Differences in Mortality and Clinical Manifestations of Dengue Hemorrhagic Fever in Taiwan in Different Years: A Comparison for Cases in 2014 and 2015 Epidemics

Evaluation of clinical and laboratory characteristics of dengue viral infection and risk factors of dengue hemorrhagic fever: a multi-center retrospective analysis

BACKGROUND

Dengue Viral Infection (DVI) has become endemic in Pakistan since the first major outbreak in Karachi in 1996. Despite aggressive measures taken by relevant authorities, Pakistan has been dealing with a worsening dengue crisis for the past two decades. DHF is severe form of dengue infection which is linked with significant morbidity and mortality. Early identification of severe dengue infections can reduce the morbidity and mortality. In this context we planned current study in which we find out the different factors related with DHF as well as clinical laboratory features of DHF and compare them to DF so that patients can be best evaluated for DHF and managed accordingly at admission.

METHODS

Retrospective study conducted over a period of 6 years (2013-2018) in two tertiary care hospitals in Pakistan. Data were collected by using a pre-structured data collection form. Data were statistically analyzed to determine the clinical and laboratory characteristics of DVI and risk factors of dengue hemorrhagic fever (DHF).

RESULTS

A total 512 dengue cases (34.05 ± 15.08 years; Male 69.53%) were reviewed. Most common clinical manifestations of DVI were fever (99.60%), headache (89.1%), chills (86.5%), rigors (86.5%), myalgia (72.3%). Less common clinical manifestations were vomiting (52.5%), arthralgia (50.2%) and skin rashes (47.5%). Furthermore, nasal bleeding (44.1%), gum bleeding (32.6%), pleural effusion (13.9%) and hematuria (13.1%) were more profound clinical presentations among DHF patients. Mortality rate was 1.5% in this study. Logistic regression analysis indicated that delayed hospitalization (OR: 2.30) and diabetes mellitus (OR:2.71), shortness of breath (OR:2.21), association with risk groups i.e., living near stagnant water, travelling to endemic areas, living in endemic regions (OR:1.95), and presence of warning signs (OR:2.18) were identified as risk factors of DHF. Statistically we found that there is strong association of diabetes mellitus (DM) with DHF while the patient suffering from DM individually had higher odds (2.71) of developing DHF than patients without disease.

CONCLUSIONS

The current study demonstrated that the clinical and laboratory profiles of DF and DHF are significantly distinct. Significant predictors of DHF were advanced age, diabetes mellitus, ascites, pleural effusion, thick gallbladder and delayed hospitalization. The identification of these factors at early stage provides opportunities for the clinicians to identify high risk patients and to reduce dengue-related morbidity and mortality.

Frailty in Older Adults with Dengue Fever

Background and objectives: Dengue is one of the most common epidemic infections around the world. Dengue infections in older adults are related to an atypical presentation and a high mortality. Frailty is associated with poor recovery from hospitalization due to infection. However, few studies describe frailty and functional decline after dengue infection. The current case series study aims to investigate the baseline frailty status, functional decline, and time to recovery in older adults after dengue infection. Method: We studied seven patients with post-dengue frailty who had been admitted to the geriatric ward in one tertiary medical center in Taiwan during the 2023 dengue fever outbreak. Result: The mean age was 82 years old. The clinical frailty scale worsened from a mean of 4.7 at baseline to 6.3 at dengue diagnosis. The mean Katz Index of independence in activities of daily living decreased from 10.6 at baseline to 4.7 with dengue, and it recovered to 6.7 one month after discharge. Conclusions: Our preliminary data suggest that there is indeed an increase in frailty in older adults due to dengue. Post-dengue frailty and functional decline might be profound and persistent. Acute geriatric care intervention rehabilitation for frailty after dengue may benefit this population.

Aspergillus coinfection in critically Ill patients with severe dengue

In 2014-2015, a significant outbreak of dengue fever occurred in southern Taiwan, with a subsequent decline in dengue incidence. Despite this, there is emerging concern about virus-associated aspergillosis, yet limited research has explored coinfections involving dengue and aspergillosis. We conducted a retrospective study at a single center in Southern Taiwan, specifically focusing on dengue patients admitted to the intensive care unit during the period between July and November 2015. Among the 142 dengue patients studied, only 8.06 % (10/142) underwent serum galactomannan testing, with a single patient undergoing bronchoalveolar lavage (BAL) galactomannan assay. Out of those tested, 20 % (2/10) returned positive serum galactomannan results. Herein, we present two consecutive cases of coinfection involving dengue and pulmonary aspergillosis in immunocompetent patients.

