Dengue infection in India: A systematic review and meta-analysis

Seroprevalence and Serotypes of Dengue Virus Infection in Ghana: A Systematic Review and Meta-Analysis

BACKGROUND

Dengue virus (DENV) infection poses a serious and growing public health threat in many tropical and subtropical regions worldwide, including Ghana. Despite the heightened risks due to suitable climatic conditions and the presence of competent vectors, the epidemiology of DENV in Ghana remains poorly understood, underscoring the critical need for a comprehensive assessment of the burden and circulation of the virus in the country.

METHODS

The review was conducted in accordance with the PRISMA guidelines. A literature search was conducted using the PubMed, Web of Science, and Scopus databases from inception to 24 September 2024. Studies presenting primary DENV seroprevalence data among Ghanaian populations were included. Quality was assessed using JBI tools. Meta-analyses estimated pooled prevalence with 95% CIs using random-effects models. Heterogeneity was evaluated using I2 statistic.

RESULTS

A total of nine studies met the selection criteria, with eight studies involving febrile patients and one involving blood donors. The pooled seroprevalence rates were 33.3% (95% CI: 16.2-50.4%) for IgG, 5.9% (95% CI: 0-12.5%) for IgM, 1.5% (95% CI: 0.4-2.6%) for DENV RNA, and 32.3% (95% CI: 0-68.5%) for IgG/IgM combined. Notably, the IgG seroprevalence exhibited substantial heterogeneity (I2 = 99%). DENV-2 and DENV-3 were the predominant serotypes identified. There was potential bias in seroprevalence estimates from hospital-based febrile samples.

CONCLUSIONS

This review has established the prevalence and circulation of DENV serogroups in Ghana. The higher seropositivity and heterogeneity underscore the need for standardized large-scale surveillance to optimize disease characterization and guide control. Integrating dengue prevention into existing vector control programs could help reduce risks in Ghana.

Imported fever in returning travellers and migrants in Spain, 2009-2021. Analysis by the +REDIVI network

BACKGROUND

Travellers and migrants commonly present to health services with febrile syndrome, which can have different causes, including some that are life-threatening. A better understanding of these causes may help guide management and determine appropriate empirical treatments.

OBJECTIVES

The aim was to identify the leading causes of fever and to assess their association with the region of travel and type of travellers.

METHODS

This prospective, multicentre study was conducted within the +REDIVI network. Data were collected on febrile syndrome cases among migrants, travellers, and people visiting friends and relatives (VFRs) from 2009 to 2021. Comparative analyses were performed according to patient categories and regions of travel/origin.

RESULTS

Of the 4186 patients with febrile syndrome, the most frequent diagnosis was malaria (31.0 %), followed by dengue fever (12.0 %) and nonspecific fever of less than three weeks' duration (11.6 %). Malaria predominated in people coming from sub-Saharan Africa (58.4 %), while dengue fever was more common in the rest of the regions (19.0 % in South America, 25.0 % in Central America and the Caribbean, 34.2 % in Southeast Asia, and 18.1 % in South-Central Asia). By type of traveller, tuberculosis was more frequent in migrants, malaria in VFRs, and dengue and other arboviral infections in travellers and VFRs.

CONCLUSIONS

Geographical area of travel and type of traveller are the main determinants of imported fever aetiology. Malaria remains the most common cause of febrile syndrome, especially in VFRs from sub-Saharan Africa, while dengue fever prevails in the other tropical regions.

Prevalence of Different Dengue Serotypes in Northern India, 2021-2022: A Tertiary Care Hospital-Based Study

Dengue fever is a substantial emerging and reemerging arboviral virus in tropical and subtropical areas that seriously threatens public health worldwide. India is experiencing rising dengue epidemics in urban and rural regions linked to all four serotypes. The objective is to examine the serotypes and genotypes of the circulating dengue virus (DENV) at a tertiary care center in eastern Uttar Pradesh, India, from 2020 to 2021. This retrospective cross-sectional observational study involved dengue patients from January 2021 to December 2022. The genetic analysis of the circulating DENV was conducted by amplifying the partial CprM (511-bp) gene using nested reverse transcriptase polymerase chain reaction (RT-PCR), followed by sequencing. Only those positive for NS1 antigen (n = 581) were included in the study. A total of 204 cases (35.1%) were seropositive, with 96 cases (37.4%) out of 257 in 2021 and 108 cases (33.3%) out of 324 in 2022. With 119 cases (58.3%), men were most affected. The nested RT-PCR for dengue revealed three DENV-1 to DENV-3, except for DENV-4. DENV-2 and DENV-3 were the most predominant serotypes, with 98 (48%) and 94 (46%) cases, respectively. Conversely, DENV-1 was the least prevalent with cases 3 (1.6%). Unfortunately, 35 (17.2%) of the 204 cases died. DENV-2 had the highest mortality rate, with 23 deaths (65.7%). In cases with DENV-3, nine (25.7%) died. This study revealed regional disparities in DENV serotype prevalence in India. If regional differences in the most common serotypes and genotypes are identified early in the season, molecular surveillance may predict major dengue outbreaks and severity.

Urinary leptospiral sphingomyelinases as diagnostic markers of leptospirosis in dengue patients co-infected with leptospirosis

The study aims to evaluate the diagnostic potential of pathogen-specific leptospiral sphingomyelinases, LipL32, LipL41, and HbpA in human patients with dengue-leptospirosis coinfection. Patients (n-86), upon clinical evaluation, were categorized into Group I (n-37; leptospirosis), Group II (n-39; dengue-leptospirosis coinfection), and Group III (n-10; negative for both dengue and leptospirosis). ELISA identified significant levels of the four leptospiral antigens in the urine of Group I and II, but not in Group III patients. Immunoblot analysis of the urinary proteins with specific antibodies identified the tissue-damaging true sphingomyelinases Sph2 and pore-forming SphH. Urinary leptospiral antigens identified patients with leptospirosis and with dengue-leptospirosis coinfection. Patients with renal damage and proteinuria showed high urinary excretion of anti-leptospiral antibodies, with markedly low values in the serum. Proteinuria resulted in the loss of the circulating proteins, reflected by the low levels of anti-leptospiral antibodies in serum, with urine showing albumin and high levels of anti-leptospiral antibodies. IMPORTANCE: The study highlights the diagnostic potential of all four leptospiral antigens. Since early detection of urinary sphingomyelinases is possible, their diagnostic and prognostic potential can be evaluated on a larger sample size. Non-invasive, point-of-care diagnostic devices can be developed for use in endemic regions, particularly during monsoon seasons.

Development of a Scoring Model to Predict Severe Dengue in Children at Admission to Emergency Care: An Observational Study

OBJECTIVE

Dengue has emerged as the most widely spread mosquito-borne disease, hyperendemic in India. Although severe dengue occurs only in a small proportion of cases, delays in the recognition and management can result in significant morbidity and mortality. Risk stratification of children in the emergency care and identifying those at risk for worsening during hospital stay facilitates optimum utilization of health care resources. The objective of our study was to develop and validate a scoring model to predict the development of severe dengue in hospitalized children by identifying risk factors present in them at the time of admission to the emergency department.

METHODS

A retrospective study of consecutive children aged 1 month to 18 years admitted with serologically confirmed dengue from January 2019 through December 2021 was conducted. Analysis of clinical and laboratory parameters of children resulted in the development of a comprehensive predictive scoring model. This model was internally validated prospectively on 107 children presenting with nonsevere dengue to emergency care.

