Circulating dengue virus serotypes in Bangladesh from 2013 to 2016

Evolving epidemiology, clinical features, and genotyping of dengue outbreaks in Bangladesh, 2000-2024: a systematic review

Background

The 2023 dengue outbreak has proven that dengue is not only an endemic disease but also an emerging health threat in Bangladesh. Integrated studies on the epidemiology, clinical characteristics, seasonality, and genotype of dengue are limited. This study was conducted to determine recent trends in the molecular epidemiology, clinical features, and seasonality of dengue outbreaks.

Methods

We analyzed data from 41 original studies, extracting epidemiological information from all 41 articles, clinical symptoms from 30 articles, and genotypic diversity from 11 articles. The study adhered to the standards of the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) Statement and Cochrane Collaboration guidelines.

Results

A total of 565,438 dengue cases and 2,587 fatalities were documented from January 2000 to March 2024. Notably, 60% of cases during the 2019 and 2023 outbreaks were reported in regions previously considered non-endemic. Fatalities were more frequent among women (70%). The majority of the studies (95-100%) used the NS1Ag test, followed by IgG or IgM and RT-PCR tests. New hotspots of dengue transmission were identified in the southern (Khulna, 10.8% and Barishal, 11.8%) and southeastern (Chattogram, 13.8%) regions of Bangladesh. Serotyping was conducted on 92.4% (1,456 of 1,575) of isolates between 2012 and 2023. Of the four serotypes, DENV3 was the most prevalent (57%), followed by DENV2 (30%), DENV1 (11%), and DENV4 (<1%). Genotype DENV3-I (43 of 59 isolates) was the most prevalent, followed by DENV3-II (8 of 59). The highest frequency of dengue cases was observed in August (26.3%), followed by September (22.5%), October (20.2%), and November (13.08%). Fever (90.51, 95% CI 85-100%) was the most prevalent symptom, followed by headache (57.98, 95% CI 12-100%), vomiting (51.16, 95% CI 23-91%), abdominal pain (34.12, 95% CI 12-85%), and myalgia (25.53, 95% CI 13-85%), respectively.

Conclusion

This study provides integrated insights into the molecular epidemiology, clinical features, seasonality, and transmission of dengue in Bangladesh and highlights research gaps for future studies.

Resurgence of Dengue Virus Serotype 2: Findings from the 2023 Bangladesh Outbreak

Bangladesh experienced the largest and deadliest dengue outbreak in 2023, after the virus had reappeared in the country 2 decades earlier. A total of 1,705 people died in Bangladesh, representing the highest case fatality rate (0.5%) due to dengue in the world for that year. The severity of dengue infection is to some extent related to the emergence of new circulating serotypes. To identify the possible predominant serotype in 2023, the reverse transcription polymerase chain reaction-based identification technique was used on stored serum samples of suspected dengue patients during the period between July and December 2023. The overall result of molecular serotyping showed that dengue virus (DENV-2) reappeared as the predominant serotype (74.1%), followed by a moderate number of samples with DENV-1 (19.8%) and DENV-3 (6.1%), in 2023. However, DENV-1 was found to be dominant in a few rural areas of Cox's Bazar districts. During the 2019 outbreak, DENV-3 was the dominant serotype, which seemed to be replaced by the DENV-2 serotype; this may have impacted the increased case fatality in 2023.

An effective pan-serotype dengue vaccine and enhanced control strategies could help in reducing the severe dengue burden in Bangladesh-A perspective

Dengue is an important vector-borne disease occurring globally. Dengue virus (DENV) infection can result in a potentially life-threatening disease. To date, no DENV-specific antiviral treatment is available. Moreover, an equally effective pan-serotype dengue virus vaccine is not available. Recently, two DENV vaccines, Dengvaxia and Qdenga, were licensed for limited use. However, none of them have been approved in Bangladesh. DENV is transmitted by Aedes mosquitoes, and global warming caused by climate change favoring Aedes breeding plays an important role in increasing DENV infections in Bangladesh. Dengue is a serious public health concern in Bangladesh. In the year 2023, Bangladesh witnessed its largest dengue outbreak, with the highest number of dengue cases (n = 321,179) and dengue-related deaths (n = 1,705) in a single epidemic year. There is an increased risk of severe dengue in individuals with preexisting DENV-specific immunoglobulin G if the individuals become infected with different DENV serotypes. To date, vector control has remained the mainstay for controlling dengue; therefore, an immediate, strengthened, and effective vector control program is critical and should be regularly performed for controlling dengue outbreaks in Bangladesh. In addition, the use of DENV vaccine in curbing dengue epidemics in Bangladesh requires more consideration and judgment by the respective authority of Bangladesh. This review provides perspectives on the control and prevention of dengue outbreaks. We also discuss the challenges of DENV vaccine use to reduce dengue epidemics infection in Bangladesh.

