Epidemiology of hepatitis B, C, E, and G virus infections and molecular analysis of hepatitis G virus isolates in Bolivia

Higher Risk of HEV Transmission and Exposure among Blood Donors in Europe and Asia in Comparison to North America: A Meta-Analysis

Background and aims: The increasing number of diagnosed hepatitis E virus (HEV) infections in Europe has led to the implementation of the testing of blood products in various countries. Many nations have not yet implemented such screening. To assess the need for HEV screening in blood products worldwide, we conducted a systematic review and meta-analysis assessing HEV RNA positivity and anti-HEV seroprevalence in blood donors. Methods: Studies reporting anti-HEV IgG/IgM or HEV RNA positivity rates among blood donors worldwide were identified via predefined search terms in PubMed and Scopus. Estimates were calculated by pooling study data with multivariable linear mixed-effects metaregression analysis. Results: A total of 157 (14%) of 1144 studies were included in the final analysis. The estimated HEV PCR positivity rate ranged from 0.01 to 0.14% worldwide, with strikingly higher rates in Asia (0.14%) and Europe (0.10%) in comparison to North America (0.01%). In line with this, anti-HEV IgG seroprevalence in North America (13%) was lower than that in Europe (19%). Conclusions: Our data demonstrate large regional differences regarding the risk of HEV exposure and blood-borne HEV transmission. Considering the cost–benefit ratio, this supports blood product screening in high endemic areas, such as Europe and Asia, in contrast to low endemic regions, such as the U.S.

Risk assessment of hepatitis E transmission through tissue allografts

Hepatitis E virus (HEV) is a small non-enveloped single stranded RNA virus whose genotypes 3 and 4 have been associated with zoonotic transmission in industrialized countries. HEV infection is considered the main cause of acute hepatitis worldwide. In some cases, transfusion of blood components or organ transplantation have been reported as the source of infection. We have conducted a literature review on the risk of transmission through cell and tissue allografts. Although no case was found, measures to control this risk should be taken when donor profile (based upon geographical and behavioural data) recommended it. Issues to be considered in donor screening and tissue processing to assess and to reduce the risk of HEV transmission are approached.

Review of human pegivirus: Prevalence, transmission, pathogenesis, and clinical implication

Human pegivirus (HPgV-1), previously known as GB virus C (GBV-C) or hepatitis G virus (HGV), is a single-stranded positive RNA virus belonging to the genus Pegivirus of the Flaviviridae family. It is transmitted by percutaneous injuries (PIs), contaminated blood and/or blood products, sexual contact, and vertical mother-to-child transmission. It is widely prevalent in general population, especially in high-risk groups. HPgV-1 viremia is typically cleared within the first 1–2 years of infection in most healthy individuals, but may persist for longer periods of time in immunocompromised individuals and/or those co-infected by other viruses. A large body of evidences indicate that HPgV-1 persistent infection has a beneficial clinical effect on many infectious diseases, such as acquired immunodeficiency syndrome (AIDS) and hepatitis C. The beneficial effects seem to be related to a significant reduction of immune activation, and/or the inhabitation of co-infected viruses (e.g. HIV-1). HPgV-1 has a broad cellular tropism for lymphoid and myeloid cells, and preferentially replicates in bone marrow and spleen without cytopathic effect, implying a therapeutic potential. The paper aims to summarize the natural history, prevalence and distribution characteristics, and pathogenesis of HPgV-1, and discuss its association with other human viral diseases, and potential use in therapy as a biovaccine or viral vector.

Serologic evidence of the circulation of the hepatitis E virus and the prevalence of antibodies against hepatitis A in an indigenous population in northern Argentina

In 2005 a universal vaccination program against hepatitis A was introduced in Argentina. Nevertheless, there are still some unvaccinated marginal population groups. There are no data about the seroprevalence of hepatitis E in the northern region of Argentina mainly because of lack of awareness of this emergent pathogen. We aimed to determine the seroprevalence of hepatitis A, and hepatitis E in an indigenous population in northern Argentina. One hundred and twenty six (126) donor serum samples collected near San Salvador de Jujuy were analyzed for anti-HAV IgG and HEV IgG and IgM, alkaline phosphatase and transaminase values. Volunteers were interviewed about their living conditions, animal farming, consumption of tap water or river water, and level of education. Seroprevalence of specific anti-HAV antibodies was high (80.2%, 95% confidence interval, 72.1-86.7%) in children under 5 years of age, indicating early infection in life. Seroprevalence of anti-HEV antibodies was 5.6% (95% CI: 2.3-11.2%), being slightly higher than the values found in healthy patients from other regions of the country. Although we could not characterize the genotype of the circulating HEV strain, the clear epidemiological difference between seroprevalence of HAV and HEV in a community with poor sanitary conditions suggest that the circulating HEV strains spread through a different transmission route than HAV. Furthermore a significant correlation between anti-HEV IgG and swine farming was found (p<0.05), which supports a zoonotic transmission path. We reassessed the epidemiological pattern of HAV infection and reported evidence of HEV infection for the first-time in a community belonging to the Guarani ethnic group, highlighting the need to include hepatitis E testing in routine diagnostics in the region.