RESULTS

A total of 743 children with confirmed dengue were studied out of which 216 (29.1%) had severe dengue. Presence of third spacing (odds ratio [OR] 3.74, 95% confidence interval [CI] 1.088-7.42, P < 0.001), tender hepatomegaly (OR 1.62, 95% CI 1.04-2.52, P < 0.032), respiratory distress (OR 3.50, 95% CI 1.89-6.51, P < 0.001), and moderate (OR 3.51, 95% CI 1.82-6.74, P < 0.001) to severe (OR 4.76, 95% CI 2.59-8.76, P < 0.001) elevation of aspartate aminotransferase were independent risk factors found to be associated with development of severe dengue. A score ≥7 had a specificity of 87%, negative predictive value of 86%, and overall diagnostic accuracy of 78.5% for predicting severe dengue.

CONCLUSIONS

The dengue severity scoring model was found to have reasonable diagnostic accuracy in predicting severe disease prior to hospitalization. However, more studies are required to validate the score in different emergency care settings with varied pediatric populations.

LL-37, the master antimicrobial peptide, its multifaceted role from combating infections to cancer immunity

Antimicrobial peptides (AMPs) represent a unique group of naturally occurring molecules having diverse biological activities, including potent antimicrobial properties. Among them, LL-37 has emerged as a significant player, demonstrating its multifaceted roles during bacterial, fungal, and viral infections, as well as exhibiting intriguing implications in cancer. This review delves into the versatile functions of LL-37, elucidating its mechanisms of action against microbial pathogens and its potential to modulate immune responses. We explored the efficacy of LL-37 in disrupting bacterial membranes, inhibiting fungal growth, and interfering with viral replication, highlighting its potential as a therapeutic agent against a wide array of infectious diseases. Furthermore, we discussed the emerging role of LL-37 in cancer immunity, where its immunomodulatory effects and direct cytotoxicity towards cancer cells offer novel avenues for cancer therapy in the near future. We provided a comprehensive overview of the activities of LL-37 across various diseases and underscored the importance of further research into harnessing the therapeutic potential of this potential antimicrobial peptide along with other suitable candidates.

Advances in drug discovery of flavivirus NS2B-NS3pro serine protease inhibitors for the treatment of Dengue, Zika, and West Nile viruses

Flaviviruses are vector-borne RNA viruses that seriously threaten global public health due to their high transmission index in humans, mainly in endemic areas. They spread infectious diseases that affect approximately 400 million people globally, primarily in developing countries struggling with persistent epidemic diseases. Viral infections manifest as hemorrhagic fever, encephalitis, congenital abnormalities, and fatalities. Despite nearly two decades of drug discovery campaigns, researchers have not identified promising lead compounds for clinical trials to treat or prevent flavivirus infections. Although scientists have made substantial progress through drug discovery approaches and vaccine development, resolving this complex issue might need some time. New therapeutic agents that can safely and effectively target key components of flaviviruses need to be identified. NS2B-NS3pro is an extensively studied pharmacological target among viral proteases. It plays a key role in the viral replication cycle by cleaving the polyprotein of flaviviruses and triggering the formation of structural and non-structural proteins. In this review, studies published from 2014 to 2023 were examined, and the specificity profile of compounds targeting NS2B-NS3 pro proteases for treating flavivirus infections was focused on. Additionally, the latest advancements in clinical trials were discussed. This article might provide information on the prospects of this promising pharmacological target.

Dengue infections in India: A meta-analysis

The escalating impact of dengue infection on health and mortality is a critical global issue. Therefore, it is of interest to assess the current trends of dengue infection in India. We searched through a wide range of internet databases to gather comprehensive studies on the incidence, prevalence, sero-prevalence, cost effectiveness and mortality rate of dengue infection in India from 2014 to 2023 (10 years) in a total of 127 studies. Analysis shows significant heterogeneity (diversity) in reported outcomes (p-values < 0.001). Thus, public health strategies should include early detection of dengue infection in our country.

Dengue in Pune city, India (2017-2019): a comprehensive analysis

Objectives

To understand the dynamics of dengue disease with special reference to (1) age (2) primary/secondary infections (3) serostatus and (4) serotypes examined during three consecutive years.

Methods

During 3 dengue seasons (2017-19), NS1/IgM ELISAs were used for dengue diagnosis in one of the 15 administrative wards of Pune City, India. Predefined symptoms were recorded at the time of diagnosis/hospitalization. IgG-capture ELISA (Panbio) was used to differentiate primary/secondary infections. DENV serotypes were determined for 260 viral RNA-positive patients.

Results

During the 3 years, 3,014/6,786 (44.4%, 41.4-49.9%) suspected cases were diagnosed as dengue. Use of either NS1 or IgM would have missed 25.5% or 43% of the confirmed dengue cases, respectively. Notably, a higher proportion of secondary dengue cases remained mild while a substantial proportion of primary infections developed warning signs. The symptoms among Dengue/non-dengue patients and primary/secondary infections varied and influenced by age and serostatus. The number and proportion of dengue serotypes varied yearly. A remarkable decline in dengue cases was observed during the COVID-19 pandemic years.

Conclusion

A substantial proportion of primary and secondary dengue patients progress to warning signs/severity or mild infection respectively, underscoring the possible role of non-ADE mechanisms in causing severe dengue that requires hospitalization. Both NS1 and IgM should be used for efficient diagnosis.

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.

Serotype-specific clinical features and spatial distribution of dengue in northern Kerala, India

Background

Collection and compilation of spatial, meteorological, entomological, and virological data are critical in mitigating climate-sensitive emerging infections like dengue. This study was a holistic attempt to understand the dengue situation in the Kasaragod district of Kerala, India.

Methods

This cross-sectional study was conducted in 13 health institutions from June to July 2021. Adult patients presenting with fever and testing positive for NS1 ELISA were subjected to Dengue RT-PCR and serotyping. The spatial and clinical features of the RT-PCR-positive patients, the district's meteorological data, and the vector indices were studied.

Results

The pre-epidemic months were marked by intermittent rainfall, peak ambient temperature and high larval indices. Among the 136 dengue RT-PCR patients studied, 41.2% had DENV2 followed by DENV1 (22.8%), DENV3 (5.9%) and DENV4 (4.4%); with 25% mixed infections. DENV1 showed a higher risk of gastrointestinal manifestations (80.6%, p=0.019) and musculoskeletal symptoms (77.4%, p=0.026) compared with other serotypes.

Conclusions

In the context of dengue hyperendemicity, the possibility of an emerging serotype's dominance coupled with the mixing up of strains should warn the health system regarding future outbreaks. Furthermore, the study emphasizes the importance of monitoring larval indices and the window of opportunity to intervene between environmental predictors and dengue outbreaks.

Age, gender, and infectious status-wise assessments of hematological parameters among patients with dengue infection

Background

The aim of this study was to examine the impact of different stages of dengue infection on immune cell counts among dengue patients and to compare them with cases of non-dengue febrile illness.

Methods

The recruited patients were divided into two groups: the first group served as a control (n = 55), representing non-dengue febrile illness, and the second group was identified as dengue febrile illness (n = 149), which was further divided into three groups based on infection stage. Blood samples were collected from the selected patients and subjected to blood cell component analysis. To find IgG and IgM as well as the dengue virus non-structural antigen-1 (NS1), an immunochromatographic test (ICT) kit was utilized. Additionally, a hematological analyzer was used to determine complete blood cell counts (CBC). Data was thoroughly analyzed using Graph Pad Prism 6 software. The differences in means of different groups were calculated by applying the student's t-test.