Understanding dengue outbreaks in Rajshahi district, Bangladesh: A comprehensive case study

Background and aims

The 2023 dengue outbreak in Bangladesh marked an unprecedented increase in fatalities, particularly in Dhaka, and demonstrated extensive prevalence nationwide, including Rajshahi district. Dengue fever remains a significant public health challenge in Southeast Asia, with complex epidemiological patterns. Previous research has mainly focused on den serotypes in Dhaka. Therefore, this study aims to identify serotypes in the Rajshahi district under endemic conditions.

Methods

Blood samples from suspected dengue patients were collected at Rajshahi Medical College Hospital. Initial rapid detection of dengue-positive cases was performed using (Nonstructural Protein 1 L) NS1, (Immunoglobulin G) IgG, and (Immunoglobulin M) IgM tests. Upon confirmation of dengue positivity, viral RNA was extracted for molecular testing. The dengue serotype was identified using real-time reverse transcription-polymerase chain reaction (rRT-PCR).

Results

The study revealed that 93.3 % of the patient were infected with (Dengue virus type 2) DENV2 and rest 6.7 % of the patient were (Dengue virus type 3) DENV3 among 30 dengue positive patients. Demographic observations show the distribution of dengue over nine upazilas. In Paba upazila, we found two DENV3 alongside DENV2.

Conclusion

The study concludes that the 2023 dengue outbreak in Rajshahi district, Bangladesh, predominantly involved the DENV2 serotype. Geospatial analysis underscores the importance of understanding regional distribution patterns to enhance targeted interventions against dengue fever in endemic areas.

Safety and durable immunogenicity of the TV005 tetravalent dengue vaccine, across serotypes and age groups, in dengue-endemic Bangladesh: a randomised, controlled trial

BACKGROUND

Morbidity and mortality from dengue virus (DENV) is rapidly growing in the large populations of south Asia. Few formal evaluations of candidate dengue vaccine candidates have been undertaken in India, Pakistan, or Bangladesh. Tetravalent vaccines must be tested for safety and immunogenicity in all age groups and in those previously exposed and naive to DENV infections. TV005 is a live, attenuated tetravalent dengue vaccine. We evaluated the safety and immunogenicity of a single dose of TV005 across age groups in dengue-endemic Bangladesh.

METHODS

We performed a randomised, placebo-controlled age de-escalating clinical trial of TV005 at a single clinical site in dengue-endemic Dhaka, Bangladesh, following a technology transfer from the USA. Healthy (as determined by history, clinical examination, and safety laboratory test results) volunteers aged 1-50 years were randomly assigned 3:1 (stratified by four age groups) to receive a single dose of TV005 vaccine or placebo. Participants were followed up for 3 years. The study was double blind and was unmasked at day 180; outcome assessors, clinic staff, and volunteers remained blind throughout. Primary outcomes were safety, evaluated per-protocol as proportion of volunteers with solicited related adverse events of any severity through 28 days post dosing, and post-vaccination seropositivity by day 180 using serotype-specific neutralising antibodies (PRNT50 ≥10). Secondary outcomes included viremia, impact of past dengue exposure, and durability of antibody responses. This study is registered with Clinicaltrials.gov, NCT02678455, and is complete.

FINDINGS

Between March 13, 2016, and Feb 14, 2017, 192 volunteers were enrolled into four age groups (adults [18-50 years; 20 male and 28 female], adolescents [11-17 years; 27 male and 21 female], children [5-10 years; 15 male and 33 female], and young children [1-4 years; 29 male and 19 female]) with 48 participant per group. All participants were Bangladeshi. Vaccination was well tolerated and most adverse events were mild. Rash was the most common vaccine-associated solicited adverse event, in 37 (26%) of 144 vaccine recipients versus six (12%) of 48 placebo recipients; followed by fever in seven (5% of 144) and arthralgias in seven (6% of 108), which were only observed in vaccine recipients. Post-vaccine, volunteers of all ages (n=142) were seropositive to most serotypes with 118 (83%) seropositive to DENV 1, 141 (99%) to DENV 2, 137 (96%) to DENV 3, and 124 (87%) to DENV 4, overall by day 180. Post-vaccination, viraemia was not consistently found and antibody titres were higher (10-15-fold for DENV 1-3 and 1·6-fold for DENV 4) in individuals with past dengue exposure compared with the dengue-naive participants (DENV 1 mean 480 [SD 4·0] vs 32 [2·4], DENV 2 1042 [3·2] vs 105 [3·1], DENV 3 1406 [2·8] vs 129 [4·7], and DENV 4 105 [3·3] vs 65 [3·1], respectively). Antibody titres to all serotypes remained stable in most adults (63-86%) after 3 years of follow-up. However, as expected for individuals without past exposure to dengue, titres for DENV 1, 3, and 4 waned by 3 years in the youngest (1-4 year old) cohort (69% seropositive for DENV 2 and 22-28% seropositive for DENV 1, 3, and 4).

