RESUMO
INTRODUCTION: The Amazon tropical rainforest has the most dense and diverse ecosystem worldwide. A few studies have addressed rodent-borne diseases as potential hazards to humans in this region. METHODS: A retrospective survey was conducted using enzyme-linked immunosorbent assay for detecting mammarenavirus and orthohantavirus antibodies in 206 samples collected from rural settlers of the Brazilian Western Amazonian region. RESULTS: Six (2.91%) individuals in the age group of 16 to 36 years were found to possess antibodies against mammarenavirus. CONCLUSION: Evidence of previous exposure to mammarenavirus in the rural population points to its silent circulation in this region.
Assuntos
Anticorpos Antivirais/sangue , Infecções por Arenaviridae/epidemiologia , Arenaviridae/imunologia , Reservatórios de Doenças/veterinária , Hepatite Viral Humana/epidemiologia , Orthohepadnavirus/imunologia , Roedores/virologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Arenaviridae/classificação , Infecções por Arenaviridae/diagnóstico , Infecções por Arenaviridae/transmissão , Brasil/epidemiologia , Criança , Pré-Escolar , Feminino , Hepatite Viral Humana/diagnóstico , Hepatite Viral Humana/transmissão , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Orthohepadnavirus/classificação , Estudos Retrospectivos , Roedores/classificação , População Rural , Fatores Socioeconômicos , Adulto JovemRESUMO
During the Brazilian slavery period, many African migrants were brought to the American continent. Historically, some of these migrants escaped from the Brazilian gold mines and farms to which they had been brought and settled in remote valleys and this was the main mode of resistance to the slavery system. These runaway-slave descendant communities are called quilombos, a group with distinct ethnic identity, specific behavioral habits, including geographic isolation and conservative practices. The objective of this study was to investigate the prevalence of rodent-borne viruses in two Afro-descendent communities from Mato Grosso do Sul State, Midwestern Brazil. A total of 319 individuals from rural and urban quilombola communities were enrolled. Twelve (3.76%) had anti-rodent-borne virus IgG antibodies. Seven (2.19%) were anti-mammarenavirus reactive and nine (2.82%) had anti-orthohantavirus antibodies. The literature includes limited data on the health status of quilombola communities, but all the studies emphasize the disparity of attention of local healthcare personnel to these communities compared to the general population. The findings of this study highlight the vulnerability and the precarious health conditions of quilombola groups, especially those living in rural areas and thus, point to the need of preventive measures to improve access to healthcare for this ethnic group.
Assuntos
Anticorpos Antivirais/sangue , Infecções por Arenaviridae/epidemiologia , Arenaviridae/imunologia , Infecções por Hantavirus/epidemiologia , Imunoglobulina G/sangue , Orthohantavírus/imunologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Infecções por Arenaviridae/diagnóstico , População Negra , Brasil/epidemiologia , Criança , Pré-Escolar , Feminino , Infecções por Hantavirus/diagnóstico , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Roedores/virologia , Estudos Soroepidemiológicos , Fatores Socioeconômicos , Adulto JovemRESUMO
While five arenaviruses cause human hemorrhagic fevers in the Western Hemisphere, only Junin virus (JUNV) has a vaccine. The GP1 subunit of their envelope glycoprotein binds transferrin receptor 1 (TfR1) using a surface that substantially varies in sequence among the viruses. As such, receptor-mimicking antibodies described to date are type-specific and lack the usual breadth associated with this mode of neutralization. Here we isolate, from the blood of a recipient of the live attenuated JUNV vaccine, two antibodies that cross-neutralize Machupo virus with varying efficiency. Structures of GP1-Fab complexes explain the basis for efficient cross-neutralization, which involves avoiding receptor mimicry and targeting a conserved epitope within the receptor-binding site (RBS). The viral RBS, despite its extensive sequence diversity, is therefore a target for cross-reactive antibodies with activity against New World arenaviruses of public health concern.