Results

The findings revealed the presence of severe leucopenia and thrombocytopenia at stages 1 and 2, accompanied by lymphopenia at stage 1. Group comparisons indicated that only teenagers exhibited a significantly lower white blood cell count compared to older individuals, while no significant differences were observed in lymphocytes, platelets, and monocytes across all age groups. Comparing different age groups of normal individuals to dengue-infected patients, the results unveiled that leucopenia was most severe in adults, followed by teenagers and children, with no significant difference in the elderly. Furthermore, adults showed the greatest degree of thrombocytopenia, followed by teens and kids, with the elderly showing the greatest degree of thrombocytopenia. Adults and teens showed extreme neutrophilia, whereas young children and the elderly showed no discernible abnormalities. Elderly patients experienced a marked decrease in monocyte count, a phenomenon not observed in other age groups.

Conclusion

In conclusion both, leucopenia & thrombocytopenia, are most severe in stages 1 and 2, whereas neutrophilia & lymphopenia are predominantly severe in stage 1. These results imply that the consequences associated with dengue infection are more severe in the early stages and tend to ameliorate as the patient progresses toward recovery.

Anti-Dengue Sanitation Practices: A Health Education Approach for Municipal Sanitary Workers in Puducherry, India

Introduction Dengue is a mosquito-borne disease of global health concern, especially in tropical areas. Aedes aegypti, its vector, thrives in inadequate sanitation conditions. The role of sanitary workers is pivotal in dengue control and prevention efforts; hence, educating them is essential for enhancing their vector control awareness. Methods This study was conducted among 109 municipal sanitary workers in selected areas of Puducherry, India. Their baseline knowledge, attitudes, and practices (KAP) regarding dengue were assessed through a pretested, semi-structured questionnaire, followed by a targeted health education intervention incorporating novel communication methods such as pocket awareness cards. The impact of the intervention was assessed through an increment in KAP scores, qualitative interviews, and surprise visits to the field during their work hours. Results The mean (± SD) scores in terms of knowledge (4.29 ± 1.77 vs. 7.17 ± 1.02; p < 0.01), attitudes (3.58 ± 1.42 vs. 4.69 ± 0.71; p < 0.01), and practices (1.98 ± 0.84 vs. 4.28 ± 1.12; p < 0.01) significantly increased post-intervention. Qualitative interviews revealed the utility of the intervention, with additional insights on implementation barriers and strategies for the future. Conclusion The study's findings imply that the targeted health education intervention for sanitary workers was effective in improving their knowledge and practices on dengue control. These results demonstrate the potential of future educational initiatives to promote vector control measures among sanitary staff and thereby combat dengue transmission in the community.

Distinct inflammatory markers in primary and secondary dengue infection: can cytokines CXCL5, CXCL9, and CCL17 act as surrogate markers?

Dengue fever poses a significant global health threat, with symptoms including dengue hemorrhagic fever and dengue shock syndrome. Each year, India experiences fatal dengue outbreaks with severe manifestations. The primary cause of severe inflammatory responses in dengue is a cytokine storm. Individuals with a secondary dengue infection of a different serotype face an increased risk of complications due to antibody-dependent enhancement. Therefore, it is crucial to identify potential risk factors and biomarkers for effective disease management. In the current study, we assessed the prevalence of dengue infection in and around Aligarh, India, and explored the role of cytokines, including CXCL5, CXCL9, and CCL17, in primary and secondary dengue infections, correlating them with various clinical indices. Among 1,500 suspected cases, 367 tested positive for dengue using Real-Time PCR and ELISA. In secondary dengue infections, the serum levels of CXCL5, CXCL9, and CCL17 were significantly higher than in primary infections (P < 0.05). Dengue virus (DENV)-2 showed the highest concentrations of CXCL5 and CCL17, whereas DENV-1 showed the highest concentrations of CXCL9. Early detection of these cytokines could serve as potential biomarkers for diagnosing severe dengue, and downregulation of these cytokines may prove beneficial for the treatment of severe dengue infections.

Knowledge, attitudes, and practices of health care professionals regarding dengue fever: need for training and provision of diagnostic equipment in Togo in 2022, a cross-sectional study

Background

Health statistics on dengue are virtually non-existent, despite the fact that the virus is circulating in Togo. This study aimed to assess the knowledge, attitudes, and practices (KAP) of health professionals in the Kara health region.

Methods

A cross-sectional study was conducted from March to June 2022 among healthcare professionals who had worked in the Kara region of northern Togo were selected using an exhaustive recruitment method. Data were collected by trained resident doctors with a face-to-face interview using a standardized, pretested questionnaire based on the WHO 2009 dengue guide. Three multivariate regression models were utilized to investigate factors associated with knowledge, attitudes and, and practices.

Results

A total of 464 respondents (37.1% female), median age 35 years, interquartile range (29-43 years) were included. Only (3.0%) of the participants had received training on dengue fever diagnosis, treatment and prevention in the last 3 years, and 10.3% had dengue rapid diagnostic tests available at their hospital. Half of the respondents (49.1%) had good knowledge of dengue fever, compared with 30.0% who had positive attitudes. Of a total of 256 professionals who had encountered a case of dengue fever in their practice, only 24 (9.4%) had appropriate practices for diagnosing and treating dengue fever. In multivariate analysis, the healthcare professionals who had taken part in ongoing training on dengue fever were more likely to have adequate dengue diagnosis and treatment practice aOR = 8.1; CI 95% = [1.7-36.0].

Conclusion

Strengthening healthcare professionals' dengue-related skills through ongoing training and the provision of dengue diagnostic tests could help improve early detection practices and management of dengue fever in Togo.

Role of auto-antibodies in the mechanisms of dengue pathogenesis and its progression: a comprehensive review

A complex interaction among virulence factors, host-genes and host immune system is considered to be responsible for dengue virus (DENV) infection and disease progression. Generation of auto-antibodies during DENV infection is a major phenomenon that plays a role in the pathophysiology of dengue hemorrhagic fever and dengue shock syndrome. Hemostasis, thrombocytopenia, hepatic endothelial dysfunction, and autoimmune blistering skin disease (pemphigus) are different clinical manifestations of dengue pathogenesis; produced due to the molecular mimicry of DENV proteins with self-antigens like coagulation factors, platelets and endothelial cell proteins. This review elaborately describes the current advancements in auto-antibody-mediated immunopathogenesis which inhibits coagulation cascade and promotes hyperfibrinolysis. Auto-antibodies like anti-endothelial cell antibodies-mediated hepatic inflammation during severe DENV infection have also been discussed. Overall, this comprehensive review provides insight to target auto-antibodies that may act as potential biomarkers for disease severity, and a ground for the development of therapeutic strategy against DENV.

Complexities of Dengue Fever: Pathogenesis, Clinical Features and Management Strategies

Dengue fever, transmitted through the bite of infected Aedes mosquitos, poses a significant global threat, particularly in the tropical and subtropical region. In this review, we aim to summarize the existent literature on dengue virus infection and to enlighten the reader on recent advances and knowledge. Dengue virus infection can cause a spectrum of clinical manifestations, ranging from asymptomatic or mild illness to more severe and potentially life-threatening complications. Pathogenesis of dengue is based on viral and host factors. Viral factors include NS1 antigen and genomic factors. Host factors include antibody dependent enhancement, anti-NS1 antibodies, cytokines, cross reactive T-Cell response, HLA allele variation and non-HLA mediated polymorphisms. The clinical picture of dengue is described on the basis of WHO 1997 and 2009 criteria. It is classified into dengue fever, dengue hemorrhagic fever (DHF), and dengue shock syndrome (DSS). Life-threatening complications can develop in severe cases, and this includes renal complications such as acute kidney injury (AKI) and hepatic complications such as hepatic dysfunction and in rare cases, fulminant hepatic failure. Neurological complications, cardiac complications and respiratory distress syndrome have also been reported. Treatment methods include targeting the dengue vector and Carica papaya, a natural remedy with antiviral properties. Additionally, the role of corticosteroids, intravenous immunoglobulins, and mast cell inhibitors has been explored in dengue treatment, aiming to reduce severity. Novel approaches involve drugs targeting dengue proteins and host factors necessary for the virus's life cycle, offering potential avenues for more targeted therapeutic interventions. In recent years, significant progress has been made in the development of vaccines against dengue, with Sanofi Pasteur's Dengvaxia being the first licensed vaccine approved for use. Utilizing various approaches such as recombinant proteins, viral vectors and viral like particles, various alternatives have been provided which aim to be safer substitutes to Dengvaxia while maintaining the effectiveness. A review on dengue is essential for clinicians and healthcare professionals to stay updated on diagnostics, treatment protocols and prevention strategies.

