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1.
Viruses ; 15(2)2023 02 16.
Artículo en Inglés | MEDLINE | ID: mdl-36851765

RESUMEN

Non-human primates contribute to the spread of yellow fever virus (YFV) and the establishment of transmission cycles in endemic areas, such as Brazil. This study aims to investigate virological, histopathological and immunohistochemical findings in livers of squirrel monkeys (Saimiri spp.) infected with the YFV. Viremia occurred 1-30 days post infection (dpi) and the virus showed a predilection for the middle zone (Z2). The livers were jaundiced with subcapsular and hemorrhagic multifocal petechiae. Apoptosis, lytic and coagulative necrosis, steatosis and cellular edema were also observed. The immune response was characterized by the expression of S100, CD11b, CD57, CD4 and CD20; endothelial markers; stress and cell death; pro and anti-inflammatory cytokines, as well as Treg (IL-35) and IL-17 throughout the experimental period. Lesions during the severe phase of the disease were associated with excessive production of apoptotic pro-inflammatory cytokines, such as IFN-γ and TNF-α, released by inflammatory response cells (CD4+ and CD8+ T lymphocytes) and associated with high expression of molecules of adhesion in the inflammatory foci observed in Z2. Immunostaining of the local endothelium in vascular cells and the bile duct was intense, suggesting a fundamental role in liver damage and in the pathogenesis of the disease.


Asunto(s)
Fiebre Amarilla , Animales , Saimiri , Virus de la Fiebre Amarilla , Hígado , Citocinas
2.
Viruses ; 14(11)2022 10 28.
Artículo en Inglés | MEDLINE | ID: mdl-36366489

RESUMEN

Understanding the interaction between viruses and ecosystems in areas with or without anthropic interference can contribute to the organization of public health services, as well as prevention and disease control. An arbovirus survey was conducted at Caxiuanã National Forest, Pará, Brazil, where 632 local residents, 338 vertebrates and 15,774 pools of hematophagous arthropods were investigated. Neutralization antibodies of the Venezuelan Equine Encephalitis virus, subtype IIIA, Mucambo virus (MUCV) were detected in 57.3% and 61.5% of humans and wild vertebrates, respectively; in addition, genomic fragments of MUCV were detected in pool of Uranotaenia (Ura.) geometrica. The obtained data suggest an enzootic circulation of MUCV in the area. Understanding the circulation of endemic and neglected arboviruses, such as MUCV, represents an important health problem for the local residents and for the people living in the nearby urban centers.


Asunto(s)
Alphavirus , Arbovirus , Culicidae , Virus de la Encefalitis Equina Venezolana , Animales , Humanos , Virus de la Encefalitis Equina Venezolana/genética , Brasil/epidemiología , Ecosistema , Vertebrados
3.
J Gen Virol ; 98(7): 1749-1754, 2017 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-28699858

RESUMEN

Chikungunya (CHIKV) and Zika (ZIKV) viruses are arboviruses which have recently broken their sylvatic isolation and gone on to spread rampantly among humans in some urban areas of the world, especially in Latin America. Given the lack of effective interventions against such viruses, the aim of this work was to evaluate the antiviral potential of bovine lactoferrin (bLf) in their infections. Through viability, plaque, immunofluorescence and nucleic acid quantification assays, our data show that bLf exerts a dose-dependent strong inhibitory effect on the infection of Vero cells by the aforementioned arboviruses, reducing their infection efficiency by up to nearly 80 %, with no expressive cytotoxicity, and that such antiviral activity occurs at the levels of input and output of virus particles. These findings reveal that bLf antimicrobial properties are extendable to CHIKV and ZIKV, underlining a generic inhibition mechanism that can be explored to develop a potential strategy against their infections.


Asunto(s)
Antivirales/farmacología , Fiebre Chikungunya/virología , Virus Chikungunya/efectos de los fármacos , Lactoferrina/farmacología , Infección por el Virus Zika/virología , Virus Zika/efectos de los fármacos , Animales , Bovinos , Virus Chikungunya/genética , Virus Chikungunya/fisiología , Chlorocebus aethiops , Humanos , Células Vero , Virus Zika/fisiología
4.
Mem. Inst. Oswaldo Cruz ; 107(8): 1021-1029, Dec. 2012. ilus
Artículo en Inglés | LILACS | ID: lil-660650

