Cytokine Expression in Dengue Fever and Dengue Hemorrhagic Fever Patients with Bleeding and Severe Hepatitis

Rhinovirus infection and co-infection in children with severe acute respiratory infection during the COVID-19 pandemic period

Rhinovirus causes respiratory tract infections in children and is found in co-infections. The objective of this research was to study the clinical profile of rhinovirus infection and co-infection in children with severe acute respiratory infection (SARI) during the COVID-19 pandemic period. We included 606 children ranging in age from 0.1 to 144 months of age from March 2020 to December 2021, hospitalized in the Pediatric Intensive Care Unit (PICU). The samples were collected by secretion from the nasopharynx region. A total of 259 children were tested positive for viral infection, 153 (59.07%) of them had a single rhinovirus infection and, 56 (36.6%) were aged between 60.1 and 144 months. Nine types of co-infections were identified and were found coinfection with three or more viruses (22/104, 21.15%). Observing the seasonality, the number of cases was similar between 2020 (49.53%) and 2021 (51.47%). Patients with a single infection (86.88%) and coinfection (67.30%) were more likely to have coughed. Patients with co-infection required the use of O2 for longer than those with a single rhinovirus infection. Hemogram results obtained from individuals with a single infection had higher levels of urea when compared to patients with co-infection with and other respiratory viruses. Multiple correspondence analyses indicated different clinical symptoms and comorbidities in patients with co-infection compared to those with single infection. The results found that the rhinovirus was much prevalent virus during the pandemic period and was found in co-infection with other virus types, what is important to diagnostic for the correct treatment of patients.

Secondary Dengue Infection Elicits Earlier Elevations in IL-6 and IL-10 Levels

This study investigates the kinetics of interleukine-6 (IL-6) and interleukine-10 (IL-10) levels in dengue virus (DENV) infections during the febrile stage. Viremic patients were categorized into two phases based on anti-DENV IgM presence. Among 259 patients, 71% were in Phase I and 29% in Phase II. Secondary infections, accounting for 38.2% of cases, exhibited earlier elevations of IL-6 and IL-10 than primary infections, suggesting that pre-existing immune memory primes faster cytokine release. Thrombocytopenia and elevated aspartate transaminase (AST) levels were associated with Phase II, secondary infections, and hospitalization. Elevated IL-6 and IL-10 levels correlated with low platelet counts, linking them to clinical manifestations. The key finding is that IL-6 and IL-10 levels rise earlier in secondary infections compared to primary infections, whereas elevated cytokine levels typically occur later in the febrile phase. This study highlights the importance of cytokine dynamics in DENV infections, particularly during the early stages. The observation of cytokine concentration changes, especially in viremic samples, provides insights into the progression of dengue disease. Further research with broader cytokine panels is warranted to validate and expand these findings.

Analysis of Dengue and SARS-CoV-2 Coinfection in a Tertiary Care Hospital: A Retrospective Study

Introduction

Coinfection of dengue virus and SARS-CoV-2 infections in dengue-endemic areas is a significant public health concern. Coinfections can result in severe illness. Hence, this study determines the incidence of dengue and COVID-19 coinfection for a better understanding of the clinical presentation, laboratory parameters, and outcomes including mortality.

Methods

The patients admitted to two tertiary hospitals with RT PCR-proven COVID-19 infection and dengue positive by NS1 rapid antigen or IgM dengue ELISA for two years between January 2020 and December 2022 were considered. Clinical data were retrieved from medical records including the laboratory findings and outcomes of these patients. The categorical data were analyzed in the form of frequency and proportion. The quantitative data were analyzed in the form of mean, median, and proportion.

Results

Out of 2301 confirmed dengue samples and 3718 confirmed COVID-19 samples, there were 14 cases of coinfection with the presence of COVID-19 and dengue infection at the same time. ICU admission of 14.2% and mean hospital stay of 7 days were noted. Mainly the symptoms reported were fever at 92.9%, myalgia at 35.7%, and headache, vomiting, and cough at 28.6%. The laboratory findings were elevated lactate dehydrogenase and C-reactive protein in 100% of patients, elevated ferritin in 92.9%, thrombocytopenia in 71.4%, elevated AST and ALT in 71.4%, and elevated D-dimer in 57.1% of patients. There was no effect on morbidity and mortality seen among coinfection.

Conclusion

COVID-19 and dengue share similar clinical features and laboratory findings. Diagnosis of one disease cannot rule out the presence of other infections. There might be chances of misdiagnosis or missed diagnosis. Hence, it is important to stress about early detection using specific methods and confirmation of disease with timely management, as it is a potentially new dimension for public health concern and management.

The interplay of co-infections in shaping COVID-19 severity: Expanding the scope beyond SARS-CoV-2

High mortality has been reported in severe cases of COVID-19. Emerging reports suggested that the severity is not only due to SARS-CoV-2 infection, but also due to coinfections by other pathogens exhibiting symptoms like COVID-19. During the COVID-19 pandemic, simultaneous respiratory coinfections with various viral (Retroviridae, Flaviviridae, Orthomyxoviridae, and Picoviridae) and bacterial (Mycobacteriaceae, Mycoplasmataceae, Enterobacteriaceae and Helicobacteraceae) families have been observed. These pathogens intensify disease severity by potentially augmenting SARSCoV-2 replication, inflammation, and modulation of signaling pathways. Coinfection emerges as a critical determinant of COVID-19 severity, principally instigated by heightened pro-inflammatory cytokine levels, as cytokine storm. Thereby, in co-infection scenario, the severity is also driven by the modulation of inflammatory signaling pathways by both pathogens possibly associated with interleukin, interferon, and cell death exacerbating the severity. In the current review, we attempt to understand the role of co- infections by other pathogens and their involvement in the severity of COVID-19.

Elevated NS1 serum levels reduce CD119 expression and CXCL-10 synthesis in patients with dengue hemorrhagic fever

BACKGROUND

The intensity of dengue virus (DV) replication and circulating non-structural protein 1 (NS1) levels may promote changes in the human immune response and favor severe forms of infection. We investigated the correlations between NS1 with CXCL-8, CXCL-10, IFN-γ, and IL-12p40 serum levels, and IFN-γ receptor α chain (CD119) expression, and CXCL10 production by peripheral blood mononuclear cells (PBMCs) stimulated with recombinant IFN-γ in DV-infected patients with different clinical forms.

