Clinical and Acoustic Alterations of Swallowing in Children Exposed to Zika Virus during Pregnancy in a Cohort in Amazonas, Brazil: A Case Series Study.

Oropharyngeal dysphagia (OD) is a swallowing disorder that involves difficulty in safely passing the food bolus from the oral cavity to the stomach. OD is a common problem in children with congenital Zika virus syndrome (CZS). In this case series, we describe the clinical and acoustic alterations of swallowing in children exposed to the Zika virus during pregnancy in a cohort from Amazonas, Brazil. From July 2019 to January 2020, 22 children were evaluated, 6 with microcephaly and 16 without microcephaly. The mean age among the participants was 35 months (±4.6 months). All children with microcephaly had alterations in oral motricity, mainly in the lips and cheeks. Other alterations were in vocal quality, hard palate, and soft palate. Half of the children with microcephaly showed changes in cervical auscultation during breast milk swallowing. In children without microcephaly, the most frequently observed alteration was in lip motricity, but alterations in auscultation during the swallowing of breast milk were not observed. Regarding swallowing food of a liquid and pasty consistency, the most frequent alterations were incomplete verbal closure, increased oral transit time, inadequacy in capturing the spoon, anterior labial leakage, and increased oral transit time. Although these events are more frequent in microcephalic children, they can also be seen in non-microcephalic children, which points to the need for an indistinct evaluation of children exposed in utero to ZIKV.

Does the Presence or a High Titer of Yellow Fever Virus Antibodies Interfere with Pregnancy Outcomes in Women with Zika Virus Infection?

Zika virus (ZIKV) and yellow fever virus (YFV) originated in Africa and expanded to the Americas, where both are co-circulated. It is hypothesized that in areas of high circulation and vaccination coverage against YFV, children of pregnant women have a lower risk of microcephaly. We evaluated the presence and titers of antibodies and outcomes in women who had ZIKV infection during pregnancy. Pregnancy outcomes were classified as severe, moderate, and without any important outcome. An outcome was defined as severe if miscarriage, stillbirth, or microcephaly occurred, and moderate if low birth weight and/or preterm delivery occurred. If none of these events were identified, the pregnancy was defined as having no adverse effects. A sample of 172 pregnant women with an acute ZIKV infection confirmed during pregnancy were collected throughout 2016. About 89% (150 of 169) of them presented immunity against YFV, including 100% (09 of 09) of those who had severe outcomes, 84% (16 of 19) of those who had moderate outcomes, and 89% (125 of 141) of those who had non-outcomes. There was no difference between groups regarding the presence of anti-YFV antibodies (p = 0.65) and YFV titers (p = 0.6). We were unable to demonstrate a protective association between the presence or titers of YFV antibodies and protection against serious adverse outcomes from exposure to ZIKV in utero.

Growth Velocity and Nutritional Status in Children Exposed to Zika Virus during Pregnancy from Amazonas Cohort, Brazil.

The high incidence of Zika virus (ZIKV) infection in the period of 2015-2016 in Brazil may have affected linear height growth velocity (GV) in children exposed in utero to ZIKV. This study describes the growth velocity and nutritional status based on the World Organization (WHO) standards of children exposed to ZIKV during pregnancy and followed up in a tertiary unit, a reference for tropical and infectious diseases in the Amazon. Seventy-one children born between March 2016 and June 2018 were monitored for anthropometric indices: z-score for body mass index (BMI/A); weight (W/A); height (H/A) and head circumference (HC/A); and growth velocity. The mean age at the last assessment was 21.1 months (SD ± 8.93). Four children had congenital microcephaly and severe neurological impairment. The other 67 were non-microcephalic children (60 normocephalic and 7 macrocephalic); of these; 24.2% (16 children) had neurological alterations, and 28.8% (19 children) had altered neuropsychomotor development. Seventeen (24.2%) children had inadequate GV (low growth velocity). The frequencies of low growth among microcephalic and non-microcephalic patients are 25% (1 of 4 children) and 23.9% (16 of 67 children); respectively. Most children had normal BMI/A values during follow-up. Microcephalic patients showed low H/A and HC/A throughout the follow-up, with a significant reduction in the HC/A z-score. Non-microcephalic individuals are within the regular ranges for H/A; HC/A; and W/A, except for the H/A score for boys. This study showed low growth velocity in children with and without microcephaly, highlighting the need for continuous evaluation of all children born to mothers exposed to ZIKV during pregnancy.

