Análise da prevalência de internações por dengue no estado do Tocantins entre 2017 e 2022 / The prevalence of hospitalizations and deaths for dengue in the state of Tocantins between 2017 and 2022 / Prevalencia de hospitalizaciones y muertes por dengue en el estado de Tocantins entre 2017 y 2022

O Tocantins é um Estado endêmico para dengue devido aos elevados índices pluviométricos e do saneamento básico escasso. Esta pesquisa objetivou investigar o número de internações por dengue no Estado do Tocantins entre 2017 e 2022. O estudo consiste em um delineamento transversal retrospectivo quantitativo, realizado a partir de dados coletados no Tabnet/DataSUS. Os resultados encontrados foram compilados no programa Microsoft Excel®, e por meio de gráficos e tabelas, foram evidenciados 28.355 casos de dengue confirmados, dos quais apenas 1.798 (6%) necessitaram de hospitalizações, com maior incidência em 2019, tendo Palmas como município mais acometido. Conclui-se, portanto, que a dengue segue sendo uma doença prevalente no Estado, de modo a demandar atenção de gestores de saúde com vistas a reduzir os números altos de casos por meio de vigilância epidemiológica ativa como, também, fornecer o melhor cuidado para os pacientes diagnosticados com dengue, quer seja no âmbito ambulatorial quer no hospitalar.

Tocantins is an endemic state for dengue due to high rainfall rates and poor sanitation. This research aimed to investigate the number of dengue hospitalizations in the State of Tocantins between 2017 and 2022. The study consists of a retrospective quantitative cross-sectional design, performed from data collected in Tabnet/DataSUS. The results found were compiled in Microsoft Excel® program, and by means of graphs and tables, 28,355 confirmed dengue cases were evidenced, of which only 1,798 (6%) required hospitalizations, with a higher incidence in 2019, with Palmas as the most affected municipality. It is concluded, therefore, that dengue remains a prevalent disease in the state, so as to demand attention from health managers with a view to reducing the high numbers of cases through active epidemiological surveillance as well as providing the best care for patients diagnosed with dengue, whether in the outpatient or hospital setting.

Tocantins es un estado endémico para el dengue debido a las altas tasas de precipitación y al saneamiento deficiente. Esta investigación tuvo como objetivo investigar el número de hospitalizaciones por dengue en el Estado de Tocantins entre 2017 y 2022. El estudio consiste en un diseño cuantitativo transversal retrospectivo, realizado a partir de datos recogidos en Tabnet/DataSUS. Los resultados encontrados fueron compilados en el programa Microsoft Excel®, y por medio de gráficos y tablas, se evidenciaron 28.355 casos confirmados de dengue, de los cuales sólo 1.798 (6%) requirieron hospitalizaciones, con mayor incidencia en 2019, siendo Palmas el municipio más afectado. Se concluye, por lo tanto, que el dengue continúa siendo una enfermedad prevalente en el estado, por lo que demanda la atención de los gestores de salud con miras a reducir las altas cifras de casos a través de la vigilancia epidemiológica activa, así como brindar la mejor atención a los pacientes diagnosticados con dengue, ya sea en el ámbito ambulatorio u hospitalario.

RACK1 Associates with RNA-Binding Proteins Vigilin and SERBP1 to Facilitate Dengue Virus Replication.

Dengue virus (DENV) is a mosquito-borne flavivirus responsible for dengue disease, a major human health concern for which no effective treatment is available. DENV relies heavily on the host cellular machinery for productive infection. Here, we show that the scaffold protein RACK1, which is part of the DENV replication complex, mediates infection by binding to the 40S ribosomal subunit. Mass spectrometry analysis of RACK1 partners coupled to an RNA interference screen-identified Vigilin and SERBP1 as DENV host-dependency factors. Both are RNA-binding proteins that interact with the DENV genome. Genetic ablation of Vigilin or SERBP1 rendered cells poorly susceptible to DENV, as well as related flaviviruses, by hampering the translation and replication steps. Finally, we established that a Vigilin or SERBP1 mutant lacking RACK1 binding but still interacting with the viral RNA is unable to mediate DENV infection. We propose that RACK1 recruits Vigilin and SERBP1, linking the DENV genome to the translation machinery for efficient infection. IMPORTANCE We recently identified the scaffolding RACK1 protein as an important host-dependency factor for dengue virus (DENV), a positive-stranded RNA virus responsible for the most prevalent mosquito-borne viral disease worldwide. Here, we have performed the first RACK1 interactome in human cells and identified Vigilin and SERBP1 as DENV host-dependency factors. Both are RNA-binding proteins that interact with the DENV RNA to regulate viral replication. Importantly, Vigilin and SERBP1 interact with RACK1 and the DENV viral RNA (vRNA) to mediate viral replication. Overall, our results suggest that RACK1 acts as a binding platform at the surface of the 40S ribosomal subunit to recruit Vigilin and SERBP1, which may therefore function as linkers between the viral RNA and the translation machinery to facilitate infection.