Global prevalence of human pegivirus-1 in healthy volunteer blood donors: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVES

The local prevalence of HPgV-1 has been reported from different countries worldwide, but the global prevalence of HPgV-1 remains unknown. The aim of this systematic review and meta-analysis was to gather data from the literature to estimate the prevalence of HPgV-1 in healthy volunteer blood donors in the world.

MATERIALS AND METHODS

We searched PubMed, EMBASE, Scopus and Google Scholar databases for records up to January 2019 and included studies reporting HPgV-1 virus prevalence amongst healthy volunteer blood donors based on the detection of HPgV-1 RNA.

RESULTS

In all, we included 79 studies for the systematic review and 63 for the meta-analysis. Based on the random effect meta-analysis of 35 468 volunteer blood donors, we found the global prevalence of HPgV-1 to be 3·1% (95% CI, 2·4-4·1). The pooled prevalences of HPgV-1 were 1·7% (95% CI, 1·1-2·6) in North America, 9·1% (95% CI, 6·4-12·7) in South America, 2·3% (95% CI, 2%, 2·8) in Europe and 2·4% (95% CI, 1·4-4) in Asia. Subgroup analyses based on age, gender or risk factors were not possible.

CONCLUSION

Approximately 3 in 100 blood donations worldwide are positive for HPgV-1 increasing the risk of infection from transfusion of their components to subsequent recipients. Further research on virus pathogenicity is required before recommending routine screening of HPgV-1 for healthy volunteer blood donors.

Human pegivirus-1 (HPgV-1) RNA prevalence and genotypes in volunteer blood donors from the Brazilian Amazon

OBJECTIVES

The objectives of this study were to evaluate the prevalence of Human Pegivirus-1 (HPgV-1) viremia and genotype diversity among healthy blood donors from the Eastern Brazilian Amazon (city of Macapá, State of Amapá). There is little information for prevalence and circulation of HPgV-1 in this remote Brazilian region.

MATERIALS AND METHODS

We conducted a study evaluating the HPgV-1 RNA prevalence and circulating genotypes in 431 volunteer blood donors originating from the Eastern Brazilian Amazon. The obtained HPgV-1 positive samples were submitted to sequencing and genotyping analysis in order to examine the genotype diversity of this virus in the Brazilian Amazon.

RESULTS

Our results demonstrated a prevalence of HPgV-1 RNA in 9.5% of the tested blood donors. The phylogenetic analyses of the detected positive samples showed the presence of HPgV-1 genotypes 1, 2 and 3. The most frequently detected genotype was 2 (78.0% of the cases) represented by sub-genotypes 2A (39.0%) and 2B (39.0%). At lower rates, genotypes 1 (14.6%) and 3 (7.4%) were also detected.

CONCLUSION

Our results revealed the presence of genotypes with European, Asiatic and African endemicity in Amazonian blood donors, probably due to the complex miscegenation processes that took place in this Brazilian region. More investigations, including information for the prevalence of HPgV-1 RNA in blood donors from other Latin American countries are needed to estimate the viremic rates and genotype distribution of this virus in a highly diverse continent like South America.

Hepatitis E seroprevalence in the Americas: A systematic review and meta-analysis

BACKGROUND & AIMS

While hepatitis E virus infections are a relevant topic in Europe, knowledge about epidemiology of hepatitis E virus infections in the USA and Latin America is still limited. Aim of this study was to estimate anti-hepatitis E virus IgG seroprevalence in the Americas and to assess whether low socioeconomic status is associated with hepatitis E virus exposure.

METHODS

We performed a systematic review and meta-analysis. Literature search was performed in PubMed for articles published 01/1994-12/2016. Prevalence was estimated using a mixed-effects model and reported in line with PRISMA reporting guidelines.

RESULTS

Seroprevalence was significantly higher in the USA than in Latin America, independently of assay, patient cohort, methodological quality or study year (OR: 1.82 (1.06-3.08), P = .03). Patients in the USA had a more than doubled estimated seroprevalence (up to 9%, confidence interval 5%-15.6%) than those in Brazil (up to 4.2%, confidence interval 2.4%-7.1%; OR: 2.27 (1.25-4.13); P = .007) and Mixed Caribbean (up to 1%, OR: 8.33 (1.15-81.61); P = .04). A comparison with published data from Europe demonstrated that anti-hepatitis E virus seroprevalence in the USA and Europe did not differ significantly (OR: 1.33 (0.81-2.19), P = .25), while rate in South America was significantly lower than that in Europe (OR: 0.67 (0.45-0.98), P = .04).

CONCLUSIONS

Hepatitis E virus is common in the USA. Surprisingly, the risk of hepatitis E virus exposure was low in many South American countries. Seroprevalence did not differ significantly between Europe and the USA. Hence, hepatitis E virus is not limited to countries with low sanitary standards, and a higher socioeconomic status does not protect populations from hepatitis E virus exposure.