INTERPRETATION

With 3 years of follow-up, the single-dose tetravalent dengue vaccine, TV005, was well tolerated and immunogenic for all four serotypes in young children to adults, including individuals with no previous dengue exposure.

FUNDING

National Institutes of Health-National Institute of Allergy and Infectious Diseases Intramural Research Program and Johns Hopkins University.

TRANSLATION

For the Bangla translation of the abstract see Supplementary Materials section.

Twenty-two years of dengue outbreaks in Bangladesh: epidemiology, clinical spectrum, serotypes, and future disease risks

Dengue is the most rapidly spreading mosquito-borne disease and has become a major public health threat, particularly for tropical and subtropical countries including Bangladesh. This comprehensive review aims to summarize the overall scenario of dengue, including disease burden, clinical spectrum, seroprevalence, circulating serotypes/genotypes, and spatial distribution since the first recorded outbreak in Bangladesh. Since the first recorded outbreak in 2000, dengue epidemiology has shown the typical epidemic pattern with more frequent and bigger outbreaks and gradual geographic expansion to non-endemic regions in Bangladesh. For instance, highly confined Rohingya refugee camps that provide shelters to nearly 1.2 million forcibly displaced vulnerable Myanmar nationals in Cox's Bazar district confronted a massive outbreak in 2022. Recent major outbreaks are found to be associated with the emergence of serotype DENV-3, which was undetected for a long time. Consequently, changes in serotypes might be attributed to increased severity in clinical manifestation in recent years. The existing weak surveillance and risk management systems are inadequate to deal with impending dengue risks. The healthcare system, particularly at the district level, is not prepared to manage impending large-scale dengue outbreaks in Bangladesh. Our findings would contribute to the development of strategies for dengue control and management in Bangladesh as well as other similar settings elsewhere in the world.

Comparative phylogenetic analysis and transcriptomic profiling of Dengue (DENV-3 genotype I) outbreak in 2021 in Bangladesh

Background

The next-generation sequencing (NGS) technology facilitates in-depth study of host-pathogen metatranscriptome. We, therefore, implicated phylodynamic and transcriptomic approaches through NGS technology to know/understand the dengue virus (DENV) origin and host response with dengue fever.

Methods

In this study, blood serum RNA was extracted from 21 dengue patients and 3 healthy individuals. Total transcriptomic data were analyzed for phylogenetic, phylodynamic, differential express gene (DEG), and gene ontology (GO) using respective bioinformatics tools.

Results

The viral genome sequence revealed dengue viral genome size ranges 10647 to 10707 nucleotide. Phylogenetic and phylodynamic analysis showed that the 2021 epidemic isolates were DENV-3 genotype-I and maintained as a new clade in compared to 2019 epidemic. Transcriptome analysis showed a total of 2686 genes were DEG in dengue patients compared to control with a q-value < 0.05. DESeq2 plot counts function of the top 24 genes with the smallest q-values of differential gene expression of RNA-seq data showed that 11 genes were upregulated, whereas 13 genes were downregulated. GO analysis showed a significant upregulation (p = < 0.001) in a process of multicellular organismal, nervous system, sensory perception of chemical stimulus, and G protein-coupled receptor signaling pathways in the dengue patients. However, there were a significant downregulation (p = < 0.001) of intracellular component, cellular anatomical entity, and protein-containing complex in dengue patients. Most importantly, there was a significant increase of a class of immunoregulatory proteins in dengue patients in compared to the controls, with increased GO of immune system process. In addition, upregulation of toll receptor (TLR) signaling pathways were found in dengue patients. These TLR pathways were particularly involved for the activation of innate system coupled with adaptive immune system that probably involved the rapid elimination of dengue virus infected cells. These differentially expressed genes could be further investigated for target based prophylactic interventions for dengue.

Conclusion

This is a first report describing DENV complete genomic features and differentially expressed genes in patients in Bangladesh. These genes may have diagnostic and therapeutic values for dengue infection. Continual genomic surveillance is required to further investigate the shift in dominant genotypes in relation to viral pathogenesis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12985-023-02030-1.

Genetic Analysis of Dengue Virus in Severe and Non-Severe Cases in Dhaka, Bangladesh, in 2018-2022

Dengue virus (DENV) infections have unpredictable clinical outcomes, ranging from asymptomatic or minor febrile illness to severe and fatal disease. The severity of dengue infection is at least partly related to the replacement of circulating DENV serotypes and/or genotypes. To describe clinical profiles of patients and the viral sequence diversity corresponding to non-severe and severe cases, we collected patient samples from 2018 to 2022 at Evercare Hospital Dhaka, Bangladesh. Serotyping of 495 cases and sequencing of 179 cases showed that the dominant serotype of DENV shifted from DENV2 in 2017 and 2018 to DENV3 in 2019. DENV3 persisted as the only representative serotype until 2022. Co-circulation of clades B and C of the DENV2 cosmopolitan genotype in 2017 was replaced by circulation of clade C alone in 2018 with all clones disappearing thereafter. DENV3 genotype I was first detected in 2017 and was the only genotype in circulation until 2022. We observed a high incidence of severe cases in 2019 when the DENV3 genotype I became the only virus in circulation. Phylogenetic analysis revealed clusters of severe cases in several different subclades of DENV3 genotype I. Thus, these serotype and genotype changes in DENV may explain the large dengue outbreaks and increased severity of the disease in 2019.

