Western Brazilian Amazon Region Research Articles

Parasitism by Amblyomma rotundatum on Teiidae lizards in the eastern part of the state of Acre, Brazil.

The aim of the present study was to report on the occurrence of parasitism by Amblyomma rotundatum ticks on two species of Teiidae lizards and test the presence of rickettsiae in the collected ticks, in the western Brazilian Amazon region. Ticks were collected in July 2019, from a fragment of terra firme forest in the municipality of Senador Guiomard, Acre, Brazil. Two lizards that were infested by immature stages of ticks were caught using mist net and Tomahawk traps. Ectoparasites were collected manually, and the lizard specimens were identified and released at the same location where they had been caught. Three nymphs and 49 larvae were collected from Ameiva ameiva, while 25 nymphs and nine larvae were collected from Tupinambis cuzcoensis, which are both in the family Teiidae. The ticks were identified morphologically as belonging to the genus Amblyomma. Nymphs were identified at species level through molecular analysis, resulting in the tick species Amblyomma rotundatum. This is the first record of parasitism by the tick A. rotundatum on T. cuzcoensis lizard, and the first report of an association between A. rotundatum and the lizard species A. ameiva and T. cuzcoensis in Acre, in the western part of the Amazon region.

Severe acute respiratory syndrome and COVID-19 under the hierarchy of the urban network of municipalities in the state of Acre, western Brazilian Amazon region, 2020-2021: a cross-sectional study.

ABSTRACTBACKGROUND:The Respiratory Syndromes Surveillance System was created by the Brazilian Ministry of Health in 2000 to monitor influenza in this country. With the emergence of the new coronavirus pandemic, it became incorporated into the surveillance network for influenza and other respiratory viruses.OBJECTIVE:To analyze the transmission of coronavirus disease 2019 (COVID-19) and severe acute respiratory syndrome (SARS) in the state of Acre through its hierarchical urban network.DESIGN AND SETTING:Cross-sectional, descriptive and ecological study, using a spatiotemporal approach and using secondary data. This study was conducted in the state of Acre, northern Brazil.METHODS:This study used secondary data, and epidemiological weeks and municipalities were taken to be the units of analysis. Incidence rates and kernel intensities were calculated for four study periods. Spatiotemporal analysis was performed using scan statistics to identify clusters of SARS cases and considering the population of each municipality.RESULTS:In general, it could be observed that there were higher kernel rates and intensities in municipalities located in the north and south of this state (i.e. its most populous municipalities).CONCLUSION:Priority areas for interventions to control transmission of COVID-19 were highlighted, with the aim of reducing the risks of transmission to more distant areas in the urban hierarchy of the state of Acre.

Prevalence of chronic noncommunicable diseases and their associated factors in adults over 39 years in riverside population in the Western Brazilian Amazon region

The prevalence of Chronic Noncommunicable Disease (CND) are rocketting over the world, including in young adults. The WHO estimates that more than half of the deaths in the world are caused by CND.
 A cross-sectional study was carried out from june to november 2016. The researchers visited 16 communities, with a sample size of 183 adult individuals performed for convenience. The patients went through screening and verified: weight, height, abdominal circumference, blood pressure, clinical-epidemiological history and performed physical and laboratory examination. Prevalence ratios were calculated with confidence intervals of 95% and with statistical significance with p<0.05.
 This study aims to estimate the prevalence of CND and its associated factors in the elderly riverside population of the Rio Madeira in Humaitá, Amazonas State, Western Brazilian Amazon.
 The prevalence of systemic arterial hypertension (SAH) was 44.7%, 52.6% in female. Of the individuals with SAH, 77.5% did not use medication. About 51.5% of them had Grade I SAH. The prevalence of type 2 diabetes mellitus was 16.4%, where no patient used medication and about 40.4% of the studied population fits in the glucose intolerance range. Metabolic syndrome presented a prevalence of 24.0%, with a higher frequency in females (33.8%) (p=0.007). Concerning chronic kidney disease, a prevalence of 12.1% was observed in both genders. The associated factors found were alcoholism, smoking, sedentary lifestyle and obesity, and more than 45% of the patients had at least two associated factors.
 The population had a high prevalence of CND and associated factors, low frequency of medication use, revealing inefficiency of the local health system. Increased coverage of the Governmental Family Health Strategy (GFHS) and the increase in number of trained Community Health Assistants , together with health education actions can increase the population’s health standard.