METHODS

Dengue virus NS1, CXCL-8, CXCL-10, IFN-γ, and IL-12p40 serum levels were measured in 152 DV-infected patients with different clinical forms and 20 non-infected individuals (NI) using enzyme-linked immunosorbent assay (ELISA). In addition, we investigated the CXCL-10 production after in vitro IFN-γ stimulation of PBMCs from 48 DV-infected individuals (with different clinical forms of dengue fever) and 20 NI individuals using ELISA, and CD119 expression on CD14+ cells with flow cytometry.

RESULTS

Patients with dengue hemorrhagic fever (DHF) had significantly higher NS1, CXCL-8, and CXCL-10 serum levels than those with classic dengue fever (DF). The response of PBMCs to IFN-γ stimulation was lower in patients with DHF than in those with DF or dengue with complications (DWC), with lower CD119 expression and reduced CXCL-10 synthesis. In addition, these alterations are associated with high NS1 serum levels.

CONCLUSIONS

Patients with DHF reported high NS1 levels, low CD119 expression, and low CXCL-10 synthesis in PBMCs, which may be associated with infection progression and severity.

Clinacanthus nutans (Burm. f.) Lindau Extract Inhibits Dengue Virus Infection and Inflammation in the Huh7 Hepatoma Cell Line

Dengue virus (DENV) infection has emerged as a global health problem, with no specific treatment available presently. Clinacanthus nutans (Burm. f.) Lindau extract has been used in traditional medicine for its anti-inflammatory and antiviral properties. We thus hypothesized C. nutans had a broad-ranged activity to inhibit DENV and the liver inflammation caused by DENV infection. The study showed that treatment using C. nutans extract during DENV infection (co-infection step) showed the highest efficiency in lowering the viral antigen concentration to 22.87 ± 6.49% at 31.25 μg/mL. In addition, the virus-host cell binding assay demonstrated that C. nutans treatment greatly inhibited the virus after its binding to Huh7 cells. Moreover, it could remarkably lower the expression of cytokine and chemokine genes, including TNF-α, CXCL10, IL-6, and IL-8, in addition to inflammatory mediator COX-2 genes. Interestingly, the activation of the NF-κB signaling cascade after C. nutans extract treatment was dramatically decreased, which could be the underlying mechanism of its anti-inflammatory activity. The HPLC profile showed that gallic acid was the bioactive compound of C. nutans extract and might be responsible for the antiviral properties of C. nutans. Taken together, our results revealed the potential of C. nutans extract to inhibit DENV infection and lower inflammation in infected cells.

Dual action effects of ethyl-p-methoxycinnamate against dengue virus infection and inflammation via NF-κB pathway suppression

Dengue virus (DENV) infection can lead to severe outcomes through a virus-induced cytokine storm, resulting in vascular leakage and inflammation. An effective treatment strategy should target both virus replication and cytokine storm. This study identified Kaempferia galanga L. (KG) extract as exhibiting anti-DENV activity. The major bioactive compound, ethyl-p-methoxycinnamate (EPMC), significantly reduced DENV-2 infection, virion production, and viral protein synthesis in HepG2 and A549 cells, with half-maximal effective concentration (EC50) values of 22.58 µM and 6.17 µM, and impressive selectivity indexes (SIs) of 32.40 and 173.44, respectively. EPMC demonstrated efficacy against all four DENV serotypes, targeting the replication phase of the virus life cycle. Importantly, EPMC reduced DENV-2-induced cytokines (IL-6 and TNF-α) and chemokines (RANTES and IP-10), as confirmed by immunofluorescence and immunoblot analyses, indicating inhibition of NF-κB activation. EPMC's role in preventing excessive inflammatory responses suggests it as a potential candidate for dengue treatment. Absorption, distribution, metabolism, excretion, and toxicity (ADMET) and drug-likeness for EPMC were predicted using SwissADME and ProTox II servers, showing good drug-like properties without toxicity. These findings highlight KG extract and EPMC as promising candidates for future anti-dengue therapeutics, offering a dual-action approach by inhibiting virus replication and mitigating inflammatory reactions.

Cytokine profiles in dengue fever and dengue hemorrhagic fever: A study from Indonesia

Recent studies have demonstrated that cytokine dysregulation has a critical role in the pathogenesis of dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). The aim of this study was to investigate the association between tumor necrosis factor (TNF- α), interleukin 6 (IL-6), interleukin 10 (IL-10), and interleukin 17 (IL-17) with infection status, and severity of dengue. A prospective cross-sectional study was conducted at three hospitals in Gianyar regency and Denpasar municipality, Bali, Indonesia, from June to December 2022. Sixty-four dengue infected patients were involved. Patients' serum was tested for dengue infection using NS1 antigen rapid test, dengue virus immunoglobulin M (IgM) and immunoglobulin G (IgG) test, and reverse transcription polymerase chain reaction (RT-PCR). Cytokine levels (TNF-α, IL-6, IL-10, and IL-17) were measured using enzyme-linked immunosorbent assay (ELISA). Infection status was determined by combining serological and RT-PCR results, categorizing patients into primary and secondary infections. The present study found that DF patients had lower TNF-α, IL-6, and IL-17 but higher IL-10 levels compared to DHF patients (p<0.001). Elevated TNF-α, IL-6, and IL-17 levels were higher in secondary infection, while IL-10 level was higher in primary infection (p<0.001). In conclusion, cytokines play a crucial role in the interplay between cytokine dysregulation and dengue infection dynamics.

Anti-inflammatory effect of Faloak (Sterculia quadrifida R. Br) stem bark on TNF-α, IL-1β, and IL-6 in DENV-3-infected Wistar rats

Background

Dengue infection can trigger an immunological response that results in an inflammatory reaction, which acts as a defensive mechanism to protect the host. Dengue infection leads to an elevation in the release of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6). These three cytokines have been shown to correlate with the development of thrombocytopenia and plasma leakage, which is related to the severity of the disease.

Aim

This study aims to investigate the effect of faloak (Sterculia quadrifida R. Br) stem bark on TNF-α, IL-1β, and IL-6 levels in Wistar rats infected with dengue, specifically DENV-3.