Manifestaciones oftalmológicas del dengue, el zika y el chikungunya / Ophthalmic manifestations of dengue, zika and chikungunya

Las infecciones por arbovirus constituyen un reto significativo para los sistemas de salud. Cada vez se incrementa el reconocimiento de complicaciones del sistema nervioso central secundarias a ellas, lo que puede ser un dilema para su diagnóstico y tratamiento. Los arbovirus pueden alterar los mecanismos de inmunidad innatos del ojo al dañar las barreras óculo-hemáticas. En esta revisión nos propusimos caracterizar los principales hallazgos oftalmológicos de las enfermedades transmitidas por mosquito, como el dengue, el zika y el chikungunya, y su posible fisiopatología. Se realizó una búsqueda de la literatura sobre el tema en la base de datos de PubMED. En los pacientes con zika y chikungunya se reconocieron frecuentemente la conjuntivitis no purulenta y la queratitis. En los casos de dengue el edema macular y las hemorragias retinianas maculares fueron frecuentes; causaron disminución de la visión y defectos campimétricos; la vasculitis y coriorretinitis periférica podía ser asintomática si la mácula no estaba comprometida. Estuvieron implicados la trombocitopenia y otros procesos fisiopatológicos. En las enfermedades estudiadas se reportaron casos raros con parálisis de nervios oculomotores o neuritis óptica como respuesta autoinmune tardía. Recientemente se reportó el síndrome de zika congénito que incluyó múltiples anomalías del desarrollo. En los neonatos afectados se describió la atrofia macular, así como la pigmentación macular bilateral, la hipoplasia del nervio óptico, la catarata, entre otros. Existen diversas lesiones oculares secundarias a infecciones por dengue, zika y chikungunya que merecen reconocimiento, pues deterioran la función visual temporal o permanentemente(AU)

Arbovirus infections pose a significant challenge to health systems. Awareness of the secondary central nervous system complications caused by these infections is on the increase, which may be a dilemma for their diagnosis and treatment. Arboviruses may alter the innate immunity mechanisms of the eye by damaging blood-retinal barriers. The objective of this review was to characterize the main ophthalmological findings of mosquito-borne diseases, such as dengue, zika and chikungunya, and their possible physiopathology. A bibliographic search about the topic was conducted in the database PubMed. Non-purulent conjunctivitis and keratitis were frequently found in zika and chikungunya patients. Dengue cases often presented macular edema and macular retinal hemorrhage, which caused vision reduction, as well as campimetric defects. Vasculitis and peripheral chorioretinitis could be asymptomatic if the macula was not involved. Thrombocytopenia and other physiopathological processes were also present. Oculomotor nerve palsy and optic neuritis as a late autoimmune response were rarely reported in the diseases studied. Recent reports refer to congenital zika syndrome, which causes multiple developmental abnormalities. Macular atrophy, bilateral macular pigmentation, optic nerve hypoplasia and cataract, among other disorders, were described in affected neonates. A variety of ocular lesions secondary to dengue, zika and chikungunya infection deserve recognition, for they damage visual function either temporarily or permanently(AU)

Regulation of innate immune responses in macrophages differentiated in the presence of vitamin D and infected with dengue virus 2.

A dysregulated or exacerbated inflammatory response is thought to be the key driver of the pathogenesis of severe disease caused by the mosquito-borne dengue virus (DENV). Compounds that restrict virus replication and modulate the inflammatory response could thus serve as promising therapeutics mitigating the disease pathogenesis. We and others have previously shown that macrophages, which are important cellular targets for DENV replication, differentiated in the presence of bioactive vitamin D (VitD3) are less permissive to viral replication, and produce lower levels of pro-inflammatory cytokines. Therefore, we here evaluated the extent and kinetics of innate immune responses of DENV-2 infected monocytes differentiated into macrophages in the presence (D3-MDMs) or absence of VitD3 (MDMs). We found that D3-MDMs expressed lower levels of RIG I, Toll-like receptor (TLR)3, and TLR7, as well as higher levels of SOCS-1 in response to DENV-2 infection. D3-MDMs produced lower levels of reactive oxygen species, related to a lower expression of TLR9. Moreover, although VitD3 treatment did not modulate either the expression of IFN-α or IFN-ß, higher expression of protein kinase R (PKR) and 2'-5'-oligoadenylate synthetase 1 (OAS1) mRNA were found in D3-MDMs. Importantly, the observed effects were independent of reduced infection, highlighting the intrinsic differences between D3-MDMs and MDMs. Taken together, our results suggest that differentiation of MDMs in the presence of VitD3 modulates innate immunity in responses to DENV-2 infection.