MOLECULAR DETECTION AND SEROPREVALENCE OF Ehrlichia sp. IN DAIRY CATTLE FROM BRAZIL’S WESTERN AMAZON REGION

Ehrlichia minasensis, a novel species of Ehrlichia that is closely related to E. canis, is known to infect cattle and deer in Canada. This rickettsial bacterium was isolated from Rhipicephalus (Boophilus) microplus ticks and from dairy and beef cattle in southeast and midwestern Brazil, respectively. The purpose of this study was to determine the seroprevalence and perform molecular detection of Ehrlichia sp. in dairy cattle in the northern region of Brazil. The study was conducted in the municipality of Ji-Paraná, located in the state of Rondônia in the western Brazilian Amazon region. Blood and serum samples were obtained between the dates September 2012 and November 2013 from dairy cows (≥ 24 months old) in 64 farms. The blood samples were subjected to polymerase chain reaction (PCR) to amplify a fragment of the Ehrlichia sp. dsb gene, and the levels of Ehrlichia sp. antibodies were measured by the immunofluorescence assay (IFA). A total of 15 of 610 (2.45%; 95% CI: 1.04-3.86%) blood samples tested positive for ehrlichial infection based on the detection of the Ehrlichia sp. dsb gene. Sequencing of PCR amplicons from samples confirmed that the amplified partial dsb gene (~295 base pairs) sequence represented E. minasensis. Anti-Ehrlichia sp. antibodies were detected in 178 cows (53.96%; 95% CI: 46.63–61.29%). Endpoint titers ranged from 40 to 5,120. However, positive results derived from this assay should be interpreted with caution. Among the variables analyzed using IFA, the number of cows aged 24 months or greater was statistically significant (p = 0.0103), and hers of approximately 51-100 cows were more likely to be infected with Ehrlichia sp. Although the animals do not show clinical disease, the chronic character of the infection can lead to decrease in productivity.

First report of Amblyomma latepunctatum and the second record of Ixodes luciae in the state of Acre, Brazil.

The state of Acre is in the western part of the Brazilian Amazon region and few studies involving ticks are available. The aim of the present study was to provide the first report of occurrence of Amblyomma latepunctatum and the second record of Ixodes luciae in Acre. Ticks were collected in October 2020 inside an open forested area in the municipality of Rio Branco, the state capital of Acre. Ixodid ticks were identified according to their external morphological characteristics. Three specimens were found on the vegetation by means of a visual search and were identified as Amblyomma scalpturatum (one male and one female) and Amblyomma latepunctatum (one male). Another specimen was found parasitizing a Didelphis marsupialis female that was caught using a Tomahawk trap; this was identified as Ixodes luciae (one male). This first report of A. latepunctatum in the state of Acre increases the number of species recorded here to 22. In addition, presence of I. luciae is confirmed in this state (second record), in the western Brazilian Amazon region.

Recurrence of Falciparum Malaria under Coartem Treatment in the City of Mâncio Lima, Acre, Brazil: A Retrospective Study

Background: Malaria remains a health problem in the Amazon and since 2005 the state of Acre has high incidence of malaria. Treatment with Coartem® for cases of falciparum malaria was introduced in Acre in August 2012. In Brazil, there is still no published study on the effectiveness of Coartem in endemic areas.
 Methods: This study was conducted in Mâncio Lima, Acre, in the western Brazilian Amazon region. All malaria cases notified in Mâncio Lima between August 01st, 2012 and October 31st, 2013 were revised. The therapeutic response to Coartem in Mâncio Lima, Acre, was evaluated. A recurrence of falciparum malaria was defined as a malaria case occurring in the same patient in a maximum interval of 40 days between the day treatments was started and the day the next diagnosis was made.
 Results: All malaria cases (7,171) notified between August 2012 and July 2013 were revised. About 23.72% (n = 1,701) were falciparum malaria. There were six cases of recurrent falciparum malaria that can be classified as treatment failure. All cases had low parasitemia. The minimum and maximum interval between the first and the recurrent malaria episode was 17 days and 33 days. Age range was 9 to 50 years. Two patients were from rural areas, while all others were from riverine areas.
 Conclusion: Possible failure to Coartem treatment was identified, however causes are not clear. Further studies are needed.