Methods

A group of 27 male Wistar rats (Rattus norvegicus) aged 2-3 months and weighting 200-300 g were divided into three distinct groups: healthy, dengue, and treatment (dengue infection and extract) groups. The rats in both the dengue and treatment groups were administered an injection of DENV-3 with a titer of 105 pfu at a dosage of 0.8 cc via the intraperitoneal route. The propagation of DENV-3 was initiated using C6/36 cells, and it underwent four passages. The extract was administered orally via a nasogastric tube at a dosage of 1,500 mg/kg body weight once daily for 7 days. The healthy group underwent blood sampling on the first day, whereas the dengue and therapy groups underwent blood sampling on the fifth and eighth, respectively.

Results

Compared with the healthy group, TNF-α levels in the dengue and treatment groups showed significant differences on day 5 post-infection. The post hoc analysis revealed a statistically significant difference between the dengue-treatment and dengue-healthy groups. The IL-1β levels in the dengue and healthy groups significantly differed on days 5 and 8 post-infection compared to the healthy group. The treatment group had less of a decrease in IL-6 levels on days 5 and 8 than the dengue group. However, no statistically significant differences were observed.

Conclusion

The stem bark of S. quadrifida shows potential as an anti-inflammatory agent in dengue infections, particularly in its ability to decrease levels of TNF-α and IL-1β.

Temporal cytokine storm dynamics in dengue infection predicts severity

The immunopathogenesis of dengue severity is convoluted. The primary objective of the research was to examine the dynamics of cytokine storm and its correlation with disease development in individuals affected by DENV infection. Additionally, the study aimed to discover potential biomarkers that could indicate severe dengue infection and determine the most suitable timeframe for predicting the severity of these biomarkers during the acute stage of dengue infections. We conducted a temporal analysis of the daily viral load and cytokine levels in 60 hospitalized dengue patients until discharge. Our findings reveal a distinct cytokine profile (elevated IL-8, IL-10, IL-6, GM-CSF, MCP-1, IL-13, and IL-4 and decreased IL-12, MIP-1β) on the third day after symptom onset is predictive of severe dengue in secondary dengue infection. The imbalanced cytokine signature may inform clinical decision-making in treating severe dengue infections.

Extracellular vesicles recovered from plasma of severe dengue patients induce CD4+ T cell suppression through PD-L1/PD-1 interaction

IMPORTANCE

Severe dengue manifestations caused by the dengue virus are a global health problem. Studies suggest that severe dengue disease depends on uncontrolled immune cell activation, and excessive inflammation adds to the pathogenesis of severe dengue disease. Therefore, it is important to understand the process that triggers the uncontrolled activation of the immune cells. The change in immune response in mild to severe dengue may be due to direct virus-to-cell interaction or it could be a contact-independent process through the extracellular vesicles (EVs) released from infected cells. The importance of circulating EVs in the context of dengue virus infection and pathogenesis remains unexplored. Therefore, understanding the possible biological function of circulating EVs may help to delineate the role of EVs in the progression of disease. Our present study highlights that EVs from plasma of severe dengue patients can have immunosuppressive properties on CD4+ T cells which may contribute to T cell suppression and may contribute to dengue disease progression.

Viremia and Inflammatory Cytokines in Dengue: Interleukin-2 as a Biomarker of Infection, and Interferon-α and -γ as Markers of Primary versus Secondary Infection

The pathogenesis of Dengue virus (DENV) infection is complex and involves viral replication that may trigger an inflammatory response leading to severe disease. Here, we investigated the correlation between viremia and cytokine levels in the serum of DENV-infected patients. Between 2013 and 2014, 138 patients with a diagnosis of acute-phase DENV infection and 22 patients with a non-dengue acute febrile illness (AFI) were enrolled. Through a focus-forming assay (FFU), we determined the viremia levels in DENV-infected patients and observed a peak in the first two days after the onset of symptoms. A higher level of viremia was observed in primary versus secondary DENV-infected patients. Furthermore, no correlation was observed between viremia and inflammatory cytokine levels in DENV-infected patients. Receiver operating characteristic (ROC) curve analysis revealed that IL-2 has the potential to act as a marker to distinguish dengue from other febrile illnesses and is positively correlated with Th1 cytokines. IFN-α and IFN-γ appear to be potential markers of primary versus secondary infection in DENV-infected patients, respectively. The results also indicate that viremia levels are not the main driving force behind inflammation in dengue and that cytokines could be used as infection biomarkers and for differentiation between primary versus secondary infection.

Complement receptor type 1 and 2 (CR1 and CR2) gene polymorphisms and plasma protein levels are associated with the Dengue disease severity

The pathological outcome of dengue disease results from complex interactions between dengue virus (DENV) and host genetics and immune response. Complement receptor types 1 and 2 (CR1 and CR2) mediate complement activation through the alternative pathway. This study investigated the possible association of genetic polymorphisms and plasma levels of CR1 and CR2 with dengue disease. A total of 267 dengue patients and 133 healthy controls were recruited for this study. CR1 and CR2 gene polymorphisms were analyzed by Sanger sequencing, while plasma CR1 and CR2 levels were measured by ELISA. The frequency of the CR1 minor allele rs6691117G was lower in dengue patients and those with severe dengue compared to healthy controls. Plasma CR1 and CR2 levels were decreased in dengue patients compared to healthy controls (P < 0.0001) and were associated with platelet counts. CR1 levels were lower in dengue patients with warning signs (DWS) compared to those without DWS, while CR2 levels were decreased according to the severity of the disease and after 5 days (T1) and 8 days (T2) of follow-up. CR2 levels were decreased in dengue patients positive for anti-DENV IgG and IgM and patients with bleeding and could discriminate DWS and SD from dengue fever patients (AUC = 0.66). In conclusion, this study revealed a reduction in CR2 levels in dengue patients and that the CR1 SNP rs6691117A/G is associated with the dengue severity. The correlation of CR2 levels with platelet counts suggests that CR2 could be an additional biomarker for the prognosis of severe dengue disease.

No Association Between Interleukin 6 and Inducible Nitric Oxide Synthase Polymorphisms and Dengue Infection: A Case-Control Study

BACKGROUND

Dengue is a life-threatening disease. The factors that lead to severe cases are not completely understood. The host immune system is involved in the response to infections and plays an important role in dengue infection. IL-6 and iNOS are components of the immune system and genetic polymorphisms in these genes may be involved in dengue virus infection. The study aimed to investigate the association of genetic polymorphisms in the IL6 and iNOS genes and dengue.

METHODS

We performed a case-control study using 60 dengue-infected individuals and 119 healthy controls. Polymorphisms in the IL6 (T15A) and iNOS (-1173CT) genes were amplified by Real-Time PCR. Statistical analyses were performed using BioEstat 5.0.