Dengue virus serotype did not contribute to clinical severity or mortality in Taiwan's largest dengue outbreak in 2015

BACKGROUND

Dengue virus serotype 2 (DENV-2) was the major serotype in the 2015 dengue outbreak in Taiwan, while DENV-1 and DENV-3 were dominant between 2005 and 2014. We aimed to investigate whether DENV-2 contributed to disease severity and mortality in the outbreak in Kaohsiung city, Taiwan.

METHODS

We collected serum samples from dengue patients to detect the presence of DENV and determine the serotypes by using quantitative reverse transcription-polymerase chain reaction. Our cohorts comprised 105 DENV-1-infected cases and 1,550 DENV-2-infected cases. Demographic data, DENV serotype, and comorbidities were covariates for univariate and multivariate analyses to explore the association with severity and mortality.

RESULTS

The results suggested that DENV-1 persisted and circulated, while DENV-2 was dominant during the dengue outbreak that occurred between September and December 2015. However, DENV-2 did not directly contribute to either severity or mortality. Aged patients and patients with diabetes mellitus (DM) or moderate to severe chronic kidney disease (CKD) had a higher risk of developing severe dengue. The mortality of dengue patients was related to a higher Charlson comorbidity index score and severe dengue. Among DENV-2-infected patients and older patients, preexisting anti-dengue IgG, DM, and moderate to severe CKD were associated with severe dengue. Moreover, female sex and severe dengue were associated with a significantly higher risk of death.

CONCLUSIONS

Our findings highlight the importance of timely serological testing in elderly patients to identify potential secondary infections and focus on the meticulous management of elderly patients with DM or moderate to severe CKD to reduce dengue-related death.

Dengue virus infection induces selective expansion of Vγ4 and Vγ6TCR γδ T cells in the small intestine and a cytokine storm driving vascular leakage in mice

Dengue is a major health problem in tropical and subtropical regions. Some patients develop a severe form of dengue, called dengue hemorrhagic fever, which can be fatal. Severe dengue is associated with a transient increase in vascular permeability. A cytokine storm is thought to be the cause of the vascular leakage. Although there are various research reports on the pathogenic mechanism, the complete pathological process remains poorly understood. We previously reported that dengue virus (DENV) type 3 P12/08 strain caused a lethal systemic infection and severe vascular leakage in interferon (IFN)-α/β and γ receptor knockout mice (IFN-α/β/γRKO mice), and that blockade of TNF-α signaling protected mice. Here, we performed transcriptome analysis of liver and small intestine samples collected chronologically from P12/08-infected IFN-α/β/γRKO mice in the presence/absence of blockade of TNF-α signaling and evaluated the cytokine and effector-level events. Blockade of TNF-α signaling mainly protected the small intestine but not the liver. Infection induced the selective expansion of IL-17A-producing Vγ4 and Vγ6 T cell receptor (TCR) γδ T cells in the small intestine, and IL-17A, together with TNF-α, played a critical role in the transition to severe disease via the induction of inflammatory cytokines such as TNF-α, IL-1β, and particularly the excess production of IL-6. Infection also induced the infiltration of neutrophils, as well as neutrophil collagenase/matrix metalloprotease 8 production. Blockade of IL-17A signaling reduced mortality and suppressed the expression of most of these cytokines, including TNF-α, indicating that IL-17A and TNF-α synergistically enhance cytokine expression. Blockade of IL-17A prevented nuclear translocation of NF-κB p65 in stroma-like cells and epithelial cells in the small intestine but only partially prevented recruitment of immune cells to the small intestine. This study provides an overall picture of the pathogenesis of infection in individual mice at the cytokine and effector levels.

Prevalence, Characteristics, and Outcomes Associated with Acute Kidney Injury among Adult Patients with Severe Dengue in Mainland China

Acute kidney injury (AKI) can occur in adult patients with severe dengue (SD) and have serious clinical outcomes. This study aimed to determine the prevalence, characteristics, risk factors, and clinical outcomes of AKI in adult patients with SD; the correlation of dengue virus (DENV) serological and virological profiles with AKI; and the clinical features of patients with severe AKI who received renal replacement treatment (RRT). This multicenter study was conducted in Guangdong Province, China, between January 2013 and November 2019. A total of 242 patients were evaluated, of which 85 (35.1%) developed AKI and 32 (13.2%) developed severe AKI (stage 3). Patients with AKI had a higher fatality rate (22.4% versus 5.7%; P < 0.001) and longer length of hospital stay (median: 13 versus 9 days; P < 0.001). Independent risk factors for AKI were hypertension (odds ratio [OR]: 2.03; 95% CI: 1.10-3.76), use of nephrotoxic drugs (OR: 1.90; 95% CI: 1.00-3.60), respiratory distress (OR: 4.15; 95% CI: 1.787-9.632), high international normalized ratio (INR) levels (OR: 6.44; 95% CI: 1.89-21.95), and hematuria (OR: 2.12; 95% CI: 1.14-3.95). There was no significant association between DENV serological and virological profiles and the presence or absence of AKI. Among patients with severe AKI, those who received RRT had a longer length of hospital stay and similar fatality rate. Hence, adult patients with SD should be closely monitored for the development of AKI to enable timely and appropriate therapy.