Syphilis, human immunodeficiency virus, herpes genital and hepatitis B in a women's prison in Cochabamba, Bolivia: prevalence and risk factors

OBJECTIVE

To determine the prevalence and factors associated with syphilis, human immunodeficiency virus (HIV), hepatitis B (HBV) and herpes type 2 (HSV2) among women in the prison of San Sebastian in Cochabamba (Bolivia).

MATERIAL AND METHODS

We carried out a cross-sectional study including a standardized questionnaire to assess socio-demographics characteristics and risk factors (sexual practices and exposure to blood); and serological tests for syphilis, HSV2, VIH, and HBV. We performed bivariate and multivariate analyses to test the associations between variables of interest and infections.

RESULTS

A total of 219 out of 220 prisoners (99.5%) participated in the study. For syphilis, 12.8% of participants had both reactive tests (RPR+/TPPA+). The prevalence of HSV2 and VIH was 62.6% and 1.4%, respectively. Anti-HBc, indicating a resolved or chronic HBV, was positive in 11.9% of participants and 0.5% had active HBV (HBsAg positive). A low level of education was associated with syphilis, HSV2 and HBV. Having occasional sexual partners was associated with syphilis and HSV2. Being over 36 years old and having more than 3 children were associated with HBV. The number of sexual partners, history of prostitution and rape, having sexual intercourses in prison and detention time were not associated with any of these infections.

DISCUSSION

The prevalence of syphilis, HIV, HSV2 and HBV was higher in this vulnerable female population than in the general population in Bolivia. Control measures in detention are needed to limit the spread of these infections both in prisons and in the community.

Detection and phylogenetic analysis of human pegivirus (GBV-C) among blood donors and patients infected with hepatitis B virus (HBV) in Qatar

Human Pegivirus (HPgV), formerly GB virus-C/Hepatitis G virus (GBV-C/HGV), collectively known as GBV-C, is widely spread and has been reported to be associated with non-A-E hepatitis. To our knowledge, no previous study was conducted about HPgV in Qatar. Thus, the objectives of this study were as follows: (i) to determine the rates of HPgV infection in Qatar among healthy blood donors and HBV-infected patients, and (ii) to determine the most predominant HPgV genotype in Qatar. A total of 714 blood plasma samples from healthy donors (612) and HBV-infected patients (102) were collected. RNA was extracted, reversed transcribed, and then subjected for HPgV detection by two round-nested PCR using primers amplifying a 208 bp of 5'-UTR of the HPgV. For genotyping, the 5'-UTR PCR products (from 25 randomly picked samples) were cloned and sequenced. The overall infection rate of HPgV in Qatar was 13.3%. There was no significant difference (P = 0.41) in the infection rates between healthy donor (13.7%) and in HBV-infected patients (10.7%). Moreover, we did not find any significant association between HPgV infection rates and nationality, sex, or age (P > 0.05). Sequence analysis of 40 5'-UTR PCR amplicons yielded the European genotype 2 as most predominant in Qatar, although other genotypes (5 and 7) were also present. Our results indicate that there is no strong correlation between HPgV infection rate, condition, nationality, age, and sex, and genotype 2 is most predominant in Qatar.

Hepatitis E virus infection in Latin America: a review

Data reported during recent years reveal the complex picture of the epidemiology of hepatitis E virus (HEV) infection in Latin America. Whereas in countries like Argentina and Brazil is almost identical to the characteristic of most countries from North America and Europe, HEV in the Caribbean and Mexico involves the water-borne, non-zoonotic viral genotypes responsible for epidemics in Asia and Africa. Nevertheless, Latin America has been considered a highly endemic region for hepatitis E in the scientific literature, a generalization that ignores the above complexity. In addition, reports from isolated Amerindian communities, which display well known, important and very specific epidemiological features for hepatitis B and D virus infections are neither taken into account when considering the epidemiology of hepatitis E in the region. This review updates compilation of the available information for the HEV infection, both among humans and other mammals, in Latin America, discusses the strengths and the weaknesses of our current knowledge, and identifies future areas of research.

Epidemiological update of hepatitis B, C and delta in Latin America

Viral hepatitis B, C and delta still remain a serious problem in Latin America. Data from the 1980s indicated that HBV and HDV infection are the main causes of chronic hepatitis. However, the spread of HBV infection could be controlled through the implementation of immunization programmes. Different countries from Mexico to Argentina display marked differences in terms of HBV genotype distribution. HBV genotype F has been identified as the most frequent in most Latin America countries, except for Mexico and Brazil, where genotypes H and A are the most frequent, respectively. In Latin America, the overall prevalence of HCV antibody is estimated to be 1.5%. Latin American countries have been very proactive in screening their blood supplies, thus minimizing risk of HCV transmission through transfusion. The number of diagnosed and treated patients is still low, thereby increasing the burden of complications such as liver cirrhosis or hepatocellular carcinoma. The most prevalent HCV genotype is 1, which is the genotype with the greatest worldwide spread, but it is a different genotype from other regions like Africa and Asia. HDV is present worldwide but its distribution pattern is not uniform. HDV was recently detected in novel geographic regions, reinforcing that it is a very serious health threat in under-developed countries. The main prevalence areas are the Mediterranean basin, the Middle East, central and northern Asia, western and central Africa, the Amazonian basin (Brazil, Peru, Venezuela and Colombia) and the Pacific islands. Novel strategies to increase HBV immunization in the Latin American population are needed to warrant thorough coverage in the rural areas.