Assuntos
Anticorpos Neutralizantes/química , Anticorpos Antivirais/química , Arenavirus do Novo Mundo/imunologia , Febre Hemorrágica Americana/prevenção & controle , Fragmentos Fab das Imunoglobulinas/química , Vírus Junin/imunologia , Proteínas do Envelope Viral/química , Sequência de Aminoácidos , Anticorpos Neutralizantes/isolamento & purificação , Anticorpos Antivirais/isolamento & purificação , Antígenos CD/química , Antígenos CD/genética , Antígenos CD/imunologia , Antígenos Virais/química , Antígenos Virais/genética , Antígenos Virais/imunologia , Arenavirus do Novo Mundo/genética , Sítios de Ligação de Anticorpos , Reações Cruzadas , Epitopos/química , Epitopos/genética , Epitopos/imunologia , Células HEK293 , Febre Hemorrágica Americana/imunologia , Febre Hemorrágica Americana/virologia , Humanos , Soros Imunes/química , Fragmentos Fab das Imunoglobulinas/isolamento & purificação , Vírus Junin/genética , Modelos Moleculares , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Estrutura Terciária de Proteína , Subunidades Proteicas/química , Subunidades Proteicas/genética , Subunidades Proteicas/imunologia , Receptores da Transferrina/química , Receptores da Transferrina/genética , Receptores da Transferrina/imunologia , Receptores Virais/química , Receptores Virais/genética , Receptores Virais/imunologia , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Proteínas do Envelope Viral/genética , Proteínas do Envelope Viral/imunologia , Vacinas Virais/administração & dosagemRESUMO
Several medically important mosquito-borne flaviviruses have been detected in Argentina in recent years: Dengue (DENV), St. Louis encephalitis (SLEV), West Nile (WNV) and Yellow Fever (YFV) viruses. Evidence of Bussuquara virus (BSQV) and Ilheus virus (ILHV) activity were found, but they have not been associated with human disease. Non-human primates can act as important hosts in the natural cycle of flaviviruses and serological studies can lead to improved understanding of virus circulation dynamics and host susceptibility. From July-August 2010, we conducted serological and molecular surveys in free-ranging black howlers (Alouatta caraya) captured in northeastern Argentina. We used 90% plaque-reduction neutralization tests (PRNT90) to analyze 108 serum samples for antibodies to WNV, SLEV, YFV, DENV (serotypes 1and 3), ILHV, and BSQV. Virus genome detection was performed using generic reverse transcription (RT)-nested PCR to identify flaviviruses in 51 antibody-negative animals. Seventy animals had antibodies for one or more flaviviruses for a total antibody prevalence of 64.8% (70/108). Monotypic (13/70, 19%) and heterotypic (27/70, 39%) patterns were differentiated. Specific neutralizing antibodies against WNV, SLEV, DENV-1, DENV-3, ILHV, and BSQV were found. Unexpectedly, the highest flavivirus antibody prevalence detected was to WNV with 9 (8.33%) monotypic responses. All samples tested by (RT)-nested PCR were negative for viral genome. This is the first detection of WNV-specific antibodies in black howlers from Argentina and the first report in free-ranging non-human primates from Latin-American countries. Given that no animals had specific neutralizing antibodies to YFV, our results suggest that the study population remains susceptible to YFV. Monitoring of these agents should be strengthened to detect the establishment of sylvatic cycles of flaviviruses in America and evaluate risks to wildlife and human health.
Assuntos
Alouatta/virologia , Infecções por Flavivirus/veterinária , Flavivirus/isolamento & purificação , Doenças dos Macacos/virologia , Animais , Argentina , Culicidae/virologia , Vírus da Dengue/classificação , Vírus da Dengue/genética , Vírus da Dengue/isolamento & purificação , Vírus da Dengue/fisiologia , Feminino , Flavivirus/classificação , Flavivirus/genética , Flavivirus/fisiologia , Infecções por Flavivirus/virologia , Masculino , Vírus do Nilo Ocidental/classificação , Vírus do Nilo Ocidental/genética , Vírus do Nilo Ocidental/isolamento & purificação , Vírus do Nilo Ocidental/fisiologiaRESUMO
In the Western hemisphere, at least five mammarenaviruses cause human viral hemorrhagic fevers with high case fatality rates. Junín virus (JUNV) is the only hemorrhagic fever virus for which transfusion of survivor immune plasma that contains neutralizing antibodies ("passive immunity") is an established treatment. Here, we report the structure of the JUNV surface glycoprotein receptor-binding subunit (GP1) bound to a neutralizing monoclonal antibody. The antibody engages the GP1 site that binds transferrin receptor 1 (TfR1)-the host cell surface receptor for all New World hemorrhagic fever mammarenaviruses-and mimics an important receptor contact. We show that survivor immune plasma contains antibodies that bind the same epitope. We propose that viral receptor-binding site accessibility explains the success of passive immunity against JUNV and that this functionally conserved epitope is a potential target for therapeutics and vaccines to limit infection by all New World hemorrhagic fever mammarenaviruses.