RESULTS

We identified that the frequency of T/A genotype of IL6 was higher in dengue fever patients and C/T genotype of iNOS was higher in dengue hemorrhagic fever patients, however, no association was found between these polymorphisms and dengue.

CONCLUSION

Polymorphisms in iNOS and IL6 were not associated with dengue infection.

Primary infection of BALB/c mice with a dengue virus type 4 strain leads to kidney injury

BACKGROUND

Dengue is a disease caused by dengue virus (DENV-1 through -4). Among the four serotypes, DENV-4 remains the least studied. Acute kidney injury is a potential complication of dengue generally associated with severe dengue infection.

OBJECTIVES

The goal of this study was to investigate the alterations caused by experimental dengue infection in the kidney of adult BALB/c mice.

METHODS

In this study, BALB/c mice were infected through the intravenous route with a DENV-4 strain, isolated from a human patient. The kidneys of the mice were procured and subject to histopathological and ultrastructural analysis.

FINDINGS

The presence of the viral antigen was confirmed through immunohistochemistry. Analysis of tissue sections revealed the presence of inflammatory cell infiltrate throughout the parenchyma. Glomerular enlargement was a common find. Necrosis of tubular cells and haemorrhage were also observed. Analysis of the kidney on a transmission electron microscope allowed a closer look into the necrotic tubular cells, which presented nuclei with condensed chromatin, and loss of cytoplasm.

MAIN CONCLUSIONS

Even though the kidney is probably not a primary target of dengue infection in mice, the inoculation of the virus in the blood appears to damage the renal tissue through local inflammation.

Differential expression of interferon inducible protein: Guanylate binding protein (GBP1 & GBP2) in severe dengue

Dengue virus is reported to activate endothelial cells (EC), but the precise cause for severe dengue (SD) is not known. Guanylate binding proteins (GBPs) are IFN-inducible proteins secreted by ECs and are involved in the anti-oxidant and anti-viral response. The involvement of GBPs in the pathogenesis of dengue remains under explored. In the present study, we quantified the mRNA and protein levels of GBP1 and 2 during acute, defervescence and convalescent phase in SD-10, dengue without warning sign-15 and dengue with warning sign-25 compared to other febrile illnesses-10 and healthy controls-8 using RT-PCR and ELISA respectively. Lipid peroxidation in plasma samples were measured using the Kei Satoh method. Protein and DNA oxidation were determined by ELISA. The efficacy of the proteins in predicting disease severity was done by Support Vector Machine (SVM) model. A significant (P ≤ 0.01) decrease in the levels of mRNA and protein of both GBP1 and GBP2 was observed during defervescence in both SD and DWW cases. The levels were significantly (P ≤ 0.05) tapered off in SD cases from acute till critical phases compared to other study groups. DNA, protein and lipid oxidation markers showed an increasing trend in SD (P ≤ 0.01). Both GBP1 & 2 were found to be negatively associated plasma leakage and oxidative stress markers. EC's activated with SD serum showed a reduced expression of GBP 1 and 2. Nevertheless, the SVM model revealed that plasma levels of proteins along with clinical symptoms could predict the disease outcomes with higher precision. This is the first study reporting a downregulated expression of GBP1 & 2 and their association with oxidative stress and plasma leakage in dengue cases. This suggests the importance of GBPs in regulating disease manifestation. However, further investigations are required to ascertain its role as a biomarker or therapeutic target in dengue infection.

The dengue virus 4 component of NIAID's tetravalent TV003 vaccine drives its innate immune signature

Annually, roughly 2.5 billion people are at risk for dengue virus (DENV) infection, and the incidence of infection has increased 30-fold since its discovery in the 1900s. At present, there are no globally licensed antiviral treatments or vaccines that protect against all four of the DENV serotypes. The NIAID Live Attenuated Tetravalent Vaccine (LATV) dengue vaccine candidate is composed of variants of three DENV serotypes attenuated by a 30 nucleotide (Δ30) deletion in the 3' untranslated region and a fourth component that is a chimeric virus in which the prM and E genes of DENV-2 replace those of DENV-4 on the rDEN4Δ30 backbone. The vaccine candidate encodes the non-structural proteins of DENV-1, DENV-3, and DENV-4, which could be of critical importance in the presentation of DENV-specific epitopes in a manner that facilitates antigen presentation and confers higher protection. Our findings demonstrate that the attenuation mechanism (Δ30) resulted in decreased viral infectivity and replication for each vaccine virus in monocyte-derived dendritic cells but were able to generate a robust innate immune response. When tested as monovalent viruses, DEN-4Δ30 displayed the most immunogenic profile. In addition, we found that the tetravalent DENV formulation induced a significantly greater innate immune response than the trivalent formulation. We demonstrate that the presence of two components with a DENV-4Δ30 backbone is necessary for the induction of RANTES, CD40, IP-10, and Type I IFN by the tetravalent formulation. Finally, we found that the DEN-4Δ30 backbone in the DENV-2 component of the vaccine enhanced its antigenic properties, as evidenced by enhanced ability to induce IP-10 and IFNα2 in monocyte-derived dendritic cells. In sum, our study shows that the Δ30 and Δ30/Δ31 mutations attenuate the DENV vaccine strains in terms of replication and infectivity while still allowing the induction of a robust innate immune response.

Potential role of transthoracic echocardiography for screening LV systolic dysfunction in patients with a history of dengue infection. A cross-sectional and cohort study and review of the literature

Background

Dengue virus can affect the cardiovascular system and men may be at higher risk of severe complications than women. We hypothesized that clinical dengue virus (DENV) infection could induce myocardial alterations of the left ventricle (LV) and that these changes could be detected by transthoracic echocardiography.

Methodology/Principal findings

We examined individuals from Acre in the Amazon Basin of Brazil in 2020 as part of the Malaria Heart Study. By questionnaires we collected information on self-reported prior dengue infection. All individuals underwent transthoracic echocardiography, analysis of left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS). We included 521 persons (mean age 40±15 years, 39% men, 50% urban areas) of which 253 (49%) had a history of dengue infection. In multivariable models adjusted for clinical and sociodemographic data, a history of self-reported dengue was significantly associated with lower LVEF (β = -2.37, P < 0.01) and lower GLS (β = 1.08, P < 0.01) in men, whereas no significant associations were found in women (P > 0.05). In line with these findings, men with a history of dengue had higher rates of LV systolic dysfunction (LVEF < 50% = 20%; GLS < 16% = 17%) than those without a history of dengue (LVEF < 50% = 7%; GLS < 16% = 8%; P < 0.01 and 0.06, respectively).