Frequency and genotypic distribution of GB virus C (GBV-C) among Colombian population with Hepatitis B (HBV) or Hepatitis C (HCV) infection

BACKGROUND

GB virus C (GBV-C) is an enveloped positive-sense ssRNA virus belonging to the Flaviviridae family. Studies on the genetic variability of the GBV-C reveals the existence of six genotypes: genotype 1 predominates in West Africa, genotype 2 in Europe and America, genotype 3 in Asia, genotype 4 in Southwest Asia, genotype 5 in South Africa and genotype 6 in Indonesia. The aim of this study was to determine the frequency and genotypic distribution of GBV-C in the Colombian population.

METHODS

Two groups were analyzed: i) 408 Colombian blood donors infected with HCV (n = 250) and HBV (n = 158) from Bogotá and ii) 99 indigenous people with HBV infection from Leticia, Amazonas. A fragment of 344 bp from the 5' untranslated region (5' UTR) was amplified by nested RT PCR. Viral sequences were genotyped by phylogenetic analysis using reference sequences from each genotype obtained from GenBank (n = 160). Bayesian phylogenetic analyses were conducted using Markov chain Monte Carlo (MCMC) approach to obtain the MCC tree using BEAST v.1.5.3.

RESULTS

Among blood donors, from 158 HBsAg positive samples, eight 5.06% (n = 8) were positive for GBV-C and from 250 anti-HCV positive samples, 3.2%(n = 8) were positive for GBV-C. Also, 7.7% (n = 7) GBV-C positive samples were found among indigenous people from Leticia. A phylogenetic analysis revealed the presence of the following GBV-C genotypes among blood donors: 2a (41.6%), 1 (33.3%), 3 (16.6%) and 2b (8.3%). All genotype 1 sequences were found in co-infection with HBV and 4/5 sequences genotype 2a were found in co-infection with HCV. All sequences from indigenous people from Leticia were classified as genotype 3. The presence of GBV-C infection was not correlated with the sex (p = 0.43), age (p = 0.38) or origin (p = 0.17).

CONCLUSIONS

It was found a high frequency of GBV-C genotype 1 and 2 in blood donors. The presence of genotype 3 in indigenous population was previously reported from Santa Marta region in Colombia and in native people from Venezuela and Bolivia. This fact may be correlated to the ancient movements of Asian people to South America a long time ago.

GB virus C infection in pregnancy: maternal and perinatal importance of the infection

OBJECTIVES

The more effective way of transmission of GB virus C (GBV-C) is parenteral, but sexual and vertical transmission seem to be the main way of spreading. We evaluated the prevalence and the effect of GBV-C infection on pregnant women, vertical transmission and viral effects on the newborn.

STUDY DESIGN

This study has consecutively enrolled 879 pregnant women. All patients had blood sampling to determine GBV-C RNA, serologic tests for chronic viral infections and seric tests of hepatic damage. The newborns from infected mothers had blood sampling to detect the presence of GBV-C at birth, and after 3 and 6 months. Positive babies were checked until 18 months.

RESULTS

36 (4.1%) women resulted GBV-C positive. Among the positive patients none presented complications during pregnancy. Neither embryonic-fetal abnormalities nor relevant differences in fetal birth weight and week of gestation at delivery were found. 20 out of 36 babies had a follow-up. At birth, 13 (65%) babies were positive. 4 out of 9 vaginal deliveries (44%) and 9 out of 11 cesarean sections (82%) resulted positive to GBV-C RNA. The risk of GBV-C vertical transmission was not significantly increased by type of delivery (p=0.274). At 3 months, 13 babies were GBV-C positive (65%) and 7 were negative (35%). At the end of the follow-up, 9 babies were positive (45%), while 11 were negative (55%).

CONCLUSION

The percentage of patients positive to GBV-C RNA was comparatively high (4.1%). This prevalence, in a population without particular risk factors, confirms that common ways of transmission, such as the sexual and vertical ones, might have an important role in viral diffusion. Our data suggest that the infection does not influence the course of pregnancy. The rate of transmission found in our study is high. Type of delivery does not seem to be actually involved in vertical transmission and the protective role of cesarean section has not been confirmed.

Hepatitis G virus exposure in dialysis patients

BACKGROUND

Hepatitis G virus (HGV) is a blood-borne virus. The predominant route of its transmission is parenteral. The aim of this study was to assess the frequency of HGV exposure in haemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) patients in Iran.

METHODS

This study was performed in a major dialysis centre in Tehran, Iran. The study cohort consisted of 77 patients on HD and 13 patients on CAPD. The presence of anti-HGV envelope protein E2 (anti-E2) in the blood serum, as determined by means of an ELISA assay, indicated HGV exposure. All patients were also screened for hepatitis B surface antigen (HBsAg), hepatitis B surface antibody (anti-HBs) and hepatitis C antibody (anti-HCV). In patients who tested positive for anti-E2, HGV RNA was detected by RT-PCR using primers derived from the NS5A region of the viral genome.

