Development of monoclonal antibodies against oropouche virus and its applicability to immunohistochemical diagnosis.

Orthobunyavirus oropouche ense virus (OROV), the causative agent of Oropouche fever, is widely dispersed in Brazil and South America, causing sporadic outbreaks. Due to the similarity of initial clinical symptoms caused by OROV with other arboviruses found in overlapping geographical areas, differential diagnosis is challenging. As for most neglected tropical diseases, there is a shortage of reagents for diagnosing and studying OROV pathogenesis. We therefore developed and characterized mouse monoclonal antibodies and, one of them recognizes the OROV nucleocapsid in indirect immunofluorescent (IFA) and immunohistochemistry (IHC) assays. Considering that it is the first monoclonal antibody produced for detecting OROV infections, we believe that it will be useful not only for diagnostic purposes but also for performing serological surveys and epidemiological surveillance on the dispersion and prevalence of OROV in Brazil and South America.

Oropouche virus: A neglected global arboviral threat.

The Oropouche virus is an important arthropod-borne virus in the Peribunyaviridae family that can cause febrile illnesses, and it is widely distributed in tropical regions such as Central and South America. Since the virus was first identified, a large number of related cases are reported every year. No deaths have been reported to date, however, the virus can cause systemic infections, including the nervous and blood systems, leading to serious complications. The transmission of Oropouche virus occurs through both urban and sylvatic cycles, with the anthropophilic biting midge Culicoides paraensis serving as the primary vector in urban areas. Direct human-to-human transmission of Oropouche virus has not been observed. Oropouche virus consists of three segments, and the proteins encoded by the different segments enables the virus to replicate efficiently in the host and to resist the host's immune response. Phylogenetic analyses showed that Oropouche virus sequences are geographically distinct and have closer homologies with Iquitos virus and Perdoes virus, which belong to the family Peribunyaviridae. Despite the enormous threat it poses to public health, there are currently no licensed vaccines or specific antiviral treatments for the disease it causes. Recent studies have utilised imJatobal virusmunoinformatics approaches to develop epitope-based peptide vaccines, which have laid the groundwork for the clinical use of vaccines. The present review focuses on the structure, epidemiology, immunity and phylogeny of Oropouche virus, as well as the progress of vaccine development, thereby attracting wider attention and research, particularly with regard to potential vaccine programs.

Antiviral Activity and Molecular Dynamics Simulation of Hops Compounds against Oropouche Virus (Peribunyaviridae).

The Oropouche virus (OROV) is a member of the family Peribunyaviridae (order Bunyavirales) and the cause of a dengue-like febrile illness transmitted mainly by biting midges and mosquitoes. In this study, we aimed to explore acylphloroglucinols and xanthohumol from hops (Humulus lupulus L.) as a promising alternative for antiviral therapies. The evaluation of the inhibitory potential of hops compounds on the viral cycle of OROV was performed through two complementary approaches. The first approach applies cell-based assay post-inoculation experiments to explore the inhibitory potential on the latest steps of the viral cycle, such as genome translation, replication, virion assembly, and virion release from the cells. The second part covers in silico methods evaluating the ability of those compounds to inhibit the activity of the endonuclease domain, which is essential for transcription, binding, and cleaving RNA. In conclusion, the beta acids showed strongest inhibitory potential in post-treatment assay (EC50 = 26.7 µg/mL). Xanthohumol had the highest affinity for OROV endonuclease followed by colupulone and cohumulone. This result contrasts with that observed for docking and MM/PBSA analysis, where cohumulone was found to have a higher affinity. Finally, among the three tested ligands, Lys92 and Arg33 exhibited the highest affinity with the protein.

Review on Main Arboviruses Circulating on French Guiana, An Ultra-Peripheric European Region in South America.