Would Zika virus Infection in Pregnancy Be a Sentence of Poor Neurological Prognosis for Exposed Children? Neurodevelopmental Outcomes in a Cohort from Brazilian Amazon.

Infections with Flavivirus in pregnant women are not associated with vertical transmission. However, in 2015, severe cases of congenital infection were reported during the Zika virus outbreak in Brazil. More subtle infections in children born to mothers with ZIKV still remain uncertain and the spectrum of this new congenital syndrome is still under construction. This study describes outcomes regarding neurodevelopment and neurological examination in the first years of life, of a cohort of 77 children born to pregnant women with ZIKV infection in Manaus, Brazil, from 2017 to 2020. In the group of normocephalic children (92.2%), most showed satisfactory performance in neuropsychomotor development, with a delay in 29.6% and changes in neurological examination in 27.1%, with two children showing muscle-strength deficits. All microcephalic children (5.2%) evolved with severe neuropsychomotor-development delay, spastic tetraparesis, and alterations in the imaging exam. In this cohort, 10.5% of the children had macrocephaly at birth, but only 2.6% remained in this classification. Although microcephaly has been considered as the main marker of congenital-Zika-virus syndrome in previous studies, its absence does not exclude the possibility of the syndrome. This highlights the importance of clinical follow-up, regardless of the classification of head circumference at birth.

Zika Brazilian Cohorts (ZBC) Consortium: Protocol for an Individual Participant Data Meta-Analysis of Congenital Zika Syndrome after Maternal Exposure during Pregnancy.

Despite great advances in our knowledge of the consequences of Zika virus to human health, many questions remain unanswered, and results are often inconsistent. The small sample size of individual studies has limited inference about the spectrum of congenital Zika manifestations and the prognosis of affected children. The Brazilian Zika Cohorts Consortium addresses these limitations by bringing together and harmonizing epidemiological data from a series of prospective cohort studies of pregnant women with rash and of children with microcephaly and/or other manifestations of congenital Zika. The objective is to estimate the absolute risk of congenital Zika manifestations and to characterize the full spectrum and natural history of the manifestations of congenital Zika in children with and without microcephaly. This protocol describes the assembly of the Consortium and protocol for the Individual Participant Data Meta-analyses (IPD Meta-analyses). The findings will address knowledge gaps and inform public policies related to Zika virus. The large harmonized dataset and joint analyses will facilitate more precise estimates of the absolute risk of congenital Zika manifestations among Zika virus-infected pregnancies and more complete descriptions of its full spectrum, including rare manifestations. It will enable sensitivity analyses using different definitions of exposure and outcomes, and the investigation of the sources of heterogeneity between studies and regions.

Zika virus RNA excretion in sweat with concomitant detection in other body fluid specimens.

We evaluated sweat, blood and urine specimens obtained from an ongoing cohort study in Brazil. Samples were collected at pre-established intervals after the initial rash presentation and tested for Zika virus (ZIKV) RNA presence by real-time reverse transcriptase polymerase chain reaction (rRT-PCR). From 254 participants with confirmed infection, ZIKV RNA was detected in the sweat of 46 individuals (18.1%). Sweat presented a median cycle threshold (Ct) of 34.74 [interquartile range (IQR) 33.44-36.04], comparable to plasma (Ct 35.96 - IQR 33.29-36.69) and higher than urine (Ct 30.78 - IQR 28.72-33.22). Concomitant detection with other specimens was observed in 33 (72%) of 46 participants who had a positive result in sweat. These findings represent an unusual and not yet investigated virus shedding through eccrine glands.

Cohort profile: Study on Zika virus infection in Brazil (ZIKABRA study).