RESULTS

In total, 3.89% of the HD patients and none of the CAPD patients tested positive for anti-E2. None of the patients tested positive for HGV RNA. The mean age of the anti-E2-positive patients was 53.3 +/- 26.5 years, with 66.66% having previously received blood transfusion. The mean duration of dialysis of the anti-E2-positive patients was 68 +/- 64 months. Co-infection with HCV or HBV was not observed in the anti-E2 positive patients.

CONCLUSION

The rate of exposure to HGV was low among the dialysis patients in our study. The appearance of anti-E2 was accompanied by clearance of serum HGV-RNA. No relationship was noted between HGV exposure and age, sex, history of blood transfusion, time on dialysis and HCV or HBV markers.

Chronic hepatitis B: current epidemiology in the Americas and implications for management

Hepatitis B virus (HBV) remains a serious health threat in many parts of the world. Although its prevalence is lower in the Americas than in Asia, Africa and the Middle East, it is responsible for significant morbidity and mortality in North, Central and South America. There is a nonuniform pattern of distribution throughout this region, with HBV prevalence related to geographical, social and cultural factors that predispose certain individuals to infection. This report details the incidence, modes of viral transmission of hepatitis B in the Americas and clinical course of disease in different regions of the Americas. Additionally, the implications for management focusing on issues predominant in high-risk populations are presented.

Genomic characterization of HBV genotype F in Bolivia: genotype F subgenotypes correlate with geographic distribution and T(1858) variant

Hepatitis B virus (HBV) strains were classified into eight genotypes from A to H. Genotype F, an indigenous genotype in Central and South America, has been classified into subgenotypes. An in-depth phylogenetic analysis was performed using two full-length Bolivian HBV sequences and other genotype F strains from the database. A novel nomenclature of subgenotypes of genotype F was proposed, in which Bolivia strains belonged to subgenotype F4. This subgenotype had both Leu(45) and Ile(110) in the S gene, and linked to the T(1858) in the precore. This novel nomenclature demonstrated the relation between variability of the HBV genome and the restricted geographical distribution of the virus in some parts of Central and South America.

African origin of GB virus C determined by phylogenetic analysis of a complete genotype 5 genome from South Africa

GB virus C (GBV-C), a positive-strand RNA virus, currently infects approximately one-sixth of the world's population. This virus exists as a collection of genotypes whose global distribution correlates with geographical origin. Genotyping of GBV-C isolates by phylogenetic analysis has relied upon the use of 5'-untranslated region (5'-UTR) sequences, however, complete genome sequences are used to demonstrate definitively their existence and geographical correlation. Initial identification of the fifth genotype from South Africa was based upon phylogenetic analysis of the 5'-UTR. It was sought to confirm this classification by analysis of full-length E2 genes from South African isolates and by analysis of a complete genotype 5 genome. Analysis of full-length E2 genes from 28 GBV-C-infected South African individuals revealed the existence of a unique group of 18 isolates, distinct from the other four genotypes. Bootstrap analysis provided strong support (95 %) for this fifth group. The remaining isolates were either genotype 1 (n=8) or 2 (n=2). Analysis of human E2 gene sequences, with the E2 gene from the chimpanzee variant GBV-Ctro included as the outgroup, produced a tree rooted on the genotype 1 branch. The complete genome nucleotide sequence of South African genotype 5 isolate D50 was determined. Phylogenetic analysis of the 5'-UTR and open reading frame produced congruent trees that grouped the sequences into five major genotypes. Inclusion of the corresponding region of the chimpanzee isolate GBV-Ctro in the analysis produced trees rooted on the branch leading to the genotype 5 isolate D50, suggesting an ancient African origin of GBV-C.

Detection and genotyping of GBV-C virus in the United Arab Emirates

GB virus-C/Hepatitis G virus (GBV-C/HGV), collectively known as GBV-C, is spread widely and has been reported to be associated with non A-E hepatitis. The aim of the current project was to determine the rate of infection and genotypic characteristics of GBV-C in the United Arab Emirates (UAE). A total of 379 plasma/serum samples representing different populations in the UAE and comprising healthy as well as patients positive for HBV and HCV were screened using RT-PCR/nested PCR of the 5'-untranslated region (UTR). National subjects (n=168) and non-nationals residing in the UAE (n=211) were tested. The results obtained showed that the rate of GBV-C infection in healthy nationals, and those positive for HCV or HBV were 11.1%, 14.3%, and 5.7%, respectively, compared to 8.3%, 33.3%, and 8.6%, respectively, in non-nationals. No statistically significant correlation between infection with GBV-C and HCV or HBV (P>0.05) was found. Sequence analysis of the 5'-UTR using 37 and 46 clones from 8 and 6 healthy nationals and non-nationals, respectively, revealed the prevalence of the European/North American genotype 2 when compared to the five reference genotypes in GenBank.