Moderation effects of serotype on dengue severity across pregnancy status in Mexico

BACKGROUND

Pregnancy increases a woman's risk of severe dengue. To the best of our knowledge, the moderation effect of the dengue serotype among pregnant women has not been studied in Mexico. This study explores how pregnancy interacted with the dengue serotype from 2012 to 2020 in Mexico.

METHOD

Information from 2469 notifying health units in Mexican municipalities was used for this cross-sectional analysis. Multiple logistic regression with interaction effects was chosen as the final model and sensitivity analysis was done to assess potential exposure misclassification of pregnancy status.

RESULTS

Pregnant women were found to have higher odds of severe dengue [1.50 (95% CI 1.41, 1.59)]. The odds of dengue severity varied for pregnant women with DENV-1 [1.45, (95% CI 1.21, 1.74)], DENV-2 [1.33, (95% CI 1.18, 1.53)] and DENV-4 [3.78, (95% CI 1.14, 12.59)]. While the odds of severe dengue were generally higher for pregnant women compared with non-pregnant women with DENV-1 and DENV-2, the odds of disease severity were much higher for those infected with the DENV-4 serotype.

CONCLUSION

The effect of pregnancy on severe dengue is moderated by the dengue serotype. Future studies on genetic diversification may potentially elucidate this serotype-specific effect among pregnant women in Mexico.

Risk Factors for Mortality in Patients with Dengue: A Systematic Review and Meta-Analysis

OBJECTIVE

To investigate risk factors for mortality in dengue.

METHODS

Systematic review and meta-analysis searching MEDLINE, Embase, SciELO, LILACS Bireme, and OpenGrey to identify eligible observational studies of patients with dengue, of both genders, aged 14 years or older, that analyzed risk factors associated with mortality and reported adjusted risk measures with their respective confidence intervals (CIs). We estimated the pooled weighted mean difference and 95% CIs with a DerSimonian and Laird random-effects model. Methodological quality was assessed using the Newcastle-Ottawa Scale.

RESULTS

Of 1,170 citations reviewed, 18 papers, with a total of 25,851 patients, were included in the systematic review and 12 in the meta-analysis. Severe hepatitis (OR 29.222, 95% CI: 3.876-220.314), dengue shock syndrome (OR 23.575, 95% CI 3.664-151.702), altered mental status (OR 3.76, 95% CI 1.67-8.42), diabetes mellitus (OR 3.698, 95% CI 1.196-11.433), and higher pulse rate (OR 1.039, 95% CI 1.011-1.067) are associated with mortality in patients with dengue. All studies included were classified as having a high quality.

CONCLUSIONS

Proper identification and management of these risk factors should be considered to improve patient outcomes and reduce the hidden burden of this neglected tropical disease. Future well-designed studies are needed to investigate the association of other clinical, radiological, and laboratorial findings with mortality in dengue, as well as to develop prognostic models based on the risk factors found in our study.

Severe dengue in adults and children, Ouagadougou (Burkina Faso), West Africa, October 2015–January 2017

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Severe dengue was common in this sudy.

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In contrast to multiple prior studies, the risk of severe dengue was greater for patients with primary dengue compared to those with secondary infection.

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Additional risk factors for severe dengue included age, male sex, haemoglobin S, diabetes, and hypertension.  Case mapping showed that dengue cases were more concentrated  in sectors located in the centre of the city and close to the health centres.

Introduction

Although dengue is the most common arbovirus infection worldwide, studies of severe dengue in Africa are lacking, and risk factors for severe dengue have been insufficiently described. This study was conducted in the context of the 2016 dengue epidemic in Burkina Faso to determine the prevalence of severe dengue, identify factors associated with severe dengue, and perform mapping of dengue cases in the country's capital, Ouagadougou.

Methods

This cross-sectional study was conducted from November 2015 to January 2017. Data were collected in 15 public and private health centres, and included sociodemographic, clinical and patient outcome variables. Dengue was diagnosed using SD Bioline Dengue Duo rapid diagnostic tests. Data were analysed using Epi-Info Version 7. Logistic regression was used to identify predictors of severe dengue. P<0.05 was considered significant. Dengue case mapping was performed using Geographic Information System software (ArcGIS).