Distinguishing non severe cases of dengue from COVID-19 in the context of co-epidemics: A cohort study in a SARS-CoV-2 testing center on Reunion island.

BACKGROUND: As coronavirus 2019 (COVID-19) is spreading globally, several countries are handling dengue epidemics. As both infections are deemed to share similarities at presentation, it would be useful to distinguish COVID-19 from dengue in the context of co-epidemics. Hence, we performed a retrospective cohort study to identify predictors of both infections. METHODOLOGY/PRINCIPAL FINDINGS: All the subjects suspected of COVID-19 between March 23 and May 10, 2020, were screened for COVID-19 within the testing center of the University hospital of Saint-Pierre, Reunion island. The screening consisted in a questionnaire surveyed in face-to-face, a nasopharyngeal swab specimen for the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) reverse transcription polymerase chain-reaction and a rapid diagnostic orientation test for dengue. Factors independently associated with COVID-19 or with dengue were sought using multinomial logistic regression models, taking other febrile illnesses (OFIs) as controls. Adjusted Odds ratios (OR) and 95% Confidence Intervals (95%CI) were assessed. Over a two-month study period, we diagnosed 80 COVID-19, 61 non-severe dengue and 872 OFIs cases eligible to multivariate analysis. Among these, we identified delayed presentation (>3 days) since symptom onset (Odds ratio 1.91, 95% confidence interval 1.07-3.39), contact with a COVID-19 positive case (OR 3.81, 95%CI 2.21-6.55) and anosmia (OR 7.80, 95%CI 4.20-14.49) as independent predictors of COVID-19, body ache (OR 6.17, 95%CI 2.69-14.14), headache (OR 5.03, 95%CI 1.88-13.44) and retro-orbital pain (OR 5.55, 95%CI 2.51-12.28) as independent predictors of dengue, while smoking was less likely observed with COVID-19 (OR 0.27, 95%CI 0.09-0.79) and upper respiratory tract infection symptoms were associated with OFIs. CONCLUSIONS/SIGNIFICANCE: Although prone to potential biases, these data suggest that non-severe dengue may be more symptomatic than COVID-19 in a co-epidemic setting with higher dengue attack rates. At clinical presentation, nine basic clinical and epidemiological indicators may help to distinguish COVID-19 or dengue from each other and other febrile illnesses.

Case report: An unusual presentation of acute promyelocytic leukemia in a middle aged female mimicking dengue infection.

RATIONALE: Acute promyelocytic leukemia (APL) is an uncommon subtype of acute myeloid leukemia (AML). M3v phenotype is a less common presentation of APL and these patients usually present with leukocytosis and abnormal promyelocytes that are characterized by sparse granulation and are less likely to have faggot cells with multiple Auer rods. Distinguishing M3v phenotype from acute febrile illness can be challenging as the diagnosis relies on examination of peripheral smear. PATIENT CONCERNS: Fifty-seven-year-old female who presented after recent trip to Dominican Republic for high grade fever and gum bleeding. She was exposed to patients with Dengue fever during her stay. At presentation, patient had leukocytosis, thrombocytopenia, and urinalysis showing bacteria and white cell. She was started on treatment for urinary tract infection. Patient remained febrile and thrombocytopenia worsened. On day 2, flow cytometry of the peripheral smear showed 43% medium sized blasts. Fluorescence in situ hybridization was positive for promyelocytic leukemia/retinoic acid receptor alpha. DIAGNOSES: The patient was diagnosed with APL. INTERVENTIONS: Patient was started on treatment with all-trans retinoic acid and arsenic trioxide along with supportive care OUTCOMES:: Patient had a favorable clinical response and her symptoms subsided. LESSONS: Flow cytometry of the peripheral smear is key to diagnosis of suspected APL. One must maintain high suspicion for this life-threatening condition as early diagnosis saves lives.

