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Epidemiology and molecular characterization of hepatitis B virus infection in isolated villages in the Western Brazilian Amazon.

ABSTRACT: Individuals from three isolated, rural communities in the western Brazilian Amazon were evaluated for serological markers of hepatitis B virus (HBV) infection, HBV genotype, and the presence of risk factors for infection and transmission. Of the 225 individuals studied, 79.1% had serological evidence of HBV infection; 10.2% individuals were chronic carriers for HBV surface antigen (HBsAg-positive). Analysis of risk factors indicates that HBV is transmitted mainly horizontally within the family from a chronic "active" carrier for hepatitis B "e" antigen (HBeAg-positive), though a strong possibility of vertical transmission remains. The predominance of HBV genotype F, with a higher genomic similarity between the isolates, indicated a relatively recent introduction of HBV, from a common source, to the area. This study sheds light on the HBV epidemiology in the Brazilian Amazon region and highlights the need for greater emphasis on HBV control and immunization programs.

SUBMITTER: Castilho Mda C

PROVIDER: S-EPMC3516333 | biostudies-literature | 2012 Oct

REPOSITORIES: biostudies-literature

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Epidemiology and molecular characterization of hepatitis B virus infection in isolated villages in the Western Brazilian Amazon.

Castilho Márcia da Costa Mda C Oliveira Cintia Mara Costa de CM Gimaque João Bosco de Lima JB Leão Jorge Di Tommaso JD Braga Wornei Silva Miranda WS

The American journal of tropical medicine and hygiene 20120820 4

Individuals from three isolated, rural communities in the western Brazilian Amazon were evaluated for serological markers of hepatitis B virus (HBV) infection, HBV genotype, and the presence of risk factors for infection and transmission. Of the 225 individuals studied, 79.1% had serological evidence of HBV infection; 10.2% individuals were chronic carriers for HBV surface antigen (HBsAg-positive). Analysis of risk factors indicates that HBV is transmitted mainly horizontally within the family f ...[more]

PMID: 22908032

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Project description:BACKGROUND: Simian malaria is still an open question concerning the species of Plasmodium parasites and species of New World monkeys susceptible to the parasites. In addition, the lingering question as to whether these animals are reservoirs for human malaria might become important especially in a scenario of eradication of the disease. To aid in the answers to these questions, monkeys were surveyed for malaria parasite natural infection in the Amazonian state of Rondônia, Brazil, a state with intense environmental alterations due to human activities, which facilitated sampling of the animals. METHODS: Parasites were detected and identified in DNA from blood of monkeys, by PCR with primers for the 18S rRNA, CSP and MSP1 genes and sequencing of the amplified fragments. Multiplex PCR primers for the 18S rRNA genes were designed for the parasite species Plasmodium falciparum and Plasmodium vivax, Plasmodium malariae/Plasmodium brasilianum and Plasmodium simium. RESULTS: An overall infection rate of 10.9% was observed or 20 out 184 monkey specimens surveyed, mostly by P. brasilianum. However, four specimens of monkeys were found infected with P. falciparum, two of them doubly infected with P. brasilianum and P. falciparum. In addition, a species of monkey of the family Aotidae, Aotus nigriceps, is firstly reported here naturally infected with P. brasilianum. None of the monkeys surveyed was found infected with P. simium/P. vivax. CONCLUSION: The rate of natural Plasmodium infection in monkeys in the Brazilian state of Rondônia is in line with previous surveys of simian malaria in the Amazon region. The fact that a monkey species was found that had not previously been described to harbour malaria parasites indicates that the list of monkey species susceptible to Plasmodium infection is yet to be completed. Furthermore, finding monkeys in the region infected with P. falciparum clearly indicates parasite transfer from humans to the animals. Whether this parasite can be transferred back to humans and how persistent the parasite is in monkeys in the wild so to be efficient reservoirs of the disease, is yet to be evaluated. Finding different species of monkeys infected with this parasite species suggests indeed that these animals can act as reservoirs of human malaria.

Project description:BackgroundHepatitis B virus (HBV) and hepatitis D virus (HDV) represent important public health problems in the Western Amazon region with reported cases of fulminant hepatitis. This cross sectional study describes HBV and HDV genotypes circulating in the Brazilian Amazon region.MethodsHBsAg positive individuals (n = 224) were recruited in Manaus/Amazonas State (130 blood donors from the Hematology and Hemotherapy Foundation from Amazonas/HEMOAM; 60 subjects from outpatient clinic) and in Eirunepe city (n = 34) from 2003-2009. Most participants (n = 153) lived in Manaus, 63 were from 20 remote isolated municipalities, 8 lived outside Amazonas State. Genotyping was based on PCR products: HBV genotype A-F specific primers, restricted length polymorphism for HDV. HDV isolates were directly sequenced (delta antigen 405 nucleotide fragment) and phylogenetic analysis performed (MEGA; neighbor-joining, Kimura's two parameter).ResultsMost participants were young adult males and HBV mono-infection predominated (70.5%, 158/224). Among blood donors, outpatient subjects and individuals from Eirunepe, HBV/A prevailed followed by HBV/D and F (p > 0.05). HBV/A was more frequent in blood donors (p < 0.05). HBV-HDV coinfection rate was 8.5% in blood donors (11/130), 65.0% (39/60) in outpatient subjects and 47.0% (16/34) in individuals from Eirunepe. Compared to blood donors, coinfection was higher in outpatient subjects (65.0% versus 8.5%; RR = 5.0; CI 3.4-7.9; p < 0.0001) and in subjects from Eirunepe (47.0% versus 8.5%; RR = 5.5; CI 3.0-9.9; p < 0.0001). HBV-HDV coinfection rates were higher in patients from highly endemic remote cities. Only HDV genotype 3 was detected, HBV/F-HDV/3 predominated (20/38; 52.7%), followed by HBV/A-HDV/3 (31.6%; 12/38) and HBV/D-HDV/3 (15.8%; 6/38).ConclusionsThe description of HBV and HDV genotypes circulating in the western Amazon can contribute to a better understanding of their relevance on the regional epidemics. These infections are highly endemic in the Amazon where their control is challenged by its vast territorial dimension with small, hard-to-reach municipalities dispersed into the jungle and populated by diverse ethnic groups.

Dataset Information

Epidemiology and molecular characterization of hepatitis B virus infection in isolated villages in the Western Brazilian Amazon.

Publications

Epidemiology and molecular characterization of hepatitis B virus infection in isolated villages in the Western Brazilian Amazon.

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