Results

Of the 811 patients who tested positive for dengue, 609 (75%) had early dengue (AgNS1 positive) and 272 (33.5%) had severe dengue. Patient age ranged from 1 to 83 years (median 30.5 years) and 393 (48.3%) were female. Renal failure (13.1%) and severe bleeding (10.6%) were the most common signs of severe dengue. Risk factors for severe dengue included age, male sex, haemoglobin S, diabetes, hypertension, and primary dengue. Dengue cases were more concentrated  in sectors located in the centre of the city and close to the health centres.

Conclusion

Dengue is increasingly common in Africa and factors associated with severity should be sought systematically as soon as a patient tests positive. Additional studies are needed to determine if the factors found to be associated with severity can be used to identify patients at risk for dengue-related complications, and to provide early and specialized management to reduce morbidity and mortality related to dengue in Africa.

Dengue fever and dengue virus in the People's Republic of China

Infection with dengue virus (DENV) leads to symptoms variable from dengue fever to severe dengue, which has posed a huge socioeconomic and disease burden to the world population, particularly in tropical and subtropical regions. To date, four serotypes of DENV (DENV-1 to DENV-4) have been identified to sustain the transmission cycle in humans. In the past decades, dengue incidences have become more frequent, and four serotypes and various genotypes have been identified in PR China. Several large-scale dengue outbreaks and frequent local endemics occurred in the southern and coastal provinces, and the imported dengue cases accounted primarily for the initiation of the epidemics. No antiviral drug exists for dengue, and no vaccine has been approved to use in PR China, however strategies including public awareness, national reporting system of infectious diseases and public health emergencies, vector mosquito control, personal protection, and improved environmental sanitation have greatly reduced dengue prevalence. Some new technologies in vector mosquito control are emerging and being applied for dengue control. China's territory spans tropical, subtropical, and temperate climates, hence understanding the dengue status in China will be of beneficial for the global prevention and control of dengue. Here, we review the dengue status in PR China for the past decades and the strategies emerging for dengue control.

Use of seroprevalence to guide dengue vaccination plans for older adults in a dengue non-endemic country

A shift in dengue cases toward the adult population, accompanied by an increased risk of severe cases of dengue in the elderly, has created an important emerging issue in the past decade. To understand the level of past DENV infection among older adults after a large dengue outbreak occurred in southern Taiwan in 2015, we screened 1498 and 2603 serum samples from healthy residents aged ≥ 40 years in Kaohsiung City and Tainan City, respectively, to assess the seroprevalence of anti-DENV IgG in 2016. Seropositive samples were verified to exclude cross-reaction from Japanese encephalitis virus (JEV), using DENV/JEV-NS1 indirect IgG ELISA. We further identified viral serotypes and secondary DENV infections among positive samples in the two cities. The overall age-standardized seroprevalence of DENV-IgG among participants was 25.77% in Kaohsiung and 11.40% in Tainan, and the seroprevalence was significantly higher in older age groups of both cities. Although the percentages of secondary DENV infection in Kaohsiung and Tainan were very similar (43.09% and 44.76%, respectively), DENV-1 and DENV-2 spanned a wider age range in Kaohsiung, whereas DENV-2 was dominant in Tainan. As very few studies have obtained the serostatus of DENV infection in older adults and the elderly, this study highlights the need for further investigation into antibody status, as well as the safety and efficacy of dengue vaccination in these older populations.

Field Deployment of a Mobile Biosafety Laboratory Reveals the Co-Circulation of Dengue Viruses Serotype 1 and Serotype 2 in Louga City, Senegal, 2017

Dengue virus (DENV) is the most prevalent arboviral threat worldwide. This virus belonging to genus Flavivirus, Flaviviridae family, is responsible for a wide spectrum of clinical manifestations, ranging from asymptomatic or mild febrile illness (dengue fever) to life-threatening infections (severe dengue). Many sporadic cases and outbreaks have occurred in Senegal since 1970. Nevertheless, this article describes a field investigation of suspected dengue cases, between 05 September 2017 and 17 December 2017 made possible by the deployment of a Mobile Biosafety Laboratory (MBS-Lab). Overall, 960 human sera were collected and tested in the field for the presence of viral RNA by real-time RT-PCR. Serotyping, sequencing of complete E gene, and phylogenetic analysis were also performed. Out of 960 suspected cases, 131 were confirmed dengue cases. The majority of confirmed cases were from Louga community. Serotyping revealed two serotypes, Dengue 1 (100/104; 96, 15%) and Dengue 2 (04/104; 3, 84%). Phylogenetic analysis of the sequences obtained indicated that the Dengue 1 strain was closely related to strains isolated, respectively, in Singapore (Asia) in 2013 (KX380803.1) outbreak and it cocirculated with a Dengue 2 strain closely related to strains from a Burkina Faso dengue outbreak in 2016 (KY62776.1). Our results showed the co-circulation of two dengue virus serotypes during a single outbreak in a short time period. This co-circulation highlighted the need to improve surveillance in order to prevent future potential severe dengue cases through antibody-dependent enhancement (ADE). Interestingly, it also proved the reliability and usefulness of the MBS-Lab for expedient outbreak response at the point of need, which allows early cases management.