Climatic variables associated with dengue incidence in a city of the Western Brazilian Amazon region

This study aimed to examine the impact of climate variability on the incidence of dengue fever in the city of Rio Branco, Brazil. The association between the monthly incidence of dengue fever and climate variables such as precipitation, temperature, humidity, and the Acre River level was evaluated, using generalized autoregressive moving average models with negative binomial distribution. Multiple no-lag, 1-month lag, and 2-month lag models were tested. The no-lag model showed that the incidence of dengue fever was associated with the monthly averages of the Acre River level (incidence rate ratio [IRR]: 1.09; 95% confidence interval [CI]: 1.02-1.17), compensated temperature (IRR: 1.54; 95% CI: 1.22-1.95), and maximum temperature (IRR: 0.68; 95% CI: 0.58-0.81). The 1-month lag model showed that the incidence of dengue fever was predicted by the monthly averages of total precipitation (IRR: 1.21; 95% CI: 1.06-1.39), minimum temperature (IRR: 1.54; 95% CI: 1.24-1.91), compensated relative humidity (IRR: 0.90; 95% CI: 0.82-0.99), and maximum temperature (IRR: 0.76; 95% CI: 0.59-0.97). The 2-month lag model showed that the incidence of dengue fever was predicted by the number of days with precipitation (IRR: 1.03; 95% CI: 1.00-1.06) and maximum temperature (IRR: 1.23; 95% CI: 1.05-1.44). Considering the impact of global climate change on the region, these findings can help to predict trends in dengue fever incidence.

Toxoplasma gondii, Neospora caninum and Leishmania amazonensis antibodies in domestic dogs in the western Brazilian Amazon region

Amostras de sangue de 99 cães domiciliados foram coletadas no meio urbano (n = 33) e rural (n = 66) do município de Lábrea, estado do Amazonas, Brasil. Dentre as amostras rurais, 40 foram obtidas em comunidades ribeirinhas e 26 em comunidades indígenas, ambas ao longo do rio Purus. Durante a amostragem foi aplicado um questionário com informações sobre sexo, idade, viver em áreas secas ou alagadiças, acesso ou não às ruas (cães urbanos) e acesso à floresta. A presença de anticorpos contra Toxoplasma gondii, Neospora caninum, Leishmania infantum chagasi e Leishmania amazonensis foi detectada pela reação de imunofluorescência indireta (RIFI) com ponto de corte de, respectivamente, 16, 50, 40 e 40. Associação entre as variáveis qualitativas e a positividade para cada um dos parasitos foi avaliada pelo teste do χ2 (p < 0,05). A ocorrência de animais com anticorpos contra T. gondii, N. caninum e L. amazonensis foi de, respectivamente, 61,6%; 7,1% e 8,1%. Nenhuma amostra foi positiva para L. infantum chagasi. A variável viver em área urbana (p=0,041) apresentou associação com ocorrência de T. gondii e o número de cães positivos a T. gondii aumentou com a idade (p = 0,0006). A variável sexo (machos) apresentou associação com N. caninum (p = 0,018) e nenhuma variável apresentou associação com L. amazonensis. Os títulos de anticorpos contra T. gondii variaram de 64 a 32.768; contra N. caninum de 100 a 800 e contra L. amazonensis de 40 a 640. T. gondii e L. amazonensis são dois agentes de importantes zoonoses e encontram-se ativos na região. O município estudado, especialmente as comunidades ribeirinhas, possuem peculiaridades geográficas, sociais e ecológicas distintas e necessitam maior atenção das autoridades para o controle desses agentes.

