Role of cognitive parameters in dengue hemorrhagic fever and dengue shock syndrome

Exploring the interplay between miRNAs, apoptosis and viral load, in Dengue virus infection

Dengue virus (DENV) is a major global health concern, causing millions of infections annually. Understanding the cellular response to DENV infection is crucial for developing effective therapies. This study provides an in-depth analysis of the cellular response to Dengue virus (DENV) infection, with a specific focus on the interplay between microRNAs (miRNAs), apoptosis, and viral load across different DENV serotypes. Utilizing a variety of cell lines infected with four DENV serotypes, the research methodically quantifies viral load, and the expression levels of miRNA-15, miRNA-16, and BCL2 protein, alongside measuring apoptosis markers. Methodologically, the study employs quantitative PCR for viral load and miRNA expression analysis, and Western blot for apoptosis and BCL2 detection, with a statistical framework that includes ANOVA and correlation analysis to discern significant differences and relationships. The findings reveal that despite similar viral loads across DENV serotypes, DENV-2 exhibits a marginally higher load. A notable upregulation of miRNA-15 and miRNA-16 correlates positively with increased viral load, suggesting their potential role in modulating viral replication. Concurrently, a marked activation of caspases 3 and 7, along with changes in BCL2 protein levels, underscores the role of apoptosis in the cellular response to DENV infection. Conclusively, the study enhances the understanding of miRNA involvement in DENV pathogenesis, highlighting miRNA-15 and miRNA-16 as potential regulatory agents in viral replication and apoptosis. These findings pave the way for further exploration into miRNA-based therapeutic strategies against DENV infection.

Distinct serum exosomal miRNA profiles detected in acute and asymptomatic dengue infections: A community-based study in Baiyun District, Guangzhou

Background

In recent years, research on exosomal miRNAs has provided new insights into exploring the mechanism of viral infection and disease prevention. This study aimed to investigate the serum exosomal miRNA expression profile of dengue-infected individuals through a community survey of dengue virus (DENV) infection.

Methods

A seroprevalence study of 1253 healthy persons was first conducted to ascertain the DENV infection status in Baiyun District, Guangzhou. A total of 18 serum samples, including 6 healthy controls (HC), 6 asymptomatic DENV infections (AsymptDI), and 6 confirmed dengue fever patients (AcuteDI), were collected for exosome isolation and then sRNA sequencing. Through bioinformatics analysis, we discovered distinct serum exosomal miRNA profiles among the different groups and identified differentially expressed miRNAs (DEMs). These findings were further validated by qRT-PCR.

Results

The community survey of DENV infection indicated that the DENV IgG antibody positivity rate among the population was 11.97 % in the study area, with asymptomatic infected individuals accounting for 93.06 % of the anti-DENV IgG positives. The age and Guangzhou household registration were associated with DENV IgG antibody positivity by logistic regression analysis. Distinct miRNA profiles were observed between healthy individuals and DENV infections. A total of 1854 miRNAs were identified in 18 serum exosome samples from the initial analysis of the sequencing data. Comparative analysis revealed 23 DEMs comprising 5 upregulated and 18 downregulated miRNAs in the DENV-infected group (mergedDI). In comparison to AcuteDI, 18 upregulated miRNAs were identified in AsymptDI. Moreover, functional enrichment of the predicted target genes of DEMs indicated that these miRNAs were involved in biological processes and pathways related to cell adhesion, focal adhesion, endocytosis, and ECM-receptor interaction. Eight DEMs were validated by qRT-PCR.

Conclusion

The Baiyun District of Guangzhou exhibits a notable proportion of asymptomatic DENV infections as suggested in other research, highlighting the need for enhanced monitoring and screening of asymptomatic persons and the elderly. Differential miRNA expression among healthy, symptomatic and asymptomatic DENV-infected individuals suggests their potential as biomarkers for distinguishing DENV infection and offers new avenues of investigating the mechanisms underlying DENV asymptomatic infections.

Molecular characterization of circulating Dengue virus 2 during an outbreak in Northern Senegal's Saint-Louis region in 2018

Globally, 390 million people are at risk of dengue infection and over the past 50 years, the virus incidence increased thirty-fold. In Senegal, an unprecedented occurrence of outbreaks and sporadic cases have been noticed since 2017. In October 2018, an outbreak of Dengue virus 2 (DENV-2) was reported in the north of Senegal affecting multiple areas including Saint-Louis, Richard Toll, and Rosso which are located at the border with Mauritania. Of these 173 blood specimen samples collected from patients, 27 were positive for dengue by quantitative reverse transcription PCR (qRT-PCR), and eight were serologically confirmed to be positive for DENV immunoglobulin M (IgM). Serotyping using qRT-PCR reveals that isolates were positive for DENV-2. A subset of DENV-2 positive samples was selected and subjected to whole-genome sequencing followed by phylogenetic analysis. Analysis of six nearly complete genome sequences revealed that the isolates belong to the cosmopolitan genotype and are closely related to the Mauritanian strains detected between 2017 and 2018 and those detected in many West African countries such as Burkina Faso or Cote d'Ivoire. Our results suggest a transboundary circulation of the DENV-2 cosmopolitan genotype between Senegal and Mauritania and call for a need for coordinated surveillance of arboviruses between these two countries. Interestingly, a high level of homology between West African isolates highlights endemicity and calls for the set-up of subregional viral genomic surveillance which will lead to a better understanding of viral dynamics, transmission, and spread across Africa.