Increasing Dengue Burden and Severe Dengue Risk in Bangladesh: An Overview

Dengue is a prevalent and rapidly spreading mosquito-borne viral disease affecting humans. The geographic range of dengue is expanding, and much like in many other tropical regions of the world, dengue has become a major public health issue in Bangladesh. Until a large epidemic dengue outbreak in 2000, sporadic outbreaks have occurred in Bangladesh since 1964. After 2000, varying intensities of dengue activity were observed each year until 2018. However, in 2019, Bangladesh experienced the largest dengue epidemic in its history, with 101,354 dengue cases and 164 dengue-related deaths. Notably, this outbreak occurred in many regions that were previously considered free of the disease. As of 10 December 2022, a total of 60,078 dengue cases and 266 dengue-related deaths were reported in Bangladesh, with the 2022 outbreak being the second largest since 2000. There is an increased genetic diversity of the dengue virus (DENV) in Bangladesh and all four DENV serotypes are prevalent and co-circulating, which increases the risk for severe dengue owing to the antibody-dependent enhancement effect. Vector control remains the mainstay of dengue outbreak prevention; however, the vector control programs adopted in Bangladesh seem inadequate, requiring improved vector control strategies. In this review, we provide an overview of the epidemiology of DENV infection and the risks for a severe dengue outbreak in Bangladesh. Additionally, we discuss different dengue vector control strategies, from which the most suitable and effective measures can be applied in the context of Bangladesh for tackling future dengue epidemics.

S-Adenosyl-l-Homocysteine Exhibits Potential Antiviral Activity Against Dengue Virus Serotype-3 (DENV-3) in Bangladesh: A Viroinformatics-Based Approach

Dengue outbreak is one of the concerning issues in Bangladesh due to the annual outbreak with the alarming number of death and infection. However, there is no effective antiviral drug available to treat dengue-infected patients. This study evaluated and screened antiviral drug candidates against dengue virus serotype 3 (DENV-3) through viroinformatics-based analyses. Since 2017, DENV-3 has been the predominant serotype in Bangladesh. We selected 3 non-structural proteins of DENV-3, named NS3, NS4A, and NS5, as antiviral targets. Protein modeling and validation were performed with VERIFY-3D, Ramachandran plotting, MolProbity, and PROCHECK. We found 4 drug-like compounds from DRUGBANK that can interact with these non-structural proteins of DENV-3. Then, the ADMET profile of these compounds was determined by admetSAR2, and molecular docking was performed with AutoDock, SWISSDOCK, PatchDock, and FireDock. Furthermore, they were subjected to molecular dynamics (MD) simulation study using the DESMOND module of MAESTRO academic version 2021-4 (force field OPLS_2005) to determine their solution's stability in a predefined body environment. Two drug-like compounds named Guanosine-5'-Triphosphate (DB04137) and S-adenosyl-l-homocysteine (DB01752) were found to have an effective binding with these 3 proteins (binding energy > 33.47 KJ/mole). We found NS5 protein was stable and equilibrated in a 100 ns simulation run along with a negligible (<3Å) root-mean-square fluctuation value. The root-mean-square deviation value of the S-adenosyl-l-homocysteine-NS5 complex was less than 3Å, indicating stable binding between them. The global binding energy of S-adenosyl-l-homocysteine with NS5 was -40.52 KJ/mole as ∆G. Moreover, these 2 compounds mentioned above are non-carcinogenic according to their ADMET (chemical absorption, distribution, metabolism, excretion, and toxicity) profile (in silico). These outcomes suggest the suitability of S-adenosyl-l-homocysteine as a potential drug candidate for dengue drug discovery research.

Pars Plana Vitrectomy for a Sub-Internal Limiting Membrane Hemorrhage and Vitreous Hemorrhage Secondary to Dengue Fever: A Case Report

Although rare, dengue fever-associated ocular manifestations are a valid cause of visual impairment. Clinicians usually have a dilemma between vitrectomy and medical management if there is an associated vitreous hemorrhage. Vitrectomy has been rarely reported previously in the management of vitreous hemorrhage secondary to dengue fever.

