, Bern University Hospital and University of Bern, Bern, Switzerland

²Hepatology Unit, Department of Visceral Surgery and Medicine University Hospital Bern, Bern, Switzerland

³Institute for Infectious Diseases, University of Bern, Bern, Switzerland

  

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