Age- and region-specific hepatitis B prevalence in Turkey estimated using generalized linear mixed models: a systematic review

Toy M, Önder FO, Wörmann T, et al. Age- and region-specific hepatitis B prevalence in Turkey estimated using generalized linear mixed models: a systematic review. BMC infectious diseases. 2011;11(1): 337.BACKGROUND: To provide a clear picture of the current hepatitis B situation, the authors performed a systematic review to estimate the age- and region-specific prevalence of chronic hepatitis B (CHB) in Turkey. METHODS: A total of 339 studies with original data on the prevalence of hepatitis B surface antigen (HBsAg) in Turkey and published between 1999 and 2009 were identified through a search of electronic databases, by reviewing citations, and by writing to authors. After a critical assessment, the authors included 129 studies, divided into categories: 'age-specific'; 'region-specific'; and 'specific population group'. To account for the differences among the studies, a generalized linear mixed model was used to estimate the overall prevalence across all age groups and regions. For specific population groups, the authors calculated the weighted mean prevalence. RESULTS: The estimated overall population prevalence was 4.57, 95% confidence interval (CI): 3.58, 5.76, and the estimated total number of CHB cases was about 3.3 million. The outcomes of the age-specific groups varied from 2.84, (95% CI: 2.60, 3.10) for the 0-14-year olds to 6.36 (95% CI: 5.83, 6.90) in the 25-34-year-old group. CONCLUSION: There are large age-group and regional differences in CHB prevalence in Turkey, where CHB remains a serious health problem

Molecular characterization of hepatitis A virus isolated from acute infections in Turkey

WOS: 000317376400015PubMed ID: 23794310Background/aims: Hepatitis A virus is a global public health problem, especially in developing countries, and the most common cause of hepatitis in childhood. Hepatitis A virus is a single- stranded positive RNA virus subdivided to 6 genotypes (3 human, 3 simian). The aim of this study was to determine the prevalent genotype in Turkey using sera of acute hepatitis A virus-infected patients from different geographical regions of the country. Materials and Methods: Sera of 137 patients with acute hepatitis A virus from different geographical regions were collected for phylogenetic analysis. The VP1-2A region of the hepatitis A virus genome was amplified by real-time-polymerase chain reaction in 76 patients where possible. Amplified polymerase chain reaction fragments were sequenced, and phylogenetic analysis was done together with other reference hepatitis A virus sequences obtained from GenBank database. Results: Sequencing and phylogenetic analysis of the VP1-2A junction of hepatitis A virus showed that the most prevalent genotype in Turkey is IB (100%). Comparison of Turkish isolates and reference sequences of genotype IB showed a similarity of 94.9%. The same comparison was done between Turkish isolates and reference hepatitis A virus genotype IB and HM175, and it was found that similarity between them ranged from 93.0-95.9%. When Turkish isolates were compared according to Mean Percentage Nucleotide Distance analysis, similarity ranged between 95.3%400%. Conclusions: Phylogenetic analysis pointed out that all Turkish isolates belong to genotype IB. Sequence analysis is a useful tool in revealing hepatitis A outbreaks, and allows us to detect and distinguish the presence of epidemic and small outbreaks

CLONAL ANALYSIS OF THE QUASISPECIES OF ANTIVIRAL RESISTANT HBV GENOMES IN PATIENTS WITH ENTECAVIR RESISTANCE TREATED WITH RESCUE LAMIVUDINE-ADEFOVIR COMBINATION THERAPY

60th Annual Meeting of the American-Association-for-the-Study-of-Liver-Diseases -- OCT 30-NOV 03, 2009 -- Boston, MAWOS: 000270456000417Amer Assoc Study Liver Di

Emergence of a Novel Mutation in the FLLA Region of Hepatitis B Virus during Lamivudine Therapy

The emergence of resistance to lamivudine has been one of the major stumbling blocks to successful treatment and control of hepatitis B virus (HBV) infections. The major mechanism of resistance has been attributed to the alteration in the YMDD motif of the HBV polymerase due to an amino acid change of rtM204 to V/I and an accompanying rtL180M conversion. A novel mutation pattern in a patient having clinical breakthrough under lamivudine therapy was discovered. The mutant had a rtL180C/M204I genotype and was detected after 2 years of therapy with lamivudine. To characterize this novel variant, site-directed mutagenesis was performed using a vector construct containing the HBV genome. Transient transfection studies in human hepatoma cells with HBV carrying the new mutant demonstrated that the rtL180C/M204I mutant was resistant to lamivudine up to 10 μM. The resistance profile was comparable to that of the previously reported rtL180 M/M204I-containing virus. These observations were further confirmed by generation of stable cultures transfected with the mutant virus

Age- and region-specific hepatitis B prevalence in Turkey estimated using generalized linear mixed models: a systematic review

Background: To provide a clear picture of the current hepatitis B situation, the authors performed a systematic review to estimate the age-and region-specific prevalence of chronic hepatitis B (CHB) in Turkey.Methods: A total of 339 studies with original data on the prevalence of hepatitis B surface antigen (HBsAg) in Turkey and published between 1999 and 2009 were identified through a search of electronic databases, by reviewing citations, and by writing to authors. After a critical assessment, the authors included 129 studies, divided into categories: 'age-specific'; 'region-specific'; and 'specific population group'. To account for the differences among the studies, a generalized linear mixed model was used to estimate the overall prevalence across all age groups and regions. For specific population groups, the authors calculated the weighted mean prevalence.Results: The estimated overall population prevalence was 4.57, 95% confidence interval (CI): 3.58, 5.76, and the estimated total number of CHB cases was about 3.3 million. The outcomes of the age-specific groups varied from 2.84, (95% CI: 2.60, 3.10) for the 0-14-yearolds to 6.36 (95% CI: 5.83, 6.90) in the 25-34-year-old group.Conclusion: There are large age-group and regional differences in CHB prevalence in Turkey, where CHB remains a serious health problem

Effectiveness and safety of entecavir and tenofovir in chronic hepatitis b patients: A multicenter Turkish study in clinical practice

64th Annual Meeting and Postgraduate Course of the American-Association-for-the-Study-of-Liver-Diseases -- NOV 01-05, 2013 -- Washington, DCWOS: 000330252203197Amer Assoc Study Liver Di