Conclusions/Significance

The findings of this study suggest that a clinical infection by dengue virus could induce myocardial alterations, mainly in men and in the LV, which could be detected by conventional transthoracic echocardiography. Hence, these results highlight a potential role of echocardiography for screening LV dysfunction in participants with a history of dengue infection. Further larger studies are warranted to validate the findings of this study.

Antrodia cinnamomea Suppress Dengue Virus Infection through Enhancing the Secretion of Interferon-Alpha

Dengue caused by dengue virus (DENV) is a mosquito-borne disease. Dengue exhibits a wide range of symptoms, ranging from asymptomatic to flu-like illness, and a few symptomatic cases may develop into severe dengue, leading to death. However, there are no effective and safe therapeutics for DENV infections. We have previously reported that cytokine expression, especially inflammatory cytokines, was altered in patients with different severities of dengue. Antrodia cinnamomea (A. cinnamomea) is a precious and endemic medical mushroom in Taiwan. It contains unique chemical components and exhibits biological activities, including suppressing effects on inflammation and viral infection-related diseases. According to previous studies, megakaryocytes can support DENV infection, and the number of megakaryocytes is positively correlated with the viral load in the serum of acute dengue patients. In the study, we investigated the anti-DENV effects of two ethanolic extracts (ACEs 1-2) and three isolated compounds (ACEs 3-5) from A. cinnamomea on DENV infection in Meg-01 cells. Our results not only demonstrated that ACE-3 and ACE-4 significantly suppressed DENV infection, but also reduced interleukin (IL)-6 and IL-8 levels. Moreover, the level of the antiviral cytokine interferon (IFN)-α was also increased by ACE-3 and ACE-4 in Meg-01 cells after DENV infection. Here, we provide new insights into the potential use of A. cinnamomea extracts as therapeutic agents against DENV infection. However, the detailed mechanisms underlying these processes require further investigation.

MDA5 signaling induces type 1 IFN- and IL-1-dependent lung vascular permeability which protects mice from opportunistic fungal infection

Lungs balance threat from primary viral infection, secondary infection, and inflammatory damage. Severe pulmonary inflammation induces vascular permeability, edema, and organ dysfunction. We previously demonstrated that poly(I:C) (pICLC) induced type 1 interferon (t1IFN) protected mice from Cryptococcus gattii (Cg) via local iron restriction. Here we show pICLC increased serum protein and intravenously injected FITC-dextran in the lung airspace suggesting pICLC induces vascular permeability. Interestingly, pICLC induced a pro-inflammatory signature with significant expression of IL-1 and IL-6 which depended on MDA5 and t1IFN. Vascular permeability depended on MDA5, t1IFN, IL-1, and IL-6. T1IFN also induced MDA5 and other MDA5 signaling components suggesting that positive feedback contributes to t1IFN dependent expression of the pro-inflammatory signature. Vascular permeability, induced by pICLC or another compound, inhibited Cg by limiting iron. These data suggest that pICLC induces t1IFN which potentiates pICLC-MDA5 signaling increasing IL-1 and IL-6 resulting in leakage of antimicrobial serum factors into lung airspace. Thus, induced vascular permeability may act as an innate defense mechanism against opportunistic fungal infection, such as cryptococcosis, and may be exploited as a host-directed therapeutic target.

Dengue Vaccines: An Update

Dengue is one of the most prevalent mosquito-borne diseases in the world, affecting an estimated 390 million people each year, according to models. For the last two decades, efforts to develop safe and effective vaccines to prevent dengue virus (DENV) infections have faced several challenges, mostly related to the complexity of conducting long-term studies to evaluate vaccine efficacy and safety to rule out the risk of vaccine-induced DHS/DSS, particularly in children. At least seven DENV vaccines have undergone different phases of clinical trials; however, only three of them (Dengvaxia^®, TV003, and TAK-003) have showed promising results, and are addressed in detail in this review in terms of their molecular design, efficacy, and immunogenicity. Safety-related challenges during DENV vaccine development are also discussed.

Short-term, medium-term, and long-term risks of nonvariceal upper gastrointestinal bleeding after dengue virus infection

Dengue patients have an increased risk of acute gastrointestinal (GI) bleeding. However, whether dengue virus (DENV) infection can cause an increased long-term risk of GI bleeding remains unknown, especially among elderly individuals who commonly take antithrombotic drugs. A retrospective population-based cohort study was conducted by analyzing the National Health Insurance Research Databases. Laboratory-confirmed dengue patients from 2002 to 2012 and four matched nondengue controls were identified. Multivariate Cox proportional hazard regression was used to evaluate the acute (<30 days), medium-term (31–365 days), and long-term (>365 days) risks of nonvariceal upper GI bleeding after DENV infection. Stratified analyses by age group (≤50, 51–64, ≥65 years old) were also performed. In total, 13267 confirmed dengue patients and 53068 nondengue matched controls were included. After adjusting for sex, age, area of residence, comorbidities, and medications, dengue patients had a significantly increased risk of nonvariceal upper GI bleeding within 30 days of disease onset (adjusted HR 55.40; 95% CI: 32.17–95.42). However, DENV infection was not associated with increased medium-term and long-term risks of upper GI bleeding overall or in each age group. Even dengue patients who developed acute GI bleeding did not have increased medium-term (adjusted HR; 0.55, 95% CI 0.05–6.18) and long-term risks of upper GI bleeding (adjusted HR; 1.78, 95% CI 0.89–3.55). DENV infection was associated with a significantly increased risk of nonvariceal upper GI bleeding within 30 days but not thereafter. Recovered dengue patients with acute GI bleeding can resume antithrombotic treatments to minimize the risk of thrombosis.

Dengue fever is a mosquito-borne tropical disease caused by the dengue virus. Dengue patients can have low platelet counts and might have acute gastrointestinal bleeding (tarry stool, bloody stool or bloody vomiting). Most dengue patients will fully recover and return to their previous health levels. Previous studies have indicated that some dengue patients have persistent low platelet counts and high inflammatory responses. The medium-term and long-term upper gastrointestinal bleeding risks remain unknown. Our study suggested that dengue was significantly associated with an increased risk of nonvariceal upper GI bleeding within 30 days after infection but was not associated with increased medium-term (31–365 days) and long-term risks (>365 days) of upper GI bleeding. Therefore, the risk of acute gastroenterology bleeding returned to baseline levels after 30 days. Recovered dengue patients with acute GI bleeding can resume antiplatelet, antithrombotic, and oral anticoagulation (OAC) treatments.