Validation of educational booklet: an educational technology in dengue prevention / Validación de cartilla educativa: una tecnología educacional en la prevención del dengue / Validação de cartilha educativa: uma tecnologia educacional na prevenção da dengue

ABSTRACT Objective: to validate a booklet on dengue prevention in order to make it an educational technology to be used with the population. Method: methodological study, carried out with two groups of judges specialized in health and other areas. For data analysis, the calculation of Content Validity Index was carried out. Results: the booklet, in general, was considered valid by the expert judges, since it obtained an overall CVI of 70%. However, it has undergone a textual and aesthetic re-elaboration. The changes were based on the substitution of expressions, phrases, information additions and language adequacy. The illustrations were redone, adding clarity, expressiveness, movement, interaction and contextualization. Conclusion: the booklet is valid to be used for the population, with the purpose of informing, in a playful way, the forms of prevention and combat to mosquito transmitting dengue.

RESUMEN Objetivo: validar una cartilla sobre prevención del dengue, con el fin de hacerla una tecnología educativa para ser utilizada con la población. Método: estudio metodológico, realizado con dos grupos de jueces especialistas de la Salud y de otras áreas. Para el análisis de los datos, se realizó el cálculo del Índice de Validez de Contenido. Resultados: se considera que la cartilla, en general, fue considerada válida por los jueces especialistas, ya que obtuvo un IVC global del 70%. Sin embargo, pasó por una reelaboración textual y estética. Los cambios recae sobre la sustitución de expresiones, frases, acrecimiento de informaciones y adecuación de lenguaje. Las ilustraciones fueron rehechas, añadiendo claridad, expresividad, movimiento, interacción y contextualización. Conclusión: la cartilla es válida para ser utilizada para la población, con el objetivo de informar, de manera lúdica, las formas de prevención y combate al mosquito transmisor del dengue.

RESUMO Objetivo: validar uma cartilha sobre prevenção da dengue, a fim de torná-la uma tecnologia educacional para ser utilizada com a população. Método: estudo metodológico, realizado com dois grupos de juízes especialistas da Saúde e de outras áreas. Para a análise dos dados, foi realizado o cálculo de Índice de Validade de Conteúdo. Resultados: a cartilha, em geral, foi considerada válida pelos juízes especialistas, visto que obteve um IVC global de 70%. Entretanto, passou por uma reelaboração textual e estética. As alterações recaíram sobre a substituição de expressões, frases, acréscimo de informações e adequação de linguagem. As ilustrações foram refeitas, acrescentando clareza, expressividade, movimento, interação e contextualização. Conclusão: a cartilha é válida a ser utilizada para a população, com o objetivo de informar, de maneira lúdica, as formas de prevenção e combate ao mosquito transmissor da dengue.

Clinical and epidemiological teaching of dengue through simulated practice / Enseñanza clínica y epidemiológica de dengue por medio de la práctica simulada / Ensino clínico e epidemiológico de dengue por meio da prática simulada

ABSTRACT Objective: to describe the experience of clinical teaching on dengue and the practice of epidemiological surveillance using problematization methodology. Method: report of experience on educational activity with undergraduate nursing students, held in March 2016, at a public university in the city of São Paulo, conceived in four stages: dialogic lecture, active search of Aedes aegypti, case study and simulation of nursing consultation to individuals with dengue. Results: The activity allowed to retrieve previous knowledge about the disease, respond to exercises that addressed different clinical situations and epidemiological surveillance, including in situ evaluation of possible mosquito outbreaks, and discuss the need to expand prevention and health of the individual and the community, the impact of the media in the dissemination of cases and the coping difficulties experienced in the different levels of attention. Conclusion: the methodology adopted enabled qualified training of students to cope with dengue.

RESUMEN Objetivo: describir la experiencia de enseñanza clínica sobre la dengue y la práctica de vigilancia epidemiológica utilizando metodología de la problematización. Método: relato de experiencia sobre actividad educativa con graduandos de Enfermería, realizada en marzo de 2016, en una universidad pública de la ciudad de São Paulo, concebida en cuatro etapas: clase expositiva dialogada, busca activa del Aedes aegypti, estudio de caso y simulación de consulta de enfermería a individuos con dengue. Resultados: La actividad permitió rescatar conocimientos previos sobre la enfermedad, responder a ejercicios que abordaban distintas situaciones clínicas y de vigilancia epidemiológica, incluyendo evaluación "in loco" de posibles focos del mosquito, y discutir la necesidad de ampliación de las acciones de prevención y promoción de la salud del individuo y colectividad, el impacto del medio de comunicación en la divulgación de los casos y las dificultades de enfrentamiento vividas en los diferentes niveles de atención. Conclusión: la metodología adoptada posibilitó capacitación cualificada de los alumnos para enfrentamiento de la dengue.

