RESUMO
St. Louis encephalitis virus (SLEV) and West Nile virus (WNV) are arboviruses transmitted by Culex mosquitoes and amplified in avian hosts. The present study aimed to investigate the presence and seasonal circulation of SLEV and WNV in La Rioja province, within the semiarid ecoregion of the Monte, Argentina. Over a two-year period, avian sera were collected and tested for neutralizing antibodies against SLEV and WNV. Our results reveal the enzootic activity of both viruses in this challenging environment. SLEV seroprevalence was 4.5% (35/778), with higher activity in spring (2016) and autumn (2017). WNV seroprevalence was 3.5% (27/778), peaking during the summer 2016-2017. Greater seroprevalence for SLEV in 2016 was detected for the Lark-like Brushrunner (Coryphistera alaudina) and the Short-billed Canastero (Asthenes baeri) and in 2017 for the Black-crested Finch (Lophospingus pusillus) and Lark-like Brushrunner, whereas for WNV greater seroprevalence in 2016 was detected for the Picui Ground Dove (Columbina picui) and in 2017 for the Lark-like Brushrunner and Band-tailed Seedeater (Catamenia analis). Additionally, five avian individuals experienced seroconversion during the sampling period, namely the Lark-like Brushrunner and White-fronted Woodpecker (Melanerpes cactorum) for SLEV, and the Lark-like Brushrunner, Greater Wagtail Tyrant (Stigmatura budytoides) and Many-colored Chaco Finch (Saltatricula multicolor) for WNV. The study highlights the persistence and circulation of these viruses in a semiarid ecosystem, raising questions about overwintering mechanisms and transmission dynamics. This research contributes to understanding arbovirus ecology in diverse environments. Further investigations are needed to assess the specific mechanisms facilitating virus persistence in the Monte ecoregion.
Assuntos
Encefalite de St. Louis , Tentilhões , Febre do Nilo Ocidental , Vírus do Nilo Ocidental , Animais , Argentina/epidemiologia , Columbidae , Ecossistema , Vírus da Encefalite de St. Louis , Encefalite de St. Louis/epidemiologia , Estudos Soroepidemiológicos , Febre do Nilo Ocidental/epidemiologia , Febre do Nilo Ocidental/veterináriaRESUMO
Arthropod-borne viruses (arboviruses) count among emerging infections, which represent a major challenge for transfusion safety worldwide. To assess the risk of arboviruses-transmission by transfusion (ATT), we performed a survey to evaluate the potential threat for transfusion safety. Samples were retrospectively and randomly collected from donors who donated during the peak of dengue incidence in Cordoba (years: 2016 and 2019-2022). A cost-efficient strategy for molecular screening was implemented with a nucleic acid test (NAT) configured with Flavivirus and Alphavirus-universal degenerated primers targeting conserved gene regions. Besides, we evaluated the neutralizing antibody (NAb) prevalence by plaque reduction neutralization test (PRNT). A total of 1438 samples were collected. Among the NAT-screened samples, one resulted positive for Flavivirus detection. Subsequent sequencing of the PCR product revealed Saint Louis Encephalitis Virus (SLEV) infection (GeneBank accession number OR236721). NAb prevalence was 2.95% for anti-Dengue, 9.94% anti-SLEV, 1.09% anti-West Nile Virus, and 0% anti-Chikungunya. One of the NAb-positive samples also resulted positive for IgM against SLEV but negative by ARN detection. This is the first haemovigilance study developed in Argentina that evaluates the potential risk of ATT and the first research to determine the prevalence of NAb against Flavivirus through PNRT to avoid possible cross-reactions between Ab against Flavivirus. Herein, the finding of one SLEV-viremic donor and the detection of anti-SLEV IgM in a different donor demonstrated a potential threat for transfusion safety and emphasized the need for increased vigilance and proactive measures to ensure the safety of blood supplies.