RESUMEN

Because an enriched environment (EE) enhances T-cell activity and T-lymphocytes contribute to immunopathogenesis during heterologous dengue virus (DENV) infections, we hypothesised that an EE increases dengue severity. To compare single serotype (SS) and antibody-enhanced disease (AED) infections regimens, serial intraperitoneal were performed with DENV3 (genotype III) infected brain homogenate or anti-DENV2 hyperimmune serum followed 24 h later by DENV3 (genotype III) infected brain homogenate. Compared AED for which significant differences were detected between the EE and impoverished environmental (IE) groups (Kaplan-Meyer log-rank test, p = 0.0025), no significant differences were detected between the SS experimental groups (Kaplan-Meyer log-rank test, p = 0.089). Survival curves from EE and IE animals infected with the AED regimen were extended after corticoid injection and this effect was greater in the EE than in the IE group (Kaplan-Meyer log-rank test, p = 0.0162). Under the AED regimen the EE group showed more intense clinical signs than the IE group. Dyspnoea, tremor, hunched posture, ruffled fur, immobility, pre-terminal paralysis, shock and death were associated with dominant T-lymphocytic hyperplasia and presence of viral antigens in the liver and lungs. We propose that the increased expansion of these memory T-cells and serotype cross-reactive antibodies facilitates the infection of these cells by DENV and that these events correlate with disease severity in an EE.


Asunto(s)
Animales , Femenino , Ratones , Anticuerpos Antivirales/inmunología , Acrecentamiento Dependiente de Anticuerpo/inmunología , Virus del Dengue/inmunología , Dengue/inmunología , Linfocitos B/inmunología , Dengue/virología , Ecología , Activación de Linfocitos/inmunología , Linfocitos T/inmunología
5.
Mem Inst Oswaldo Cruz ; 107(8): 1021-9, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23295753

RESUMEN

Because an enriched environment (EE) enhances T-cell activity and T-lymphocytes contribute to immunopathogenesis during heterologous dengue virus (DENV) infections, we hypothesised that an EE increases dengue severity. To compare single serotype (SS) and antibody-enhanced disease (AED) infections regimens, serial intraperitoneal were performed with DENV3 (genotype III) infected brain homogenate or anti-DENV2 hyperimmune serum followed 24 h later by DENV3 (genotype III) infected brain homogenate. Compared AED for which significant differences were detected between the EE and impoverished environmental (IE) groups (Kaplan-Meyer log-rank test, p = 0.0025), no significant differences were detected between the SS experimental groups (Kaplan-Meyer log-rank test, p = 0.089). Survival curves from EE and IE animals infected with the AED regimen were extended after corticoid injection and this effect was greater in the EE than in the IE group (Kaplan-Meyer log-rank test, p = 0.0162). Under the AED regimen the EE group showed more intense clinical signs than the IE group. Dyspnoea, tremor, hunched posture, ruffled fur, immobility, pre-terminal paralysis, shock and death were associated with dominant T-lymphocytic hyperplasia and presence of viral antigens in the liver and lungs. We propose that the increased expansion of these memory T-cells and serotype cross-reactive antibodies facilitates the infection of these cells by DENV and that these events correlate with disease severity in an EE.


Asunto(s)
Anticuerpos Antivirales/inmunología , Acrecentamiento Dependiente de Anticuerpo/inmunología , Virus del Dengue/inmunología , Dengue/inmunología , Animales , Linfocitos B/inmunología , Dengue/virología , Ecología , Femenino , Activación de Linfocitos/inmunología , Ratones , Linfocitos T/inmunología
6.
Emerg Infect Dis ; 17(5): 800-6, 2011 May.
Artículo en Inglés | MEDLINE | ID: mdl-21529387

RESUMEN

Oropouche virus (OROV) is the causative agent of Oropouche fever, an urban febrile arboviral disease widespread in South America, with >30 epidemics reported in Brazil and other Latin American countries during 1960-2009. To describe the molecular epidemiology of OROV, we analyzed the entire N gene sequences (small RNA) of 66 strains and 35 partial Gn (medium RNA) and large RNA gene sequences. Distinct patterns of OROV strain clustered according to N, Gn, and large gene sequences, which suggests that each RNA segment had a different evolutionary history and that the classification in genotypes must consider the genetic information for all genetic segments. Finally, time-scale analysis based on the N gene showed that OROV emerged in Brazil ≈223 years ago and that genotype I (based on N gene data) was responsible for the emergence of all other genotypes and for virus dispersal.


