Variability of the PreS1/PreS2/S regions of hepatitis B virus in Hungary

Phylogenetic analysis of a nosocomial transmission of hepatitis B virus at a paediatric haematology ward

A nosocomial Hepatitis B virus (HBV) outbreak at a paediatric onco-haematology unit was investigated using molecular biological methods to determine the origin of the infections. The National Reference Laboratory of Hepatitis Viruses received seven HBsAg positive sera from patients and one from the brother of a patient. A fragment of the preS1/preS2/S genes from all samples was amplified, the PCR products were sequenced and a rooted phylogenetic tree was constructed. All nucleotide sequences from the different patients were very similar and 6 of the 8 sequences were identical, suggesting a common origin of the infections. These sequences were closely related to those amplified from a nosocomial HBV epidemic in another hospital in Hungary. The on-scene investigation revealed several malpractices. The two hospital departments had close connections and some of the patients were treated in both institutions. Present report underlines the importance of developing screening protocols for hepatitis viruses and that of the introduction of regular training programs for health care professionals in the field of hospital hygiene.

Distribution of hepatitis B virus genotypes and viral load levels in Brazilian chronically infected patients in São Paulo city

The objective of the present study was to evaluate the serum viral load in chronically infected Hepatitis B virus (HBV) patients and to investigate the distribution of HBV genotypes in São Paulo city. Quantitative HBV-DNA assays and HBV genotyping have gained importance for predicting HBV disease progression, have been employed for assessing infectivity, for treatment monitoring and for detecting the emergence of drug resistance. Twenty-nine Brazilian patients with suspected chronic hepatitis B were studied, using real time PCR for viral load determination and direct DNA sequencing for the genotyping. The serology revealed chronic HBV infection in 22 samples. The HBV-DNA was positive in 68% samples (15/22). The phylogenetic analysis disclosed that eleven patients were infected with HBV genotype A, two with genotype F and two with genotype D. Thus, the genotype A was the most prevalent in our study.

Geographical and genetic diversity of the human hepatitis B virus

Hepatitis B virus (HBV) is one of the most widely distributed viruses that infect humankind. Distinct clinical and virological characteristics of the HBV-infection have been reported in different geographical parts of the world and are increasingly associated with genetic diversity of the infecting virus. HBV is classified into genotypes and subgenotypes that are associated with ethnicity and geography. The genetic diversity of HBV in its various aspects has been the subject of extensive investigations during the last few decades. Since molecular epidemiology research tools have become widely available, the number of new publications in this field has grown exponentially. This review summarises the recent publications on the geographical distribution of genetic variants of HBV, and proposes updated criteria for the identification of new genotypes and subgenotypes of the virus.

Mutation spectra of the surface-protein-coding region of the HBV genome in HBV-vaccinated and non-vaccinated individuals in Hungary

Hepatitis B virus (HBV) infection has a major effect on health care systems, with about one-third of the world's population currently infected with the virus. There is an effective vaccine against HBV, which contains a recombinant "surface antigen" produced in an expression vector. Vaccination has proved to be successful in Hungary: the number of acute HBV cases has decreased in the past 10 years. Although an increasing number of publications report on "vaccine-escape" HBV variants which can infect HBV-vaccinated individuals, such mutant HBV strains have not yet been detected in Hungary. We therefore surveyed two risk groups for vaccine-escape or immunoglobulin-escape HBV mutations in Hungary: 28 actively and/or passively HBV-immunized children of HBV carrier mothers who proved to be HBsAg and/or anti-HBc positive and 40 symptomless HBV carrier pregnant women (presumably carrying genotype B or C). We focused on the coding sequences of the "a" immundominant region of the surface protein. We could not detect the G145R amino acid substitution associated with vaccine escape mutant virus. However, we could map other mutations potentially affecting the immunodominant "a" region of the HBV surface protein.

Multiple genotypes and subtypes of hepatitis B and C viruses in Belarus: similarities with Russia and western European influences

The Republic of Belarus reports a seroprevalence of 4.8% for hepatitis B virus (HBV) and 1.26% for hepatitis C virus (HCV), but little is known about the molecular characteristics of the circulating viruses. This study analysed 69 HBV surface antigen (HBsAg)-positive and 113 anti-HCV-positive donors attending a national reference hospital in Minsk. Among the HCV patients, 70% were co-infected with human immunodeficiency virus (HIV). Phylogenetic analysis of 12 complete genomes and 31 partial HBV sequences, as well as 78 core/E1 HCV sequences, revealed that multiple genotypes and subtypes of both viruses were circulating in Belarus. Of the HBV strains, 11.6% were genotype A2 and 88.6% were genotype D. The genotype D strains segregated into four recently described subtypes, with D2 being the most prevalent (58.1%), followed by D3 (16.3%), D1 (11.6%) and D4 (2.3%), but with inter-subtypic distances lower than the minimal 4% distance proposed to define subtypes. The 78 HCV strains belonged to subtypes 1b (53.8%), 3a (38.5%), 1a (5.1%), 4a (1.3%) and 4d (1.3%). Subtype 1b was less prevalent (45.1% vs. 70.4%) among HCV/HIV co-infected donors, while subtype 3a was more prevalent (29.6% vs. 43.1%). The relative prevalence of HBV and HCV genotypes in Belarus corresponded to the prevalence in Russia, although with a clear European influence that reflected the socio-political context of the country.