Assuntos
Arbovírus , Encefalite de St. Louis , Flavivirus , Humanos , Arbovírus/genética , Doadores de Sangue , Argentina/epidemiologia , Estudos Retrospectivos , Flavivirus/genética , Vírus da Encefalite de St. Louis/genética , Anticorpos Neutralizantes , Imunoglobulina MRESUMO
Saint Louis encephalitis virus (SLEV) infection is an arbovirosis associated with a broad spectrum of neurological complications. We present a case of a 55-year-old man hailing from Manaus, a city situated in the heart of the Amazon Rainforest, who exhibited symptoms of vertigo, tremors, urinary and fecal retention, compromised gait, and encephalopathy 3 weeks following SLEV infection. Neuroaxis MRI revealed diffuse, asymmetric, and poorly defined margins hyperintense lesions with peripheral and ring enhancement in subcortical white matter, as well as severe spinal cord involvement. Serology for SLEV was positive both on serum and cerebrospinal fluid. To the best of our knowledge, the present report is the first to show brain lesions along with myelitis as a post-infectious complication of SLEV infection.
Assuntos
Encefalite de St. Louis , Encefalomielite Aguda Disseminada , Masculino , Humanos , Pessoa de Meia-Idade , Vírus da Encefalite de St. Louis/fisiologia , Encefalomielite Aguda Disseminada/diagnóstico por imagem , Encefalomielite Aguda Disseminada/etiologia , Encefalite de St. Louis/complicações , Encefalite de St. Louis/diagnósticoRESUMO
St. Louis encephalitis virus (SLEV) is endemic in the Americas and its transmission networks involve Culex mosquitoes and avian species. In 2015, a human encephalitis outbreak took place in Arizona and California, indicating the re-emergence of this pathogen in the US. Viral strains isolated in that outbreak belong to genotype III SLEV previously detected only in South America. In this study, genotype III SLEV was detected in mosquitoes collected in Mar Chiquita Lagoon (Córdoba, Argentina), an overwintering site for numerous migratory bird species. The genotype III SLEV sequence detected in this site shares the closest known ancestor with those introduced in Arizona in 2015. Our results highlight the potential significance of wetlands as key sites for arbovirus maintenance and emergence.
Assuntos
Culicidae , Encefalite de St. Louis , Animais , Humanos , Estados Unidos , Vírus da Encefalite de St. Louis/genética , Encefalite de St. Louis/epidemiologia , Argentina/epidemiologia , Áreas Alagadas , Aves , GenótipoRESUMO
St. Louis encephalitis virus (SLEV) is a neglected mosquito-borne Flavivirus that may cause severe neurological disease in humans and other animals. There are no specific treatments against SLEV infection or disease approved for human use, and drug repurposing may represent an opportunity to accelerate the development of treatments against SLEV. Here we present a scalable, medium-throughput phenotypic cell culture-based screening assay on Vero CCL81 cells to identify bioactive compounds that could be repurposed against SLEV infection. We screened eighty compounds from the Medicines for Malaria Venture (MMV) COVID Box library to identify nine (11%) compounds that protected cell cultures from SLEV-induced cytopathic effects, with low- to mid-micromolar potencies. We validated six hit compounds using viral plaque-forming assays to find that the compounds ABT-239, Amiodarone, Fluphenazine, Posaconazole, Triparanol, and Vidofludimus presented varied levels of antiviral activity and selectivity depending on the mammalian cell type used for testing. Importantly, we identified and validated the antiviral activity of the anti-flavivirus nucleoside analog 7DMA against SLEV. Triparanol and Fluphenazine reduced infectious viral loads in both Vero CCL81 and HBEC-5i cell cultures and, similar to the other validated compounds, are likely to exert antiviral activity through a molecular target in the host.