Clinical characteristics and risk factors for intracranial hemorrhage or infarction in patients with dengue

BACKGROUND

Intracranial hemorrhage (ICH) or infarction in dengue cases is rare but very challenging for clinicians. We report these uncommon complications of dengue patients and focused on the significant factors associated with ICH or infarction in dengue patients.

METHODS

This investigation was a retrospective study of 182 adult dengue patients who received brain computed tomography at three Taiwan hospitals during the 2014 and 2015 dengue outbreaks. This included 13 hemorrhage cases, 26 infarction cases and 143 cases without brain infarction or hemorrhage.

RESULTS

Among them, 13 (7.14%) suffered from ICH (6 had subdural hemorrhage, 3 had subarachnoid hemorrhage, 1 had subdural and subarachnoid hemorrhage, and 3 had intracerebral hemorrhage) and 26 (14.3%) had brain infarction. The overall mortality rate was 4/13 (30.8%) in the ICH group and 3/26 (11.5%) in the infarction group. The significant variables from the univariate analysis, including difference between 2014 and 2015, age, history of cerebrovascular accident, bone pain, arthralgia, dizziness, altered consciousness, and a higher Charlson comorbidity score. Multivariate analysis revealed that significant risk factors for ICH/infarction in dengue cases were the year of occurrence, 2014 vs. 2015 (p < 0.0001, OR = 25.027, 95% CI = 8.205-76.336), Charlson score >4 (p = 0.01, OR = 3.764, 95% CI = 1.364-10.386) and altered consciousness (p < 0.0001, OR = 6.3, 95% CI = 2.242-17.7). The factors physicians should notice in dengue endemic regions for brain infarction or ICH include altered consciousness and a Charlson score >4, especially in the year that a higher frequency of infarction/ICH was observed.

Aggressive organ penetration and high vector transmissibility of epidemic dengue virus-2 Cosmopolitan genotype in a transmission mouse model

Dengue virus (DENV) causes dengue fever and severe hemorrhagic fever in humans and is primarily transmitted by Aedes aegypti and A. albopictus mosquitoes. The incidence of DENV infection has been gradually increasing in recent years due to global urbanization and international travel. Understanding the virulence determinants in host and vector transmissibility of emerging epidemic DENV will be critical to combat potential outbreaks. The DENV serotype 2 (DENV-2), which caused a widespread outbreak in Taiwan in 2015 (TW2015), is of the Cosmopolitan genotype and is phylogenetically related to the virus strain linked to another large outbreak in Indonesia in 2015. We found that the TW2015 virus was highly virulent in type I and type II interferon-deficient mice, with robust replication in spleen, lung, and intestine. The TW2015 virus also had high transmissibility to Aedes mosquitoes and could be effectively spread in a continuous mosquitoes-mouse-mosquitoes-mouse transmission cycle. By making 16681-based mutants carrying different segments of the TW2015 virus, we identified the structural pre-membrane (prM) and envelope (E) genes as key virulence determinants in the host, with involvement in the high transmissibility of the TW2015 virus in mosquitoes. The transmission mouse model will make a useful platform for evaluation of DENV with high epidemic potential and development of new strategies against dengue outbreaks.

Value of C-reactive protein in differentiating viral from bacterial aetiologies in patients with non-malaria acute undifferentiated fever in tropical areas: a meta-analysis and individual patient data study

C-reactive protein (CRP) is used to discriminate common bacterial and viral infections, but its utility in tropical settings remains unknown. We performed a meta-analysis of studies performed in Asia and Africa. First, mean CRP levels for specific tropical infections were calculated. Thereafter, individual patient data (IPD) from patients with non-malarial undifferentiated fever (NMUF) who were tested for viral and bacterial pathogens were analysed, calculating separate cut-off values and their performance in classifying viral or bacterial disease. Mean CRP levels of 7307 patients from 13 countries were dengue 12.0 mg/l (standard error [SE] 2.7), chikungunya 41.0 mg/l (SE 19.5), influenza 15.9 mg/l (SE 6.3), Crimean-Congo haemorrhagic fever 9.7 mg/l (SE 4.7), Salmonella 61.9 mg/l (SE 5.4), Rickettsia 61.3 mg/l (SE 8.8), Coxiella burnetii 98.7 mg/l (SE 44.0) and Leptospira infections 113.8 mg/l (SE 23.1). IPD analysis of 1059 NMUF patients ≥5 y of age showed CRP <10 mg/l had 52% sensitivity (95% confidence interval [CI] 48 to 56) and 95% specificity (95% CI 93 to 97) to detect viral infections. CRP >40 mg/l had 74% sensitivity (95% CI 70 to 77) and 84% specificity (95% CI 81 to 87) to identify bacterial infections. Compared with routine care, the relative risk for incorrect classification was 0.64 (95% CI 0.55 to 0.75) and the number needed to test for one extra correctly classified case was 8 (95% CI 6 to 12). A two cut-off value CRP test may help clinicians to discriminate viral and bacterial aetiologies of NMUF in tropical areas.