French Guiana (FG), a French overseas territory in South America, is susceptible to tropical diseases, including arboviruses. The tropical climate supports the proliferation and establishment of vectors, making it difficult to control transmission. In the last ten years, FG has experienced large outbreaks of imported arboviruses such as Chikungunya and Zika, as well as endemic arboviruses such as dengue, Yellow fever, and Oropouche virus. Epidemiological surveillance is challenging due to the differing distributions and behaviors of vectors. This article aims to summarize the current knowledge of these arboviruses in FG and discuss the challenges of arbovirus emergence and reemergence. Effective control measures are hampered by the nonspecific clinical presentation of these diseases, as well as the Aedes aegypti mosquito's resistance to insecticides. Despite the high seroprevalence of certain viruses, the possibility of new epidemics cannot be ruled out. Therefore, active epidemiological surveillance is needed to identify potential outbreaks, and an adequate sentinel surveillance system and broad virological diagnostic panel are being developed in FG to improve disease management.

Transmission risk of Oropouche fever across the Americas.

BACKGROUND: Vector-borne diseases (VBDs) are important contributors to the global burden of infectious diseases due to their epidemic potential, which can result in significant population and economic impacts. Oropouche fever, caused by Oropouche virus (OROV), is an understudied zoonotic VBD febrile illness reported in Central and South America. The epidemic potential and areas of likely OROV spread remain unexplored, limiting capacities to improve epidemiological surveillance. METHODS: To better understand the capacity for spread of OROV, we developed spatial epidemiology models using human outbreaks as OROV transmission-locality data, coupled with high-resolution satellite-derived vegetation phenology. Data were integrated using hypervolume modeling to infer likely areas of OROV transmission and emergence across the Americas. RESULTS: Models based on one-support vector machine hypervolumes consistently predicted risk areas for OROV transmission across the tropics of Latin America despite the inclusion of different parameters such as different study areas and environmental predictors. Models estimate that up to 5 million people are at risk of exposure to OROV. Nevertheless, the limited epidemiological data available generates uncertainty in projections. For example, some outbreaks have occurred under climatic conditions outside those where most transmission events occur. The distribution models also revealed that landscape variation, expressed as vegetation loss, is linked to OROV outbreaks. CONCLUSIONS: Hotspots of OROV transmission risk were detected along the tropics of South America. Vegetation loss might be a driver of Oropouche fever emergence. Modeling based on hypervolumes in spatial epidemiology might be considered an exploratory tool for analyzing data-limited emerging infectious diseases for which little understanding exists on their sylvatic cycles. OROV transmission risk maps can be used to improve surveillance, investigate OROV ecology and epidemiology, and inform early detection.

Oropouche virus infection induces ROS production and oxidative stress in liver and spleen of mice.

Oropouche virus (OROV) is the aetiological agent of Oropouche fever, the symptoms of which are common to most arboviruses, such as fever, headache, malaise, nausea and vomiting. More than half a million people have been infected with OROV since its isolation in 1955. Although Oropouche fever is classified as a neglected and emerging disease, to date, there are no antiviral drugs or vaccines available against the infection and little is known about its pathogenicity. Therefore, it is essential to elucidate the possible mechanisms involved in its pathogenesis. Since oxidative stress plays a pivotal role in the progression of various viral diseases, in this study, redox homeostasis in the target organs of OROV infection was evaluated using an animal model. Infected BALB/c mice exhibited reduced weight gain, splenomegaly, leukopenia, thrombocytopenia, anaemia, development of anti-OROV neutralizing antibodies, increased liver transaminases, and serum levels of pro-inflammatory cytokines tumour necrosis factor (TNF-α) and interferon-γ (IFN-γ). The OROV genome and infectious particles were detected in the liver and spleen of infected animals, with liver inflammation and an increase in the number and total area of lymphoid nodules in the spleen. In relation to redox homeostasis in the liver and spleen, infection led to an increase in reactive oxygen species (ROS) levels, increased oxidative stress biomarkers malondialdehyde (MDA) and carbonyl protein, and decreased activity of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT). Taken together, these results help elucidate some important aspects of OROV infection that may contribute to the pathogenesis of Oropouche.

Oropouche Virus Glycoprotein Topology and Cellular Requirements for Glycoprotein Secretion.