Clinical and seasonal pattern of dengue in a tertiary care hospital of South West India

Background

Dengue is an emerging global viral disease with an increase 30-fold in incidence in the past fifty years. In the past decade it was restricted to only few a states of South and Northern India but in the recent past it has affected almost all the states in India. The objective of this study was to assess the clinical profile, trends and outcome of dengue cases.

Methods

This retrospective record based cross-sectional study was conducted in tertiary hospital, Mangaluru in Southern India. The study population included all dengue positive cases diagnosed either by IgM Capture ELISA or Dengue Non-structural Protein NS1 antigen over a period of five years. Information from pre-recorded case sheets were used for data collection. The data was analyzed using SPSS Version 20. Results from the analysis have been expressed in percentages, means and graphs.

Results

The study included 401 dengue cases. Most cases were in the age range of 20-40 years with a male to female ratio of 3:2. Overall seropositivity rate was 23.94% with High IgM prevalence. Monthly distribution showed a maximum cases were in the months of June and July and minimum were in January and February. Among the study participants, 91.5% of patients recovered completely and 1.7% of patients had died. 6.8% of patients were discharged against medical advice.

Conclusions

Dengue continues to be major public health problem in this part of the globe affecting mainly the working age group. Low seropositivity with High IgM prevelance makes dengue an important differential for febrile illness of vague nature and invokes the need for robust public health response to curb the hyper-endemicity.

The burden of dengue and force of infection among children in Kerala, India; seroprevalence estimates from Government of Kerala-WHO Dengue study

Background

Dengue shows high geographic heterogeneity within and across endemic countries. In the context of increasing burden and predicted outbreaks due to climate change, understanding the heterogeneity will enable us to develop region specific targeted interventions, including vaccination. World Health Organisation (WHO) suggests standard methodologies to study the burden and heterogeneity at national and subnational levels. Regional studies with robust and standard methodology to capture heterogeneity are scarce. We estimated the seroprevalence of dengue in children aged 9-12 years and the force of infection in Kerala, India, from where Zika cases also have been reported recently.

Methods

We conducted a school-based cross-sectional survey in 38 clusters; selected by stratified random sampling, representing rural, urban, high burden and low-burden administrative units. Validation of Indirect IgG ELISA was done by Plaque Reduction Neutralization Test (PRNT90) using the local isolates of all four serotypes. Force of infection (FOI) was estimated using the WHO-FOI calculator. We conducted a follow-up survey among a subsample of seronegative children, to estimate the rate of sero-conversion.

Results

Among 5236 children tested, 1521 were positive for anti-dengue IgG antibody. The overall seroprevalence in the state was 29% (95% CI 24.1-33.9). The validity corrected seroprevalence was 30.9% in the overall sample, 46.9% in Thiruvananthapuram, 26.9% in Kozhikkode and 24.9% in Kollam. Age-specific seroprevalence increased with age; 25.7% at 9 years, 29.5% at 10 years, 30.9% at 11 years and 33.9% at 12 years. Seroprevalence varied widely across clusters (16.1%-71.4%). The estimated force of infection was 3.3/100 person-years and the seroconversion rate was 4.8/100 person-years. 90% of children who tested positive were not aware of dengue infection. All the four serotypes were identified in PRNT and 40% of positive samples had antibodies against multiple serotypes.

Interpretation

The study validates the WHO methodology for dengue serosurveys and confirms its feasibility in a community setting. The overall seroprevalence in the 9-12 year age group is low to moderate in Kerala; there are regional variations; high burden and low burden clusters co-exist in the same districts. The actual burden of dengue exceeds the reported numbers. Heterogeneity in prevalence, the high proportion of inapparent dengue and the hyperendemic situation suggest the need for region-specific and targeted interventions, including vaccination.

Funding

World Health Organization.

Clinical manifestations of dengue, Zika and chikungunya in the Pacific Islands: A systematic review and meta-analysis

Dengue, Zika and chikungunya outbreaks pose a significant public health risk to Pacific Island communities. Differential diagnosis is challenging due to overlapping clinical features and limited availability of laboratory diagnostic facilities. There is also insufficient information regarding the complications of these arboviruses, particularly for Zika and chikungunya. We conducted a systematic review and meta-analysis to calculate pooled prevalence estimates with 95% confidence intervals (CI) for the clinical manifestations of dengue, Zika and chikungunya in the Pacific Islands. Based on pooled prevalence estimates, clinical features that may help to differentiate between the arboviruses include headache, haemorrhage and hepatomegaly in dengue; rash, conjunctivitis and peripheral oedema in Zika; and the combination of fever and arthralgia in chikungunya infections. We estimated that the hospitalisation and mortality rates in dengue were 9.90% (95% CI 7.67-12.37) and 0.23% (95% CI 0.16-0.31), respectively. Severe forms of dengue occurred in 1.92% (95% CI 0.72-3.63) of reported cases and 23.23% (95% CI 13.58-34.53) of hospitalised patients. Complications associated with Zika virus included Guillain-Barré syndrome (GBS), estimated to occur in 14.08 (95% CI 11.71-16.66) per 10,000 reported cases, and congenital brain malformations such as microcephaly, particularly with first trimester maternal infection. For chikungunya, the hospitalisation rate was 2.57% (95% CI 1.30-4.25) and the risk of GBS was estimated at 1.70 (95% CI 1.06-2.48) per 10,000 reported cases. Whilst ongoing research is required, this systematic review enhances existing knowledge on the clinical manifestations of dengue, Zika and chikungunya infections and will assist Pacific Island clinicians during future arbovirus outbreaks.

Coexisting bilateral ciliochoroidal effusion syndrome and an isolated cytotoxic corpus callosum lesion in dengue fever

Dengue fever is a major health concern in India. There are various reports in the literature regarding the ocular manifestations of this febrile illness. We are reporting a rare case of a woman in her late 30s who developed coexisting bilateral ciliochoroidal effusion syndrome with an isolated cytotoxic corpus callosum lesion associated with dengue febrile illness. To the best of our knowledge, this is the first case of its kind. It opens the avenues for neurological and radioimaging attention for such cases with bilateral ciliochoroidal effusion syndrome.

