Decreasing prevalence of Hepatitis B and absence of Hepatitis C Virus infection in the Warao indigenous population of Venezuela

Seroprevalence of hepatitis B, C, and D and associated factors in the semi-isolated Yanomami Amazonian indigenous community

BACKGROUND

Viral hepatitis is a significant health concern among indigenous population in the Americas. In Brazil, reports find high endemicity of HBV and HDV infections has been reported in several indigenous groups. However, few studies have documented the prevalence of HBV, HCV and HDV in the Yanomami. In this study, the prevalence of hepatitis B, C, and D serological markers and potential risk factors were investigated to provide guidance for the development of strategies aimed at reducing viral transmission in the Yanomami indigenous villages.

METHODS

This cross-sectional study was carried out in March 2015 and included 430 individuals from four Yanomami villages: Alapusi (n = 78), Castanha/Ahima (n = 126), Gasolina (n = 105), and Taibrapa (n = 121). A rapid test was used for detection of HBsAg and anti-HCV and chemiluminescent immunoassay for anti-HBs, anti-HBc, and anti-HDV antibodies.

RESULTS

HBsAg, anti-HBc, and anti-HBs were detected in 8.8, 45.5, and 49.4% of the participants, respectively. The estimated HBV status: current infection 9.6% (38/395); resolved infection 43.3% (171/395); vaccine immunity 20.5% (81/395), and susceptible to HBV 26.6% (105/395). Gasolina presented the lowest prevalence of HBV infection (6.5%) and the highest prevalence of vaccine immunity (26.9%). Children < 15 years old were highly susceptible to infection, as 53.1% did not have antibodies to HBV, while more than 80% of individuals over 45 years of age had been exposed to HBV. The markers for HDV were founded among 12.5% (4/32) of the HBsAg carriers. Anti-HCV was identified in all villages, with the highest prevalence in Alapusi (5.1%). Possible risk factors such as the use of piercings, tattoos, and contact with prospectors showed no statistical difference between the groups.

CONCLUSIONS

Viral hepatitis B and serological markers for HCV and HDV were found to be widely distributed among the Yanomami indigenous community, while the prevalence of vaccine immunity to HBV was low. This finding reinforces the importance of promoting systematized diagnostic and vaccination strategies in indigenous communities. Our data confirm that isolated and difficult-to-reach indigenous communities lack appropriate access to diagnosis, treatment, and vaccination.

The Hepatitis B Virus Genotypes E to J: The Overlooked Genotypes

Hepatitis B virus (HBV) genotypes E to J are understudied genotypes. Genotype E is found almost exclusively in West Africa. Genotypes F and H are found in America and are rare in other parts of the world. The distribution of genotype G is not completely known. Genotypes I and J are found in Asia and probably result from recombination events with other genotypes. The number of reported sequences for HBV genotypes E to J is small compared to other genotypes, which could impact phylogenetic and pairwise distance analyses. Genotype F is the most divergent of the HBV genotypes and is subdivided into six subgenotypes F1 to F6. Genotype E may be a recent genotype circulating almost exclusively in sub-Saharan Africa. Genotype J is a putative genotype originating from a single Japanese patient. The paucity of data from sub-Saharan Africa and Latin America is due to the under-representation of these regions in clinical and research cohorts. The purpose of this review is to highlight the need for further research on HBV genotypes E to J, which appear to be overlooked genotypes.

A time-series analysis of morbidity and mortality of viral hepatitis in Venezuela, 1990-2016

BACKGROUND

Viral hepatitis (VH) is a leading contributor to morbidity and mortality worldwide, constituting a public health problem associated with the level of human development. In recent years, Venezuela has experienced a political, social, and economic crisis and has been impacted by natural disasters that have led to the deterioration of sanitary and health infrastructures modifying the determinants of VH. Despite epidemiological studies conducted in specific regions of the country or populations, the national epidemiological behaviour of VH remains unclear.

METHODS

This is a time series study involving records of morbidity and mortality by VH in Venezuela reported during the period from 1990 to 2016. The Venezuelan population was taken as the denominator of the morbidity and mortality rates, according to the Venezuelan National Institute of Statistics and the 2016 population projections from the latest census published on the website of the responsible Venezuelan agency.