Asunto(s)
Infecciones por Bunyaviridae/epidemiología , Infecciones por Bunyaviridae/virología , Epidemiología Molecular , Orthobunyavirus/genética , Animales , Brasil/epidemiología , Chlorocebus aethiops , Evolución Molecular , Genes Virales/genética , Variación Genética/genética , Genotipo , Humanos , Datos de Secuencia Molecular , Orthobunyavirus/clasificación , Filogenia , ARN Viral/genética , Células Vero
7.
J Virol Methods ; 174(1-2): 29-34, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21419803

RESUMEN

Yellow fever virus (YFV), a member of the family Flaviviridae, genus Flavivirus is endemic to tropical areas of Africa and South America and is among the arboviruses that pose a threat to public health. Recent outbreaks in Brazil, Bolivia, and Paraguay and the observation that vectors capable of transmitting YFV are presenting in urban areas underscore the urgency of improving surveillance and diagnostic methods. Two novel methods (RT-hemi-nested-PCR and SYBR(®) Green qRT-PCR) for efficient detection of YFV strains circulating in South America have been developed. The methods were validated using samples obtained from golden hamsters infected experimentally with wild-type YFV strains as well as human serum and tissue samples with acute disease.


Asunto(s)
Técnicas de Diagnóstico Molecular/métodos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Virología/métodos , Fiebre Amarilla/diagnóstico , Virus de la Fiebre Amarilla/aislamiento & purificación , Animales , Cricetinae , Humanos , Mesocricetus , Suero/virología , América del Sur , Fiebre Amarilla/virología , Virus de la Fiebre Amarilla/genética
8.
J Virol Methods ; 171(1): 13-20, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-20946918

RESUMEN

Various assays have been developed to diagnose dengue virus infection, relying on techniques from the fields of serology and molecular biology. Many of these assays have been successful, but there is still an urgent need for accurate, simple and rapid diagnostic assays to diagnose dengue virus infection and to assist in patient management. Using a panel of well-characterized sera and a collection of retrospective samples obtained during the dengue epidemics that occurred in Belém, Brazil, between 2002 and 2009, a modified immunoglobulin M-specific capture enzyme-linked immunosorbent assay (Rapid-MAC-ELISA) was evaluated and compared with the "gold standard" MAC-ELISA, in order to assess the specificity, sensitivity, stability, reproducibility and cost-effectiveness of this new assay. These results demonstrated that the Rapid-MAC-ELISA is comparable to the MAC-ELISA in terms of sensitivity and specificity and is highly reproducible; additionally, it is easily performed, less expensive than other available formats and can be completed within three hours. Furthermore, the Rapid-MAC-ELISA can be used for the diagnosis of dengue virus infections in resource-limited areas where dengue is endemic.


Asunto(s)
Anticuerpos Antivirales/sangre , Virus del Dengue/inmunología , Dengue/diagnóstico , Inmunoglobulina M/sangre , Virología/métodos , Brasil , Ensayo de Inmunoadsorción Enzimática/métodos , Humanos , Sensibilidad y Especificidad
9.
J Gen Virol ; 91(Pt 10): 2420-7, 2010 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-20592112

RESUMEN

Saint Louis encephalitis virus (SLEV), a member of the genus Flavivirus (family Flaviviridae), is an encephalitogenic arbovirus broadly distributed in the Americas. Phylogenetic analysis based on the full-length E gene sequences obtained for 30 Brazilian SLEV strains was performed using different methods including Bayesian and relaxed molecular clock approaches. A new genetic lineage was suggested, hereafter named genotype VIII, which co-circulates with the previously described genotype V in the Brazilian Amazon region. Genotypes II and III were restricted to São Paulo state (South-east Atlantic rainforest ecosystem). The analysis also suggested the emergence of an SLEV common ancestor between 1875 and 1973 (mean of 107 years ago), giving rise to two major genetic groups: genotype II, more prevalent in the North America, and a second group comprising the other genotypes (I and III-VIII), broadly dispersed throughout the Americas, suggesting that SLEV initially emerged in South America and spread to North America. In conclusion, the current study demonstrates the high genetic variability of SLEV and its geographical dispersion in Brazil and other New World countries.