Mosquito-borne diseases in India over the past 50 years and their Global Public Health Implications: A Systematic Review

Mosquito-borne diseases (MBDs) pose a significant public health concern globally, and India, with its unique eco-sociodemographic characteristics, is particularly vulnerable to these diseases. This comprehensive review aims to provide an in-depth overview of MBDs in India, emphasizing their impact and potential implications for global health. The article explores distribution, epidemiology, control or elimination, and economic burden of the prevalent diseases such as malaria, dengue, chikungunya, Japanese encephalitis, and lymphatic filariasis, which collectively contribute to millions of cases annually. It sheds light on their profound effects on morbidity, mortality, and socioeconomic burdens and the potential for international transmission through travel and trade. The challenges and perspectives associated with controlling mosquito populations are highlighted, underscoring the importance of effective public health communication for prevention and early detection. The potential for these diseases to spread beyond national borders is recognized, necessitating a holistic approach to address the challenge. A comprehensive literature search was conducted, covering the past five decades (1972-2022), utilizing databases such as Web of Science, PubMed, and Google Scholar, in addition to in-person library consultations. The literature review analyzed 4,082 articles initially identified through various databases. After screening and eligibility assessment, 252 articles were included for analysis. The review focused on malaria, dengue, chikungunya, Japanese encephalitis, and lymphatic filariasis. The included studies focused on MBDs occurrence in India, while those conducted outside India, lacking statistical analysis, or published before 1970 were excluded. This review provides valuable insights into the status of MBDs in India and underscores the need for concerted efforts to combat these diseases on both national and global scales through consilience.

Spatial Mapping the Dengue and Chikungunya Burden in a Rural Area near Bangalore: a Descriptive Cross-Sectional Study

Background

The burden of dengue and chikungunya diseases across geographical regions of India is poorly quantified more so during Covid19 pandemic and from hospital-based studies. The objective was to assess the prevalence of dengue and chikungunya in the study mainly area and to visualize the spatial distribution of dengue and chikungunya cases using the Quantum Geographic Information System (QGIS).

Methods

This descriptive cross-sectional study was conducted among the population in villages coming under a medical college's rural field practice area near Bangalore. A total of 31 villages were selected through a simple random sampling method and 3356 subjects were surveyed through household visits. QGIS was used for spatial mapping of cases.

Results

3356 subjects were surveyed, and the prevalence of dengue and chikungunya was 1.13% and 0.02%, respectively. The overall prevalence of dengue and chikungunya cases together was 1.16%. All 39 (100%) cases had reported fever and 31 cases (79.5%) reported myalgia followed by arthralgia 22 (56.4%). QGIS supported spatial mapping of the cases and no clustering of cases was found in the study area.

Conclusion

The burden of dengue and chikungunya is under reported, and the surveillance system needs to be strengthened in the rural area. QGIS was found to be useful in the spatial mapping of the cases and there was no clustering of cases observed.

Impact of secondary infections on dengue presentation: A cross-sectional study in a tertiary care hospital in Uttar Pradesh, India

BACKGROUND

Recently, a wide range variety of manifestations, including a self‑limiting to severe illness, has been increasingly reported in dengue. Few studies attract attention to severe dengue, mainly observed in secondary infection. With this background, this study aims to provide a comprehensive overview to differentiate primary from secondary dengue using serology (IgG) and the possible association of severity of illness in secondary dengue.

METHODS

Present retrospective cross-sectional study was conducted at a North Indian tertiary care center from September 2021 to January 2022. Clinical data of confirmed dengue patients from the medicine department were collected and assigned as primary and secondary dengue.

RESULTS

Of the 220 dengue patients, 22 (10 %) had secondary dengue infection. Hemorrhagic manifestations were reported in 58/220 (26.4 %) cases while 7/22 (31.8 %) in secondary dengue. Prevalent hemorrhagic manifestations in secondary dengue include purpura (27.3 %), vaginal bleeding (4.5 %), melaena (9.1 %), and epistaxis (4.5 %). In addition, 42 (19.1 %) patients had pancytopenia, and 8 (36.6 %) cases were of secondary dengue. Hepatic dysfunction was noted in 164 (74.5 %) cases. Notably, all secondary dengue cases (22;100 %) had hepatic dysfunction and severe in 9 (40.9 %) cases. In addition, in secondary dengue patients, evidence of plasma leakages such as hypoproteinemia 7 (31.8 %) and ascites (35 %) were statistically more frequent. Overall, two deaths (0.9 %) were reported, and were one in each group.

CONCLUSIONS

Many parameters, including hemorrhagic manifestation (melaena), hematological characteristic (pancytopenia), evidence of plasma leakage (hypoproteinemia and ascites), gastrointestinal (GB wall thickening and hepatic dysfunction) and reduction in mean hemoglobin and platelet count were found to be statistically significant in secondary dengue infection. Additionally, early classification of secondary dengue may help to anticipate its severity and allow for early strategic intervention/management to lower morbidity and mortality.

Updates in the Management of Dengue Shock Syndrome: A Comprehensive Review

Dengue is a very serious public health problem that can manifest a wide range of symptoms from asymptomatic to fatal conditions, such as dengue shock syndrome (DSS). It is a life-threatening mosquito-borne viral infection widely spread in tropical areas. Dengue virus transmission occurs from an infected Aedes mosquito to humans. Various factors are responsible for the occurrence of the disease, such as viral load, age of the host, immune status of the host, and genetic variability. Dengue infection occurs in three phases: febrile, critical, and recovery. The febrile phase lasts for seven days and manifests symptoms such as high-grade fever, headache, arthralgia, and backache, and in some cases, the upper respiratory tract and gastrointestinal tract are also involved. Severe dengue is characterized by endothelial dysfunction that causes vascular permeability and plasma leakage. The fundamental mechanisms of these immune pathologies are not yet known. Dengue manifests various complications such as dengue encephalopathy, encephalitis, stroke, ocular involvement, acute transverse myelitis, myalgia, and cerebellar syndrome, but the most commonly seen is liver involvement. Dengue is managed supportively because there are no proven curative treatments. The cornerstone of care during the critical period of dengue is prudent fluid resuscitation. The first fluid of preference is a crystalloid. Prophylactic transfusion of platelets is not advised. The occurrence of four antigenically different dengue virus serotypes, each able to elicit a cross-reactive and disease-enhancing antibody response against the other three serotypes, has made the creation of the dengue vaccine a difficult undertaking. The development of a dengue vaccine has faced significant challenges due to a lack of the best animal models and a variety of immunological conditions in people, particularly in endemic locations. Dengvaxia is a live attenuated vaccine, which was developed by Sanofi. It is made up of four chimeric vaccine viruses produced by Vero cells.

Interactions of urbanisation, climate variability, and infectious disease dynamics: insights from the Coimbatore district of Tamil Nadu

Climate change and shifts in land use/land cover (LULC) are critical factors affecting the environmental, societal, and health landscapes, notably influencing the spread of infectious diseases. This study delves into the intricate relationships between climate change, LULC alterations, and the prevalence of vector-borne and waterborne diseases in Coimbatore district, Tamil Nadu, India, between 1985 and 2015. The research utilised Landsat-4, Landsat-5, and Landsat-8 data to generate LULC maps, applying the maximum likelihood algorithm to highlight significant transitions over the years. This study revealed that built-up areas have increased by 67%, primarily at the expense of agricultural land, which was reduced by 51%. Temperature and rainfall data were obtained from APHRODITE Water Resources, and with a statistical analysis of the time series data revealed an annual average temperature increase of 1.8 °C and a minor but statistically significant rainfall increase during the study period. Disease data was obtained from multiple national health programmes, revealing an increasing trend in dengue and diarrhoeal diseases over the study period. In particular, dengue cases surged, correlating strongly with the increase in built-up areas and temperature. This research is instrumental for policy decisions in public health, urban planning, and climate change mitigation. Amidst limited research on the interconnections among infectious diseases, climate change, and LULC changes in India, our study serves as a significant precursor for future management strategies in Coimbatore and analogous regions.

Emerging Pathogenic Viral Infections of the Eye

Global health security threats and the public health impact resulting from emerging infectious diseases including the ongoing COVID-19 pandemic and recent Ebola virus disease outbreaks continuously emphasize the need for a comprehensive approach to preparedness, management of disease outbreaks, and health sequelae associated with emergent pathogens. A spectrum of associated ophthalmic manifestations, along with the potential persistence of emerging viral pathogens in ocular tissues, highlight the importance of an ophthalmic approach to contributing to efforts in the response to public health emergencies from disease outbreaks. This article summarizes the ophthalmic and systemic findings, epidemiology, and therapeutics for emerging viral pathogens identified by the World Health Organization as high-priority pathogens with epidemic potential.