RESUMO Objetivo: descrever a experiência de ensino clínico sobre a dengue e a prática de vigilância epidemiológica utilizando metodologia da problematização. Método: relato de experiência sobre atividade educativa com graduandos de Enfermagem, realizada em março de 2016, em uma universidade pública da cidade de São Paulo, concebida em quatro etapas: aula expositiva dialogada, busca ativa do Aedes aegypti, estudo de caso e simulação de consulta de enfermagem a indivíduos com dengue. Resultados: A atividade permitiu resgatar conhecimentos prévios sobre a doença, responder a exercícios que abordavam distintas situações clínicas e de vigilância epidemiológica, incluindo avaliação "in loco" de possíveis focos do mosquito, e discutir a necessidade de ampliação das ações de prevenção e promoção da saúde do indivíduo e coletividade, o impacto da mídia na divulgação dos casos e as dificuldades de enfrentamento vivenciadas nos diferentes níveis de atenção. Conclusão: a metodologia adotada possibilitou capacitação qualificada dos alunos para enfrentamento da dengue.

Suppressive effect of dengue virus envelope protein domain III on megakaryopoiesis.

Dengue virus (DENV) infection can cause severe, life-threatening events, and no specific treatments of DENV infection are currently approved. Although thrombocytopenia is frequently observed in dengue patients, its pathogenesis is still not fully understood. Previous studies have suggested that DENV-induced thrombocytopenia occurs through viral-replication-mediated megakaryopoiesis inhibition in the bone marrow; however, the exact mechanism for megakaryopoiesis suppression remains elusive. In this study, a reductionist approach was applied, in which C57B/6J mice were inoculated with recombinant DENV-envelope protein domain III (DENV-EIII) instead of the full viral particle. Our results demonstrated that DENV-EIII-suppressed megakaryopoiesis is similar to those observed with DENV infection. Furthermore, in agreement with our in vivo analyses, DENV-EIII sufficiently suppressed the megakaryopoiesis of progenitor cells from murine bone marrow and human cord blood in vitro. Additional analyses suggested that autophagy impairment and apoptosis are involved in DENV-EIII-mediated suppression of megakaryopoiesis. These data suggest that, even without viral replication, the binding of DENV-EIII to the cell surface is sufficient to suppress megakaryopoiesis.

Decrease in Dengue virus-2 infection and reduction of cytokine/chemokine production by Uncaria guianensis in human hepatocyte cell line Huh-7

ABSTRACT BACKGROUND Dengue fever may present hemorrhages and cavitary effusions as result of exacerbated immune responses. We investigated hydro-alcoholic extracts from leaves (UGL) and bark (UGB) of the medicinal species Uncaria guinanensis with respect to antiviral effects in Dengue virus (DENV) infection and in immunological parameters associated with in vivo physiopathological features. METHODS Chemical profiles from UGB or UGL were compared in thin layer chromatography and 1H nuclear magnetic resonance using flavonoid compounds and a pentacyclic oxindole alkaloid-enriched fraction as references. DENV-2-infected hepatocytes (Huh-7) were treated with extracts. Cell viability, DENV antigens and immunological factors were detected by enzyme-linked immunosorbent assay (ELISA) or flow cytometry. FINDINGS The UGL mainly differed from UGB by selectively containing the flavonoid kaempferitrin. UGB and UGL improved hepatocyte viability. Both extracts reduced intracellular viral antigen and inhibited the secretion of viral non-structural protein (NS1), which is indicative of viral replication. Reduction in secretion of macrophage migration inhibitory factor was achieved by UGB, of interleukin-6 by UGL, and of interleukin-8 by both UGB and UGL. MAIN CONCLUSIONS The U. guianensis extracts presented, antiviral and immunomodulatory effects for DENV and possibly a hepatocyte-protective activity. Further studies may be performed to consider these products as potential candidates for the development of an herbal product for the future treatment of dengue.

Humoral cross-reactivity between Zika and dengue viruses: implications for protection and pathology.

Zika virus (ZIKV) is a re-emerging mosquito-borne flavivirus that has recently caused extensive outbreaks in Central and South America and the Caribbean. Given its association with Guillain-Barré syndrome in adults and neurological and ocular malformities in neonates, ZIKV has become a pathogen of significant public health concern worldwide. ZIKV shares a considerable degree of genetic identity and structural homology with other flaviviruses, including dengue virus (DENV). In particular, the surface glycoprotein envelope (E), which is involved in viral fusion and entry and is therefore a chief target for neutralizing antibody responses, contains regions that are highly conserved between the two viruses. This results in immunological cross-reactivity, which in the context of prior DENV exposure, may have significant implications for the generation of immune responses to ZIKV and affect disease outcomes. Here we address the issue of humoral cross-reactivity between DENV and ZIKV, reviewing the evidence for and discussing the potential impact of this cross-recognition on the functional quality of antibody responses against ZIKV. These considerations are both timely and relevant to future vaccine design efforts, in view of the existing overlap in the distribution of ZIKV and DENV and the likely spread of ZIKV to additional DENV-naive and experienced populations.