We report a case of a young adult who presented with bilateral vitreous hemorrhages. The diagnosis of dengue was confirmed by serology and a typical epidemiological context. The patient presented already having undergone yttrium aluminum garnet (YAG) laser hyaloidotomy for preretinal hemorrhage in the other eye, with a subsequent vitreous spread of the hemorrhage. Vitrectomy with internal limiting membrane (ILM) peeling was performed for the affected eye and the visual acuity was fully regained after a few weeks.

Dengue fever can present with dense or sub-ILM hemorrhages. In our case, the vision quickly recovered after vitrectomy and ILM peeling. We, therefore, recommend early vitrectomy in cases with vitreous hemorrhage associated with sub-ILM involvement so as not to delay visual recovery.

Clinicopathological alteration of symptoms with serotype among dengue infected pediatric patients

Dengue fever is a self-limiting, acute febrile illness caused by an arbovirus. This infection may be asymptomatic or symptomatic with its potential life-threatening form as DHF/DSS. Severe dengue cases occur typically in children due to overproduction of pro-inflammatory and anti-inflammatory cytokines (called cytokines storm) as well as increased microvascular permeability in them. This study aimed to find prevalent circulating dengue serotype and their clinicopathological association among pediatric patients admitted to tertiary care hospitals in Kolkata, India. Overall, 210 patients were approached and among them, 170 dengue suspected children admitted to three tertiary care hospitals were included in this study. Dengue samples were screened for the presence of NS1 antigen and dengue IgM antibodies by ELISA. Viral RNA was extracted from NS1 seropositive serum samples and subjected to molecular serotyping by semi-nested RT-PCR. All patients were followed up for clinical manifestations and biochemical parameters associated with dengue. Co-circulation of all four serotypes was observed and DENV2 was the major circulating strain. Physiological classification of associated clinical symptoms was done and represented as a percentage variable. A multivariate logistic regression approach was used for making a regression model including dengue-associated clinical symptoms with dengue positivity and negativity as dependent variables. Thrombocytopenia was observed in 69% of patients and the commonest bleeding manifestation was petechia. Liver function profiles of infected patients were observed during follow-up and represented using a box plot. A significant change in trends of dengue-associated clinical manifestations and differential expression of liver functional profile with different phase transitions of dengue fever was obtained in the study population. This article is protected by copyright. All rights reserved.

A retrospective study on the socio-demographic factors and clinical parameters of dengue disease and their effects on the clinical course and recovery of the patients in a tertiary care hospital of Bangladesh

Dengue, a mosquito transmitted febrile viral disease, is a serious public health concern in Bangladesh. Despite significant number of incidences and reported deaths each year, there are inadequate number of studies relating the temporal trends of the clinical parameters as well as socio-demographic factors with the clinical course of the disease. Therefore, this study aims to associate the clinical parameters, demographic and behavioral factors of the dengue patients admitted in a tertiary care hospital in Dhaka, Bangladesh during the 2019 outbreak of dengue with the clinical course of the disease. Data were collected from the 336 confirmed dengue in-patients and analyzed using SPSS 26.0 software. Majority of the patients were male (2.2 times higher than female) who required longer time to recover compared to females (p < 0.01), urban resident (54.35%) and belonged to the age group of 18–40 years (73.33%). Dengue fever (90.77%) and dengue hemorrhagic fever (5.95%) were reported in most of the dengue patients while fever (98%) was the most frequently observed symptom. A significantly positive association was found between patient’s age and number of manifested symptoms (p = 0.013). Average duration of stay in the hospital was 4.9 days (SD = 1.652) and patient’s recovery time was positively correlated with delayed hospitalization (p < 0.01). Additionally, recovery time was negatively correlated with initial blood pressure (both systolic (p = 0.001, and diastolic (p = 0.023)) and platelet count (p = 0.003) of the patients recorded on the first day of hospitalization. Finally, a statistical model was developed which predicted that, hospital stay could be positively associated with an increasing trend of temperature, systolic blood pressure and reduced platelets count. Findings of this study may be beneficial to better understand the clinical course of the disease, identify the potential risk factors and ensure improved patient management during future dengue outbreaks.

Comparison of clinical manifestation of dengue fever in Bangladesh: an observation over a decade

BACKGROUND

The clinical presentation of dengue fever had been observed to change with time since its first outbreak in 2000 in Bangladesh. This report showed the clinical presentation of the 2019 outbreak in Bangladesh along with its comparison to previous outbreaks witnessed in this region.

METHODS

This hospital-based cross-sectional study was conducted in one of the largest tertiary care hospitals in Dhaka city. A total of 553 laboratory-confirmed and 194 probable dengue cases were interviewed. The clinical manifestation of the confirmed cases of the current outbreak was compared with three of the outbreak reports retrieved from the databases. R version 3.6.3 was used for data analysis.