Assuntos
Encefalite de St. Louis , Flavivirus , Malária , Triparanol , Animais , Humanos , Vírus da Encefalite de St. Louis , Encefalite de St. Louis/diagnóstico , Flufenazina , Antivirais/farmacologia , MamíferosRESUMO
Infections with arboviruses are reported worldwide. Saint Louis encephalitis (SLEV) and West Nile (WNV) viruses are closely related flaviviruses affecting humans and animals. SLEV has been sporadically detected in humans, and corresponding antibodies have been frequently detected in horses throughout Brazil. WNV was first reported in western Brazil over a decade ago, has been associated with neurological disorders in humans and equines and its prevalence is increasing nationwide. Herein, we investigated by molecular and serological methods the presence of SLEV and WNV in equines from Rio de Janeiro. A total of 435 serum samples were collected from healthy horses and tested for specific neutralizing antibodies by plaque reduction neutralization test (PRNT90). Additionally, samples (serum, cerebrospinal fluid, central nervous system tissue) from 72 horses, including horses with neurological disorders resulting in a fatal outcome or horses which had contact with them, were tested by real-time reverse transcription-polymerase chain reaction (RT-qPCR) for both viruses. Adopting the criterion of four-fold antibody titer difference, 165 horses (38%) presented neutralizing antibodies for flaviviruses, 89 (20.4%) for SLEV and five (1.1%) for WNV. No evidence of SLEV and WNV infection was detected by RT-qPCR and, thus, such infection could not be confirmed in the additional samples. Our findings indicate horses of Rio de Janeiro were exposed to SLEV and WNV, contributing to the current knowledge on the distribution of these viruses in Brazil.
Assuntos
Encefalite de St. Louis , Flavivirus , Doenças dos Cavalos , Febre do Nilo Ocidental , Vírus do Nilo Ocidental , Animais , Humanos , Cavalos , Vírus do Nilo Ocidental/genética , Encefalite de St. Louis/epidemiologia , Encefalite de St. Louis/veterinária , Brasil/epidemiologia , Anticorpos Antivirais , Febre do Nilo Ocidental/epidemiologia , Febre do Nilo Ocidental/veterinária , Anticorpos Neutralizantes , Doenças dos Cavalos/epidemiologiaRESUMO
In Argentina, the Pampa ecoregion has been almost completely transformed into agroecosystems. To evaluate the environmental (agricultural area, tree coverage, distance to the nearest water body and urban site) and biological (dove, cowbird, and sparrow abundance) effects on free-ranging bird exposure to St. Louis encephalitis virus (SLEV) and West Nile virus (WNV), we used generalized linear mixed models. For 1,019 birds sampled during 2017-2019, neutralizing antibodies were found against SLEV in samples from 60 (5.8%) birds and against WNV for 21 (2.1%). The best variable for explaining SLEV seroprevalence was agricultural area, which had a positive effect; however, for WNV, no model was conclusive. Our results suggest that agroecosystems in the La Pampa ecoregion increase the exposure of avian hosts to SLEV, thus potentially increasing virus activity.
Assuntos
Doenças das Aves , Encefalite de St. Louis , Febre do Nilo Ocidental , Vírus do Nilo Ocidental , Animais , Argentina/epidemiologia , Aves , Vírus da Encefalite de St. Louis , Encefalite de St. Louis/epidemiologia , Encefalite de St. Louis/veterinária , Estudos Soroepidemiológicos , Febre do Nilo Ocidental/epidemiologia , Febre do Nilo Ocidental/veterináriaRESUMO
We describe the circulation of Saint Louis encephalitis virus (SLEV) in two Brazilian States during outbreaks of Dengue and Zika viruses. We detected the virus in a patient from Araraquara, State of São Paulo, and in patients and in a mosquito pool of Culex quinquefasciatus from Sinop, State of Mato Grosso. Phylogenetic analysis grouped samples from this study within genotype V, which are closely related to other strains that previously circulated in other parts of the country. Genotype V seems to have established circulation in Brazil.