Epidemiology of viruses causing chronic hepatitis among populations from the Amazon Basin and related ecosystems

On the last twenty years, viral hepatitis has emerged as a serious problem in almost all the Amerindian communities studied in the Amazon Basin and in other Amazon-related ecological systems from the North and Center of South America. Studies performed on communities from Bolivia, Brazil, Colombia, Peru and Venezuela have shown a high endemicity of the hepatitis B virus (HBV) infection all over the region, which is frequently associated to a high prevalence of infection by hepatitis D virus among the chronic HBV carriers. Circulation of both agents responds mainly to horizontal virus transmission during childhood through mechanisms that are not fully understood. By contrast, infection by hepatitis C virus (HCV), which is present in all the urban areas of South America, is still very uncommon among them. At the moment, there is not data enough to evaluate properly the true incidence that such endemicity may have on the health of the populations affected. Since viral transmission might be operated by mechanisms that could not be acting in other areas of the World, it seems essential to investigate such mechanisms and to prevent the introduction of HCV into these populations, which consequences for health could be very serious.

[Prevalence of infections by hepatitis A, B, C and E viruses in two different socioeconomic groups of children from Santa Cruz, Bolivia]

BACKGROUND AND OBJECTIVES

The epidemiology of hepatitis A, E, B and C was analyzed in 1,393 children living in Santa Cruz de la Sierra, Bolivia. They were distributed in two groups according to the social condition.

MATERIALS AND METHOD

1,393 children were selected from two different schools: one attended by children belonging to a high social class of the town (group A), and the other school attended by children belonging to the poorest social class (group B). Blood samples were drawn by a team of physicians from Rome University La Sapienza. Serum antibodies against hepatitis A, B, C and E virus, and the hepatitis B surface antigen were evaluated by immunometric methods. The significance was evaluated using the *2 test.

RESULTS

Antibodies against hepatitis A virus were detected in 82% of examined children, with a significant difference between the two groups (56.3% vs 94.8%). The incidence of anti-HBc antibodies increased with age, so the infection is acquired prevalently in adolescence with a significant difference between both groups (1.1% vs 3.8%). The same phenomenon was observed with anti-HCV antibodies (4.7% positivity only in group B). Serum antibodies against hepatitis E virus were observed in 1.7% cases.

CONCLUSIONS

In Bolivia, as in other developing countries, viral hepatitis represents a serious burden for public health. Spreading of viral hepatitis can be controlled upon improving hygienic conditions and customs. Moreover, a vaccination plan against hepatitis A and B virus is necessary for the population living in endemic areas.

High prevalence of GB virus C/hepatitis G virus genotype 3 among autochthonous Venezuelan populations

GB virus C or hepatitis G virus (GBV-C/HGV) is highly prevalent among population groups at risk of parenterally transmitted viral agents, but it has also a worldwide distribution in other non-risk population groups. GBV-C/HGV RNA and antibodies against its envelope protein (anti-E2 Abs) were found in 3/86 (3%) and 7/89 (8%) of biomedical science personnel (BSP), in 31/453 (7%) and 37/200 (19%) of blood donors (BD), and in 6/64 (9%) and 26/59 (44%) of hemodialysis patients (HD) from Caracas, Venezuela. A significant gradient of GBV-C/HGV exposure (anti-E2 Abs and/or GBV-C/HGV RNA) was found between BSP (lowest prevalence), BD, and HD (P < 0.001). GBV-C/HGV RNA and anti-E2 Abs were also found in 2/69 (2.9%) and 2/44 (4.5%) of individuals from a rural community, in 9/162 (5.5%) and 2/40 (5%) of West Amerindians, and in 14/56 (25%) and 4/53 (7.5%) of South Amerindians. Socioeconomic and cultural factors may have contributed to the relatively high risk of exposure to GBV-C/HGV in BD and Amerindians. Whereas GBV-C/HGV genotypes 1 (n = 1), 2 (n = 6), and 3 (n = 22) were present in Venezuela, only the Asiatic genotype 3 was found infecting Amerindians and rural populations (n = 16). Genotype assignment based on the 5' noncoding region of the GBV- C/HGV genome was corroborated in some isolates by genetic analysis of the E2 region. This report confirms the circulation of the Asiatic genotype of GBV-C/HGV among Amerindians, suggesting an old origin of GBV-C/HGV. This might be associated with the apparently low pathogenesis of this virus.

Prevalence of blood-borne infectious diseases in blood donors in Ghana

Transfusion-transmissible infections among 808 blood donors in Ghana were investigated in 1999. Antibody seroprevalences of 3.8, 0.7, 8.4, and 13.5%, respectively, for human immunodeficiency virus, human T-cell lymphotrophic virus type 1, hepatitis C virus (HCV), and Treponema pallidum were obtained. The seroprevalence of HCV infection was confirmed to be 0.9% after supplementary testing, and the transfusion risk potential of these pathogens was demonstrated.