Patterns of serum immune biomarkers during elephant endotheliotropic herpesvirus viremia in Asian and African elephants

Hemorrhagic disease (HD) caused by a group of elephant endotheliotropic herpesviruses (EEHV) is one of the leading causes of death for young elephants in human care. These viruses are widespread and typically persist latently in adult elephants with no negative effects; however, in juvenile Asian and more recently young African elephants, the onset of disease can be rapid and the mortality rate high. Measuring biomarkers associated with the immune response could be beneficial to understanding underlying disease processes, as well as the management of infection and HD. The goal of this study was to measure acute phase proteins and cytokines in serum collected from elephants infected with EEHV (13 Asian and 1 African) and compare concentrations according to presence, severity and outcome of disease. Serum amyloid A (SAA) and haptoglobin (HP) were higher in elephants with EEHV viremia than those without; concentrations increased with increasing viral load, and were higher in fatal cases compared to those that survived. In Asian elephants, SAA was also higher during EEHV1 viremia compared to EEHV5. Cytokine concentrations were typically low, and no statistical differences existed between groups. However, in individuals with detectable levels, longitudinal profiles indicated changes in tumor necrosis factor alpha (TNF-α) and interleukin-2 (IL-2) that may reflect an immune response to EEHV infection. However, the overall low concentrations detected using previously validated assays do not support the presence of a 'cytokine storm' and suggest more work is needed to understand if sub-optimal immune responses could be involved in disease progression. These results highlight the potential benefit of measuring circulating biomarker concentrations, such as APPs and cytokines, to improve our understanding of EEHV viremia and HD, assist with monitoring the progression of disease and determining the impact of interventions.

Multisystem Inflammatory Syndrome Associated with SARS-CoV-2 Infection in an Adult: A Case Report from the Maldives

The multisystem inflammatory syndrome in adults (MIS-A) is a novel syndrome observed during COVID-19 outbreaks. This hyper-inflammatory syndrome is seen predominantly in children and adolescents. The case of an adult from the Maldives who had asymptomatic SARS-CoV-2 infection three weeks before presenting to the hospital with fever, rash, and shock is presented. De-identified clinical data were retrospectively collected to summarize the clinical progression and treatment during hospitalization and the six-month follow-up. SARS-CoV-2 infection was confirmed by RT-PCR. Other laboratory findings included anemia (hemoglobin: 9.8 g/dL), leukocytosis (leukocytes: 20,900/µL), neutrophilia (neutrophils: 18,580/µL) and lymphopenia (lymphocytes: 5067/µL), and elevated inflammatory markers, including C-reactive protein (34.8 mg/dL) and ferritin (2716.0 ng/dL). The electrocardiogram had low-voltage complexes, and the echocardiogram showed hypokinesia, ventricular dysfunction, and a pericardial effusion suggestive of myocardial dysfunction compromising hemodynamics and causing circulatory shock. These findings fulfilled the diagnostic criteria of MIS-A. The case was managed in the intensive care unit and required non-invasive positive pressure ventilation, inotropes, and steroids. With the new surges of COVID-19 cases, more cases of MIS-A that require the management of organ failure and long-term follow-up to recovery are anticipated. Clinicians should therefore be vigilant in identifying cases of MIS-A during the pandemic.

Viral coinfections in COVID-19

The most consequential challenge raised by coinfection is perhaps the inappropriate generation of recombinant viruses through the exchange of genetic material among different strains. These genetically similar viruses can interfere with the replication process of each other and even compete for the metabolites required for the maintenance of the replication cycle. Due to the similarity in clinical symptoms of most viral respiratory tract infections, and their coincidence with COVID-19, caused by SARS-CoV-2, it is recommended to develop a comprehensive diagnostic panel for detection of respiratory and nonrespiratory viruses through the evaluation of patient samples. Given the resulting changes in blood markers, such as coagulation factors and white blood cell count following virus infection, these markers can be of diagnostic value in the detection of mixed infection in individuals already diagnosed with a certain viral illness. In this review, we seek to investigate the coinfection of SARS-CoV-2 with other respiratory and nonrespiratory viruses to provide novel insights into the development of highly sensitive diagnostics and effective treatment modalities.

A Cluster of Dengue Cases in Travelers: A Clinical Series from Thailand

Dengue is an overlooked tropical disease for which billions of people are at risk. The disease, caused by a Flavivirus with four distinct serotypes, is transmitted primarily by urban Aedes mosquito species. The infection leads to a spectrum of clinical manifestations, with the majority being asymptomatic. Primary dengue fever and, to a greater extent, a subsequent infection with a different serotype is associated with increased severity. Increased global travel and recreational tourism expose individuals naïve to the dengue viruses, the most common arboviral infections among travelers. We describe a cluster of possible primary acute dengue infections in a group of 12 individuals who presented to Bangkok Hospital for Tropical Diseases in 2017. Infection was confirmed by dengue NS1 antigen and multiplex real-time RT-PCR. Nine individuals required hospitalization, and four developed dengue warning signs. Leukocytes, neutrophils, and platelets declined towards defervescence and were negatively correlated with day of illness. Six clinical isolates were identified as dengue serotype-1, with 100% nucleotide identity suggesting that these patients were infected with the same virus.

Clinical Features of Acute Chikungunya Virus Infection in Children and Adults during an Outbreak in the Maldives

The chikungunya virus is an arthritogenic arbovirus that has re-emerged in many tropical and subtropical regions, causing explosive outbreaks. This re-emergence is due to a genomic polymorphism that has increased the vector susceptibility of the virus. The majority of those infected with chikungunya virus exhibit symptoms of fever, rash, and debilitating polyarthralgia or arthritis. Symptoms can persist for weeks, and patients can relapse months later. Fatalities are rare, but individuals of extreme age can develop severe infection. Here, we describe the 2019 outbreak, the second-largest since the virus re-emerged in the Maldives after the 2004 Indian Ocean epidemic, in which a total of 1,470 cases were reported to the Health Ministry. Sixty-seven patients presenting at the main referral tertiary care hospital in the Maldives capital with acute undifferentiated illness were recruited following a negative dengue serology. A novel point-of-care antigen kit was used to screen suspected cases, 50 of which were subsequently confirmed using real-time reverse transcription-polymerase chain reaction. We describe the genotype and polymorphism of Maldives chikungunya virus using phylogenetic analysis. All isolates were consistent with the East Central South African genotype of the Indian Ocean lineage, with a specific E1-K211E mutation. In addition, we explored the clinical and laboratory manifestations of acute chikungunya in children and adults, of which severe infection was found in some children, whereas arthritis primarily occurred in adults. Arthritides in adults occurred irrespective of underlying comorbidities and were associated with the degree of viremia.