Zika virus (ZIKV) has been detected in blood, urine, semen, cerebral spinal fluid, saliva, amniotic fluid, and breast milk. In most ZIKV infected individuals, the virus is detected in the blood to one week after the onset of symptoms and has been found to persist longer in urine and semen. To better understand virus dynamics, a prospective cohort study was conducted in Brazil to assess the presence and duration of ZIKV and related markers (viral RNA, antibodies, T cell response, and innate immunity) in blood, semen, saliva, urine, vaginal secretions/menstrual blood, rectal swab and sweat. The objective of the current manuscript is to describe the cohort, including an overview of the collected data and a description of the baseline characteristics of the participants. Men and women ≥ 18 years with acute illness and their symptomatic and asymptomatic household contacts with positive reverse transcriptase-polymerase chain reaction test for ZIKV in blood and/or urine were included. All participants were followed up for 12 months. From July 2017 to June 2019, a total of 786 participants (284 men, 502 women) were screened. Of these, 260 (33.1%) were enrolled in the study; index cases: 64 men (24.6%), 162 (62.3%) women; household contacts: 12 men (4.6%), 22 (8.5%) women. There was a statistically significant difference in age and sex between enrolled and not enrolled participants (p<0.005). Baseline sociodemographic and medical data were collected at enrollment from all participants. The median and interquartile range (IQR) age was 35 (IQR; 25.3, 43) for men and 36.5 years (IQR; 28, 47) for women. Following rash, which was one of the inclusion criteria for index cases, the most reported symptoms in the enrollment visit since the onset of the disease were fever, itching, arthralgia with or without edema, non-purulent conjunctivitis, headache, and myalgia. Ten hospitalizations were reported by eight patients (two patients were hospitalized twice) during follow up, after a median of 108 days following symptom onset (range 7 to 266 days) and with a median of 1.5 days (range 1 to 20 days) of hospital stay. A total of 4,137 visits were performed, 223 (85.8%) participants have attended all visits and 37 (14.2%) patients were discontinued.

Zika virus RNA excretion in sweat with concomitant detection in other body fluid specimens

We evaluated sweat, blood and urine specimens obtained from an ongoing cohort study in Brazil. Samples were collected at pre-established intervals after the initial rash presentation and tested for Zika virus (ZIKV) RNA presence by real-time reverse transcriptase polymerase chain reaction (rRT-PCR). From 254 participants with confirmed infection, ZIKV RNA was detected in the sweat of 46 individuals (18.1%). Sweat presented a median cycle threshold (Ct) of 34.74 [interquartile range (IQR) 33.44-36.04], comparable to plasma (Ct 35.96 - IQR 33.29-36.69) and higher than urine (Ct 30.78 - IQR 28.72-33.22). Concomitant detection with other specimens was observed in 33 (72%) of 46 participants who had a positive result in sweat. These findings represent an unusual and not yet investigated virus shedding through eccrine glands.

Zika Virus in Rectal Swab Samples.

We detected Zika virus RNA in rectal swab samples from 10 patients by using real-time reverse transcription PCR, and we isolated the virus from 1 patient. The longest interval from symptom onset to detection was 14 days. These findings are applicable to diagnosis and infection prevention recommendations.

Genomic, epidemiological and digital surveillance of Chikungunya virus in the Brazilian Amazon.

BACKGROUND: Since its first detection in the Caribbean in late 2013, chikungunya virus (CHIKV) has affected 51 countries in the Americas. The CHIKV epidemic in the Americas was caused by the CHIKV-Asian genotype. In August 2014, local transmission of the CHIKV-Asian genotype was detected in the Brazilian Amazon region. However, a distinct lineage, the CHIKV-East-Central-South-America (ECSA)-genotype, was detected nearly simultaneously in Feira de Santana, Bahia state, northeast Brazil. The genomic diversity and the dynamics of CHIKV in the Brazilian Amazon region remains poorly understood despite its importance to better understand the epidemiological spread and public health impact of CHIKV in the country. METHODOLOGY/PRINCIPAL FINDINGS: We report a large CHIKV outbreak (5,928 notified cases between August 2014 and August 2018) in Boa vista municipality, capital city of Roraima's state, located in the Brazilian Amazon region. We generated 20 novel CHIKV-ECSA genomes from the Brazilian Amazon region using MinION portable genome sequencing. Phylogenetic analyses revealed that despite an early introduction of the Asian genotype in 2015 in Roraima, the large CHIKV outbreak in 2017 in Boa Vista was caused by an ECSA-lineage most likely introduced from northeastern Brazil. Epidemiological analyses suggest a basic reproductive number of R0 of 1.66, which translates in an estimated 39 (95% CI: 36 to 45) % of Roraima's population infected with CHIKV-ECSA. Finally, we find a strong association between Google search activity and the local laboratory-confirmed CHIKV cases in Roraima. CONCLUSIONS/SIGNIFICANCE: This study highlights the potential of combining traditional surveillance with portable genome sequencing technologies and digital epidemiology to inform public health surveillance in the Amazon region. Our data reveal a large CHIKV-ECSA outbreak in Boa Vista, limited potential for future CHIKV outbreaks, and indicate a replacement of the Asian genotype by the ECSA genotype in the Amazon region.

