[Prevalence of serologic markers of hepatitis B and D viruses in children of the Caiabi and Txucarramãe tribes from the Indian Reservation of Xingu, central Brazil]

Seroprevalence of hepatitis B, C and D markers in indigenous patients seen at the Native American Outpatient Clinic of Universidade Federal de São Paulo

Objective

Methods

Results

Conclusion

Hepatitis B virus American genotypes: Pathogenic variants ?

Hepatitis B virus (HBV) chronic infection is responsible for almost 900.000 deaths each year, due to cirrhosis or hepatocellular carcinoma (HCC). Ten HBV genotypes have been described (A-J). HBV genotype F and H circulate in America. HBV genotypes have been further classified in subgenotypes. There is a strong correlation between the genetic admixture of the American continent and the frequency of genotypes F or H: a high frequency of these genotypes is found in countries with a population with a higher ratio of Amerindian to African genetic admixture. The frequency of occult HBV infection in Amerindian communities from Latin America seems to be higher than the one found in other HBV-infected groups, but its association with American genotypes is unknown. There is growing evidence that some genotypes might be associated with a faster evolution to HCC. In particular, HBV genotype F has been implicated in a frequent and rapid progression to HCC. However, HBV genotype H has been associated to a less severe progression of disease. This study reviews the diversity and frequency of autochthonous HBV variants in the Americas and evaluates their association to severe progression of disease. Although no significant differences were found in the methylation pattern between different genotypes and subgenotypes of the American types, basal core promoter mutations might be more frequent in some subgenotypes, such as F1b and F2, than in other American subgenotypes or genotype H. F1b and probably F2 may be associated with a severe presentation of liver disease as opposed to a more benign course for subgenotype F4 and genotype H. Thus, preliminary evidence suggests that not all of the American variants are associated with a rapid progression to HCC.

Determination of hepatitis B, C and D prevalence among urban and Amerindian populations from the Eastern Brazilian Amazon: a cross sectional study

Background

This study was conducted to determine the prevalence of HBV, HCV, and HDV in urban populations and Amerindians living in the state of Tocantins (Eastern Amazon).

Methods

A total of 948 individuals were recruited in Tocantinopolis city (Tocantins state) of whom 603 were Amerindians (from 6 tribes) and 345 were non-Amerindians (6 urban areas of Tocantinópolis city). Anti-HCV, HBsAg, anti-HBc, anti-HBs, anti-HBc IgM, anti-HBe, HBeAg, and anti-delta antibodies were determined using enzyme immunoassay.

Results

HBV cleared infection (both anti-HBc/anti-HBs+), chronic inactive/immune controlled HBV infection (anti-HBc + only), previous HBV vaccination (anti-HBs + only), active HBV infection (HBsAg+), individuals susceptible to HBV, and anti-HCV reactivity were found in 12.9, 1.8, 27.2, 0.5, 57.7, 1.2% in Amerindians and 12.1, 2.0, 37.1, 0.3, 55.4, 0.3% in non-Amerindians respectively. Out of 139 anti-HBc reactive individuals, 70 were anti-HBe reactive and none presented HBeAg or anti-HBc IgM. Anti-HBc prevalence was associated to older age (p < 0.0001). Overall anti-Delta prevalence was 0.3% and regarding anti-HBc reactive individuals, anti-delta prevalence was 3.4 and 0% in Amerindians and non-Amerindians respectively.

Conclusions

Overall low prevalence of HBV and HCV infection was found in the populations studied, but high HBV and HCV prevalence was observed in Amerindians compared to non-Amerindians suggesting that these individuals have a higher likelihood of acquiring to these infections. Anti-delta antibodies were found among Amerindians from Eastern Amazon suggesting a risk for this population. Of note is that nearly half of Amerindians had no anti-HBs, indicating a need for HBV vaccination campaigns in this population.

Evidências científicas sobre a hepatite Delta no Brasil: revisão integrativa da literatura

Resumo Objetivo: Descrever o nível de evidência científica sobre a infecção por vírus da hepatite Delta (VHD) no Brasil. Métodos: Revisão integrativa da literatura, com buscas realizadas nas bases de dados do Medical Literature Analysis and Retrieval System Online, Literatura Latino-americana e do Caribe em Ciências da Saúde, Scientific Eletronic Library Online e Scopus, com análise centrada no nivelamento do rigor metodológico de acordo com o modelo de Melnyk e Fineout-Overholt. Resultados: A busca revelou uma média de duas publicações por ano no intervalo entre 1987 e 2017. Foram selecionados 33 artigos, tendo a maioria (91%) apresentado nível de evidência VI. As publicações ficaram concentradas em periódicos da área de medicina tropical (46%) e virologia (15%). Dos trabalhos, 85% tinha profissional médico com autor e o delineamento mais encontrado foi o descritivo/transversal (69,6%). Conclusão: A produção científica sobre a infecção por VHD no Brasil está centrada em estudos de prevalência, mostrando-se incipiente quanto à produção de estudos com delineamentos mais rígidos como ensaios clínicos.