RESULTS

During the study period, 630,502 cases and 4,679 deaths from VH in Venezuela were analysed. Most of the cases (n = 457,278; 72.6%) were classified as unspecific VH (UVH). The deaths were mainly attributed to VHB (n = 1,532; 32.7%), UVH (n = 1,287; 27.5%), and sequelae of VH (n = 977; 20.8%). The mean rates of cases and deaths from VH in the country were 95 ± 40.4 cases per 100,000 inhabitants and 0.7 ± 0.1 deaths per 100,000 inhabitants, respectively, showing a large dispersion that is evident from the calculation of the coefficients of variation. There was document a strong correlation between UVH and VHA cases (0.78, p < 0.01) morbidity rates. VHB mortality rate was very strongly correlated with sequelae of VH (-0.9, p < 0.01).

CONCLUSIONS

VH is a major burden of morbidity and mortality in Venezuela with an endemic-epidemic trend and an intermediate prevalence for VHA, VHB, and VHC. Epidemiological information is not published in a timely manner and diagnostic tests are insufficient in primary health services. There is an urgent need to resume epidemiological surveillance of VH and to optimise the classification system for a better understanding of UVH cases and deaths due to sequelae of VHB and VHC.

Seroprevalence of viral and bacterial pathogens among malaria patients in an endemic area of southern Venezuela

BACKGROUND

Malaria remains a leading public health problem worldwide. Co-infections with other pathogens complicate its diagnosis and may modify the disease's clinical course and management. Similarities in malaria clinical presentation with other infections and overlapping endemicity result in underdiagnosis of co-infections and increased mortality. Thus, the aim of this study was to determine the seroprevalence of viral and bacterial pathogens among diagnosed malaria patients in malaria-endemic areas in Venezuela.

METHODS

A cross-sectional study was conducted on malaria patients attending three reference medical centres in Ciudad Bolivar, Venezuela. Clinical evaluation and laboratory tests for dengue virus (DENV), chikungunya virus (CHIKV), viral hepatitis [hepatitis A virus (HAV), hepatitis B virus (HBV), and hepatitis C virus (HCV)], and leptospirosis (LEP) were performed by enzyme-linked immunosorbent assays. Previous exposure to these pathogens was defined by the presence of specific immunoglobulin (Ig) G, and co-infection or recent exposure (CoRE) was determined by the presence of specific IgM alone or IgM + IgG. Data analysis considered descriptive statistics. Parameter distribution was statistically evaluated using Kolmogorov-Smirnov test and the necessary comparison tests. Odds ratio (OR) for complications was determined according to CoRE presence with a 95% confidence interval (CI).

RESULTS

A total of 161 malaria patients were studied, 66% infected with Plasmodium vivax, 27% with P. falciparum, and 7.5% harboured P. vivax/P. falciparum mixed infection. Previous exposure to DENV (60%) and CHIKV (25%) was frequent. CoRE was confirmed in 55 of the 161 malaria patients (34%) and were more frequent in P. falciparum (49%) than in P. vivax (29%) and mixed malaria patients (25%) (OR = 2.43, 95% CI: 1.39-4.25, P = 0.018). The most frequent CoRE was DENV (15%), followed by HAV (12%), HBV (6.2%), CHIKV (5.5%), and LEP (3.7%); HCV CoRE was absent. Complicated malaria was significantly more frequent in patients with CoRE (56%) than those without CoRE (36%; OR = 2.31, 95% CI: 1.18-4.92, P = 0.013).

CONCLUSIONS

We found high CoRE prevalence in malaria patients as determined by serology in the study region; cases were associated with a worse clinical outcome. Further prospective studies with samples from different infection sites and the use of molecular tools are needed to determine the clinical significance of these findings.