Acute monocyte pro inflammatory response predicts higher positive to negative acute phase reactants ratio and severe hemostatic derangement in dengue fever

PURPOSE

The present study was intended to investigate whether monocyte immune activation shapes plasma positive to negative acute phase reactants (APRs) ratio and predicts disease severity in dengue infection.

METHODS

Serum level of ferritin, ceruloplasmin and transferrin was measured by means of electrochemiluminescence and immunoturbidimetry, respectively. Gene expression and plasma level for TNF-α, IL-6 and IL1-β was measured by means of RT-qPCR and ELISA.

RESULTS

A significant increased serum ferritin to transferrin [6.6 (3-11.7) vs 3.4 (1.9-6.1)] and ceruloplasmin to transferrin ratio [0.48 (0.21-0.87) vs 0.22 (0.13-0.43)] has been detected among the subjects with secondary dengue infection (SDENI) compared to primarily infected (PDENI) subjects (P < 0.001). Significant increased expression for CD14⁺ monocyte TNF-α, IL-6 and IL-1β has been detected in SDENI patients (vs PDENI and control, P < 0.001). Plasma ferritin to transferrin ratio was found in a significant association with high level of plasma TNF-α [ρ = 0.6522, 95% CI (0.4714-0.7805)], IL-6 [ρ = 0.6181, 95% CI (0.4257-0.7571)] and IL- 1β [ρ = 0.4119, 95% CI (0.1689-0.6077)] level among SDENI patients at 5th day time point after progression of the disease, with significantly low platelet [P < 0.001] and prolonging prothrombin time [P < 0.001] compared to control and PDENI subjects, respectively.

CONCLUSION

Acute proinflammatory cytokine response is significantly associated with increased positive to negative APRs ratio in SDENI patients, which predicts intense immune activation, and renders SDENI patients extremely susceptible to hemostatic derangement.

Dengue and the Lectin Pathway of the Complement System

Dengue is a mosquito-borne viral disease causing significant health and economic burdens globally. The dengue virus (DENV) comprises four serotypes (DENV1-4). Usually, the primary infection is asymptomatic or causes mild dengue fever (DF), while secondary infections with a different serotype increase the risk of severe dengue disease (dengue hemorrhagic fever, DHF). Complement system activation induces inflammation and tissue injury, contributing to disease pathogenesis. However, in asymptomatic or primary infections, protective immunity largely results from the complement system’s lectin pathway (LP), which is activated through foreign glycan recognition. Differences in N-glycans displayed on the DENV envelope membrane influence the lectin pattern recognition receptor (PRR) binding efficiency. The important PRR, mannan binding lectin (MBL), mediates DENV neutralization through (1) a complement activation-independent mechanism via direct MBL glycan recognition, thereby inhibiting DENV attachment to host target cells, or (2) a complement activation-dependent mechanism following the attachment of complement opsonins C3b and C4b to virion surfaces. The serum concentrations of lectin PRRs and their polymorphisms influence these LP activities. Conversely, to escape the LP attack and enhance the infectivity, DENV utilizes the secreted form of nonstructural protein 1 (sNS1) to counteract the MBL effects, thereby increasing viral survival and dissemination.

Antibody-dependent enhancement representing in vitro infective progeny virus titer correlates with the viremia level in dengue patients

Dengue virus (DENV) causes dengue fever (DF) and dengue hemorrhagic fever in humans. Some DF patients suddenly develop severe symptoms around the defervescent period. Although the pathogenic mechanism of the severe symptoms has not been fully elucidated, the viremia level in the early phase has been shown to correlate with the disease severity. One of the hypotheses is that a phenomenon called antibody-dependent enhancement (ADE) of infection leads to high level of viremia. To examine the plausibility of this hypothesis, we examined the relationship between in vitro ADE activity and in vivo viral load quantity in six patients with dengue diseases. Blood samples were collected at multiple time points between the acute and defervescent phases, and the balance between neutralizing and enhancing activities against the autologous and prototype viruses was examined. As the antibody levels against DENV were rapidly increased, ADE activity was decreased over time or partially maintained against some viruses at low serum dilution. In addition, positive correlations were observed between ADE activity representing in vitro progeny virus production and viremia levels in patient plasma samples. The measurement of ADE activity in dengue-seropositive samples may help to predict the level of viral load in the subsequent DENV infection.

Post-Chikungunya Virus Infection Musculoskeletal Disorders: Syndromic Sequelae after an Outbreak

The Chikungunya virus is a re-emerging mosquito-borne alphavirus. Outbreaks are unpredictable and explosive in nature. Fever, arthralgia, and rash are common symptoms during the acute phase. Diagnostic tests are required to differentiate chikungunya virus from other co-circulating arboviruses, as symptoms can overlap, causing a dilemma for clinicians. Arthritis is observed during the sub-acute and chronic phases, which can flare up, resulting in increased morbidity that adversely affects the activities of daily living. During the 2019 chikungunya epidemic in Thailand, cases surged in Bangkok in the last quarter of the year. Here, we demonstrate the chronic sequelae of post-chikungunya arthritis in one of our patients one year after the initial infection. An inflammatory process involving edema, erythema, and tenderness to palpation of her fingers' flexor surfaces was observed, with positive chikungunya IgG and negative IgM tests and antigen. The condition produced stiffness in the patient's fingers and limited their range of motion, adversely affecting daily living activities. Resolution of symptoms was observed with a short course of an anti-inflammatory agent. More research is required to determine whether sanctuaries enable chikungunya virus to evade the host immune response and remain latent, flaring up months later and triggering an inflammatory response that causes post-chikungunya arthritis.