Pathogenesis of vascular leak in dengue virus infection.

Endothelial dysfunction leading to vascular leak is the hallmark of severe dengue. Vascular leak typically becomes clinically evident 3-6 days after the onset of illness, which is known as the critical phase. This critical phase follows the period of peak viraemia, and lasts for 24-48 hr and usually shows rapid and complete reversal, suggesting that it is likely to occur as a result of inflammatory mediators, rather than infection of the endothelium. Cytokines such as tumour necrosis factor-α, which are known to be elevated in the critical phase of dengue, are likely to be contributing factors. Dengue NS1, a soluble viral protein, has also been shown to disrupt the endothelial glycocalyx and thus contribute to vascular leak, although there appears to be a discordance between the timing of NS1 antigenaemia and occurrence of vascular leak. In addition, many inflammatory lipid mediators are elevated in acute dengue viral infection such as platelet activating factor (PAF) and leukotrienes. Furthermore, many other inflammatory mediators such as vascular endothelial growth factor and angiopoietin-2 have been shown to be elevated in patients with dengue haemorrhagic fever, exerting their action in part by inducing the activity of phospholipases, which have diverse inflammatory effects including generation of PAF. Platelets have also been shown to significantly contribute to endothelial dysfunction by production of interleukin-1ß through activation of the NLRP3 inflammasome and also by inducing production of inflammatory cytokines by monocytes. Drugs that block down-stream immunological mediator pathways such as PAF may also be beneficial in the treatment of severe disease.

Platelets: much more than bricks in a breached wall.

Platelets have various roles in vascular biology and homeostasis. They are the first actor in primary haemostasis and play important roles in thrombosis pathogenesis, but they are also part of innate immunity, which initiates and accelerate many inflammatory conditions. In some contexts, their immune functions are protective, while in others they contribute to adverse inflammatory outcomes. Platelets express numerous receptors and contain hundreds of secretory molecules that are crucial for platelet functional responses. The capacity of platelets to produce and secrete cytokines, chemokines and related molecules, under the control of specific intracellular pathways, is intimately related to their key role in inflammation. They are also able to intervene in tissue regeneration and repair because they produce pro-angiogenic mediators. Due to this characteristic platelets are involved in cancer progression and spreading. In this review we discuss the complex role of platelets, which bridges haemostasis, inflammation and immune response both in physiological and pathological conditions.

Severity of Plasma Leakage Is Associated With High Levels of Interferon γ-Inducible Protein 10, Hepatocyte Growth Factor, Matrix Metalloproteinase 2 (MMP-2), and MMP-9 During Dengue Virus Infection.

BACKGROUND: Dengue virus infection typically causes mild dengue fever, but, in severe cases, life-threatening dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) occur. The pathophysiological hallmark of DHF and DSS is plasma leakage that leads to enhanced vascular permeability, likely due to a cytokine storm. METHODS: Ninety patients with dengue during 2010-2012 in Singapore were prospectively recruited and stratified according to their disease phase, primary and secondary infection status, and disease severity, measured by plasma leakage. Clinical parameters were recorded throughout the disease progression. The levels of various immune mediators were quantified using comprehensive multiplex microbead-based immunoassays for 46 immune mediators. RESULTS: Associations between clinical parameters and immune mediators were analyzed using various statistical methods. Potential immune markers, including interleukin 1 receptor antagonist, interferon γ-inducible protein 10, hepatocyte growth factor, soluble p75 tumor necrosis factor α receptor, vascular cell adhesion molecule 1, and matrix metalloproteinase 2, were significantly associated with significant plasma leakage. Secondary dengue virus infections were also shown to influence disease outcome in terms of disease severity. CONCLUSIONS: This study identified several key markers for exacerbated dengue pathogenesis, notably plasma leakage. This will allow a better understanding of the molecular mechanisms of DHF and DSS in patients with dengue.

B Cell Responses during Secondary Dengue Virus Infection Are Dominated by Highly Cross-Reactive, Memory-Derived Plasmablasts.