Oropouche virus (OROV; genus Orthobunyavirus) is the etiological agent of Oropouche fever, a debilitating febrile illness common in South America. We used recombinant expression of the OROV M polyprotein, which encodes the surface glycoproteins Gn and Gc plus the nonstructural protein NSm, to probe the cellular determinants for OROV assembly and budding. Gn and Gc self-assemble and are secreted independently of NSm. Mature OROV Gn has two predicted transmembrane domains that are crucial for glycoprotein translocation to the Golgi complex and glycoprotein secretion, and unlike related orthobunyaviruses, both transmembrane domains are retained during Gn maturation. Disruption of Golgi function using the drugs brefeldin A and monensin inhibits glycoprotein secretion. Infection studies have previously shown that the cellular endosomal sorting complexes required for transport (ESCRT) machinery is recruited to Golgi membranes during OROV assembly and that ESCRT activity is required for virus secretion. A dominant-negative form of the ESCRT-associated ATPase VPS4 significantly reduces recombinant OROV glycoprotein secretion and blocks virus release from infected cells, and VPS4 partly colocalizes with OROV glycoproteins and membranes costained with Golgi markers. Furthermore, immunoprecipitation and fluorescence microscopy experiments demonstrate that OROV glycoproteins interact with the ESCRT-III component CHMP6, with overexpression of a dominant-negative form of CHMP6 significantly reducing OROV glycoprotein secretion. Taken together, our data highlight differences in M polyprotein processing across orthobunyaviruses, indicate that Golgi and ESCRT function are required for glycoprotein secretion, and identify CHMP6 as an ESCRT-III component that interacts with OROV glycoproteins. IMPORTANCE Oropouche virus causes Oropouche fever, a debilitating illness common in South America that is characterized by high fever, headache, myalgia, and vomiting. The tripartite genome of this zoonotic virus is capable of reassortment, and there have been multiple epidemics of Oropouche fever in South America over the last 50 years, making Oropouche virus infection a significant threat to public health. However, the molecular characteristics of this arbovirus are poorly understood. We developed a recombinant protein expression system to investigate the cellular determinants of OROV glycoprotein maturation and secretion. We show that the proteolytic processing of the M polypeptide, which encodes the surface glycoproteins (Gn and Gc) plus a nonstructural protein (NSm), differs between OROV and its close relative Bunyamwera virus. Furthermore, we demonstrate that OROV M glycoprotein secretion requires the cellular endosomal sorting complexes required for transport (ESCRT) membrane-remodeling machinery and identify that the OROV glycoproteins interact with the ESCRT protein CHMP6.

Oropouche orthobunyavirus infection is mediated by the cellular host factor Lrp1.

Oropouche orthobunyavirus (OROV; Peribunyaviridae) is a mosquito-transmitted virus that causes widespread human febrile illness in South America, with occasional progression to neurologic effects. Host factors mediating the cellular entry of OROV are undefined. Here, we show that OROV uses the host protein low-density lipoprotein-related protein 1 (Lrp1) for efficient cellular infection. Cells from evolutionarily distinct species lacking Lrp1 were less permissive to OROV infection than cells with Lrp1. Treatment of cells with either the high-affinity Lrp1 ligand receptor-associated protein (RAP) or recombinant ectodomain truncations of Lrp1 significantly reduced OROV infection. In addition, chimeric vesicular stomatitis virus (VSV) expressing OROV glycoproteins (VSV-OROV) bound to the Lrp1 ectodomain in vitro. Furthermore, we demonstrate the biological relevance of the OROV-Lrp1 interaction in a proof-of-concept mouse study in which treatment of mice with RAP at the time of infection reduced tissue viral load and promoted survival from an otherwise lethal infection. These results with OROV, along with the recent finding of Lrp1 as an entry factor for Rift Valley fever virus, highlight the broader significance of Lrp1 in cellular infection by diverse bunyaviruses. Shared strategies for entry, such as the critical function of Lrp1 defined here, provide a foundation for the development of pan-bunyaviral therapeutics.

Presence and Multi-Species Spatial Distribution of Oropouche Virus in Brazil within the One Health Framework.