Dengue virus serotype 2 imported case from Côte d'Ivoire to Senegal, 2017

Dengue fever is the most common arboviral infection worldwide. Its epidemiology in Africa is not yet fully understood due to the lack of awareness, the presence of other dengue-like febrile diseases, and insufficient laboratory capabilities. This paper reports on the import of dengue virus serotype 2 case from Côte d'Ivoire to Senegal in West Africa. Phylogenetic analysis based on full-length genome sequence revealed that the isolate clustered with strains of cosmopolitan genotypes from the Burkina Faso outbreak in 2016 and those from the ongoing dengue fever outbreak in Côte d'Ivoire. This suggests a possible spread of strains from the Burkina Faso outbreak to other West African countries including Côte d'Ivoire and Senegal.

Mathematical Model of Antiviral Immune Response against the COVID-19 Virus

This work presents a mathematical model to investigate the current outbreak of the coronavirus disease 2019 (COVID-19) worldwide. The model presents the infection dynamics and emphasizes the role of the immune system: both the humoral response as well as the adaptive immune response. We built a mathematical model of delay differential equations describing a simplified view of the mechanism between the COVID-19 virus infection and the immune system. We conduct an analysis of the model exploring different scenarios, and our numerical results indicate that some theoretical immunotherapies are successful in eradicating the COVID-19 virus.

Use of Animal Models in Studying Roles of Antibodies and Their Secretion Cells in Dengue Vaccine Development

The cardinal feature of adaptive immunity is its ability to form memory responses that can be rapidly recalled to contain pathogens upon reencountering. Conferring a robust memory immune response to an infection is a key feature for a successful vaccination program. The plasmablasts are cells that not only can secret non-neutralizing antibodies but also can secrete the specific antibodies essential to neutralize and inactivate the invading pathogens. Dengue has been recognized as one of the most important vector-borne human viral diseases globally. Currently, supportive care with vigilant monitoring is the standard practice since there is as yet no approved therapeutic modality to treat dengue. Even though the approved vaccine has become available, its low efficacy with the potential to cause harm is the major hurdle to promote the widespread usage of the vaccine. Despite the decades of research on dengue, the major challenge in dengue vaccine development is the absence of suitable experimental animal models that reflect the pathological features and clinical symptoms, as seen in humans. Dengue is transmitted by the bite of mosquitoes carrying infectious dengue virus (DENV), which has four distinct serotypes. Recently, cases resulting from unconventional transmission routes, such as blood transfusion, organs as well as stem cells and bone marrow transplantations, and mother-to-infant vertical transmission, have been reported, suggesting an alternate route of DENV transmission exists in nature. This review discusses issues and challenges needing to be resolved to develop an effective dengue vaccine. Development of a robust and reliable dengue animal model that can reflect not only dynamic human clinical symptoms but also can answer around why preexisting neutralizing antibodies do not confer protection upon re-infection and immune protection marker for dengue vaccine efficacy evaluation.

Dengue haemorrhagic fever: An emerging disease in Nigeria, West Africa

INTRODUCTION

In Nigeria, dengue fever caused by dengue virus, types 1 and 2 has been diagnosed for many years. Although, seroepidemiological surveys have shown that dengue virus activity is, widespread in the country, there is scanty information on dengue, hemorrhagic fever with little attention paid to dengue fever largely, because it presents as classical dengue fever characterized by fever, myalgia, headache, arthralgia, retro-orbital pain, gastro intestinal, symptoms and skin rash. We are updating the current information of dengue, in Nigeria, as well as DHF which is an emerging disease in the west, African country.

METHODS

PUBMED, Google scholar, cross-reference databases and individual publications not publicly archived were used. All available literature on, dengue from Nigeria were identified.

RESULTS

Dengue virus 3 and 4 have been recently detected in Nigeria, with the emergence of dengue haemorrhagic fever for the first time. Poor, surveillance, underreporting, and misdiagnosis of the disease as malaria, are major problems.

CONCLUSION

Priority must be given to increasing surveillance activity to, detect more dengue haemorrhagic fever cases and determine the magnitude, of the dengue problem. It is important to enhance the capacity of, laboratories to diagnose dengue haemorrhagic fever by providing them with, modern equipment, reagents and new infrastructure.