UNLABELLED: Dengue virus (DENV) infection results in the production of both type-specific and cross-neutralizing antibodies. While immunity to the infecting serotype is long-lived, heterotypic immunity wanes a few months after infection. Epidemiological studies link secondary heterotypic infections with more severe symptoms, and cross-reactive, poorly neutralizing antibodies have been implicated in this increased disease severity. To understand the cellular and functional properties of the acute dengue virus B cell response and its role in protection and immunopathology, we characterized the plasmablast response in four secondary DENV type 2 (DENV2) patients. Dengue plasmablasts had high degrees of somatic hypermutation, with a clear preference for replacement mutations. Clonal expansions were also present in each donor, strongly supporting a memory origin for these acutely induced cells. We generated 53 monoclonal antibodies (MAbs) from sorted patient plasmablasts and found that DENV-reactive MAbs were largely envelope specific and cross neutralizing. Many more MAbs neutralized DENV than reacted to envelope protein, emphasizing the significance of virion-dependent B cell epitopes and the limitations of envelope protein-based antibody screening. A majority of DENV-reactive MAbs, irrespective of neutralization potency, enhanced infection by antibody-dependent enhancement (ADE). Interestingly, even though DENV2 was the infecting serotype in all four patients, several MAbs from two patients neutralized DENV1 more potently than DENV2. Further, half of all type-specific neutralizing MAbs were also DENV1 biased in binding. Taken together, these findings are reminiscent of original antigenic sin (OAS), given that the patients had prior dengue virus exposures. These data describe the ongoing B cell response in secondary patients and may further our understanding of the impact of antibodies in dengue virus pathogenesis. IMPORTANCE: In addition to their role in protection, antibody responses have been hypothesized to contribute to the pathology of dengue. Recent studies characterizing memory B cell (MBC)-derived MAbs have provided valuable insight into the targets and functions of B cell responses generated after DENV exposure. However, in the case of secondary infections, such MBC-based approaches fail to distinguish acutely induced cells from the preexisting MBC pool. Our characterization of plasmablasts and plasmablast-derived MAbs provides a focused analysis of B cell responses activated during ongoing infection. Additionally, our studies provide evidence of OAS in the acute-phase dengue virus immune response, providing a basis for future work examining the impact of OAS phenotype antibodies on protective immunity and disease severity in secondary infections.

A systematic review of observational studies on oxidative/nitrosative stress involvement in dengue pathogenesis / Revisión sistemática de los estudios observacionales sobre el papel del estrés oxidativo-nitrosativo en la patogénesis del dengue

Objective: Our objective was to systematically review the published observational research related to the role of oxidative-nitrosative stress in pathogenesis of dengue. Methods: We searched electronic databases (PubMed, EMBASE, The COCHRANE library, ScienceDirect, Scopus, SciELO, LILACS via Virtual Health Library, Google Scholar) using the term: dengue, dengue virus, severe dengue, oxidative stress, nitrosative stress, antioxidants, oxidants, free radicals, oxidized lipid products, lipid peroxides, nitric oxide, and nitric oxide synthase. Articles were selected for review by title and abstract excluding letter, review, in vivo and in vitro studies, and duplicates studies. Selected articles were reviewed for study design, original purposes, sample size, main outcomes, methods, and oxidative-nitrosative stress markers values. Results: In total, 4,331 non-duplicates articles were identified from electronic databases searches, of which 16 were eligible for full text searching. Data from the observational studies originate from Asian countries (50%; 8/16), South American countries (31.2%; 5/16), and Central America and the Caribbean countries (18.8%; 3/16). Case-control study was the type of design most common in researches reviewed. The 1997 World Health Organization (WHO) dengue case classification criteria were used in all studies included in this review. Conclusions: Based on published data found in peer-reviewed literature, oxidative and nitrosative stress are demonstrated by changes in plasma levels of nitric oxide, antioxidants, lipid peroxidation and protein oxidation markers in patients with dengue infection. Additionally, elevated serum protein carbonyls and malondialdehyde levels appear to be associated with dengue disease severity.