Unexplored Amazonian diversity: rare and phylogenetically enigmatic tree species are newly collected

The Amazon is renowned to hold an unprecedented, yet poorly­known or unexplored plant diversity. This study aimed to report new collections on five rare or little­known and phylogenetically enigmatic trees, Aguiaria excelsa (Malvaceae, Bombacoideae), Hylocarpa heterocarpa (Humiriaceae), and the papilionoid legumes Monopteryx uaucu , Petaladenium urceoliferum , and Uleanthus erythrinoides , that became available after recent fieldwork in the western and central Brazilian Amazon region. All five genera, except for Monopteryx , are monospecific and represented in herbaria by only the type or at most few collections made more than 30 years ago. Comments on morphological affinities, never­seen­before photographs, and a distribution map of all species are given. A lectotype for U. erythrinoides is here designated. We also provide a complete taxonomic description for P. urceoliferum , whose pods until presently were unknown. Since these genera are missing branches in the molecular phylogenetic trees of Leguminosae, Humiriaceae, and Malvaceae, the opportunity to include them in future phylogenetic studies will certainly clarify the evolutionary history and taxonomy of their respective families.

Survey of Bancroftian filariasis infection in humans and Culex mosquitoes in the western Brazilian Amazon region: implications for transmission and control

The aim of this work was to identify possible lymphatic filariasis foci in the western Brazilian Amazonian that could be established from the reports of Rachou in the 1950s. The study was conducted in three cities of the western Brazilian Amazon region - Porto Velho and Guajará-Mirim (State of Rondônia) and Humaitá (State of Amazonas). For human infection evaluation thick blood smear stained with Giemsa was used to analyze samples collected from 10pm to 1am. Polymerase chain reaction (PCR) was used to examine mosquito vectors for the presence of Wuchereria bancrofti DNA. Humans were randomly sampled from night schools students and from inhabitants in neighborhoods lacking sanitation. Mosquitoes were collected from residences only. A total 2,709 night students enrolled in the Program for Education of Young Adults (EJA), and 935 people registered in the residences near the schools were examined, being 641 from Porto Velho, 214 from Guajará-Mirim and 80 from Humaitá. No individual examined was positive for the presence of microfilariae in the blood stream. A total of 7,860 female Culex quinquefasciatus specimens examined were negative by PCR. This survey including human and mosquito examinations indicates that the western Amazon region of Brazil is not a focus of Bancroftian filariasis infection or transmission. Therefore, there is no need to be included in the Brazilian lymphatic filariasis control program.

Enhanced understanding of infectious diseases by fusing multiple datasets: a case study on malaria in the Western Brazilian Amazon region.

BackgroundA common challenge to the study of several infectious diseases consists in combining limited cross-sectional survey data, collected with a more sensitive detection method, with a more extensive (but biased) syndromic sentinel surveillance data, collected with a less sensitive method. Our article describes a novel modeling framework that overcomes this challenge, resulting in enhanced understanding of malaria in the Western Brazilian Amazon.Methodology/Principal FindingsA cohort of 486 individuals was monitored using four cross-sectional surveys, where all participants were sampled regardless of symptoms (aggressive-active case detection), resulting in 1,383 microscopy and 1,400 polymerase chain reaction tests. Data on the same individuals were also obtained from the local surveillance facility (i.e., passive and active case detection), totaling 1,694 microscopy tests. Our model accommodates these multiple pathogen and case detection methods. This model is shown to outperform logistic regression in terms of interpretability of its parameters, ability to recover the true parameter values, and predictive performance. We reveal that the main infection determinant was the extent of forest, particularly during the rainy season and in close proximity to water bodies, and participation on forest activities. We find that time residing in Acrelandia (as a proxy for past malaria exposure) decreases infection risk but surprisingly increases the likelihood of reporting symptoms once infected, possibly because non-naïve settlers are only susceptible to more virulent Plasmodium strains. We suggest that the search for asymptomatic carriers should focus on those at greater risk of being infected but lower risk of reporting symptoms once infected.Conclusions/SignificanceThe modeling framework presented here combines cross-sectional survey data and syndromic sentinel surveillance data to shed light on several aspects of malaria that are critical for public health policy. This framework can be adapted to enhance inference on infectious diseases whenever asymptomatic carriers are important and multiple datasets are available.