Targeting heat shock factor 1 as an antiviral strategy against dengue virus replication in vitro and in vivo

Fever onset is correlated with viremia in dengue virus (DENV) patients. Heat shock factor 1 (HSF1), a heat stress response host transcription factor, plays a crucial role in regulating multiple cellular functions, as well as the onset of infectious diseases. This study evaluated the role of HSF1 in DENV replication as a means of regulating DENV infection in vitro and in vivo. DENV infection activated HSF1 in both Ca²⁺ and protein kinase A-dependent manners. Inhibiting HSF1 effectively reduced DENV replication, not only in THP-1 cells but also in primary human monocytes. Activated HSF1 contributed to DENV replication by upregulating autophagy-related protein (Atg) 7, as autophagy is crucial for virus replication. Heat stress also activated HSF1, which in turn facilitated DENV replication. Activated HSF1, the increased Atg7, and autophagic induction were founded in the DENV-infected brains and pharmacologically inhibiting HSF1 reduced autophagy, viral protein expression, neuropathy, and mortality. These results provide new insight into HSF1 as a novel host factor for DENV infection through its role in facilitating autophagy-regulated viral replication in the brains.

The value of daily platelet counts for predicting dengue shock syndrome: Results from a prospective observational study of 2301 Vietnamese children with dengue

BACKGROUND

Dengue is the most important mosquito-borne viral infection to affect humans. Although it usually manifests as a self-limited febrile illness, complications may occur as the fever subsides. A systemic vascular leak syndrome that sometimes progresses to life-threatening hypovolaemic shock is the most serious complication seen in children, typically accompanied by haemoconcentration and thrombocytopenia. Robust evidence on risk factors, especially features present early in the illness course, for progression to dengue shock syndrome (DSS) is lacking. Moreover, the potential value of incorporating serial haematocrit and platelet measurements in prediction models has never been assessed.

METHODOLOGY/PRINCIPAL FINDINGS

We analyzed data from a prospective observational study of Vietnamese children aged 5-15 years admitted with clinically suspected dengue to the Hospital for Tropical Diseases in Ho Chi Minh City between 2001 and 2009. The analysis population comprised all children with laboratory-confirmed dengue enrolled between days 1-4 of illness. Logistic regression was the main statistical model for all univariate and multivariable analyses. The prognostic value of daily haematocrit levels and platelet counts were assessed using graphs and separate regression models fitted on each day of illness. Among the 2301 children included in the analysis, 143 (6%) progressed to DSS. Significant baseline risk factors for DSS included a history of vomiting, higher temperature, a palpable liver, and a lower platelet count. Prediction models that included serial daily platelet counts demonstrated better ability to discriminate patients who developed DSS from others, than models based on enrolment information only. However inclusion of daily haematocrit values did not improve prediction of DSS.

CONCLUSIONS/SIGNIFICANCE

Daily monitoring of platelet counts is important to help identify patients at high risk of DSS. Development of dynamic prediction models that incorporate signs, symptoms, and daily laboratory measurements, could improve DSS prediction and thereby reduce the burden on health services in endemic areas.

Association of lipid profile alterations with severe forms of dengue in humans

Previous studies have shown a relationship between circulating lipids and dengue virus infection; however, the association of altered lipid profiles with severe dengue remains little studied. The aim of this study was to determine the association between circulating lipid content and severe dengue and/or platelet counts. Ninety-eight patients (2-66 years old) classified as having dengue without warning signs (DNWS), dengue with warning signs (DWWS), or severe dengue (SD) and 62 healthy individuals were studied. Blood samples were tested for NS1, anti-dengue IgM, platelet content, total cholesterol (TC), triglycerides (T), high-density lipoproteins (HDL), low-density lipoproteins (LDL) and very-low-density lipoproteins (VLDL). Lipid alterations were observed mainly in patients with SD. Increased T and VLDL was observed in SD, and increased HDL was observed in DWWS and SD. Decreased TC was found in all forms of dengue, and the lowest LDL values were found in SD. Platelet counts were significantly decreased in DWWS and SD when compare to DNWS. A positive correlation (p = 0.019) between LDL values and platelet counts and a negative correlation (p = 0.0162) between VLDL values and platelet counts were found. Lipid profile alterations were associated with severe dengue.

Rhamnolipids: solution against Aedes aegypti?

Aedes aegypti mosquitoes are the primary transmitters of dengue fever, urban yellow fever, and chikungunya viruses. This mosquito has developed resistance to the insecticides currently used to control their populations. These chemical insecticides are harmful to the environment and can have negative effects on human health. Rhamnolipids are environmentally compatible biological surfactants, but their insecticidal activity has not been extensively studied. The present study evaluated the potential larvicidal, insecticidal, and repellent activities of rhamnolipids against A. aegypti. At concentrations of 800, 900, and 1000 mg/L, rhamnolipids eliminated all mosquito larvae in 18 h and killed 100% of adults at 1000 mg/L. According to the results it may be conclude that rhamnolipids should be applied to control larvae and mosquitos besides present the repellency activity against A. aegypti.