The population genomics of hepatitis B virus

Hepatitis B virus (HBV) infection is considered as the fifth leading cause of death due to infectious diseases and has a worldwide prevalence. The particular geographical distribution of the eight previously defined genotypes of HBV suggests that the viral population is highly structured. The presence of such population structure is likely to affect the geographical distribution of polymorphisms involved in disease progression. In this study, we determined the structure of the HBV population using a clustering approach based on the observed allele frequencies at the polymorphic loci. We used all full-genome sequences publicly available and obtained a significant clustering of the HBV population into four main clusters, strongly associated with the current classification into genotypes. One of these main clusters could itself be split into three well-supported subclusters, highlighting the hierarchical nature of the population differentiation between HBV strains. The extremely clear-cut subdivision of the HBV population further indicates that recombination in HBV is not as extensive as previously assumed.     

Phosphoglycolate phosphatase in several population groups in Israel

The genetic polymorphism of phosphoglycolate phosphatase (PGP) found in red blood cells has been investigated in several population groups in Israel: Ashkenazi Jews, non-Ashkenazi Jews from Iraq, Yemen, Turkey, Iran, Balkan, North Africa and Arabs. The distribution of the PGP genes was not homogeneous (chi 2 = 40.545; d.f. = 20; p less than 0.005). The PGP2 gene frequency varied between 0.0185 in the Yemenite and 0.0688 in the Iranian Jews. PGP3 gene frequency ranged between 0.0062 in the Iranian and 0.0547 in the Moroccan Jews. Depsite this heterogeneity all the Israeli population groups showed some unifying characteristics which differentiated them from a random European population sample, namely higher frequencies of PGP1 gene (92-97% as opposed to 82% in th European sample) and lower frequencies of PGP2 gene (1.8-6.8% compared to 12.9% among Europeans).     

Prevalence of hepatitis B virus in chronic hepatitis B patients

The aim of the current study was to detect HBV by Real time - PCR in chronic hepatitis B patients. Fifty-eight sera of chronic hepatitis B patients were subjected during the period March 2009 to April 2010 in Ilam cities in West of Iran. Sera assayed by real-time PCR and ELISA methods. Twenty serum samples from healthy volunteers and non-hepatitis B patients and negative for hepatitis B seromarkers served as negative controls for the study. Among fifty-eight sera, ELISA showed fifty-five (94.8%) of the samples were positive for HBsAg and three (5.2%) negative results obtained while real-time PCR specified fifty-eight (100%) positive results in chronic hepatitis B patients. HBsAg status did not necessarily reflect HBV DNA level in the serum, as 5.2% of chronic Hepatitis B patients were positive for HBV DNA but negative for HBsAg. HBV DNA was not found to be positive amongst any of the negative controls. Real time - PCR is a sensitive and reproducible assay for HBV DNA quantization.     

Multiplication of hepatitis B virus in fulminant hepatitis B.

The presence in serum of hepatitis B e antigen (HBeAg) and hepatitis B virus DNA, which are each regarded as reflecting multiplication of hepatitis B virus, were looked for one to five days after the onset of hepatic encephalopathy in 64 patients with fulminant hepatitis B. HBeAg and hepatitis B virus DNA were found in the serum of only 24 (37%) and six (9%) patients, respectively. Hepatitis B virus DNA was absent from the serum in all 13 patients positive for anti-HBs. These findings indicate that replication of hepatitis B virus stopped after the onset of hepatic encephalopathy in most of the patients and support the view that an enhanced immune response stops the replication. Agents that inhibit viral multiplication would probably not have any effect at this stage of the disease.     

Genetic polymorphism of delta-aminolevulinate dehydrase in several population groups in Israel

The genetic polymorphism of red cell delta aminolevulinate dehydrase (ALADH) has been investigated in several population groups in Israel: Ashkenazi Jews, non-Ashkenazi Jews from North Africa, Egypt, Turkey, Iraq, Iran, Yemen and the Balkans, and Arabs. The distribution of the ALADH genes was not homogeneous (chi 2 = 36.83; d.f. = 8; p less than 0.0005). A significantly higher frequency of the ALADH2 gene was observed among the Ashkenazi Jews (0.2021) than among the non-Ashkenazi Jews and Arabs (gene frequencies 0.0825-0.1290) or all the other population samples so far studied (Liberia, Japan, Italy, Germany and Spain).     