Description of Adults and Nymph, and Redescription of the Larva, of Ornithodoros marinkellei (Acari: Argasidae), with Data on Its Phylogenetic Position

The argasid tick Ornithodoros marinkellei Kohls, Clifford, and Jones, 1969 was described 4 decades ago based on larval specimens collected from bats (Pteronotus spp.) in Colombia and Panama. Thereafter, larval O. marinkellei parasitizing bats were reported from Venezuela, Guyana, and Brazil. Herein, we describe the adults and nymph, and redescribe the larva of O. marinkellei based on specimens recently collected in the western Brazilian Amazon region. In contrast to all other known adult argasids, the idiosoma of both males and females of O. marinkellei is covered with sclerotized plaques. The idiosoma of the nymph of O. marinkellei is entirely micromamillated, and differs from the adults by the absence of plaques. The larva of O. marinkellei is morphologically similar to the larvae of the 2 other species belonging to the subgenus Subparmatus , i.e., Ornithodoros viguerasi Cooley and Kohls, 1941 and Ornithodoros mormoops Kohls, Clifford, and Jones, 1969 . Because of the long and narrow dorsal plate, the larva of O. marinkellei is readily distinguished from O. viguerasi and O. mormoops. Comparison of our larvae from Brazil with O. marinkellei paratype specimens from Colombia confirmed their taxonomic identification. However, a few morphological differences, particularly in the size of the gnathosoma, were observed. Further studies are necessary to clarify whether O. marinkellei is a complex of different species, or a single species represented by morphologically polymorphic, and geographically distinct populations. Partial mitochondrial 16S rDNA gene sequences were generated for O. marinkellei specimens from Brazil, and compared with available homologous sequences in GenBank. Phylogenetic analyses revealed O. marinkellei to be distinct from the remaining argasid species available in GenBank, including other bat-associated tick species that are found in sympatry with O. marinkellei in the Neotropical region.

Prevalence of infection for HIV, HTLV, HBV and of syphilis and chlamydia in pregnant women in a tertiary health unit in the western Brazilian Amazon region

to estimate the prevalence infection of human immunodeficiency virus (HIV), human T-cell lymphotropic vírus (HTLV), hepatitis B virus (HBV), Chlamydia trachomatis (C. trachomatis) and syphilis in pregnant women, as well as risk factors associated with these infections, in Fundação de Medicina Tropical do Amazonas (FMTAM). a cross-sectional study was carried including 674 pregnant women consecutively attended of the spontaneous demand of FMTAM between March and September 2008. Demographic, epidemiologic, socioeconomic, clinical and obstetric information have been collected through specific questionnaires. Patients had blood sample collected by peripheral venous for accomplishment of serological tests of HIV, HTLV, HBV and syphilis. Cervical secretion sample has been collected for C. trachomatis antigens detection test. The Odds Ratio has been used to evaluate risk factors associated to infections. Statistical analysis has been done with the t-Student, chi2 and Fisher's exact tests. the average age was 23.9 years old (SD 6.3). The observed prevalence was 0.6% to infection by HIV; 0.7% by HBsAg; 1.0% of syphilis and 2.7% by C. trachomatis. All the samples went negatives to HTLV. There were no variables associated with infection by HIV, HBV and syphilis. Significative statistically association was observed between pregnant woman with age under 20 years and of first pregnancy with C. trachomatis infection. the study evidenced that the prevalence infection by HIV in pregnant women assisted in FMTAM is similar to the values described in the Brazilian literature, while the prevalence by HTLV, HBV, syphilis and C. trachomatis in the studied population are below found by other authors. The main risk factor for the infection by C. trachomatis was being under 20 years old.