Hepatite E

O vírus da hepatite E (VHE) é o segundo vírus de transmissão fecal-oral com hepatotropismo confirmado, após o vírus da hepatite A. As grandes epidemias de hepatite das décadas de 50 e 60 na Índia foram causadas pelo VHE. Observaram-se surtos da infecção na África Central, América Latina, Oriente Médio e Repúblicas independentes da ex-União Soviética. O quadro clínico da doença assemelha-se ao de outras hepatites virais. Não há casos descritos de hepatite E crônicas. Cerca de 20% das mulheres que adquirem a doença durante a gravidez desenvolvem formas graves, com insuficiência hepática fulminante. Confirma-se o diagnóstico quando se encontra no soro anticorpos (método de ELISA) das classes IgM (fase aguda) e/ou IgG (curados). O imunoblot e o PCR-RNA podem ser usados quando necessário. Não há tratamento específico. O uso de imunoglobulina hiperimune tem sido aconselhado por alguns autores. A prevenção se faz pelos cuidados higiênicos e dietéticos habituais. Não há vacina eficaz contra a doença.

Reconstructing the origins of human hepatitis viruses

Infections with hepatitis B and C viruses (HBV, HCV) are widespread in human populations throughout the world, and are major causes of chronic liver disease and liver cancer. HBV, HCV and the related hepatitis G virus or GB virus C (referred to here as HGV/GBV-C) are capable of establishing persistent, frequently lifelong infections characterized by high levels of continuous replication. All three viruses show substantial genetic heterogeneity, which has allowed each to be classified into a number of distinct genotypes that have different geographical distributions and associations with different risk groups for infection. Information on their past transmission and epidemiology might be obtained by estimation of the time of divergence of the different genotypes of HCV, HBV and HGV/GBV-C using knowledge of their rates of sequence change. While information on the latter is limited to short observation periods and is therefore subject to considerable error and uncertainty, the relatively recent times of origin for genotype of each virus predicted by this method (HCV, 500-2000 years; HBV, 3000 years; HGV/GBV-C, 200 years) are quite incompatible with their epidemiological distributions in human populations. They also cannot easily be reconciled with the recent evidence for species-associated variants of HBV and HGV/GBV-C in a range of non-human primates. The apparent conservatism of viruses over long periods implied by their epidemiological distributions instead suggests that nucleotide sequence change may be subject to constraints peculiar to viruses with single-stranded genomes, or with overlapping reading frames that defy attempts to reconstruct evolution according to the principles of the 'molecular clock'. Large population sizes and intense selection pressures that optimize fitness may be additional factors that set virus evolution apart from that of their hosts.

The origin and evolution of hepatitis viruses in humans

The spread and origins of hepatitis C virus (HCV) in human populations have been the subject of extensive investigations, not least because of the importance this information would provide in predicting clinical outcomes and controlling spread of HCV in the future. However, in the absence of historical and archaeological records of infection, the evolution of HCV and other human hepatitis viruses can only be inferred indirectly from their epidemiology and by genetic analysis of contemporary virus populations. Some information on the history of the latter may be obtained by dating the time of divergence of various genotypes of HCV, hepatitis B virus (HBV) and the non-pathogenic hepatitis G virus (HGV)/GB virus-C (GBV-C). However, the relatively recent times predicted for the origin of these viruses fit poorly with their epidemiological distributions and the recent evidence for species-associated variants of HBV and HGV/GBV-C in a wide range of non-human primates. The apparent conservatism of viruses over long periods implied by these latter observations may be the result of constraints on sequence change peculiar to viruses with single-stranded genomes, or with overlapping reading frames. Large population sizes and intense selection pressures that optimize fitness may be the factors that set virus evolution apart from that of their hosts.

A review of hepatitis E virus

Hepatitis E virus (HEV) is a major cause of outbreaks and sporadic cases of viral hepatitis in tropical and subtropical countries but is infrequent in industrialized countries. The virus is transmitted by the fecal-oral route with fecally contaminated drinking water being the usual vehicle. Hepatitis resulting from HEV infection is a moderately severe jaundice that is self-limiting in most patients. Young adults, 15 to 30 years of age, are the main targets of infection, and the overall death rate is 0.5 to 3.0%. However, the death rate during pregnancy approaches 15 to 25%. Death of the mother and fetus, abortion, premature delivery, or death of a live-born baby soon after birth are common complications of hepatitis E infection during pregnancy. Hepatitis E virus is found in both wild and domestic animals; thus, HEV is a zoonotic virus. The viruses isolated from swine in the United States or Taiwan are closely related to human HEV found in those areas. The close genetic relationship of the swine and human virus suggests that swine may be a reservoir of HEV. In areas where swine are raised, swine manure could be a source of HEV contamination of irrigation water or coastal waters with concomitant contamination of produce or shellfish. Increasing globalization of food markets by industrialized countries has the potential of introducing HEV into new areas of the world. The purpose of this review is to cover certain aspects of hepatitis E including the causative agent, the disease, diagnosis, viral detection, viral transmission, epidemiology, populations targeted by HEV, and the role of animals as potential vectors of the virus.