Safety of temporary interruption of antiplatelet therapy in dengue fever with thrombocytopenia

Thrombocytopenia commonly occurs in dengue and may be complicated by bleeding. Dengue can occur in adults who may be on long term antiplatelet therapy for ischemic heart disease or stroke. In these cases, clinicians may temporarily discontinue antiplatelet therapy to minimize the risk of bleeding in the absence of clear guidelines. We conducted a retrospective cohort study of laboratory-confirmed adult dengue patients on antiplatelet therapy and evaluated participants whose antiplatelet therapy was continued versus discontinued. Primary outcome was a composite outcome of major adverse cardiac and cerebrovascular events (MACCE), and all-cause mortality in-hospital and for 1-year post discharge. Secondary outcomes were platelet and blood transfusion, and occurrence of dengue haemorrhagic fever (DHF), dengue shock syndrome, dengue with warning signs and severe dengue according to World Health Organization criteria. Discontinuation of antiplatelet therapy did not result in higher composite outcome (p=0.192). Continuation of antiplatelet therapy did not result in more platelet or blood transfusion (p=0.489 and p=0.567 respectively), DHF (p=0.923). Our results suggest that discontinuation or continuation of antiplatelet therapy based on clinical judgement in dengue with thrombocytopenia, is largely safe but further studies are needed.

Viral Interference Between Dengue Virus and Hepatitis C Virus Infections

Both dengue virus (DENV) and hepatitis C virus (HCV) belong to the Flaviviridae family and could induce hepatitis. We aimed to investigate the interference between them. In total, 515 patients confirmed with dengue fever (DF) were enrolled. Thirty-two patients (6.21%) were seropositive for anti-HCV; 12 of 32 anti-HCV-positive patients had detectable HCV-RNA at presentation of DF. The proportion of dengue hemorrhagic fever was comparable between patients with or without anti-HCV and between those with or without HCV-RNA. Eleven of 32 patients received HCV-RNA testing during a median interval of 23 months after DF, which revealed significantly increased HCV-RNA levels (5.43 ± 0.77 vs 3.09 ± 1.24 log IU/mL, follow-up vs acute-DF phase; P = .003). Four of 11 patients with baseline HCV-RNA values before DF demonstrated a nadir viremia during acute DF. We also included age-, sex-, and follow-up duration–matched HCV-monoinfected patients as controls; higher delta HCV-RNA changes were demonstrated in patients with DF than in controls during the follow-up period (2.34 ± 1.15 vs –0.27 ± 0.76 log IU/mL; P < .001). Further in vitro experiments showed that HCV nonstructural protein 5A was downregulated in Con1 HCV replicon cells infected by DENV1. These clinical and experimental findings suggested possible viral interference in DENV/HCV. However, HCV viremia did not affect the disease outcomes of DF.

Epidemiological analysis of the Kaohsiung city strategy for dengue fever quarantine and epidemic prevention

Background

Dengue is endemic in over 100 countries and is an important public health problem worldwide. Dengue fever is not endemic in Taiwan; the importation of dengue viruses from neighboring countries via close commercial links and air travel is considered to be the cause of local outbreaks. Therefore, efforts toward disease control have focused on preventing the importation of dengue into Taiwan. In this study, we investigated the relationships between the numbers of imported and indigenous dengue cases to test the validity of this strategy.

Methods

Data on cases of dengue fever that occurred between 2013 and 2018 were obtained from the surveillance systems of the Taiwan Center for Disease Control and Kaohsiung City Health Department. Standard epidemiological data, including the monthly numbers of indigenous and imported cases of dengue, were calculated. Potential associations between the numbers of indigenous and imported cases were investigated using correlation analyses.

Results

We identified a possible relationship between the period of disease concealment and the number of imported dengue cases, which resulted in epidemics of indigenous dengue fever within local communities. Further analysis of confirmed cases during previous epidemics in Kaohsiung City found that the risk of indigenous dengue fever may be related to the likelihood that patients with imported dengue fever will stay within local communities.

Conclusion

Given the correlations found between imported and indigenous cases of dengue fever, as well as the relationship between the disease concealment period and the risk of indigenous dengue fever, prevention of disease importation and efficient identification of dengue cases within high-risk communities remain the major priorities for disease control.