Oropouche virus (OROV) is an emerging vector-borne arbovirus with high epidemic potential, causing illness in more than 500,000 people. Primarily contracted through its midge and mosquito vectors, OROV remains prevalent in its wild, non-human primate and sloth reservoir hosts as well. This virus is spreading across Latin America; however, the majority of cases occur in Brazil. The aim of this research is to document OROV's presence in Brazil using the One Health approach and geospatial techniques. A scoping review of the literature (2000 to 2021) was conducted to collect reports of this disease in humans and animal species. Data were then geocoded by first and second subnational levels and species to map OROV's spread. In total, 14 of 27 states reported OROV presence across 67 municipalities (second subnational level). However, most of the cases were in the northern region, within the tropical and subtropical moist broadleaf forests biome. OROV was identified in humans, four vector species, four genera of non-human primates, one sloth species, and others. Utilizing One Health was important to understand the distribution of OROV across several species and to suggest possible environmental, socioeconomic, and demographic drivers of the virus's presence. As deforestation, climate change, and migration rates increase, further study into the spillover potential of this disease is needed.

Arbovirus outbreak in a rural region of the Brazilian Amazon.

BACKGROUND: An outbreak of febrile illness was reported from January to February 2018 in the Expedito Ribeiro Settlement, ​​Santa Bárbara do Pará municipality, Pará State, Brazil. OBJECTIVE: This study aimed to investigate the pathogenic agent responsible for the outbreak and the circulation of arboviruses in the region. STUDY DESIGN: We analyzed 94 individuals through laboratory tests for arboviruses. Forty out of 94 individuals were asymptomatic but were living with or near febrile cases, and 55 participants were symptomatic. RESULTS: Our results showed that 51.1% of the investigated individuals were positive for arboviruses (Oropouche, Mayaro, and Chikungunya), of which 77.8% were symptomatic. We detected 93.7% of positive cases for Oropouche infection, 2.1% for Mayaro fever, and 4.2% were positive for both Oropouche and Chikungunya infection. CONCLUSION: Oropouche virus was mainly responsible for the outbreak; however, we also detected a few Chikungunya and Mayaro fever cases. Serologic assays showed evidence of arboviruses circulation of different genera in the area.

Epidemiological aspects of the Oropouche virus (Orthobunyavirus) in South America: A systematic review

SUMMARY Introduction: The Oropouche virus (OROV) is an arbovirus that belongs to the genus Orthobunyavirus and family Peribunyaviridae, responsible for causing Oropouche fever (OF) in humans. The clinical diagnosis of is doubtful due to the non-specificity of the symptoms, which can lead to a mistaken diagnosis of other arboviruses. Thus, the survey of epidemiological data on the occurrence of has been a major challenge for public health authorities, especially in of South America. Aim: To determine the general exposure rate of OROV in Brazil and other countries in South America by a systematic review. An article search was carried out in the Pubmed/ Medline, Scopus, Cochrane, Lilacs, Electronic Scientific Online Library (SciELO) and Virtual Health Library (VHL) databases. Results: 18 studies were selected as eligible to compose this review on epidemiological aspects of OROV. The studies were published from 1989 to 2020. Most studies were carried out in Brazil (12/18; 66.66%) and Peru (5/18; 27.77%), only one study collected samples from Peru, Ecuador, Bolivia and Paraguay. The test for the OROV was realized mainly by serological analysis. Of the 8005 samples analyzed, 1570 tested positive for the presence of OROV thus accounting a general exposure rate in South America of 19.61%. Brazil was responsible for more than half of the cases of OROV identified in South America (855/1570; 54.46%), however Peru has the highest rate of exposure to the virus (23.43% of frequency in Peru vs. 16.77% of frequency in Brazil). Conclusion: OROV stands out as an important public health problem in Amazonian countries in South America.

Introdução: o virus Oropouche (OROV) é um arbovírus pertencente ao gênero Orthobunyavirus e família Peribunyaviridae, responsável por causar a febre Oropouche (FO) em humanos. O diagnóstico clínico da FO é duvidoso devido à não especificidade dos sintomas, o que pode levar a um diagnóstico equivocado de outras arboviroses. Assim, o levantamento de dados epidemiológicos sobre a ocorrência de FO tem sido um grande desafio para as autoridades de saúde pública, principalmente na América do Sul. Objetivo: determinar a taxa geral de exposição de OROV no Brasil e em outros países da América do Sul por meio de uma revisão sistemática. Foi realizada busca de artigos nas bases de dados Pubmed/ Medline, Scopus, Cochrane, Lilacs, Electronic Scientific Online Library (SciELO) e Virtual Health Library (BVS). Resultados: 18 estudos foram selecionados como elegíveis para compor esta revisão sobre aspectos epidemiológicos da OROV. Os estudos foram publicados de 1989 a 2020. A maioria dos estudos foi realizada no Brasil (18/12; 66,66%) e Peru (18/5; 27,77%), apenas um estudo coletou amostras do Peru, Equador, Bolívia e Paraguai. O teste para o OROV foi realizado principalmente por análise sorológica. Das 8005 amostras analisadas, 1570 testaram positivo para a presença de OROV, representando assim uma taxa de exposição geral na América do Sul de 19,61%. O Brasil foi responsável por mais da metade dos casos de OROV identificados na América do Sul (855/1570; 54,46%), porém o Peru tem a maior taxa de exposição ao vírus (23,43% de frequência no Peru vs. 16,77% de frequência em Brasil). Conclusão: OROV destaca-se como um importante problema de saúde pública nos países amazônicos da América do Sul.