South Asian Transplant Infectious Disease Guidelines for Solid Organ Transplant Candidates, Recipients, and Donors

These guidelines discuss the epidemiology, screening, diagnosis, posttransplant prophylaxis, monitoring, and management of endemic infections in solid organ transplant (SOT) candidates, recipients, and donors in South Asia. The guidelines also provide recommendations for SOT recipients traveling to this region. These guidelines are based on literature review and expert opinion by transplant physicians, surgeons, and infectious diseases specialists, mostly from South Asian countries (India, Pakistan, Bangladesh, Nepal, and Sri Lanka) as well as transplant experts from other countries. These guidelines cover relevant endemic bacterial infections (tuberculosis, leptospirosis, melioidosis, typhoid, scrub typhus), viral infections (hepatitis A, B, C, D, and E; rabies; and the arboviruses including dengue, chikungunya, Zika, Japanese encephalitis), endemic fungal infections (mucormycosis, histoplasmosis, talaromycosis, sporotrichosis), and endemic parasitic infections (malaria, leishmaniasis, toxoplasmosis, cryptosporidiosis, strongyloidiasis, and filariasis) as well as travelers' diarrhea and vaccination for SOT candidates and recipients including travelers visiting this region. These guidelines are intended to be an overview of each topic; more detailed reviews are being published as a special supplement in the Indian Journal of Transplantation .

Trend analysis in seroprevalence of dengue, chikungunya and malaria: A seven-year serological study from a tertiary care hospital of Maharashtra, India

BACKGROUND & OBJECTIVES

Dengue, chikungunya and malaria are mosquito-borne infections, which have shared endemicity and similar clinical presentation. Simultaneous co-infection with more than one infectious agent complicates the diagnosis and further course of treatment. This study aims to determine the seroprevalence and trend of malaria, dengue and chikungunya from 2014-2020 in a tertiary care hospital of western India.

METHODS

The present study was retrospective descriptive record-based. Serum samples from clinically suspected dengue and chikungunya were subjected to both IgM antibody capture ELISA kits produced by National Institute of Virology (NIV), Pune, India. They were also subjected to ELISA based NS1Ag testing. In Suspected malaria cases, blood collected in EDTA tubes was subjected for Rapid Malaria antigen testing. Statistical analysis was performed using MS Excel and JMP Software.

RESULTS

Seropositivity of malaria was comparatively higher in 2014 (5.53%) and a decreasing trend was observed in subsequent years. Majority of malarial infections were caused by Plasmodium vivax (81.67%). There is drastic increase in seropositivity of chikungunya from 2016 (23.67%) and thereafter as compared to 2014 (6.57%) and 2015 (7.29%) indicating its re-emergence. The dengue seropositivity in 2019 (40.19%) was highest in last seven years. Males were predominantly affected, and most affected age group was 21-30 years. Peak transmission was observed in post-monsoon seasons. Dengue and chikungunya co-infection was observed to be 5.79%.

INTERPRETATION & CONCLUSION

This study emphasizes the importance of surveillance studies to understand the trend of vector-borne diseases for prompt diagnosis, management of patients in hospital setup and for early detection and curtailment of outbreaks and epidemics by public health sectors through appropriate vector control programs.

Insight into the seroepidemiology and dynamics of circulating serotypes of dengue virus over a 4 year period in western Uttar Pradesh, India

An important public health problem in India is dengue infection, with every year seeing an increase in cases of dengue fever. Dengue affects all individuals irrespective of their gender and age, although the infection rate is higher among males and younger people. Despite low severity in general, dengue virus can cause severe health conditions in some individuals. Genetic characterization of circulating endemic dengue virus (DENV) serotypes plays a significant role in providing epidemiological knowledge and subsequent vaccine development. In the present study, over a 4 year period, we assessed DENV transmission dynamics in major regions of western Uttar Pradesh in North India. ELISA tests were used to diagnose dengue, and PCRs were used to determine the circulating serotype. We found that dengue infection peaks after the rainy season and affects all sexes and ages. A total of 1277 individuals were found positive for dengue; among them, 61.7 % were male and 38.3 % were female. DEN-1 was found in 23.12 %, DEN-2 in 45 %, DEN-3 in 29.06 % and DEN-4 in 1.5 % of the dengue-infected individuals. All four DENV serotypes were circulating in the study area, and DENV serotype-2 (DEN-2) was the most prevalent serotype.

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.

Global and local evolutionary dynamics of Dengue virus serotypes 1, 3, and 4

Evolutionary studies on Dengue virus (DENV) in endemic regions are necessary since naturally occurring mutations may lead to genotypic variations or shifts in serotypes, which may lead to future outbreaks. Our study comprehends the evolutionary dynamics of DENV, using phylogenetic, molecular clock, skyline plots, network, selection pressure, and entropy analyses based on partial CprM gene sequences. We have collected 250 samples, 161 in 2017 and 89 in 2018. Details for the 2017 samples were published in our previous article and that of 2018 are presented in this study. Further evolutionary analysis was carried out using 800 sequences, which incorporate the study and global sequences from GenBank: DENV-1 (n = 240), DENV-3 (n = 374), and DENV-4 (n = 186), identified during 1944-2020, 1956-2020, and 1956-2021, respectively. Genotypes V, III, and I were identified as the predominant genotypes of the DENV-1, DENV-3, and DENV-4 serotypes, respectively. The rate of nucleotide substitution was found highest in DENV-3 (7.90 × 10-4 s/s/y), followed by DENV-4 (6.23 × 10-4 s/s/y) and DENV-1 (5.99 × 10-4 s/s/y). The Bayesian skyline plots of the Indian strains revealed dissimilar patterns amongst the population size of the three serotypes. Network analyses showed the presence of different clusters within the prevalent genotypes. The data presented in this study will assist in supplementing the measures for vaccine development against DENV.

Scrub Typhus and Dengue Co-infection in an Adolescent Girl: A Diagnostic Challenge

Scrub typhus and dengue fever are common infectious diseases in tropical regions, and both have overlapping clinico-epidemiological and laboratory features, which often pose a diagnostic challenge. This case report discusses a 15-year-old girl from the Indian subcontinent who presented with acute undifferentiated febrile illness (AUFI) without typical features of any of the common tropical infections. She was diagnosed with co-infection of scrub typhus and dengue fever using laboratory tests with good diagnostic accuracy. The patient was managed on an ambulatory basis, treated with oral doxycycline, and showed symptomatic improvement within 48 hours. Co-infections in endemic areas present a significant diagnostic and therapeutic challenge. This case report highlights the importance of considering co-infections in the differential diagnosis of AUFI, especially during the post-monsoon period, and the use of highly sensitive and specific tests for the diagnosis of co-infections.