Homologous recombination in GB virus C/hepatitis G virus

Analysis of 33 GB virus C/hepatitis G virus (GBV-C/HGV) full or nearly full genome sequences revealed several putative inter- and intrasubtype recombinants. The breakpoints of the recombinant regions were mapped using a maximum-likelihood method, and the statistical significance for each region was tested using Monte Carlo simulation. The results were highly significant and provided evidence for the existence of complex mosaic genomes showing as many as nine recombination events, with breakpoints in the 5' UTR and in all of the coding regions except the short NS4b gene. Recombination was confirmed by separate phylogenetic analysis of the various recombinant regions and by Sawyer's runs test. Taken together, these findings demonstrate for the first time that recombination is common in natural populations of GBV-C and that it takes place both within and between subtypes. The wide-ranging implications of such nonclonal history for reconstructing the spread and timescale of GBV-C evolution are discussed.

Hepatitis E virus immunoglobulin G antibodies in different populations in Campinas, Brazil

The seroprevalence of anti-hepatitis E virus (HEV) antibodies was investigated by enzyme immunoassay in 205 volunteer blood donors, 214 women who attended a center for anonymous testing for human immunodeficiency virus (HIV) infection, and 170 hospital employees in Campinas, a city in southeastern Brazil. The prevalence of anti-HEV antibodies ranged from 2.6% (3 of 117) in health care professionals to 17.7% (38 of 214) in women who considered themselves at risk for HIV. The prevalence of anti-HEV antibodies in health care professionals was not significantly different from that in healthy blood donors (3.0%, 5 of 165) and blood donors with raised alanine aminotransferase levels (7.5%, 3 of 40). The prevalence of anti-HEV antibodies (13.2%, 7 of 53) in cleaning service workers at a University hospital was similar to that among women at risk for HIV infection. These results suggest that HEV is circulating in southeastern Brazil and that low socioeconomic status is an important risk factor for HEV infection in this region.

Prevalence of GB virus C (also called hepatitis G virus) markers in Norwegian blood donors

GB virus C (GBV-C), also called hepatitis G virus (HGV), occurs worldwide, but the clinical significance of this virus is still unclear. Plasma samples from 1,001 blood donors were tested by reverse transcription PCR using primers from the NS5 region and by a commercial enzyme-linked immunosorbent assay (ELISA) for the detection of immunoglobulin G antibodies against the putative envelope of HGV (anti-HGV E2). GBV-C/HGV RNA was present in the plasma from 2.5% of the blood donors, and anti-HGV E2 antibodies could be detected in 10.5% of the samples. Only one of the blood donors with viremia had elevated levels of alanine aminotransferase. Among ELISA-positive donors, there was a significantly higher percentage (16.5%) of individuals who had been treated by acupuncture than individuals who had not been given this treatment (9.4%). No other variables showed significant differences. Screening of medical records from 401 recipients of blood from PCR-positive donors revealed no association with liver disease. Four of 12 partners (33%) were HGV RNA positive, and sequence analyses of the strains showed that four of the couples probably were infected with the same strains, while strains from different couples were not identical. Anti-HGV E2 antibodies were detected in serum samples from four other partners. The prevalence of GBV-C/HGV among blood donors in our region is dramatically higher than the prevalence of hepatitis C virus (0.03%).

Phylogenetic analysis of GBV-C/hepatitis G virus

Comparison of 33 epidemiologically distinct GBV-C/hepatitis G virus complete genome sequences suggests the existence of four major phylogenetic groupings that are equally divergent from the chimpanzee isolate GBV-C(tro) and have distinct geographical distributions. These four groupings are not consistently reproduced by analysis of the virus 5'-noncoding region (5'-NCR), or of individual genes or subgenomic fragments with the exception of the E2 gene as a whole or of 200-600 nucleotide fragments from its 3' half. This region is upstream of a proposed anti-sense reading frame and contains conserved potential RNA secondary structures that may be capable of directing the internal initiation of translation. Phylogenetic analysis of this region from certain South African isolates is consistent with previous analysis of the 5'-NCR suggesting that these belong to a fifth group. The geographical distribution of virus variants is consistent with a long evolutionary history that may parallel that of pre-historic human migrations, implying that the long-term evolution of this RNA virus is extremely slow.

The entire nucleotide sequence of two hepatitis G virus isolates belonging to a novel genotype: isolation in Myanmar and Vietnam

A novel genotype of hepatitis G virus (HGV) was recently identified in sera of subjects from countries in South-East Asia. These isolates were recovered from serum of Myanmarese (designated HGV-MY14) and Vietnamese (designated HGV-VT48) subjects, respectively. To characterize the viral genome in more detail, the full-length nucleotide sequence of the two different HGV isolates belonging to the novel genotype was cloned. Both HGV isolates were composed of 9228 nt and had a single open reading frame spanning 8529 nt and encoding 2843 aa residues. The isolates differed from previously reported HGV/GBV-C isolates types 1 to 3 by 13-15% (nucleotide sequence) and 4-6% (amino acid sequence). The putative core region of both isolates was not clearly identifiable as it consisted of only 16 aa residues. Based on phylogenetic analysis of full-length genome sequences and 5'-UTR sequences, HGV-MY14 and HGV-VT48 isolates can be classified as a novel genotype, designated type 4.