Effects of Chinese and Western Medicine on Patients with Dengue Fever

Dengue fever is an important epidemic disease with a high prevalence in tropical and subtropical countries. We aimed to investigate the effects of a treatment integrating traditional Chinese (TCM) and Western medicines on dengue inpatients with warning signs (i.e., group B) according to the World Health Organization dengue classification in this retrospective cohort study of medical records. Inpatients who were treated with conventional Western therapies in the absence or presence of TCM were assigned to the control and treatment groups, respectively. Data were compared using an analysis of variance, general linear analysis, and chi-square test. The most common clinical symptoms and signs of dengue fever were fever and muscle ache. The treatment group patients were significantly more likely to present general weakness and poor appetite than the control group patients. Patients in the treatment group were more likely to experience stomachache than those in the control group. Moreover, comparisons of the changes in hemoglobin and alanine aminotransferase levels over time revealed significant differences between the patient groups. Zhu Ye Shi Gao Tang, Gui Pi Tang, Paeonia suffruticosa, and Clerodendrum cyrtophyllum were the most commonly administered TCM formula and single herbs in this study. Patients in the treatment group experienced a resolution of symptoms, signs, and laboratory data and were discharged smoothly, without deterioration to death or critical care. Our findings suggest that the integration of TCM and Western medicine may yield an appropriate treatment for dengue fever.

High levels of serum hyaluronan is an early predictor of dengue warning signs and perturbs vascular integrity

BACKGROUND

A main pathological feature of severe dengue virus infection is endothelial hyper-permeability. The dengue virus nonstructural protein 1 (NS1) has been implicated in the vascular leakage that characterizes severe dengue virus infection, however, the molecular mechanisms involved are not known.

METHODS

A cohort of 250 dengue patients has been followed from the onset of symptoms to the recovery phase. Serum hyaluronan levels and several other clinical parameters were recorded. The effect of NS1 treatment of cultured fibroblasts and endothelial cells on the expressions of hyaluronan synthetic and catabolic enzymes and the hyaluronan receptor CD44, were determined, as have the effects on the formation of hyaluronan-rich matrices and endothelial permeability.

FINDINGS

Elevated serum hyaluronan levels (≥70 ng/ml) during early infection was found to be an independent predictor for occurrence of warning signs, and thus severe dengue fever. High circulating levels of the viral protein NS1, indicative of disease severity, correlated with high concentrations of serum hyaluronan. NS1 exposure decreased the expression of CD44 in differentiating endothelial cells impairing the integrity of vessel-like structures, and promoted the synthesis of hyaluronan in dermal fibroblasts and endothelial cells in synergy with dengue-induced pro-inflammatory mediators. Deposited hyaluronan-rich matrices around cells cultured in vitro recruited CD44-expressing macrophage-like cells, suggesting a mechanism for enhancement of inflammation. In cultured endothelial cells, perturbed hyaluronan-CD44 interactions enhanced endothelial permeability through modulation of VE-cadherin and cytoskeleton re-organization, and exacerbated the NS1-induced disruption of endothelial integrity.

INTERPRETATION

Pharmacological targeting of hyaluronan biosynthesis and/or its CD44-mediated signaling may limit the life-threatening vascular leakiness during moderate-to-severe dengue virus infection. FUND: This work was supported in part by grants from the Swedish Cancer Society (2018/337; 2016/445), the Swedish Research Council (2015-02757), the Ludwig Institute for Cancer Research, Uppsala University, the Ministry of Science and Technology, Taiwan (106-2314-B-037-088- and 106-2915-I-037-501-), Kaohsiung Medical University Hospital (KMUH103-3 T05) and Academy of Finland. The funders played no role in the design, interpretation or writing of the manuscript.

An RT-PCR panel for rapid serotyping of dengue virus serotypes 1 to 4 in human serum and mosquito on a field-deployable PCR system

Background

Dengue fever, a mosquito-borne disease, is caused by dengue virus (DENV) which includes four major serotypes (DENV-1, -2, -3, and -4). Some serotypes cause more severe diseases than the other; severe dengue is associated with secondary infections by a different serotype. Timely serotyping can provide early warning of dengue epidemics to improve management of patients and outbreaks. A mobile insulated isothermal PCR (iiPCR) system is available to allow molecular detection of pathogens near points of need.