Chronic HDV/HBV co-infection: predictors of disease stage---a case series of HDV-3 patients.

BACKGROUND & AIMS: Chronic HDV/HBV co-infection is perhaps the most intriguing amongst all viral hepatitis. Only few studies focus deeply on this topic, particularly with patients infected with HDV-3. This study aimed to identify predictors of advanced disease, examining a cross-sectional data of 64 patients. METHODS: Histological grading was used to characterize the disease stages and viral loads were tested as predictors of necroinflammatory activity and fibrosis. RESULTS: We identified three HDV/HBV co-infection patterns: patients with predominant HDV replication (56.3%), patients with similar viral loads of both viruses (40.6%), and patients with predominant HBV replication (3.1%). Mean HDV-RNA showed a positive trend regarding inflammatory activity and grade of fibrosis. HDV viral load correlated positively with serum levels of liver enzymes and inversely with platelets count. HBV viral load showed no correlation with any of the above parameters. Advanced fibrosis was associated with age, splenomegaly, and HDV viral load of more than 2 log10. Multiple logistic regression confirmed the independent effect of HDV viral predominance. Advanced necroinflammatory activity was independently associated with HDV viral load and splenomegaly. CONCLUSIONS: HDV may possibly play an important and direct role in the establishment of necroinflammatory activity and fibrosis. Data show an indigenous HDV genotype, HDV-3, similar to those described in the Amazon region.

Hepatitis D virus infection in the Western Brazilian Amazon - far from a vanishing disease / Infecção pelo vírus da hepatite D na Amazônia brasileira - longe de uma doença em declínio

INTRODUCTION: A decline in hepatitis D virus (HDV) occurrence was described in Europe and Asia. We estimated HDV prevalence in the Brazilian Amazon following hepatitis B vaccination. METHODS: This is a cross-sectional survey of HDV measured by total antibodies to HDV (anti-HD T). RESULTS: HDV prevalence was 41.9% whiting HBsAg carries and was associated with age (PR = 1.96; 95% CI 1.12-3.42; p = 0.01), hepatitis B virus (HBV) infection (PR = 4.38; 95% CI 3.12-6.13; p < 0.001), and clinical hepatitis (PR =1.44; 95% CI 1.03-2.00; p = 0.03). Risk factors were related to HDV biology, clinical or demographic aspects such as underlying HBV infection, clinical hepatitis and age. CONCLUSIONS: Our study demonstrated that HDV infection continues to be an important health issue in the Brazilian Amazon and that the implementation of the HBV vaccination in rural Lábrea had little or no impact on the spread of HDV. This shows that HDV has not yet disappeared from HBV hyperendemic areas and reminding that it is far from being a vanishing disease in the Amazon basin.

INTRODUÇÃO: É descrito declínio na ocorrência do vírus da hepatite D (VHD) na Europa e Ásia. Estimamos a prevalência de infecção pelo VHD na Amazônia Ocidental, após a introdução da vacinação contra hepatite B. MÉTODOS: Este é um estudo de corte transversal da prevalência do VHD medido pela ocorrência de anticorpos totais (anti-HD T). RESULTADOS: A prevalência do VHD encontrada foi 41,9% entre os portadores do HBsAg, e esteve associado à idade (RP = 1,96; IC 95% 1,12-3,42; p = 0,01), infecção pelo HBV (RP = 4,38; IC 95% 3,12-6,13; p < 0,001) e história clínica de hepatite (RP =1,44; IC 95% 1,03-2,00; p = 0,03). Fatores de risco mostraram-se associados à biologia do HDV, aspectos clínicos e demográficos como infecção prévia pelo VHB e idade. CONCLUSÕES: O estudo demonstra que a infecção pelo VHD continua sendo um importante problema de saúde pública na região, e que a implantação da vacinação contra o VHB na área rural de Lábrea teve um impacto pouco significativo no controle do VHD, percebe-se que este ainda não desapareceu de áreas hiperendêmicas do VHB, e está longe de poder ser classificado como uma doença em declínio na bacia Amazônica.