Assuntos
Culicidae/virologia , Vírus da Encefalite de St. Louis/genética , Encefalite de St. Louis/virologia , Genótipo , Adolescente , Animais , Brasil/epidemiologia , Criança , Pré-Escolar , Dengue/epidemiologia , Surtos de Doenças , Vírus da Encefalite de St. Louis/isolamento & purificação , Feminino , Humanos , Lactente , Masculino , Filogenia , Infecção por Zika virus/epidemiologiaRESUMO
Introducción: Constantin von Economo reportó en 1917 múltiples casos de manifestaciones neurológicas secundarias a la pandemia de la gripe española, clasificándolos en tres grandes grupos: forma somnolienta-oftalmopléjica, mutismo y la hipercinética, con secuelas similares a la enfermedad de Parkinson. Objetivo: presentar un caso de reciente aparición de patología rara en Cali, Colombia con manejo adecuado en unidad de cuidados intensivos (UCI). Presentación del caso: paciente de 9 años con disminución de la fuerza en extremidades, disartria y somnolencia, que inició deterioro neurológico progresivo requiriendo manejo en UCI. El equipo multidisciplinario diagnosticó encefalitis letárgica e iniciaron manejo con plasmaféresis e inmunosupresión con mejoría significativa. Discusión y conclusiones: como la prevalencia es escasa, el diagnóstico exige un alto índice de sospecha como la ocurrencia de un cuadro infeccioso previo al inicio de los síntomas, ya que se considera una reacción autoinmune cruzada contra antígenos de la sustancia nigra. En algunos casos hay alteraciones en los estudios imagenológicos o en citoquímico de líquido cefalorraquídeo. El manejo con pulsos de metilprednisolona y filtración de plasma con plasmaféresis brinda mejoría significativa con disminución de las secuelas a futuro.
Introduction: In 1917, Constantin von Economo reported multiple cases of neurological manifestations secondary to the Spanish flu pandemic. He classified them into three main clinical forms: somnolent-ophthalmoplegic, mutism and hyperkinetic, causing sequelae resembling Parkinson Ìs disease. Objective: to present a case of a recent appearance rare disease entity, in Cali Colombia, receiving appropriate management in the Intensive Care Unit (ICU). Case presentation: 9-year-old patient presenting with limb muscle weakness, dysarthria and somnolence, evidencing progressive neurological deterioration requiring admission to the ICU for management. A diagnosis of encephalitis lethargica (EL) was made by the attending multidisciplinary team and management with plasmapheresis and immunosuppression was started, obtaining significant improvement. Discussion and conclusions: as the prevalence is low, the diagnosis requires a high level of suspicion in cases presenting with infectious conditions prior to the development of symptoms, since it is considered an autoimmune cross-reaction against substantia nigra antigens. Alterations in brain imaging or in cerebrospinal fluid cytometry may be found in some cases. Management with methylprednisolone pulse therapy and filtration plasmapheresis provides significant improvement with a decrease in future sequelae.
Assuntos
Humanos , Feminino , Criança , Doença de Parkinson Pós-Encefalítica , Encefalite de St. Louis , Febre , Autoimunidade , Influenza HumanaRESUMO
We conducted serologic surveillance for flaviviruses and orthobunyaviruses in vertebrate animals in Mexico in 2018-2019. Sera were collected from 856 vertebrate animals, including 323 dogs, 223 horses, and 121 cows, from 16 species. The animals were from 3 states: Chihuahua in northwest Mexico (704 animals) and Guerrero and Michoacán on the Pacific Coast (27 and 125 animals, respectively). Sera were assayed by plaque reduction neutralization test using four flaviviruses (dengue type 2, St. Louis encephalitis, West Nile, and Zika viruses) and six orthobunyaviruses from the Bunyamwera (BUN) serogroup (Cache Valley, Lokern, Main Drain, Northway, Potosi, and Tensaw viruses). Antibodies to West Nile virus (WNV) were detected in 154 animals of 9 species, including 89 (39.9%) horses, 3 (21.4%) Indian peafowl, and 41 (12.7%) dogs. Antibodies to St. Louis encephalitis virus (SLEV) were detected in seven animals, including three (0.9%) dogs. Antibodies to Lokern virus (LOKV) were detected in 22 animals: 19 (8.5%) horses, 2 (1.7%) cows, and a dog (0.3%). Antibodies to Main Drain virus (MDV) were detected in three (1.3%) horses. WNV and LOKV activity was detected in all three states, SLEV activity was detected in Chihuahua and Michoacán, and MDV activity was detected in Chihuahua. None of the animals was seropositive for Cache Valley virus, the most common and widely distributed BUN serogroup virus in North America. In conclusion, we provide serologic evidence that select flaviviruses and BUN serogroup viruses infect vertebrate animals in Chihuahua, Guerrero, and Michoacán. We also provide the first evidence of LOKV and MDV activity in Mexico.