Hepatitis B virus and hepatitis delta virus genotypes in outbreaks of fulminant hepatitis (Labrea black fever) in the western Brazilian Amazon region

The genotypes of hepatitis B (HBV) and delta (HDV) viruses circulating among fulminant hepatitis cases from the western Amazon Basin of Brazil were characterized in this study. HBV and HDV isolates were obtained from liver samples from 14 patients who developed fulminant hepatitis and died during 1978-1989. HBV DNA and HDV RNA were detected in all samples. Phylogenetic analyses of HDV sequences showed that they all clustered with previously characterized sequences of HDV genotype 3 (HDV-3). HBV genotypes F, A and D were found in 50.0, 28.6 and 21.4 % of cases, respectively. These results confirm the predominance of HDV-3 in South America and its association with the severe form of hepatitis, and the finding of the co-infection of HDV-3 with different genotypes of HBV suggests that the association between HDV-3 and HBV-F is not necessarily causally related to a more severe clinical course of infection.

Prevalence of hepatitis A virus infection: the paradoxical example of isolated communities in the western Brazilian Amazon region

This study evaluated the prevalence of hepatitis A virus infection in the rural area of Lábrea, in the western Brazilian Amazon region. Communities and households were selected randomly. Serum samples were analyzed by means of the immunoenzymatic method for the presence of total antibodies against HAV. The study included 1,499 individuals. The prevalence of anti-HAV was 74.6% (95% CI 72.3-76.8). Univariate analysis showed associations with age (chi-square for linear trend = 496.003, p < 0.001), presence of outside toilet (p < 0.001), history of hepatitis (p < 0.001) and family history of hepatitis (p = 0.05). After adjusting for age, HAV infection also showed an association with the number of people in the family (p = 0.03). The overall prevalence rates were high, but not more than 60% of the children under the age of ten years had already been infected. Very high prevalence was detected only within older cohorts, thus paradoxically defining this as a region with intermediate endemicity, even under the conditions of poverty encountered.

HTLV‐1 infection in blood donors from the Western Brazilian Amazon region: Seroprevalence and molecular study of viral isolates

To determine the seroprevalence of HTLV-1 in Brazil, and to review the virus molecular epidemiology in this Amazon population (Rio Branco-Acre), 219 blood donors were screened for HTLV-1. Only one case of infection (0.46% seroprevalence) was detected during July 2004 screening at the Acre Hospital Foundation (FUNDACRE). Neighbor-joining and Maximum Likelihood phylogenetic analyses of two (n = 2) complete LTR region sequences were performed with the PAUP* software. Since the HTLV-1 envelope surface (gp46) and transmembrane (gp21) glycoproteins are important for virus fitness, three envelope glycoproteins sequences (n = 3) were analyzed using the Prosite tool to determinate potential protein sites. Phylogenetic analysis demonstrated that the new isolate described in this study, and the unpublished LTR strain described in a previous report belong to the Transcontinental subgroup of the Cosmopolitan subtype, inside the Latin American cluster. A similar result was obtained when submitting, to the Automated Genotyping System, three LTR partial sequences from a previous study of the seroprevalence of HTLV-1 in the same Amazon population. In all analyzed env sequences, the potential protein site was found: two PKC phosphorylation sites at amino acid (aa) positions 310-312 and 342-344, one CK2 phosphorylation site at 194-197aa, three N-glycosylation sites at 222-225aa, 244-247aa and 272-275aa, and a single N-myristylation site at 327-338aa. In conclusion, potential protein sites described in HTLV-1 gp46 and gp21 confirm the presence of conserved sites in the HTLV-1 envelope proteins, likewise phylogenetic analysis suggests a possible recent introduction of the virus into North Brazil.