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

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.

Serological evidence of hantavirus infection in rural and urban regions in the state of Amazonas, Brazil.

Hantavirus disease is caused by the hantavirus, which is an RNA virus belonging to the family Bunyaviridae. Hantavirus disease is an anthropozoonotic infection transmitted through the inhalation of aerosols from the excreta of hantavirus-infected rodents. In the county of Itacoatiara in the state of Amazonas (AM), Brazil, the first human cases of hantavirus pulmonary and cardiovascular syndrome were described in July 2004. These first cases were followed by two fatal cases, one in the municipality of Maués in 2005 and another in Itacoatiara in 2007. In this study, we investigated the antibody levels to hantavirus in a population of 1,731 individuals from four different counties of AM. Sera were tested by IgG/IgM- enzyme-linked immune-sorbent assay using a recombinant nucleocapsid protein of the Araraquara hantavirus as an antigen. Ten sera were IgG positive to hantavirus (0.6%). Among the positive sera, 0.8% (1/122), 0.4% (1/256), 0.2% (1/556) and 0.9% (7/797) were from Atalaia do Norte, Careiro Castanho, Itacoatiara and Lábrea, respectively. None of the sera in this survey were IgM-positive. Because these counties are distributed in different areas of AM, we can assume that infected individuals are found throughout the entire state, which suggests that hantavirus disease could be a local emerging health problem.

Molecular characterization of the hepatitis B virus in autochthonous and endogenous populations in the Western Brazilian Amazon.

INTRODUCTION: Hepatitis B virus (HBV) infection is a serious public health issue worldwide. Hepatitis B virus is classified into eight genotypes, varying from A to H, with distinct geographical distributions. In Brazil, the most frequent genotypes are A, D, and F. METHODS: This study aimed to characterize the HBV genotypes in cases of hepatitis B virus and hepatitis D virus (HDV) co-infections in an endemic area in the Western Brazilian Amazon. We analyzed 86 serum samples reactive for HBsAg from indigenous and non-indigenous populations obtained from previous serological surveys. RESULTS: Of the 86 reactive serum samples, 39 were found to be HBV-DNA-positive by semi-nested PCR. The genotypes were established by sequencing the amplified S gene region. We obtained 20 sequences classified into three genotypes: A, D, and F. Genotype A was the most frequent (60%), followed by D (35%) and F (5%). CONCLUSIONS: The distribution of the HBV genotypes reflected the pattern of historical occupation of the region.

Prevalence of hepatitis B virus infection and carriage after nineteen years of vaccination program in the Western Brazilian Amazon.

INTRODUCTION: Reductions in the prevalence of hepatitis B virus (HBV) infection and carriage, decreases in liver cancer incidence, and changes in patterns of liver dysfunctions are described after hepatitis B vaccination. METHODS: We conducted a population-based seroprevalence study aimed at estimating the HBV prevalence and risk of infection in the rural area of Lábrea following nineteen years of HBV vaccination. RESULTS: Half of the subjects showed total anti-HBc of 52.1% (95% CI 49.6-54.7). The HBsAg prevalence was 6.2% (95% CI 5.1-7.6). Multivariate analysis showed an inverse association between HBV infection and vaccination (OR 0.62; 95% CI 0.44-0.87). HBsAg remained independently associated with past hepatitis (OR 2.44; 95% CI 1.52-3.89) and inversely to vaccination (OR 0.43; 95% CI 0.27-0.69). The prevalence of HBeAg among HBsAg-positive individuals was 20.4% (95% CI 12.8-30.1), with the positive subjects having a median age of 11 years (1-46) p=0.0003. CONCLUSIONS: We demonstrate that HBV infection is still an important public health issue and that HBV vaccination could have had better impact on HBV epidemiology. If we extrapolate these findings to other rural areas in the Brazilian Amazon, we can predict that the sources of chronic infected patients remain a challenge. Future studies are needed regarding clinical aspects, molecular epidemiology, surveillance of acute cases, and risk groups.