RESULTS

Among the confirmed cases, two-thirds were male (63.2%) and the average age was 27(± 11) years. Positive tests for NS1 and IgM were present in 99.6% (n = 525/527) and 82.6% (n = 38/46) of the cases, respectively. Thrombocytopenia was present in 66.1% of cases. Fever (100%) was common for all. Gastrointestinal (GIT) features, including abdominal pain (86.5%), anorexia and/or vomiting (69.6%), and Diarrhea (> 3 motions/day) (26.2%) were more frequent than typical rash and other pain symptoms. Hypotension was present in approximately a quarter of patients (25%). GIT features (anorexia, nausea, and/or vomiting) and hypotension were more common among adult participants while bleeding manifestation (melena and vaginal bleeding, p = 0.009 & 0.032) was more frequent in pediatric patients. Compared to outbreaks of 2008, 2016, and 2018, increasing trends in GIT symptoms e.g. anorexia, abdominal pain, and diarrhea were observed. While a negative trend in hemorrhagic manifestations (skin rash, melena, and conjunctival hemorrhage/hemorrhagic sclera) and arthralgia/joint pain were found.

CONCLUSION

The present outbreak was noticeably characterized by GIT symptoms and hypotension in addition to the typical clinical features like rash and pain symptoms. An increasing trend in GIT features and decreasing trend in hemorrhagic manifestations was noted over the last decade of dengue outbreaks.

Clinical spectrum and predictors of severity of dengue among children in 2019 outbreak: a multicenter hospital-based study in Bangladesh

BACKGROUND

The mosquito-borne arboviral disease dengue has become a global public health concern. However, very few studies have reported atypical clinical features of dengue among children. Because an understanding of various spectrums of presentation of dengue is necessary for timely diagnosis and management, we aimed to document the typical and atypical clinical features along with predictors of severity among children with dengue during the largest outbreak in Bangladesh in 2019.

METHODS

We conducted a cross-sectional study between August 15 and September 30, 2019. in eight tertiary level hospitals in Dhaka city. Children (aged < 15 years) with serologically confirmed dengue were conveniently selected for data collection through a structured questionnaire. Descriptive, inferential statistics, and multivariable logistic regression were used to analyze data.

RESULTS

Among the 190 children (mean age 8.8 years, and male-female ratio 1.22:1) included in the analysis, respectively 71.1 and 28.9% children had non-severe and severe dengue. All children had fever with an average temperature of 103.3 ± 1.2 F (SD). Gastrointestinal symptoms were the most common associated feature, including mostly vomiting (80.4%), decreased appetite (79.5%), constipation (72.7%), and abdominal pain (64.9%). Mouth sore, a less reported feature besides constipation, was present in 28.3% of children. Atypical clinical features were mostly neurological, with confusion (21.3%) being the predominant symptom. Frequent laboratory abnormalities were thrombocytopenia (87.2%), leucopenia (40.4%), and increased hematocrit (13.4%). Age (AOR 0.86, 95%CI 0.75-0.98, p = 0.023), mouth sore (AOR 2.69, 95%CI 1.06-6.96, p = 0.038) and a decreased platelet count (< 50,000/mm3) with increased hematocrit (> 20%) (AOR 4.94, 95%CI 1.48-17.31, p = 0.01) were significant predictors of severity.

CONCLUSIONS

Dengue in children was characterized by a high severity, predominance of gastrointestinal symptoms, and atypical neurological presentations. Younger age, mouth sores, and a decreased platelet with increased hematocrit were significant predictors of severity. Our findings would contribute to the clinical management of dengue in children.

Assessment of Knowledge, Attitudes, and Practices Regarding Dengue among Physicians: A Web-Based Cross-Sectional Survey

Dengue fever is one of the most important viral infections transmitted by Aedes mosquitoes and a major cause of morbidity and mortality globally. Accurate identification of cases and treatment of dengue patients at the early stages can reduce medical complications and dengue mortality rate. This survey aims to determine the knowledge, attitude, and practices (KAP) among physicians in dengue diagnosis and treatment. This study was conducted among physicians in Turkey as one nonendemic country and Bangladesh, India, and Malaysia as three dengue-endemic countries. The dosing frequencies, maximum doses, and contraindications in dengue fever were examined. The results found that physicians from Bangladesh, India, and Malaysia have higher KAP scores in dengue diagnosis and treatment compared to physicians in Turkey. This may be due to a lack of physician's exposure to a dengue patient as Turkey is considered a nonendemic country. This assessment may help establish a guideline for intervention strategies among physicians to have successful treatment outcomes and reduce dengue mortality.

Clinico-epidemiologic characteristics of the 2019 dengue outbreak in Bangladesh

BACKGROUND

Dengue fever shows a broad range of clinical presentations worldwide. Here we report on our clinical findings during the 2019 dengue outbreak in one of the largest tertiary care hospitals in Dhaka, the capital of Bangladesh.

METHODS

A total of 747 suspected dengue cases (553 confirmed and 194 probable) were interviewed with a pro forma case record form. Statistical analyses were conducted using SPSS 20.0. Ethical clearance was obtained from the Dhaka Medical College.