Singapore's 5 decades of dengue prevention and control-Implications for global dengue control

This paper summarises the lessons learnt in dengue epidemiology, risk factors, and prevention in Singapore over the last half a century, during which Singapore evolved from a city of 1.9 million people to a highly urban globalised city-state with a population of 5.6 million. Set in a tropical climate, urbanisation among green foliage has created ideal conditions for the proliferation of Aedes aegypti and Aedes albopictus, the mosquito vectors that transmit dengue. A vector control programme, largely for malaria, was initiated as early as 1921, but it was only in 1966 that the Vector Control Unit (VCU) was established to additionally tackle dengue haemorrhagic fever (DHF) that was first documented in the 1960s. Centred on source reduction and public education, and based on research into the bionomics and ecology of the vectors, the programme successfully reduced the Aedes House Index (HI) from 48% in 1966 to <5% in the 1970s. Further enhancement of the programme, including through legislation, suppressed the Aedes HI to around 1% from the 1990s. The current programme is characterised by 4 key features: (i) proactive inter-epidemic surveillance and control that is stepped up during outbreaks; (ii) risk-based prevention and intervention strategies based on advanced data analytics; (iii) coordinated inter-sectoral cooperation between the public, private, and people sectors; and (iv) evidence-based adoption of new tools and strategies. Dengue seroprevalence and force of infection (FOI) among residents have substantially and continuously declined over the 5 decades. This is consistent with the observation that dengue incidence has been delayed to adulthood, with severity highest among the elderly. Paradoxically, the number of reported dengue cases and outbreaks has increased since the 1990s with record-breaking epidemics. We propose that Singapore's increased vulnerability to outbreaks is due to low levels of immunity in the population, constant introduction of new viral variants, expanding urban centres, and increasing human density. The growing magnitude of reported outbreaks could also be attributed to improved diagnostics and surveillance, which at least partially explains the discord between rising trend in cases and the continuous reduction in dengue seroprevalence. Changing global and local landscapes, including climate change, increasing urbanisation and global physical connectivity are expected to make dengue control even more challenging. The adoption of new vector surveillance and control tools, such as the Gravitrap and Wolbachia technology, is important to impede the growing threat of dengue and other Aedes-borne diseases.

Evolutionary dynamics of dengue virus in India

More than a hundred thousand dengue cases are diagnosed in India annually, and about half of the country's population carries dengue virus-specific antibodies. Dengue propagates and adapts to the selection pressures imposed by a multitude of factors that can lead to the emergence of new variants. Yet, there has been no systematic analysis of the evolution of the dengue virus in the country. Here, we present a comprehensive analysis of all DENV gene sequences collected between 1956 and 2018 from India. We examine the spatio-temporal dynamics of India-specific genotypes, their evolutionary relationship with global and local dengue virus strains, interserotype dynamics and their divergence from the vaccine strains. Our analysis highlights the co-circulation of all DENV serotypes in India with cyclical outbreaks every 3-4 years. Since 2000, genotype III of DENV-1, cosmopolitan genotype of DENV-2, genotype III of DENV-3 and genotype I of DENV-4 have been dominating across the country. Substitution rates are comparable across the serotypes, suggesting a lack of serotype-specific evolutionary divergence. Yet, the envelope (E) protein displays strong signatures of evolution under immune selection. Apart from drifting away from its ancestors and other contemporary serotypes in general, we find evidence for recurring interserotype drift towards each other, suggesting selection via cross-reactive antibody-dependent enhancement. We identify the emergence of the highly divergent DENV-4-Id lineage in South India, which has acquired half of all E gene mutations in the antigenic sites. Moreover, the DENV-4-Id is drifting towards DENV-1 and DENV-3 clades, suggesting the role of cross-reactive antibodies in its evolution. Due to the regional restriction of the Indian genotypes and immunity-driven virus evolution in the country, ~50% of all E gene differences with the current vaccines are focused on the antigenic sites. Our study shows how the dengue virus evolution in India is being shaped in complex ways.

Recent advances in the development of methyltransferase (MTase) inhibitors against (re)emerging arboviruses diseases dengue and Zika

Emerging and/or re-emerging viral diseases such as dengue and Zika are a worldwide concern. Therefore, new antiviral therapeutics are necessary. In this sense, a non-structural protein with methyltransferase (MTase) activity is an attractive drug target because it plays a crucial role in dengue and Zika virus replication. Different drug strategies such as virtual screening, molecular docking, and molecular dynamics have identified new inhibitors that bind on the MTase active site. Therefore, in this review, we analyze MTase inhibitors, including S-adenosyl-L-methionine (SAM), S-adenosyl-l-homocysteine (SAH) and guanosine-5'-triphosphate (GTP) analogs, nitrogen-containing heterocycles (pyrimidine, adenosine, and pyridine), urea derivatives, and natural products. Advances in the design of MTase inhibitors could lead to the optimization of a possible single or broad-spectrum antiviral drug against dengue and Zika virus.

Region-specific improvisation on WHO case definition and environmental risk factors associated with dengue: a case-control analysis from Kerala, India

BACKGROUND

Region-specific variations may occur in symptomatic manifestations that need to be addressed by dynamic case definitions. Environmental risk factors for dengue also vary widely across geographic settings. Our aim was to study the test positivity rate of the World Health Organization (WHO) 2009 probable dengue case definition and to suggest region-specific improvisations to it. The study also analyses the sociodemographic and environmental risk factors of dengue fever in South Kerala, India.

METHODS

A case-control study was conducted in South Kerala from 2017 to 2019. Dengue reverse transcription polymerase chain reaction (RT-PCR)-positive and RT-PCR-negative 'probable dengue' patients were compared to identify significant symptoms for a modified definition of dengue. A group of afebrile community controls was compared with RT-PCR-positive dengue cases to study the environmental and behavioural risk factors.

RESULTS

Arthralgia, palmar erythema and rashes have high discriminatory power (odds ratio [OR] >3) for identifying dengue. Redness of eyes, altered consciousness, abdominal distension and chills were found to moderately discriminate (OR 2-3) dengue. The adjusted analysis showed the presence of mosquito breeding sites (indoor p=0.02, outdoor p=0.03), solid waste dumping (p<0.001) and open water drainage in the compound (p=0.007) as significant predictors.

CONCLUSIONS

Regional modifications should be considered when using the WHO definition in endemic settings. Control of mosquito breeding at the household level is the key towards dengue prevention.

Clinical features and risk factors for death in acute undifferentiated fever: A prospective observational study in rural community hospitals in six states of India

BACKGROUND

Acute undifferentiated fever (AUF) ranges from self-limiting illness to life-threatening infections, such as sepsis, malaria, dengue, leptospirosis and rickettsioses. Similar clinical presentation challenges the clinical management. This study describes risk factors for death in patients hospitalized with AUF in India.

METHODS

Patients aged ≥5 y admitted with fever for 2-14 d without localizing signs were included in a prospective observational study at seven hospitals in India during 2011-2012. Predictors identified by univariate analysis were analyzed by multivariate logistic regression for survival analysis.

RESULTS

Mortality was 2.4% (37/1521) and 46.9% (15/32) died within 2 d. History of heart disease (p=0.013), steroid use (p=0.011), altered consciousness (p<0.0001), bleeding (p<0.0001), oliguria (p=0.020) and breathlessness (p=0.015) were predictors of death, as were reduced Glasgow coma score (p=0.005), low urinary output (p=0.004), abnormal breathing (p=0.006), abdominal tenderness (p=0.023), leucocytosis (p<0.0001) and thrombocytopenia (p=0.001) at admission. Etiology was identified in 48.6% (18/37) of fatal cases.

CONCLUSIONS

Bleeding, cerebral dysfunction, respiratory failure and oliguria at admission, suggestive of severe organ failure secondary to systemic infection, were predictors of death. Almost half of the patients who died, died shortly after admission, which, together with organ failure, suggests that delay in hospitalization and, consequently, delayed treatment, contribute to death from AUF.