Methodology/Principle findings

In this study, side-by-side comparison with the CDC DENV-1-4 Real Time RT-PCR (qRT-PCR) was performed to evaluate the performance of four singleplex DENV-1–4 serotyping reverse transcription-iiPCR (RT-iiPCR) reagents for DENV subtyping on the mobile PCR system. The four RT-iiPCRs did not react with Zika virus and chikungunya virus; tests with serial dilutions of the four DENV serotypes made in human serum showed they had detection endpoints comparable to those of the reference method, indicating great analytical sensitivity and specificity. Clinical performance of the RT-iiPCR reagents was evaluated by testing 40 serum samples each (around 20 target serotype-positive and 20 DENV-negative); all four reagents had high agreement (97.5–100%) with the reference qRT-PCR. Moreover, testing of mosquitoes separately infected experimentally with each serotype showed that the four reagents detected specifically their target DENV serotypes in mosquito.

Conclusions/Significance

With analytical and clinical performance comparable to the reference qRT-PCR assay, the four index RT-iiPCR reagents on the field-deployable PCR system can serve as a useful tool for DENV detection near points of needs.

Prognostic Factors in Adult Patients with Dengue: Developing Risk Scoring Models and Emphasizing Factors Associated with Death ≤7 Days after Illness Onset and ≤3 Days after Presentation

Dengue is a mosquito-borne viral disease that is a threat to global health. However, information relating to mortality ≤7 days after dengue onset and ≤3 days after presentation is limited. We retrospectively analyzed 1086 adults with dengue during a 12-year period. Three scoring models were established: model-1 (death ≤3 days after presentation), model-2 (death ≤7 days after illness onset), and model-3 (overall fatality). In total, 39 patients with fatal dengue were identified, of which 17 and 14 patients died ≤7 days after illness onset and ≤3 days after presentation, respectively. In model-1 (range: 0‒4 points), gastrointestinal bleeding ≤72 h after presentation, thrombocytopenia (<50 × 10⁸ cells/L) at presentation, and acute kidney injury after hospitalization, using a cutoff level of 2 points, exhibited good discrimination (area under the receiver curve (AUC): 0.975) between survivors and non-survivors. In model-2, the significant predictors were gastrointestinal bleeding ≤72 h after presentation, and hemoconcentration and leukocytosis after hospitalization. Model-2 (range: 0⁻4 points) showed an AUC of 0.974, with a cutoff value of 2 points. The independent factors in model-2 were the predictors of overall mortality (model-3), which include thrombocytopenia (<50 × 10⁸ cells/L) at presentation. Using a cutoff value of 2 points, model-3 (range: 0⁻7 points) revealed an excellent discrimination between survivors and non-survivors (AUC: 0.963).

Seroprevalence of dengue virus in two districts of Kaohsiung City after the largest dengue outbreak in Taiwan since World War II

Dengue virus (DENV) is the leading cause of arboviral diseases in humans worldwide. In this study, we investigated the seroprevalence of DENV infection in two districts of Kaohsiung City, a metropolis in southern Taiwan, where major dengue outbreaks have occurred in the past three decades. We enrolled 1,088 participants from the Sanmin and Nanzih districts after the dengue outbreak of 2015, the largest in Taiwan since World War II, and found an overall DENV seroprevalence of 12.4% (95% confidence interval: 10.5–13.4%) based on the InBios DENV IgG ELISA kit. The ratios of clinically inapparent to symptomatic infections were 2.86 and 4.76 in Sanmin and Nanzih districts, respectively. Consistent with higher case numbers during recent outbreaks, the DENV seroprevalence was higher in Sanmin district (16.4%) than in Nanzih district (6.9%), suggesting district differences in seroprevalence and highlighting the importance of screening the DENV immune status of each individual before using the currently available DENV vaccine, Dengvaxia. In the two districts, the seroprevalence rates increased from 2.1% (in the 30–39-year age group) to 17.1% (60–69) and 50% (70–79). The pattern of a sharp and significant increase in seroprevalence in the 70–79-year age group correlated with a dramatic increase in the proportion of clinically severe DENV infections among total dengue cases in that age group. This differed from observations in the Americas and Southeast Asia and suggested that a large proportion of monotypically immune individuals together with other risk factors may contribute to clinically severe dengue among the elderly in Taiwan.

Dengue virus (DENV) is the most important cause of mosquito-borne viral disease in humans worldwide. Investigating DENV seroprevalence in Kaohsiung City after the largest dengue outbreak in Taiwan since World War II, we found an overall seroprevalence of 12.4% and heterogeneity in seroprevalence within a metropolis; this together with the low efficacy and potential disease enhancement of the currently available dengue vaccine (Dengvaxia) in DENV-naive individuals highlighted the importance of checking the DENV immune status of individuals prior to Dengvaxia vaccination. The pattern of a sharp and significant increase in DENV seroprevalence in the 70–79 year age group in Kaohsiung City was different from that in the Americas and Southeast Asia, and suggested that a large proportion of monotypically immune individuals in that age group together with other risk factors may contribute to clinically severe dengue disease among the elderly in Taiwan.