Molecular characterization of the hepatitis B virus in autochthonous and endogenous populations in the Western Brazilian Amazon / Caracterização molecular do vírus da hepatite B em população autóctone e população endógena do município de Lábrea, na Amazônia ocidental brasileira

INTRODUCTION: Hepatitis B virus (HBV) infection is a serious public health issue worldwide. Hepatitis B virus is classified into eight genotypes, varying from A to H, with distinct geographical distributions. In Brazil, the most frequent genotypes are A, D, and F. METHODS: This study aimed to characterize the HBV genotypes in cases of hepatitis B virus and hepatitis D virus (HDV) co-infections in an endemic area in the Western Brazilian Amazon. We analyzed 86 serum samples reactive for HBsAg from indigenous and non-indigenous populations obtained from previous serological surveys. RESULTS: Of the 86 reactive serum samples, 39 were found to be HBV-DNA-positive by semi-nested PCR. The genotypes were established by sequencing the amplified S gene region. We obtained 20 sequences classified into three genotypes: A, D, and F. Genotype A was the most frequent (60 percent), followed by D (35 percent) and F (5 percent). CONCLUSIONS: The distribution of the HBV genotypes reflected the pattern of historical occupation of the region.

INTRODUÇÃO: A infecção pelo vírus da hepatite B (VHB) é um importante problema de saúde pública no mundo. O VHB é classificado em oito genótipos diferentes, A-H, com distinta distribuição geográfica. No Brasil, os genótipos mais frequentes são o A, D e F. MÉTODOS: Objetivo deste estudo foi caracterizar os genótipos do VHB, em região endêmica de infecção pelos vírus da hepatite B e hepatite D (VHD), na Amazônia Ocidental Brasileira. Foram analisadas 86 amostras sororreativas para o HBsAg de indivíduos indígenas e não-indígenas, obtidas de inquéritos sorológicos realizados no município de Lábrea, Estado do Amazonas. RESULTADOS: Das 86 amostras sororreativas, 39 foram VHB-DNA positivas pela semi-nested PCR. Os genótipos foram estabelecidos pelo sequenciamento da região do gene S amplificado. Foram obtidas 20 sequências, classificadas em três genótipos A, D e F; sendo o genótipo A o mais frequente (60 por cento), seguido do D (35 por cento) e F (5 por cento). CONCLUSÕES: O perfil de distribuição dos genótipos encontrados do VHB reflete o padrão de ocupação histórica da região.

Prevalence of hepatitis B virus infection and carriage after nineteen years of vaccination program in the Western Brazilian Amazon / Prevalência da infecção e de portadores do vírus da hepatite B, após 19 anos do programa de vacinação na Amazônia ocidental Brasileira

INTRODUCTION: Reductions in the prevalence of hepatitis B virus (HBV) infection and carriage, decreases in liver cancer incidence, and changes in patterns of liver dysfunctions are described after hepatitis B vaccination. METHODS: We conducted a population-based seroprevalence study aimed at estimating the HBV prevalence and risk of infection in the rural area of Lábrea following nineteen years of HBV vaccination. RESULTS: Half of the subjects showed total anti-HBc of 52.1 percent (95 percent CI 49.6-54.7). The HBsAg prevalence was 6.2 percent (95 percent CI 5.1-7.6). Multivariate analysis showed an inverse association between HBV infection and vaccination (OR 0.62; 95 percent CI 0.44-0.87). HBsAg remained independently associated with past hepatitis (OR 2.44; 95 percent CI 1.52-3.89) and inversely to vaccination (OR 0.43; 95 percent CI 0.27-0.69). The prevalence of HBeAg among HBsAg-positive individuals was 20.4 percent (95 percent CI 12.8-30.1), with the positive subjects having a median age of 11 years (1-46) p=0.0003. CONCLUSIONS: We demonstrate that HBV infection is still an important public health issue and that HBV vaccination could have had better impact on HBV epidemiology. If we extrapolate these findings to other rural areas in the Brazilian Amazon, we can predict that the sources of chronic infected patients remain a challenge. Future studies are needed regarding clinical aspects, molecular epidemiology, surveillance of acute cases, and risk groups.