Introducción: el virus Oropouche (OROV) es un arbovirus que pertenece al género Orthobunyavirus y familia Peribunyaviridae, responsable de causar la fiebre de oropouche (FO) en humanos. El diagnóstico clínico de FO es dudoso debido a la inespecificidad de los síntomas, lo que puede conducir a un diagnóstico erróneo de otros arbovirus. Por lo tanto, el levantamiento de datos epidemiológicos sobre la ocurrencia de FO ha sido un gran desafío para las autoridades de salud pública, especialmente en el sur de América del Sur. Objetivo: determinar la tasa de exposición general de OROV en Brasil y otros países de América del Sur mediante una revisión sistemática. Se realizó una búsqueda de artículos en las bases de datos Pubmed/ Medline, Scopus, Cochrane, Lilacs, Electronic Scientific Online Library (SciELO) y Virtual Health Library (BVS). Resultados: 18 estudios fueron seleccionados como elegibles para esta revisión sobre aspectos epidemiológicos de OROV. Los estudios se publicaron entre 1989 y 2020. La mayoría de los estudios se realizaron en Brasil (12/18; 66,66 %) y Perú (5/18; 27,77 %), solo un estudio recolectó muestras de Perú, Ecuador, Bolivia y Paraguay. La prueba para el OROV se realizó principalmente por análisis serológico. De las 8005 muestras analizadas, 1570 dieron positivo a la presencia de OROV, lo que representa una tasa de exposición general en América del Sur del 19,61 %. Brasil fue responsable de más de la mitad de los casos de OROV identificados en América del Sur (855/1570; 54,46 %), sin embargo, Perú tiene la tasa más alta de exposición al virus (23,43 % de frecuencia en Perú vs. 16,77 % de frecuencia en Brasil). Conclusión: OROV se destaca como un importante problema de salud pública en los países amazónicos de América del Sur.

Outbreak of Oropouche Virus in French Guiana.

Oropouche fever is a zoonotic dengue-like syndrome caused by Oropouche virus. In August-September 2020, dengue-like syndrome developed in 41 patients in a remote rainforest village in French Guiana. By PCR or microneutralization, 23 (82.1%) of 28 tested patients were positive for Oropouche virus, documenting its emergence in French Guiana.

Vesicular Stomatitis Virus Chimeras Expressing the Oropouche Virus Glycoproteins Elicit Protective Immune Responses in Mice.