Soroprevalência de tripanossomíase americana em adultos de uma área da Amazônia ocidental Brasileira

From January to March 2001 a seroepidemiological survey for American trypanosomiasis (Chagas disease) was carried out among urban and rural human populations in areas of the Upper Purus basin, in the western Brazilian Amazon region, using serial testing with three different serological techniques. The sample was composed of 1,055 individuals: 844 from urban and 211 from rural areas. Autochthonous infection was identified in nine individuals aged 16 to 72 years: five from urban and four from rural areas. The estimated prevalences of Chagas infection for the urban and rural areas were 0.6% (95% CI: 0.2-1.4) and 1.9% (95% CI: 0.6-4.5) respectively. An apparent clustering trend was noted: seven were born along the Purus river: three lived at the same locality and two of them in the same dwelling.

INFECTION WITH HEPATITIS C VIRUS AMONG HEALTH CARE WORKERS IN THE BRAZILIAN WESTERN AMAZON REGION (RIO BRANCO, STATE OF ACRE)

Clinical and epidemiologic studies on the hepatitis C virus (HCV) in the western Brazilian Amazon region are scarce. However, reports of clinical cases of hepatitis or pathologies associated to the HCV infection are frequent. In the state of Acre, there have been no studies on the population with the greatest exposure to parenteral transmission of virus infection. The objective of this study was to determine the prevalence of HCV infection among health care workers (HCWs) in this region. Of 2,338 HCWs, 646 were randomly selected for this study. The presence of antibody to HCV was determined. If these persons were antibody positive, they were tested for HCV RNA and the viral genotype was determined. The seroprevalence of antibody to HCV was 4.8% (31 of 646), and 3.7% (24 of 646) of those tested had detectable HCV RNA. Among these 24 viremic cases, HCV genotype 1 was most common (n = 16), followed by genotypes 3 (n = 6), 2 (n = 1), and an unidentified genotype. Infection with HCV (identified by a polymerase chain reaction) was more frequent among those with lower educational levels and lower incomes, those who lived for a longer period in the city of Rio Branco, those who reported intravenous use of vitamin complexes, those with a history of dental treatment, those with alcoholism, and women with history of caesarian parturition. The high prevalence of patients with HCV observed among HCWs in the city of Rio Branco and risk factors indicate the need for prevention and control programs, in addition to assistance programs, because this region is also hyperendemic for hepatitis B virus and hepatitis D virus.

Human Hantavirus Infection, Brazilian Amazon

Human Hantavirus Infection, Brazilian Amazon

Intrafamilial prevalence of hepatitis B virus in Western Brazilian Amazon region: Epidemiologic and biomolecular study

Hepatitis B is endemic in the Amazon region. Serological markers for hepatitis B virus (HBV) were determined in 266 household members for hepatitis B surface antigen (HBsAg)-positive women (G1) and 395 household members for HBsAg-negative women (G2), randomly selected in Acre State Women's Medical Care Program, in order to evaluate the prevalence of HBV in this population. Before blood sample collection an epidemiological questionnaire was applied. The overall prevalence of HBV carriers (HBsAg) and exposed individuals (anti-HBc, IgG) was, respectively, 21.1% and 60.5% in G1 and 2.8% and 27.4% in G2 (P < 0.0000001). The frequency of HBsAg was higher among siblings from group G1 (75%) compared to the absence of any HBsAg-positive sibling in G2 (P < 0.00006). The HBV markers in other family members was as follows: G1 parents, 27.3% vs 4.5% (P < 0.03), sexual partners, 21.1% vs 2.5% (P < 0.04), and offspring, 10.4% vs 1.5% (P < 0.04). A low prevalence of HBsAg and anti-HBc (IgG) was observed for the last offspring of G2 mothers compared to the high prevalence among children of G1 mothers (0% vs 18.2%, P < 0.01 and 2.3% vs 59.1%, P < 0.0000005, respectively), with children younger than 1 year being the most affected. The frequency of the habit of sharing toothbrushes and the presence of at least one HBsAg carrier were higher in G1 than in G2 (P < 0.0001 and P < 0.000002), respectively. Genotypes A, D and G were found to be predominant by Innolipa test. There were cases that reacted to more than one genotype. Intrafamilial transmission of HBV is evident in the present study and is possibly associated with the presence of more than one HBV carrier in the family and the shared use of toothbrushes among household contacts. Genotype analysis confirms intrafamilial transmission.