Assuntos
Anticorpos Neutralizantes/química , Anticorpos Antivirais/química , Vírus Junin/química , Glicoproteínas de Membrana/química , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Sítios de Ligação , Cristalografia por Raios X , Humanos , Vírus Junin/imunologia , Glicoproteínas de Membrana/imunologia , Ligação Proteica , Conformação ProteicaRESUMO
Nhumirim virus (NHUV) is an insect-specific virus that phylogenetically affiliates with dual-host mosquito-borne flaviviruses. Previous in vitro co-infection experiments demonstrated prior or concurrent infection of Aedes albopictus C6/36 mosquito cells with NHUV resulted in a 10,000-fold reduction in viral production of West Nile virus (WNV). This interference between WNV and NHUV was observed herein in an additional Ae. albopictus mosquito cell line, C7-10. A WNV 2K peptide (V9M) mutant capable of superinfection with a pre-established WNV infection demonstrated a comparable level of interference from NHUV as the parental WNV strain in C6/36 and C7-10 cells. Culex quinquefasciatus and Culex pipiens mosquitoes intrathoracically inoculated with NHUV and WNV, or solely with WNV as a control, were allowed to extrinsically incubate the viruses up to nine and 14 days, respectively, and transmissibility and replication of WNV was determined. The proportion of Cx. quinquefasciatus mosquitoes capable of transmitting WNV was significantly lower for the WNV/NHUV group than the WNV control at seven and nine days post inoculation (dpi), while no differences were observed in the Cx. pipiens inoculation group. By dpi nine, a 40% reduction in transmissibility in mosquitoes from the dual inoculation group was observed compared to the WNV-only control. These data indicate the potential that infection of some Culex spp. vectors with NHUV could serve as a barrier for efficient transmissibility of flaviviruses associated with human disease.
Assuntos
Culex/virologia , Flaviviridae/crescimento & desenvolvimento , Insetos Vetores/virologia , Interferência Viral , Febre do Nilo Ocidental/prevenção & controle , Febre do Nilo Ocidental/transmissão , Animais , Linhagem Celular , Feminino , HumanosRESUMO
Abstract INTRODUCTION: The Amazon tropical rainforest has the most dense and diverse ecosystem worldwide. A few studies have addressed rodent-borne diseases as potential hazards to humans in this region. METHODS: A retrospective survey was conducted using enzyme-linked immunosorbent assay for detecting mammarenavirus and orthohantavirus antibodies in 206 samples collected from rural settlers of the Brazilian Western Amazonian region. RESULTS: Six (2.91%) individuals in the age group of 16 to 36 years were found to possess antibodies against mammarenavirus. CONCLUSION: Evidence of previous exposure to mammarenavirus in the rural population points to its silent circulation in this region.
Assuntos
Humanos , Animais , Masculino , Feminino , Lactente , Pré-Escolar , Criança , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Adulto Jovem , Arenaviridae/imunologia , Roedores/virologia , Reservatórios de Doenças/veterinária , Orthohepadnavirus/imunologia , Infecções por Arenaviridae/epidemiologia , Hepatite Viral Humana/epidemiologia , Anticorpos Antivirais/sangue , Arenaviridae/classificação , Roedores/classificação , População Rural , Fatores Socioeconômicos , Brasil/epidemiologia , Estudos Retrospectivos , Orthohepadnavirus/classificação , Infecções por Arenaviridae/diagnóstico , Infecções por Arenaviridae/transmissão , Hepatite Viral Humana/diagnóstico , Hepatite Viral Humana/transmissão , Pessoa de Meia-IdadeAssuntos
Anticorpos Antivirais/sangue , Infecções por Arenaviridae/epidemiologia , Adolescente , Adulto , Idoso , Infecções por Arenaviridae/diagnóstico , Infecções por Arenaviridae/imunologia , Brasil/epidemiologia , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Prevalência , Adulto JovemRESUMO
Andes virus (AND) is a hantavirus hosted by the sigmodontine rodent Oligoryzomys longicaudatus in southern Argentina, where it is responsible for most cases of hantavirus pulmonary syndrome (HPS). Our study provides data about the spatial variation in abundance of the rodent host of AND hantavirus. We report results of a longitudinal study performed in a locality of the Andean region of Chubut Province. From November 2003 (spring) to July 2006 (winter), O. longicaudatus was the most common species captured (63%) and it showed significant differences in abundance among habitats and seasons. Most antibody-positive rodents were O. longicaudatus (9.2%), followed by A. longipilis (3.6%) and A. olivaceus (1.5%). The highest number of antibody-positive animals was observed for males that belonged to the heaviest mass classes. Antibody-positive O. longicaudatus were more abundant in brush habitats. We found low richness of rodents and abundance of O. longicaudatus in areas affected by anthropogenic activity. The infection seems to be regionally persistent, but the risk to humans in a landscape would be localized. To develop accurate models for predicting HPS outbreaks, further research is needed to characterize rodent movement patterns across the landscape.