RESULTS

The mean age of the dengue cases was 27 y and approximately two-thirds were male. Positive tests for NS1 and anti-dengue immunoglobulin M antibody were present in 91.9% and 59.4% of the cases, respectively. Thrombocytopenia was present in 69% of cases and fever was present in 99.1% of cases. Gastrointestinal (GI) features, including anorexia and/or vomiting (69.4%), abdominal pain (39.8%) and diarrhoea (25.6%), were more prevalent than typical rash and pain symptoms. Hypotension was present in approximately one-quarter of patients (25.4%). Probable and confirmed dengue cases have shown similar clinical characteristics and laboratory findings.

CONCLUSIONS

The 2019 outbreak of dengue fever in Bangladesh was characterized by increased presentation with GI features. Recognition of this trend would permit early diagnosis and proper management of patients.

Epidemiology and challenges of dengue surveillance in the WHO South-East Asia Region

Dengue poses a significant health and economic burden in the WHO South-East Asia Region. Approaches for control need to be aligned with current knowledge on the epidemiology of dengue in the region. Such knowledge will ensure improved targeting of interventions to reduce dengue incidence and its socioeconomic impact. This review was undertaken to describe the contemporary epidemiology of dengue and critically analyse the existing surveillance strategies in the region. Over recent decades, dengue incidence has continued to increase with geographical expansion. The region has now become hyper-endemic for multiple dengue virus serotypes/genotypes. Every epidemic cycle was associated with a change of predominant serotype/genotype and this was often associated with severe disease with intense transmission. Classical larval indices are widely used in vector surveillance and adult mosquito samplings are not implemented as a part of routine surveillance. Further, there is a lack of integration of entomological and disease surveillance systems, often leading to inaction or delays in dengue prevention and control. Disease surveillance does not capture all cases, resulting in under-reporting, and has thus failed to adequately represent the true burden of disease in the region. Possible solutions include incorporating adult mosquito sampling into routine vector surveillance, the establishment of laboratory-based sentinel surveillance, integrated vector and dengue disease surveillance and climate-based early warning systems using available technologies like mobile apps.

Antiviral phytochemicals as potent inhibitors against NS3 protease of dengue virus

Dengue, a mosquito-borne disease, has appeared as a major infectious disease globally. The virus requires its proteins to replicate and reproduce in the host cell. The NS3 protease converts the polyprotein to functional proteins with the help of the NS2B cofactor. Thus, NS3 protease is a promising target to develop antiviral inhibitors against the dengue virus. A systematic screening including ADMET properties, molecular docking, molecular dynamics (MD) simulation, binding free energy calculation, and QSAR studies is carried out to predict potent inhibitors against the NS3 protease. From the screening of 40 antiviral phytochemicals, ADMET properties analysis was used to screen out ligands that violate ADME rules and have probable toxicity. Cyanidin 3-Glucoside, Dithymoquinone, and Glabridin were predicted to be potent inhibitors against the NS3 protease according to their binding affinity. These ligands showed several noncovalent interactions, including hydrogen bond, hydrophobic interaction, electrostatic interaction, pi-sulfur interactions. The ligand-protein complexes were further scrutinized using 250 ns molecular dynamics simulation. The MM-PBSA binding free energy calculation was conducted to investigate their binding stability in dynamic conditions. The calculated pIC50(mM) value was predicted using the QSAR model with 89.91% goodness of fit. The predicted biologocal activity value for the ligands indicates they might have good potency.

Nationwide Distribution of Dengue Virus Type 3 (DENV-3) Genotype I and Emergence of DENV-3 Genotype III during the 2019 Outbreak in Bangladesh

Bangladesh is an endemic region of dengue fever and experienced an unprecedented large outbreak with more than 100,000 confirmed cases in 2019. To understand the prevalence of dengue antibody in patients and molecular epidemiological characteristics of dengue virus (DENV) in this outbreak, a total of 179 blood samples were collected from patients in 10 districts (seven divisions) covering nearly the whole country from August to December 2019. DENV NS-1 was detected in 162 samples, among which DENV-specific IgM was positive in 119 samples (73.5%), including 60.5% samples also positive for DENV-specific IgG. Sequencing of the partial C-prM gene and its phylogenetic analysis revealed predominance of DENV type 3 genotype I, accounting for 93% of samples examined. DENV-3 genotype III was identified in two samples from separate districts, and only one DENV-2 cosmopolitan genotype was found in the capital city, Dhaka. These findings suggest the predominance of DENV-3 genotype I and occurrence of DENV-3 genotype III, associated with increased incidence of recent secondary infection in Bangladesh in 2019.