Oropouche virus (OROV) infection of humans is associated with a debilitating febrile illness that can progress to meningitis or encephalitis. First isolated from a forest worker in Trinidad and Tobago in 1955, the arbovirus OROV has since been detected throughout the Amazon basin with an estimated 500,000 human infections over 60 years. Like other members of the family Peribunyaviridae, the viral genome exists as 3 single-stranded negative-sense RNA segments. The medium-sized segment encodes a viral glycoprotein complex (GPC) that is proteolytically processed into two viral envelope proteins, Gn and Gc, responsible for attachment and membrane fusion. There are no therapeutics or vaccines to combat OROV infection, and we have little understanding of protective immunity to infection. Here, we generated a replication competent chimeric vesicular stomatitis virus (VSV), in which the endogenous glycoprotein was replaced by the GPC of OROV. Serum from mice immunized by intramuscular injection with VSV-OROV specifically neutralized wild-type OROV, and using peptide arrays we mapped multiple epitopes within an N-terminal variable region of Gc recognized by the immune sera. VSV-OROV lacking this variable region of Gc was also immunogenic in mice producing neutralizing sera that recognize additional regions of Gc. Challenge of both sets of immunized mice with wild-type OROV shows that the VSV-OROV chimeras reduce wild-type viral infection and suggest that antibodies that recognize the variable N terminus of Gc afford less protection than those that target more conserved regions of Gc. IMPORTANCE Oropouche virus (OROV), an orthobunyavirus found in Central and South America, is an emerging public health challenge that causes debilitating febrile illness. OROV is transmitted by arthropods, and increasing mobilization has the potential to significantly increase the spread of OROV globally. Despite this, no therapeutics or vaccines have been developed to combat infection. Using vesicular stomatitis (VSV) as a backbone, we developed a chimeric virus bearing the OROV glycoproteins (VSV-OROV) and tested its ability to elicit a neutralizing antibody response. Our results demonstrate that VSV-OROV produces a strong neutralizing antibody response that is at least partially targeted to the N-terminal region of Gc. Importantly, vaccination with VSV-OROV reduces viral loads in mice challenged with wild-type virus. These data provide novel evidence that targeting the OROV glycoproteins may be an effective vaccination strategy to combat OROV infection.

Neurological disease caused by Oropouche virus in northern Brazil: should it be included in the scope of clinical neurological diseases?

We describe two neurological cases of Oropouche virus infection in northern Brazil, where the virus is endemic but neglected as a pathogen. This study reiterates the necessity of developing protocols for diagnosing infections and training medical personnel to recognize the pathogenicity of Oropouche virus in neurological infections.

Oropouche Virus Infects, Persists and Induces IFN Response in Human Peripheral Blood Mononuclear Cells as Identified by RNA PrimeFlow™ and qRT-PCR Assays.

Oropouche orthobunyavirus (OROV) is an emerging arbovirus with a high potential of dissemination in America. Little is known about the role of peripheral blood mononuclear cells (PBMC) response during OROV infection in humans. Thus, to evaluate human leukocytes susceptibility, permissiveness and immune response during OROV infection, we applied RNA hybridization, qRT-PCR and cell-based assays to quantify viral antigens, genome, antigenome and gene expression in different cells. First, we observed OROV replication in human leukocytes lineages as THP-1 monocytes, Jeko-1 B cells and Jurkat T cells. Interestingly, cell viability and viral particle detection are maintained in these cells, even after successive passages. PBMCs from healthy donors were susceptible but the infection was not productive, since neither antigenome nor infectious particle was found in the supernatant of infected PBMCs. In fact, only viral antigens and small quantities of OROV genome were detected at 24 hpi in lymphocytes, monocytes and CD11c+ cells. Finally, activation of the Interferon (IFN) response was essential to restrict OROV replication in human PBMCs. Increased expression of type I/III IFNs, ISGs and inflammatory cytokines was detected in the first 24 hpi and viral replication was re-established after blocking IFNAR or treating cells with glucocorticoid. Thus, in short, our results show OROV is able to infect and remain in low titers in human T cells, monocytes, DCs and B cells as a consequence of an effective IFN response after infection, indicating the possibility of leukocytes serving as a trojan horse in specific microenvironments during immunosuppression.

Real-time RT-PCR for the detection and quantitation of Oropouche virus.

Oropouche virus (OROV) causes an acute, systemic febrile illness, and in certain regions of South America, this represents the second most common human arboviral infection after dengue virus. A new real-time RT-PCR was developed for OROV and reassortant species. The new OROV rRT-PCR proved linear across 6-7 orders of magnitude with a lower limit of 95% detection of 5.6-10.8 copies/µL. Upon testing dilutions of OROV and Iquitos virus reference genomic RNA, all dilutions with >10 copies/µL were detected in both the OROV rRT-PCR and a comparator molecular assay, but the OROV rRT-PCR detected more samples with ≤10 copies/µL (8/14 vs 0/13, respectively, P = 0.002). In a set of 100 acute-phase clinical samples from Paraguay patients with a suspected arboviral illness, no patients tested positive for OROV RNA using either assay. The OROV rRT-PCR provides a sensitive molecular assay for the study of this important yet neglected tropical arboviral infection.