Coronavirus disease 2019 and dengue: two case reports

Background

The pandemic of this century has overwhelmed the healthcare systems of affected countries, and all resources have been diverted to coronavirus disease 2019. At the onset, coronavirus disease 2019 can present as any other acute febrile undifferentiated illness. In tropical regions, clinicians are increasingly challenged to differentiate these febrile illnesses without the use of diagnostics. With this pandemic, many of these tropical diseases are neglected and go underreported. Dengue is holoendemic in the Maldives, and dengue viruses circulate throughout the year. Reports about coinfections with dengue virus and severe acute respiratory syndrome coronavirus 2 are scarce, and the outcome and the dynamics of the disease may be altered in the presence of coinfection. We have described the clinical manifestation and serial laboratory profile, and highlighted the atypical findings uncommon in dengue infection.

Case presentation

Case 1 was a 39-year old Asian male, presented on day 6 of dengue infection with warning signs. Reverse transcription polymerase chain reaction for severe acute respiratory syndrome coronavirus 2 that was done as per hospital protocol was found to be positive. Case 2 was a 38-year old Asian male, was admitted on day 5 of illness with symptoms of acute respiratory infection with positive reverse transcription polymerase chain reaction for severe acute respiratory syndrome coronavirus 2. Evaluation of progressive leukopenia and thrombocytopenia showed positive dengue serology.

Conclusion

Clinicians must be conscientious when working on the differential diagnosis of possible tropical diseases in cases of coronavirus disease 2019, specifically, when patients develop hemoconcentration, thrombocytopenia, and transaminitis with elevated expression of aspartate higher than alanine transaminase, which is frequently observed in dengue infection. Caution must be taken during the administration of intravenous fluids when treating patients with coronavirus disease 2019 and dengue coinfection, as coronavirus disease 2019 patients are more prone to develop pulmonary edema. Timely diagnosis and appropriate management are essential to avoid the devastating complications of severe forms of dengue infection. It is important to repeat and reconfirm the dengue serology in coronavirus disease 2019 patients to avoid false positivity. Diligence and care must be taken not to neglect other endemic tropical diseases in the region during the present pandemic.

Cytokine Signature of Dengue Patients at Different Severity of the Disease

Clinical presentations of dengue fever (DF) are diverse and non-specific, causing unpredictable progression and outcomes. Its progression and severity have been associated with cytokine levels alteration. In this study, dengue patients were classified into groups following the 2009 WHO dengue classification scheme to investigate the cytokine signature at different severity of the disease: dengue without warning sign symptoms (A); dengue with warning signs (B); severe dengue (C); other fever (OF) and healthy (Healthy). We analyzed 23 different cytokines simultaneously, namely IL-1b, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-17A, IL-33, CD14, CD54, CD62E, CD62L, CD62p, CD106, CD121b, CD154, CD178, GM-CSF, IFN-g, MIF, ST2 and TNF from patients admitted to National Cheng Kung University Hospital during the 2015 Taiwan dengue outbreak. Cytokines TNF, CD54, CD62E, CD62L, CD62P, GM-CSF, IL-1b, IL-2, IL-6, IL-8, IL-10, IL-12p70, IL-17A, INF-g and MIF were elevated while CD106, CD154, IL-4 and L-33 were decreased when compared to the control. IL-10 demonstrated to be a potential diagnostic marker for DF (H and A group; AUC = 0.944, H and OF group; AUC = 0.969). CD121b demonstrated to be predictive of the SD (A and B group; AUC = 0.744, B and C group; AUC = 0.775). Our results demonstrate the cytokine profile changes during the progression of dengue and highlight possible biomarkers for optimizing effective intervention strategies.

Chikungunya Manifestations and Viremia in Patients WhoPresented to the Fever Clinic at Bangkok Hospital for Tropical Diseases during the 2019 Outbreak in Thailand

Chikungunya virus is an Alphavirus belonging to the family Togaviridae that is transmitted to humans by an infected Aedes mosquito. Patients develop fever, inflammatory arthritis, and rash during the acute stage of infection. Although the illness is self-limiting, atypical and severe cases are not uncommon, and 60% may develop chronic symptoms that persist for months or even for longer durations. Having a distinct periodical epidemiologic outbreak pattern, chikungunya virus reappeared in Thailand in December 2018. Here, we describe a cohort of acute chikungunya patients who had presented to the Bangkok Hospital for Tropical Diseases during October 2019. Infection was detected by a novel antigen kit and subsequently confirmed by real-time RT-PCR using serum collected at presentation to the Fever Clinic. Other possible acute febrile illnesses such as influenza, dengue, and malaria were excluded. We explored the sequence of clinical manifestations at presentation during the acute phase and associated the viral load with the clinical findings. Most of the patients were healthy individuals in their forties. Fever and arthralgia were the predominant clinical manifestations found in this patient cohort, with a small proportion of patients with systemic symptoms. Higher viral loads were associated with arthralgia, and arthralgia with the involvement of the large joints was more common in female patients.

Kinetics of CD4+ T Helper and CD8+ Effector T Cell Responses in Acute Dengue Patients

Background: The protective or pathogenic role of T lymphocytes during the acute phase of dengue virus (DENV) infection has not been fully understood despite its importance in immunity and vaccine development.

Objectives: This study aimed to clarify the kinetics of T lymphocyte subsets during the clinical course of acute dengue patients.

Study design: In this hospital-based cohort study, 59 eligible Vietnamese dengue patients were recruited and admitted. They were investigated and monitored for T cell subsets and a panel of clinical and laboratory parameters every day until discharged and at post-discharge from the hospital.

Results: We described for the first time the kinetics of T cell response during the clinical course of DENV infection. Severe cases showed significantly lower levels of effector CD8⁺ T cells compared to mild cases at day −1 (p = 0.017) and day 0 (p = 0.033) of defervescence. After defervescence, these cell counts in severe cases increased rapidly to equalize with the levels of mild cases. Our results also showed a decline in total CD4⁺ T, Th1, Th1/17 cells during febrile phase of dengue patients compared to normal controls or convalescent phase. On the other hand, Th2 cells increased during DENV infection until convalescent phase. Cytokines such as interferon-γ, IL-12p70, IL-5, IL-23, IL-17A showed tendency to decrease on day 0 and 1 compared with convalescence and only IL-5 showed significance indicating the production during acute phase was not systemic.

Conclusion: With a rigorous study design, we uncovered the kinetics of T cells in natural DENV infection. Decreased number of effector CD8⁺ T cells in the early phase of infection and subsequent increment after defervescence day probably associated with the T cell migration in DENV infection.