Hepatitis B and C in Immigrants and Refugees in Central Brazil: Prevalence, Associated Factors, and Immunization

Introduction: Eliminating hepatitis B and C in immigrant and refugee populations is a significant challenge worldwide. Given the lack of information in Brazil, this study aimed to estimate the prevalence of infections caused by hepatitis B and C viruses and factors associated with hepatitis B in immigrants and refugees residing in central Brazil. Methods: An observational, cross-sectional, and analytical study was conducted from July 2019 to January 2020 with 365 immigrants and refugees. Hepatitis B was detected by a rapid immunochromatographic test, enzyme immunoassay, and chemiluminescence, and hepatitis C by rapid immunochromatographic test. Multiple analysis was used to assess factors associated with hepatitis B infection. Results: Of the participants, 57.8% were from Haiti and 35.6% were from Venezuela. Most had been in Brazil for less than 2 years (71.2%). The prevalence of HBV infection and exposure was 6.6% (95% CI: 4.5-9.6%) and 27.9% (95% CI: 23.6-2.8%), respectively, and 34% had isolated anti-HBs positivity. Reporting a sexually transmitted infection was statistically associated with HBV infection (OR: 7.8; 95% CI: 2.3-26.4). No participant with positive anti-HCV serology was found. Conclusions: The study showed that participants were outside the reach of prevention and control actions for hepatitis B. Therefore, public health strategies must be designed to reach, inform, and vaccinate this group.

Global prevalence of occult hepatitis C virus: A systematic review and meta-analysis

BACKGROUND

Occult hepatitis C infection (OCI) is characterized by the presence of hepatitis C virus (HCV) RNA in the liver, peripheral blood mononuclear cells (PBMC) and/or ultracentrifuged serum in the absence of detectable HCV-RNA in serum. OCI has been described in several categories of populations including hemodialysis patients, patients with a sustained virological response, immunocompromised individuals, patients with abnormal hepatic function, and apparently healthy subjects.

AIM

To highlight the global prevalence of OCI.

METHODS

We performed a systematic and comprehensive literature search in the following 4 electronic databases PubMed, EMBASE, Global Index Medicus, and Web of Science up to 6th May 2021 to retrieve relevant studies published in the field. Included studies were unrestricted population categories with known RNA status in serum, PBMC, liver tissue and/or ultracentrifuged serum. Data were extracted independently by each author and the Hoy et al tool was used to assess the quality of the included studies. We used the random-effect meta-analysis model to estimate the proportions of OCI and their 95% confidence intervals (95%CI). The Cochran's Q-test and the I² test statistics were used to assess heterogeneity between studies. Funnel plot and Egger test were used to examine publication bias. R software version 4.1.0 was used for all analyses.

RESULTS

The electronic search resulted in 3950 articles. We obtained 102 prevalence data from 85 included studies. The pooled prevalence of seronegative OCI was estimated to be 9.61% (95%CI: 6.84-12.73) with substantial heterogeneity [I² = 94.7% (95%CI: 93.8%-95.4%), P < 0.0001]. Seropositive OCI prevalence was estimated to be 13.39% (95%CI: 7.85-19.99) with substantial heterogeneity [I² = 93.0% (90.8%-94.7%)]. Higher seronegative OCI prevalence was found in Southern Europe and Northern Africa, and in patients with abnormal liver function, hematological disorders, and kidney diseases. Higher seropositive OCI prevalence was found in Southern Europe, Northern America, and Northern Africa.

CONCLUSION

In conclusion, in the present study, it appears that the burden of OCI is high and variable across the different regions and population categories. Further studies on OCI are needed to assess the transmissibility, clinical significance, long-term outcome, and need for treatment.

[Hepatitis B in indigenous people in Latin America: a literature reviewHepatite B em indígenas na América Latina: revisão da literatura]

Objetivo.

Identificar publicaciones realizadas entre los años 2000 y 2020 sobre hepatitis B en indígenas de América Latina, con el fin de conocer avances y vacíos en el tema durante los últimos 20 años.

Métodos.

Revisión exploratoria y síntesis rápida de la evidencia. El proceso de organización documental se realizó con los programas Excel^® y Rayyan^®.

Resultados.

Se seleccionaron 30 de 107 artículos encontrados, 17 corresponden a estudios epidemiológicos, 10 a revisiones documentales, dos estudios clínicos y una carta al editor. Brasil fue el país con más publicaciones (50%), la mayoría con enfoque epidemiológico. La temática más abordada fue la medición de prevalencia de la infección por hepatitis B con 22 publicaciones, le siguieron 11 estudios que informan resultados de estudios moleculares del virus, siete estudios sobre vacunación, cinco estudios sobre factores de riesgo y cuatro publicaciones con temas como la transmisión vertical y estudios sociales.

Conclusión.