Risk Assessment of Dengue Transmission in Bangladesh Using a Spatiotemporal Network Model and Climate Data

Vector-borne disease risk assessment is crucial to optimize surveillance, preventative measures (vector control), and resource allocation (medical supplies). High arthropod abundance and host interaction strongly correlate to vector-borne pathogen transmission. Increasing host density and movement increases the possibility of local and long-distance pathogen transmission. Therefore, we developed a risk-assessment framework using climate (average temperature and rainfall) and host demographic (host density and movement) data, particularly suitable for regions with unreported or underreported incidence data. This framework consisted of a spatiotemporal network-based approach coupled with a compartmental disease model and nonhomogeneous Gillespie algorithm. The correlation of climate data with vector abundance and host–vector interactions is expressed as vectorial capacity—a parameter that governs the spreading of infection from an infected host to a susceptible one via vectors. As an example, the framework is applied for dengue in Bangladesh. Vectorial capacity is inferred for each week throughout a year using average monthly temperature and rainfall data. Long-distance pathogen transmission is expressed with human movement data in the spatiotemporal network. We have identified the spatiotemporal suitability of dengue spreading in Bangladesh as well as the significant-incidence window and peak-incidence period. Analysis of yearly dengue data variation suggests the possibility of a significant outbreak with a new serotype introduction. The outcome of the framework comprised spatiotemporal suitability maps and probabilistic risk maps for spatial infection spreading. This framework is capable of vector-borne disease risk assessment without historical incidence data and can be a useful tool for preparedness with accurate human movement data.

Co-circulation of dengue virus type 3-genotype I and type 2-Cosmopolitan genotype in 2018 outbreak in Dhaka, Bangladesh

Dengue virus (DENV) that caused an outbreak in Dhaka, Bangladesh during 2018 was analysed phylogenetically. DENV samples were classified into type 2-Cosmopolitan genotype (54%) and type 3-genotype I (46%), indicating co-circulation of two DENV types and resurgence of type 3 associated with genotype replacement.

Genotype replacement of dengue virus type 3 and clade replacement of dengue virus type 2 genotype Cosmopolitan in Dhaka, Bangladesh in 2017

Dengue is a mosquito-borne disease that has spread to >100 countries and is caused by the dengue virus (DENV), which belongs to the Flavivirus genus of the family Flaviviridae. DENV comprises 4 serotypes (DENV-1 to -4), and each serotype is further divided into distinct genotypes. In India, it is reported that all 4 serotypes of DENV co-circulate. Although Bangladesh is a neighboring country of India, very few reports have published DENV sequence data for the country, especially after 2012. To understand the current distribution of DENV genotypes in Bangladesh, we determined the nucleotide sequences of envelope regions obtained from 58 DENV-positive patients diagnosed at Apollo Hospitals Dhaka during the period between September 2017 and February 2018. We found 5 DENV-1, 47 DENV-2, and 6 DENV-3 serotypes. A phylogenetic analysis of the obtained viral sequences revealed that DENV-3 genotype I was present instead of DENV-3 genotype II, which was predominant in Bangladesh between 2000 and 2009. Furthermore, we found two distinct lineages of the Cosmopolitan genotype of DENV-2, one of which was closely related to strains from Southeast Asia and has never been reported previously in Bangladesh. These results indicated that DENVs in Bangladesh have increased in genotypic diversity and suggest that the DENV genotypic shift observed in other Asian countries also might have been taking place in Bangladesh.

Prevalence and identification of arthropod-transmitted viruses in Kassala state, Eastern Sudan

Vector-borne diseases are responsible for more than 20% of the infectious diseases worldwide. The prevalence of arboviruses transmit diseases to humans in Sudan has not been investigated. Mosquito-borne viral diseases increase globally incidence, including the Sudan. Frequent unknown fever outbreaks have been reported in eastern region, Sudan. However, diagnosis was based exclusively on clinical signs and symptoms without confirmatory laboratory investigations. However, for accurate detection of these viruses in outbreaks, molecular technique is considered. The objective of this study was to determine the prevalence of six arboviruses in the Kassala state of east Sudan during unknown fever outbreak. A cross sectional hospital-based study was conducted in the Kassala, Teaching Hospital. Blood samples from 119 patients suffering from unknown fever were used for screening of six arboviruses, hepatitis E virus and malarial using molecular techniques and serology.  The overall arboviruses seroprevelance was 61.3% (73/119). The highest positivity rate was 73.1% (52/73) chikungunya virus; 29 males and 20 females patients were chikungunya positive. Other arboviruses were circulating in low rate 20.5% (15/73), and 6.8% (5/73) for sindbis and rift valley fever viruses respectively. Hepatitis E virus was negative in all cases and malaria positivity rate 13.4% (16/119). The prevalence of arboviruses among unknown fever patients present to Kassala teaching hospital of eastern region in Sudan is significantly high (61.3%). The chikungunya virus is the predominant causative agent of arboviruses. Molecular techniques such as PCR are important for accurate and rapid diagnosis of this viral outbreak.