Objetivo: Sistematizar las evidencias observacionales sobre la relación entre el estrés oxidativo-nitrosativo y la patogénesis del dengue. Métodos: Revisión sistemática de estudios observacionales en las bases de datos (PubMed, EMBASE, The COCHRANE library, ScienceDirect, Scopus, SciELO, LILACS via Virtual Health Library, Google Scholar) utilizando las siguientes palabras clave: dengue, dengue virus, severe dengue, oxidative stress, nitrosative stress, antioxidants, oxidants, free radicals, oxidized lipid products, lipid peroxides, nitric oxide y nitric oxide synthase. La selección inicial fue realizada a partir del título y resumen excluyéndose: cartas para editor, revisiones, estudios in vivo/in vitro y duplicados. A cada artículo seleccionado, se le revisó el diseño del estudio, objetivo, tamaño de la muestra, resultados principales y niveles plasmáticos de los marcadores de estrés oxidativo-nitrosativo. Resultados: De 4,331 publicaciones encontradas, 16 estudios cumplieron con los criterios de inclusión. El 50% (8/16) de los estudios revisados fueron realizados en países de Sur América, Centro América y del Caribe. El diseño de casos y controles fue el más frecuente. El anterior sistema de clasificación de casos (OMS-1997) fue utilizado en todos los estudios incluidos en esta revisión. Conclusiones: El estrés oxidativo-nitrosativo se encuentra presente en el curso de la infección por virus dengue, demostrado por los cambios en las concentraciones plasmáticas de óxido nítrico, antioxidantes y marcadores de lipoperoxidación y de oxidación de proteínas. Por último, parece existir una asociación entre la elevación de los niveles plasmáticos de los carbonilos proteicos y malondialdehído con la severidad del dengue.

Thrombocytopenia in Dengue: Interrelationship between Virus and the Imbalance between Coagulation and Fibrinolysis and Inflammatory Mediators.

Dengue is an infectious disease caused by dengue virus (DENV). In general, dengue is a self-limiting acute febrile illness followed by a phase of critical defervescence, in which patients may improve or progress to a severe form. Severe illness is characterized by hemodynamic disturbances, increased vascular permeability, hypovolemia, hypotension, and shock. Thrombocytopenia and platelet dysfunction are common in both cases and are related to the clinical outcome. Different mechanisms have been hypothesized to explain DENV-associated thrombocytopenia, including the suppression of bone marrow and the peripheral destruction of platelets. Studies have shown DENV-infected hematopoietic progenitors or bone marrow stromal cells. Moreover, anti-platelet antibodies would be involved in peripheral platelet destruction as platelets interact with endothelial cells, immune cells, and/or DENV. It is not yet clear whether platelets play a role in the viral spread. Here, we focus on the mechanisms of thrombocytopenia and platelet dysfunction in DENV infection. Because platelets participate in the inflammatory and immune response by promoting cytokine, chemokine, and inflammatory mediator secretion, their relevance as "immune-like effector cells" will be discussed. Finally, an implication for platelets in plasma leakage will be also regarded, as thrombocytopenia is associated with clinical outcome and higher mortality.

VEGF and its receptors in dengue virus infection.

Vascular permeability determines the severity of dengue virus infection. Vascular endothelial growth factor (VEGF) and its (receptor 1) R1 and (receptor 2) R2 receptors may provide insight about the neurological complications of dengue. We report VEGF and its R1 and R2 receptors level in dengue patients and correlate these with neurological complications. Consecutive patients with dengue were subjected to clinical and neurological evaluations. Their blood counts, serum chemistry, including liver and kidney function tests, serum creatine kinase (CK), and albumin were measured. VEGF, VEGFR1 and VEGFR2 were measured by ELISA in the patients and 16 matched controls. Twenty four patients with dengue were included whose ages ranged between 15 and 67 years, and nine of whom were females. Serum VEGF level was insignificantly lower in dengue patients whereas VEGFR1 was significantly higher (P = 0.01) and VEGFR2 was significantly lower (P = 0.005) compared to controls. VEGFR2 correlated with systolic blood pressure, coagulopathy, and serum CK levels. None of the other clinical and biochemical parameters correlated with VEGF and VEGFR1 levels. VEGFR1 and R2 normalized at 1 month. VEGFR2 correlates with the clinical severity of dengue and muscle dysfunction.

Neuropsychiatric manifestations of some tropical diseases.

Some tropical diseases are the direct cause of severe disturbances of cerebral function while others affect only finer cerebral systems controlling fears, anxiety and personality traits. The mechanisms by which psychiatric symptoms are produced in tropical disorders are not any different from the mechanisms that relate to any physical disorders. Neuropsychiatric symptoms may be caused by a number of different mechanisms including bacterial toxins, release of cytokines, hyperthermia, shock (poor perfusion), acute renal insufficiency, pulmonary failure (shock lung), coagulopathy, disruption of the blood-brain barrier, and/or the nest of pathogens into the central nervous system. The following tropical illnesses can be associated with neuropsychiatric symptoms: neurocysticercosis, malaria, trypanosomiasis, dengue, and schistosomiasis. Neurological and psychiatric impairments induced by tropical diseases both represent a major category of invalidating disorders, which cause profound changes in the nervous system functions, often associated with severe sequels or late-onset disturbances. It is therefore important to disseminate knowledge of the neuropsychiatric symptoms accompanying tropical diseases in order to increase the awareness of these problems and challenges.