Immunology of hepatitis B virus and hepatitis C virus infection

More than 500 million people worldwide are persistently infected with the hepatitis B virus (HBV) and/or hepatitis C virus (HCV) and are at risk of developing chronic liver disease, cirrhosis and hepatocellular carcinoma. Despite many common features in the pathogenesis of HBV- and HCV-related liver disease, these viruses markedly differ in their virological properties and in their immune escape and survival strategies. This review assesses recent advances in our understanding of viral hepatitis, contrasts mechanisms of virus-host interaction in acute hepatitis B and hepatitis C, and outlines areas for future studies.     

Spread of infection with hepatitis B and C viruses in different population groups of north-western Ukraine

The detection rate of specific markers of hepatitides B and C among the child and adult population, including 487 children in 5 boarding schools, 338 oncological, hematological, urological patients and 206 medical staff members in Rovno and the Rovno region (North-Western Ukraine), was determined. In boarding-school the markers of HB (HBsAg, anti-HBs, summary anti-HBc) were detected 3.5 times more often than among the child population in general (in 28.3 and 8.0% respectively). In children staying in a boarding school for up to 1 year (126 children) these markers were determined in 23% of cases, and in those who stayed there for 3-5 years, in 58.1% of cases. Among the members of the groups where children with HBsAg were found the markers of HB occurred 3.3 more often then among the children in the groups having no HBsAg carriers (45.3 and 13.9% respectively). The detection rates of the markers of HB in children with various kinds of C.N.S. pathology (first of all, with mongolism) and without concomitant diseases were sharply different (they were found, respectively, in 52.9 and 19.6%, including HBsAg in 17.4 and 2.7%). At the same time the detection rate of anti-HCV among boarding-school children (including those with C.N.S. lesions) was no different from that among the child population in general, which was indicative of great differences in the activity of the nonartificial transmission routes HB and HC viruses. Patients with oncological, hematological and urological diseases who had great "parenteral load", as well as medical staff members, formed a high risk group for being infected with both HB and HC viruses.     

Declining prevalence of hepatitis A virus antibodies among children from low socioeconomic groups reinforces the need for the implementation of hepatitis A vaccination in Brazil

Age-related seroprevalence studies that have been conducted in Brazil have indicated a transition from a high to a medium endemicity of hepatitis A virus (HAV) infection in the population. However, most of these studies have focused on urban populations that experience lower incidence rates of HAV infection. In the current study, the prevalence of anti-HAV antibodies was investigated in children with a low socioeconomic status (SES) that live on the periphery of three capital cities in Brazil. A total of 1,162 dried blood spot samples were collected from individuals whose ages ranged from one-18 years and tested for anti-HAV antibodies. A large number of children under five years old (74.1-90%) were identified to be susceptible to HAV infection. The anti-HAV antibody prevalence reached ≥ 50% among those that were 10-14 years of age or older. The anti-HAV prevalence rates observed were characteristics of regions with intermediate level of hepatitis A endemicity. These data indicated that a large proportion of children with a low SES that live at the periphery of urban cities might be at risk of contracting an HAV infection. The hepatitis A vaccine that is currently offered in Brazil is only available for high-risk groups or at private clinics and is unaffordable for individuals with a lower SES. The results from this study suggest that the hepatitis A vaccine should be included in the Brazilian National Program for Immunisation.     

The prevalence and genomic characteristics of hepatitis E virus in murine rodents and house shrews from several regions in China

Background

Urban rodents and house shrews are closely correlated in terms of location with humans and can transmit many pathogens to them. Hepatitis E has been confirmed to be a zoonotic disease. However, the zoonotic potential of rat HEV is still unclear. The aim of this study was to determine the prevalence and genomic characteristics of hepatitis E virus (HEV) in rodents and house shrews.