High prevalence of HBV/A1 subgenotype in native south Americans may be explained by recent economic developments in the Amazon

Native American populations present the highest prevalence of Hepatitis B Virus (HBV) infection in the Americas, which may be associated to severe disease outcomes. Ten HBV genotypes (A–J) have been described, displaying a remarkable geographic structure, which most likely reflects historic patterns of human migrations. In this study, we characterize the HBV strains circulating in a historical sample of Native South Americans to characterize the historical viral dynamics in this population. The sample consisted of 1070 individuals belonging to 38 populations collected between 1965 and 1997. Presence of HBV DNA was checked by quantitative real-time PCR, and determination of HBV genotypes and subgenotypes was performed through sequencing and phylogenetic analysis of a fragment including part of HBsAg and Pol coding regions (S/Pol). A Bayesian Skyline Plot analysis was performed to compare the viral population dynamics of HBV/A1 strains found in Native Americans and in the general Brazilian population. A total of 109 individuals were positive for HBV DNA (~ 10%), and 70 samples were successfully sequenced and genotyped. Subgenotype A1 (HBV/A1), related to African populations and the African slave trade, was the most prevalent (66–94%). The Skyline Plot analysis showed a marked population expansion of HBV/A1 in Native Americans occurring more recently (1945–1965) than in the general Brazilian population. Our results suggest that historic processes that contributed to formation of HBV/A1 circulating in Native American are related with more recent migratory waves towards the Amazon basin, which generated a different viral dynamics in this region.

Molecular epidemiology of hepatitis B virus among the indigenous population of the Curuçá and Itaquaí Rivers, Javari Valley, State of Amazonas, Brazil

INTRODUCTION

Hepatitis B virus (HBV) infection is one of the most serious public health problems in the world. In Brazil, HBV endemicity is heterogeneous, with the highest disease prevalence in the North region.

METHODS

A total of 180 samples were analyzed and subjected to polymerase chain reaction (PCR) and semi-nested PCR of the HBV S-gene, with the aim of determining the prevalence of HBV-DNA (deoxyribonucleic acid) in indigenous groups inhabiting the areas near the Curuçá and Itaquaí Rivers in the Javari Valley, State of Amazonas, Brazil.

RESULTS

The prevalence of the HBV-DNA S-gene was 51.1% (92/180). The analysis found 18 of 49 (36.7%) samples from the Marubo tribe, 68 of 125 (54.4%) from the Kanamary, and 6 of 6 (100%) from other ethnic groups to be PCR positive. There was no statistically significant difference in gender at 5% (p=0.889). Indigenous people with positive PCR for HBV-DNA had a lower median age (p<0.001) of 23 years. There was no statistical difference found in relation to sources of contamination or clinical aspects with the PCR results, except for fever (p<0.001). The high prevalence of HBV-DNA of 75% (15/20) in pregnant women (p=0.009) demonstrates an association with vertical transmission.

CONCLUSIONS

The results confirm the high prevalence of HBV-DNA in the Javari Valley, making it important to devise strategies for control and more effective prevention in combating the spread of HBV.

[Occult hepatitis B: prevalence and clinical characteristics in a population with high endemicity of hepatitis B infection in the western Brazilian Amazon region]

A persistent form of the hepatitis B virus called occult chronic hepatitis B has recently been described. Its prevalence and physiopathology are unknown. The aim of this study was to evaluate the occurrence of this clinical entity among patients in the Brazilian Amazon region. Out of 51 anti-HBc total-positive patients who were tested using the polymerase chain reaction, 17% were positive. We did not find any associations with classical risk factors for hepatitis B virus infection or with biochemical tests, hematological tests or histological patterns. However, the jaundiced and HIV-positive patients showed a statistical association with the presence of hepatitis B virus-DNA. The results demonstrated that occult hepatitis B occurred among our patients, but at prevalence rates lower than expected for this region. We believe that despite the small sample size, the occurrence might have been found to be greater if we had used primers for the S, C and X regions of the hepatitis B virus genome, thereby increasing the sensitivity of the test.