En comparación con revisiones previas realizadas por otros autores, se observa una mayor diversidad en los temas y métodos de investigación utilizados; sin embargo, aún prevalecen los enfoques epidemiológicos convencionales centrados en la medición de la prevalencia de marcadores serológicos. Esto hace necesario encarar otro tipo de investigaciones centradas en los determinantes socioculturales.

Occult Hepatitis B virus (HBV) infection and challenges for hepatitis elimination: A literature review

Occult hepatitis B infection (OBI) is characterized by the detection of hepatitis B virus (HBV) DNA in serum or liver but negativity for hepatitis B surface antigen. OBI, which is thought to be maintained by host, immunological, viral and/or epigenetic factors, is one of the most challenging clinical features in the study of viral hepatitis. Currently, there is no validated detection test for OBI. It is believed that OBI is widely distributed throughout the world, with a higher prevalence in populations at high-risk HBV, but the detailed worldwide prevalence patterns are unknown. We conducted a survey of recently published studies on OBI rates across all continents. High prevalence rates of OBI are observed in some specific groups, including patients with hepatitis C virus, human immunodeficiency virus co-infection or hepatocellular carcinoma. In 2016, the World Health Organization adopted strategies to eliminate viral hepatitis by 2030, but the difficulties in detecting and treating OBI currently challenge this goal. Subjects with OBI can transmit HBV, and episodes of reactivation can occur. Further studies to understanding the mechanisms that drive the development of OBI are needed and can contribute to efforts at eliminating viral hepatitis.

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.

MARCADORES SEROLOGICOS DEL VIRUS DE HEPATITIS B EN PUEBLOS INDIGENAS DEL ESTADO AMAZONAS, VENEZUELA

Venezuela presenta un nivel de prevalencia intermedia de Hepatitis B, con cuatro focos de alta endemicidad asociados principalmente a población indígena. Las prevalencias halladas en el Amazonas venezolano tienen distintas distribuciones entre los pueblos, observándose diferentes particularidades epidemiológicas. El objetivo del presente trabajo fue reportar la prevalencia de VHB en población indígena de diferentes pueblos y regiones geográficas del estado Amazonas, que no habían sido evaluados hasta la fecha, mediante la determinación de los marcadores serológicos: Antígeno de Superficie del Virus de Hepatitis B (AgsHB) y Anticuerpos Anticore (Anti-HBc). Se estudiaron 1390 individuos de 15 pueblos indígenas (Baniva, Baré, Curripaco, Jivi, Mapoyo, Maco, Piapoco, Piaroa, Puinave, Sáliba, Warekena, Yabarana, Yanomami, Yekuana, Yeral), resultando una prevalencia de exposición al Virus de 37,6 % (Anti-HBc), y una prevalencia de infección activa de 5,6 % (AgsHB). La prevalencia de exposición al virus es proporcional a la edad. No se encontró diferencia significativa en relación al sexo. La exposición al virus en el pueblo Sáliba fue significativamente menor al resto de los pueblos indígenas (p<0,001), y la observada en Yabarana, significativamente mayor (p<0,001). Se encontró una prevalencia de AgsHB significativamente mayor (p<0,01) en el pueblo indígena Yabarana. Se puede predecir que existe relación entre prevalencia de exposición al virus de hepatitis B y la distancia geográfica al centro urbano.

Analysis of genomic-length HBV sequences to determine genotype and subgenotype reference sequences

Hepatitis B virus (HBV) is a diverse, partially double-stranded DNA virus, with 9 genotypes (A-I), and a putative 10th genotype (J), characterized thus far. Given the broadening interest in HBV sequencing, there is an increasing requirement for a consistent, unified approach to HBV genotype and subgenotype classification. We set out to generate an updated resource of reference sequences using the diversity of all genomic-length HBV sequences available in public databases. We collated and aligned genomic-length HBV sequences from public databases and used maximum-likelihood phylogenetic analysis to identify genotype clusters. Within each genotype, we examined the phylogenetic support for currently defined subgenotypes, as well as identifying well-supported clades and deriving reference sequences for them. Based on the phylogenies generated, we present a comprehensive set of HBV reference sequences at the genotype and subgenotype level. All of the generated data, including the alignments, phylogenies and chosen reference sequences, are available online (https://doi.org/10.6084/m9.figshare.8851946) as a simple open-access resource.