Oropouche Virus Detection in Febrile Patients' Saliva and Urine Samples in Salvador, Bahia, Brazil.

Oropouche virus (OROV) is a negative-sense, single-stranded RNA arbovirus transmitted to humans by the midge Culicoides paraenesis, causing Oropouche fever. Reports of its outbreak in Brazil have so far been restricted to the Central-Northern region of the country. However, its incidence is underestimated, mainly due to its clinical similarities with other arbovirus diseases, including dengue (DENV), chikungunya (CHIKV), and zika (ZIKV), and the lack of specific diagnostic tests. Here, we report for the first time, the detection of OROV in saliva and urine samples, and cases of autochthone OROV infections in Salvador Metropolitan region, Bahia, a Northeastern capital in the coast of Brazil. Serum, saliva, and urine samples negative for DENV, CHIKV, and ZIKV were tested for OROV using a reverse transcription nested polymerase chain reaction (RT-nested-PCR) protocol, and 2 serum, 2 saliva, and 1 urine samples were positive. This report shows the need for an efficient surveillance system for controlling the spread of this virus, and suggests the use of saliva and urine as alternative samples for OROV detection in the absence of serum samples.

Evolutionary Dynamics of Oropouche Virus in South America.

The Amazon basin is home to numerous arthropod-borne viral pathogens that cause febrile disease in humans. Among these, Oropouche orthobunyavirus (OROV) is a relatively understudied member of the genus Orthobunyavirus, family Peribunyaviridae, that causes periodic outbreaks in human populations in Brazil and other South American countries. Although several studies have described the genetic diversity of the virus, the evolutionary processes that shape the OROV genome remain poorly understood. Here, we present a comprehensive study of the genomic dynamics of OROV that encompasses phylogenetic analysis, evolutionary rate estimates, inference of natural selective pressures, recombination and reassortment, and structural analysis of OROV variants. Our study includes all available published sequences, as well as a set of new OROV genome sequences obtained from patients in Ecuador, representing the first set of genomes from this country. Our results show differing evolutionary processes on the three segments that comprise the viral genome. We infer differing times of the most recent common ancestors of the genome segments and propose that this can be explained by cryptic reassortment. We also present the discovery of previously unobserved putative N-linked glycosylation sites, as well as codons that evolve under positive selection on the viral surface proteins, and discuss the potential role of these features in the evolution of OROV through a combined phylogenetic and structural approach.IMPORTANCE The emergence and reemergence of pathogens such as Zika virus, chikungunya virus, and yellow fever virus have drawn attention toward other cocirculating arboviruses in South America. Oropouche virus (OROV) is a poorly studied pathogen responsible for over a dozen outbreaks since the early 1960s and represents a public health burden to countries such as Brazil, Panama, and Peru. OROV is likely underreported since its symptomatology can be easily confounded with other febrile illnesses (e.g., dengue fever and leptospirosis) and point-of-care testing for the virus is still uncommon. With limited data, there is a need to optimize the information currently available. Analysis of OROV genomes can help us understand how the virus circulates in nature and can reveal the evolutionary forces that shape the genetic diversity of the virus, which has implications for molecular diagnostics and the design of potential vaccines.

Oropouche virus detection in saliva and urine

Oropouche virus (OROV) is an arthropod-borne virus of the Peribunyaviridae family, transmitted to humans primarily by Culicoides paraensis. It is one of the main arboviruses infecting humans in Brazil, primarily in the Amazon Region. Here, we report the detection of OROV in the saliva and urine of a patient whose samples were collected five days after the onset of symptoms. Nucleotide sequencing and phylogenetic analysis further confirmed the results. To our knowledge, this is the first study reporting the detection of OROV in the saliva and urine of an infected patient. In addition, the results of our study expand the current knowledge pertaining to the natural history of Oropouche fever.

Oropouche Virus-Associated Aseptic Meningoencephalitis, Southeastern Brazil.

Oropouche fever is a neglected arthropodborne disease and zoonosis responsible for several outbreaks of a febrile disease in Central and South America. We present a clinical case of aseptic meningoencephalitis in an immunocompetent patient that resulted from Oropouche virus acquired in northern Brazil but diagnosed in a nonendemic region.