Asunto(s)
Virus de la Encefalitis de San Luis/clasificación , Virus de la Encefalitis de San Luis/genética , Encefalitis de San Luis/epidemiología , Encefalitis de San Luis/veterinaria , Animales , Brasil/epidemiología , Análisis por Conglomerados , Virus de la Encefalitis de San Luis/aislamiento & purificación , Encefalitis de San Luis/virología , Evolución Molecular , Genotipo , Insectos/virología , Epidemiología Molecular , Datos de Secuencia Molecular , Filogenia , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Proteínas Virales/genética
10.
J Clin Virol ; 44(2): 129-33, 2009 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19117799

RESUMEN

BACKGROUND: Oropouche fever virus is an important arbovirus associated with febrile disease that re-emerged in 2006 in several municipalities of Pará State, Bragantina region, Amazon, Brazil, 26 years after the last epidemic. OBJECTIVE: To investigate an Oropouche fever outbreak in this region. STUDY DESIGN: A serologic survey and prospective study of acute febrile cases were performed in Magalhães Barata (urban and rural areas) and Maracanã (rural area) municipalities. Serology (IgM-ELISA and hemagglutination-inhibition [HI]), virus isolation, RT-PCR and real-time-PCR were used to confirm Oropouche virus (OROV) as responsible for the febrile outbreaks. RESULTS: Real-time-PCR showed high titers of OROV in acute-phase serum samples from febrile patients. From 113 of 119 acutely febrile patients with paired serum samples, OROV infections was confirmed by serologic conversion (n=76) or high titers (n=37) for both HI and IgM-ELISA. Patients had a febrile disease characterized by headache, chills, dizziness, photophobia, myalgia, nausea, and vomiting. Females and children under 15 years of age were most affected. Nucleotide sequencing of six OROV isolates identified that genotype II was associated with the human disease epidemic. CONCLUSIONS: Oropouche fever, which has re-emerged in the Bragantina region in eastern Amazon 26 years after the last epidemic, is caused by genotype II, a lineage previously found only in Peru and western Brazil.


Asunto(s)
Anticuerpos Antivirales/sangre , Infecciones por Bunyaviridae/epidemiología , Brotes de Enfermedades , Orthobunyavirus/genética , Orthobunyavirus/aislamiento & purificación , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Brasil/epidemiología , Niño , Preescolar , Ensayo de Inmunoadsorción Enzimática , Femenino , Genotipo , Pruebas de Inhibición de Hemaglutinación , Humanos , Inmunoglobulina G/sangre , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Estudios Prospectivos , ARN Viral/sangre , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Factores de Riesgo , Adulto Joven
11.
J Gen Virol ; 90(Pt 1): 223-33, 2009 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19088293

RESUMEN

Melao virus (MELV) strains BE AR8033 and BE AR633512 were isolated from pools of Ochlerotatus scapularis mosquitoes in Belém, Pará State (1955), and Alta Floresta, Rondônia State (2000), Brazil, respectively. The aim of the present study was to molecularly characterize these strains and to describe the histopathological, biochemical and immunological changes in golden hamsters (Mesocricetus auratus) following intraperitoneal injection of MELV strains. Hamsters were susceptible to both of the MELV strains studied. Viraemia was observed 3-6 days post-infection (p.i.) for BE AR633512 and only on the second day p.i. for BE AR8033. Neutralizing antibodies against both strains were detected in blood samples obtained at 5 days p.i. and persisted up to 30 days p.i. Aspartate aminotransferase, alanine aminotransferase and blood urea nitrogen were significantly altered in animals infected with the two MELV strains, while creatinine was only altered in animals inoculated with BE AR633512. Histopathological changes were observed in the central nervous system, liver, kidney and spleen of hamsters, and infection was confirmed by detection of specific MELV antigens by immunohistochemistry. Strain BE AR633512 caused more severe tissue damage than strain BE AR8033, showing increased neurovirulence and pathogenicity. Genetic analysis based on the full-length sequences of the glycoprotein (Gn and Gc) and nucleocapsid protein (N) genes revealed high levels of homology between the MELV strains. Interestingly, the greatest genetic divergence was found for the Gn gene of strain BE AR633512, in which several synonymous and non-synonymous mutations causing changes in RNA secondary structure were observed. Further studies will be necessary to investigate the role of Gn and Gc mutations in the MELV pathogenicity.


Asunto(s)
Infecciones por Bunyaviridae/patología , Infecciones por Bunyaviridae/fisiopatología , Mesocricetus/virología , Orthobunyavirus/genética , Orthobunyavirus/patogenicidad , Alanina Transaminasa/sangre , Animales , Anticuerpos Antivirales/sangre , Aspartato Aminotransferasas/sangre , Brasil , Infecciones por Bunyaviridae/inmunología , Infecciones por Bunyaviridae/virología , Sistema Nervioso Central/patología , Creatinina/sangre , Cricetinae , Riñón/patología , Hígado/patología , Modelos Moleculares , Pruebas de Neutralización , Conformación de Ácido Nucleico , Orthobunyavirus/inmunología , ARN Viral/genética , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Bazo/patología , Urea/sangre , Viremia
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