Results

We collected a total of 788 animals from four provinces in China. From the 614 collected murine rodents, 20.19% of the liver tissue samples and 45.76% of the fecal samples were positive for HEV. From the 174 house shrews (Suncus murinus), 5.17% fecal samples and 0.57% liver tissue samples were positive for HEV. All of the HEV sequences obtained in this study belonged to Orthohepevirus C1. However, we observed a lower percentage of identity in the ORF3 region upon comparing the amino acid sequences between Rattus norvegicus and Rattus losea. HEV derived from house shrews shared a high percentage of identity with rat HEV. Notably, the first near full-length of the HEV genome from Rattus losea is described in our study, and we also report the first near full-length rat HEV genomes in Rattus norvegicus from China.

Conclusion

HEV is prevalent among the three common species of murine rodents (Rattus. norvegicus, Rattus. tanezumi, and Rattus. losea) in China. HEV sequences detected from house shrews were similar to rat HEV sequences. The high identity of HEV from murine rodents and house shrews suggested that HEV can spread among different animal species.

     

Retrospective detection of a subclinical hepatitis A virus (HAV) epidemic affecting juvenile cohorts of the Hungarian population

Sero-epidemiological surveys of serum samples taken in 1982, 1987, 1994 and 1999 have been performed with hepatitis A virus-specific (HAV-specific) serological tests. Results obtained during these surveys show that the proportion of seropositive blood donors decreased from 69% to 18% within 17 years. The authors have recognised a (mainly subclinical) epidemic, affecting about 115000 teenagers in 1992-1994 in Hungary, is a threatening phenomenon. It was calculated that only about 3600 clinical diseases were associated with the epidemic, recognised retrospectively from the findings of the four sero-epidemiological surveys. Epidemiological data indicated that the excess clinical diseases caused by HAV concentrated in the southern counties of Hungary, which have been affected by the social and military activities between 1992 and 1994. Due to the decrease of subjects seropositive for HAV, sera from preselected or actively immunised donors will be required in the future and vaccination against HAV with killed virus is likely to be recommended for risk groups. Furthermore, health authorities might promote active immunisation of young children against HAV infection; for that, promotion of manufacturing combination vaccines of HAV/HBV/DPT or, for certain countries, HAV/DPT would be desirable.     

High prevalence of occult hepatitis B virus genotype H infection among children with clinical hepatitis in west Mexico

Studies on the prevalence of infection with hepatitis B virus (HBV) among children are scarce in Latin American countries, especially in Mexico. This study was aimed to investigate the prevalence of HBV infection, occult hepatitis B infection (OBI) and HBV genotypes among children with clinical hepatitis. In total, 215 children with clinical hepatitis were evaluated for HBV infection. HBV serological markers and HBV DNA were analysed. OBI diagnosis and HBV genotyping was performed. HBV infection was found in 11.2% of children with clinical hepatitis. Among these HBV DNA positive-infected children, OBI was identified in 87.5% (n = 21/24) of the cases and 12.5% (n = 3/24) were positive for both HBV DNA and hepatitis B surface antigen. OBI was more frequent among children who had not been vaccinated against hepatitis B (p < 0.05) than in those who had been vaccinated. HBV genotype H was prevalent in 71% of the children followed by genotype G (8%) and genotype A (4%). In conclusion, OBI is common among Mexican children with clinical hepatitis and is associated with HBV genotype H. The results show the importance of the molecular diagnosis of HBV infection in Mexican paediatric patients with clinical hepatitis and emphasise the necessity of reinforcing hepatitis B vaccination in children.     

Structural dynamics of strains of a hepatitis B virus population in the Ukraine and its etiological prognosis

Changes in the population structure of influenza B virus in the Ukraine since 1980 has been studied. New strains of the virus have been identified and the epidemic potentials of different strains have been compared. The data on the drift mechanism of the origin of the intermediate strains of influenza B virus have been observed. A suggestion on the etiological prognostication of the epidemic process has been made.