INTRODUÇÃO: Reduções nas taxas de prevalência de infecção pelo vírus da hepatite B (VHB) e de portadores, incidência de câncer de fígado e mudança nos padrões de doenças hepáticas são descritos, depois da introdução da vacinação contra hepatite B. MÉTODOS: Foi conduzido um estudo de soro prevalência de base populacional, com o objetivo de estimar a prevalência do VHB e fatores de risco de infecção na área rural de Lábrea, depois de 19 anos de introdução da vacinação contra hepatite B. RESULTADOS: Metade dos indivíduos investigados mostrou reatividade ao anti-HBc total, 52,1 por cento (IC 95 por cento 49,6-54,7). A prevalência do HBsAg foi 6,2 por cento (IC 95 por cento 5,1-7,6). Análises multivariadas mostrou associação inversa da infecção pelo VHB e vacinação (OR 0,62; IC 95 por cento 0<44-0,87). A presença do HBsAg permaneceu independentemente associada com o passado de hepatite (OR 2,44; IC 95 por cento 1,52-3,89) e inversamente associado a história de vacinação (OR 0,43; IC 95 por cento 0,27-0,69). A prevalência do HBeAg, entre os HBsAg positivos foi 20,4 por cento (IC95 por cento 12,8-30,1), tendo em média os indivíduos positivos 11 anos de idade (1-46) p=0,0003. CONCLUSÕES: Foi demonstrado que o VHB é ainda um importante problema de saúde publica, e que a vacinação contra o VHB poderia ter tido um impacto maior na epidemiologia do VHB na região. Se esses achados forem extrapolados para outras regiões rurais da Amazônia brasileira, podemos predizer que a fonte de pacientes crônicos é ainda um desafio a ser vencido. Estudos futuros devem focar os aspectos clínicos, a epidemiologia molecular, vigilância de casos agudos e grupos de risco.

Serological evidence of hantavirus infection in rural and urban regions in the state of Amazonas, Brazil

Hantavirus disease is caused by the hantavirus, which is an RNA virus belonging to the family Bunyaviridae. Hantavirus disease is an anthropozoonotic infection transmitted through the inhalation of aerosols from the excreta of hantavirus-infected rodents. In the county of Itacoatiara in the state of Amazonas (AM), Brazil, the first human cases of hantavirus pulmonary and cardiovascular syndrome were described in July 2004. These first cases were followed by two fatal cases, one in the municipality of Maués in 2005 and another in Itacoatiara in 2007. In this study, we investigated the antibody levels to hantavirus in a population of 1,731 individuals from four different counties of AM. Sera were tested by IgG/IgM- enzyme-linked immune-sorbent assay using a recombinant nucleocapsid protein of the Araraquara hantavirus as an antigen. Ten sera were IgG positive to hantavirus (0.6 percent). Among the positive sera, 0.8 percent (1/122), 0.4 percent (1/256), 0.2 percent (1/556) and 0.9 percent (7/797) were from Atalaia do Norte, Careiro Castanho, Itacoatiara and Lábrea, respectively. None of the sera in this survey were IgM-positive. Because these counties are distributed in different areas of AM, we can assume that infected individuals are found throughout the entire state, which suggests that hantavirus disease could be a local emerging health problem.

Hepatitis D virus infection in the Western Brazilian Amazon - far from a vanishing disease.

INTRODUCTION: A decline in hepatitis D virus (HDV) occurrence was described in Europe and Asia. We estimated HDV prevalence in the Brazilian Amazon following hepatitis B vaccination. METHODS: This is a cross-sectional survey of HDV measured by total antibodies to HDV (anti-HD T). RESULTS: HDV prevalence was 41.9% whiting HBsAg carries and was associated with age (PR = 1.96; 95% CI 1.12-3.42; p = 0.01), hepatitis B virus (HBV) infection (PR = 4.38; 95% CI 3.12-6.13; p < 0.001), and clinical hepatitis (PR =1.44; 95% CI 1.03-2.00; p = 0.03). Risk factors were related to HDV biology, clinical or demographic aspects such as underlying HBV infection, clinical hepatitis and age. CONCLUSIONS: Our study demonstrated that HDV infection continues to be an important health issue in the Brazilian Amazon and that the implementation of the HBV vaccination in rural Lábrea had little or no impact on the spread of HDV. This shows that HDV has not yet disappeared from HBV hyperendemic areas and reminding that it is far from being a vanishing disease in the Amazon basin.