[Prevalence of hepatitis B and D serological markers in the Parakanã, Apyterewa Indian Reservation, Pará State, Brazil]

In order to study the prevalence of hepatitis B (HBV) and D (HDV) viruses in the Parakanã Indians and to evaluate the impact of hepatitis B vaccination beginning there in 1995, 258 serum samples were analyzed in the year 2004 for hepatitis B and D serological markers using immunoenzymatic techniques; the results showed a moderate endemic pattern, with a total prevalence of HBV infection of 55.7% and 5.4% of virus carriers in the Apyterewa village and 49.5% with 1.1% of HBV carriers in the Xingu village; 31.4% of anti-HBs+ as an isolated marker in both villages and no detection of positive serological tests for HDV among HBV carriers. The laboratory analysis thus showed the presence of chronic HBV carriers, absence of HDV carriers, and an emerging vaccine profile among susceptibles, confirming the effectiveness and need to maintain vaccination, especially in the first year of life, and the need to implement effective epidemiological surveillance for early detection of HDV infection among HBV carriers.

HUMAN RIGHTS, BIOMEDICAL SCIENCE, AND INFECTIOUS DISEASES AMONG SOUTH AMERICAN INDIGENOUS GROUPS

Despite the efforts of international health agencies to reduce global health inequalities, indigenous populations around the world remain largely unaffected by such initiatives. This chapter reviews the biomedical literature indexed by the PubMed database published between 1963 and 2003 on South American indigenous populations, a total of 1864 studies that include 63,563 study participants. Some language family groupings are better represented than are others, and lowland groups are better represented than are highland groups. Very few studies focus on major health threats (e.g., tuberculosis, influenza), public health interventions, or mestizo-indigenous epidemiological comparisons. The prevalence rates of three frequently studied infections—parasitism, human T-cell lymphotropic viral infection (HTLV), and hepatitis—are extraordinarily high, but these facts have been overlooked by national and international health agencies. This review underscores the urgent need for interventions based on known disease prevalence rates to reduce the burden of infectious diseases in indigenous communities.

[Hepatitis B and D virus infection within Amerindians ethnic groups in the Brazilian Amazon: epidemiological aspects]

Several studies describe very high prevalence rates of infection and disease of hepatitis B and D within Native American population. This is a review of what has been described among Amerindians of Brazilian Amazon. Some groups show low prevalence rates of HBsAg, whereas, others of the same region reveal high endemic pattern, even among individuals less then 10 years of age. HDV is only found in groups of Amazonas province. Transmission may occur by interfamilial dissemination or sexual contact among young adults. Socio-cultural, genetic, and ecological factors are described as determinants of this unique pattern. Nevertheless, the origin of these two viruses is yet to be disclosed. Amerindians population and their genetic memory are a live experiment, which demands a broad investigation, weighting with modern tools, as molecular biology, the influence of historical, genetic, medical and anthropological factors.

[The occurrence of hepatitis B and delta virus infection within seven Amerindian ethnic groups in the Brazilian western Amazon]

HBV and HDV infections are a major health problem in the Amazon. This study evaluates the prevalence of these viruses within Indians groups, measuring the frequency of serological markers. The prevalence of past infection was 54.5% and HBsAg was found in 9.7%. An important variation of those markers was detected between villages, inclusively within the same ethnic group. None showed evidence of an acute infection. All HBeAg reactive were Apurinã, living in the same village and three of them from the same family. The prevalence of anti-HDT was 13.4% in HBsAg positive individuals. The authors observed high prevalence of HBV and HDV infection with the following pattern: low degree of infectivity, marked transmission in early ages, intra-familial dissemination, and lack of importance of vertical transmission. However, the results suggest that these viruses were not yet introduced effectively in some of the studied groups.

The seroprevalence of hepatitis B and C in an Amerindian population in the southwestern Brazilian Amazon

We have investigated the seroprevalence of hepatitis B and C among Karitiana Indians (n = 119) living in the State of Rondônia, southwestern Brazilian Amazon. The prevalences of anti-HBs and anti-HBc were 16.1% and 35.3%, respectively, with HBsAg being found in only four (3.4%) subjects. Anti-HCV antibodies were detected in two subjects (1.7%). Age-stratified prevalence data suggest that both vertical and horizontal (the last among adults) routes of HBV transmission are important in this community.