Co-circulation of all the four Dengue virus serotypes during 2018-2019: first report from Eastern Uttar Pradesh, India

Dengue fever is an endemic disease in India, transmitted by an infected mosquito bite. In India, the number of concurrent infections and the circulation of multiple dengue virus (DENV) serotypes has increased in recent decades. Molecular surveillance among the DENV serotype is important to keep track of the circulating serotypes, evolutionary changes, and key mutations that can alter the diagnostics. The current study included patients admitted for dengue in the Eastern Uttar Pradesh (E-UP) region during 2018-2019. The genetic characterization of the circulating DENV was accomplished through partial CprM (511 bp) gene amplification via reverse transcriptase polymerase chain reaction and sequencing. Phylogenetic analysis revealed the circulation of all four DENV1-4 serotypes. DENV-2 was the most abundant serotype (44%, 27/61), followed by DENV-3 (32%, 20/61). DENV-1 had a 16% (10/61) predominance, while DENV-4 (6%, 4/61) was found to be the least abundant serotype. DENV-2 genotypes were distributed among lineages I (7.4%), II (85%) and III (7.4%) of genotype IV, DENV-3 to lineage III of genotype III, DENV-1 to genotype III; DENV-2 to lineage B (75%) and C (25%) of genotype I. This primary report on the co-circulation of DENV1-4 serotypes from the E-UP region highlights the requirement of continuous molecular surveillance for monitoring circulating DENV serotypes.

Knowledge, attitude, and practices of the community toward dengue fever in Shabwah Governorate, Yemen: a descriptive study

BACKGROUND

In Yemen, dengue fever (DF) is a widespread, locally endemic infectious disease, with high morbidity and mortality which mainly affects impoverished regions. Thus, this study aims to evaluate the knowledge, attitudes, and behaviors of the Shabwah community in Yemen regarding DF characteristics and prevention.

METHODS

The present study is a cross-sectional community-based study conducted in Shabwah Governorate, Yemen, between June 2021 and November 2021. Simple random sampling was used to select the sample (n = 370), and a validated closed-ended questionnaire was used to collect data.

RESULTS

In total, 370 individuals participated in this study; most respondents were female (N = 247, 66.8%), and more than half (N = 214, 57.8%) were younger than age 30. More than 50% of the population had completed a primary or secondary school, while approximately 33.03% of them were illiterate. Furthermore, more than half (53.5%) of the population had good knowledge of DF, while most of those educated at a university level (64.1%) had good attitude toward DF. Most of the population (68.4%) had good practice toward DF. Moreover, participants with a university level education, followed by those who completed secondary school, had significantly higher knowledge and practice scores than primary school and illiteracy (P = 0.05).

CONCLUSION

The results of the study indicate that the residents of Yemen's Shabwah Governorate are well-informed about the symptoms and signs of DF, have a positive attitude toward the disease, and employ appropriate preventive measures. Health education via various media should be mandated to increase community awareness and dispel misconceptions about DF.

Epidemiology of dengue in SAARC territory: a systematic review and meta-analysis

BACKGROUND

Dengue is one of the common arboviral infections and is a public health problem in South East Asia. The aim of this systematic review and meta-analysis was to evaluate the prevalence and distribution of dengue in SAARC (South Asian Association for Regional Cooperation) countries.

METHODS

The PubMed, PubMed Central, Embase and Scopus databases were searched for relevant studies. Statistical analysis on data extracted from the selected studied was conducted using the Comprehensive Meta-Analysis Software (CMA) version 3 software package. Proportions were used to estimate the outcome with a 95% confidence interval (CI).

RESULTS

Across all studies, among cases of suspected dengue, 30.7% were confirmed dengue cases (proportion: 0.307, 95% CI: 0.277-0.339). The seroprevalence of dengue immunoglobulin (Ig)G, IgM or both (IgM and IgG) antibodies and dengue NS1 antigen was 34.6, 34.2, 29.0 and 24.1%, respectively. Among the different strains of dengue, dengue virus (DENV) strains DENV-1, DENV-2, DENV-3 and DENV-4 accounted for 21.8, 41.2, 14.7 and 6.3% of cases, respectively. The prevalence of dengue fever, dengue hemorrhagic fever and dengue shock syndrome was 80.5, 18.2 and 1.5%, respectively. Fever was a commonly reported symptom, and thrombocytopenia was present in 44.7% of cases. Mortality was reported in 1.9% of dengue cases.

CONCLUSIONS

Dengue is a common health problem in South East Asia with high seroprevalence. DENV-2 was found to be the most common strain causing infection, and most dengue cases were dengue fever. In addition, thrombocytopenia was reported in almost half of the dengue cases.

An assessment of remotely sensed environmental variables on Dengue epidemiology in Central India

In recent decades, dengue has been expanding rapidly in the tropical cities. Even though environmental factors and landscape features profoundly impact dengue vector abundance and disease epidemiology, significant gaps exist in understanding the role of local environmental heterogeneity on dengue epidemiology in India. In this study, we assessed the role of remotely sensed climatic factors (rainfall, temperature and humidity) and landscape variables (land use pattern, vegetation and built up density) on dengue incidence (2012–2019) in Bhopal city, Central India. Dengue hotspots in the city were assessed through geographical information system based spatial statistics. Dengue incidence increased from 0.59 cases in 2012 to 9.11 cases in 2019 per 10,000 inhabitants, and wards located in Southern Bhopal were found to be dengue hotspots. Distributed lag non-linear model combined with quasi Poisson regression was used to assess the exposure-response association, relative risk (RR), and delayed effects of environmental factors on dengue incidence. The analysis revealed a non-linear relationship between meteorological variables and dengue cases. The model shows that the risk of dengue cases increases with increasing mean temperature, rainfall and absolute humidity. The highest RR of dengue cases (~2.0) was observed for absolute humidity ≥60 g/m³ with a 5–15 week lag. Rapid urbanization assessed by an increase in the built-up area (a 9.1% increase in 2020 compared to 2014) could also be a key factor driving dengue incidence in Bhopal city. The study sheds important insight into the synergistic effects of both the landscape and climatic factors on the transmission dynamics of dengue. Furthermore, the study provides key baseline information on the climatic variables that can be used in the micro-level dengue prediction models in Bhopal and other cities with similar climatic conditions.

Dengue, a viral disease transmitted by infected Aedes mosquitoes, is a major public health concern globally. In addition to its increased incidence in recent years, dengue is also spreading to new geographical regions. Local environmental factors are known to modify the mosquito vector density that directly impacts dengue virus transmission. Understanding the influence of environmental factors (meteorological conditions and landscape features) on dengue epidemiology in local settings is important for focused dengue intervention. Here, by utilizing dengue incidence and remotely sensed environmental data from 2012–2019, we have assessed the role of environmental factors in driving dengue virus transmission in the city of Bhopal in Central India. During the study period, a 14.5 fold increase in dengue incidence was observed in Bhopal city, which is way higher than the 2.3 fold increase reported at the national level. The risk of dengue virus transmission was higher with higher temperature and absolute humidity. An increase in built-up area, a proxy for urbanization, was found to be another predictor of increased dengue incidence in Bhopal. These findings can provide a stepping-stone for the development of dengue prediction models and the identification of dengue hotspots in order to improve vector control of this disease in cities with similar environmental conditions.

Determining the optimum cut-off IgM/ IgG ratio for predicting secondary dengue infections: An observational hospital based study from Central India

PURPOSE

The present study was conducted to determine an optimum cut-off IgM/IgG ratio for differentiating between primary and secondary Dengue. The calculated cut-off was used to estimate the relative prevalence of primary and secondary Dengue in central India during the 2021 outbreak.

METHODS

To differentiate between primary and secondary Dengue, optimum cut-off IgM/IgG ratio was determined using ROC curve analysis and Area under the curve (AUC) was calculated. For this 84 IgM positive samples were selected during the study period and Dengue IgM and IgG testing was performed.

RESULTS

Based on sero-positivity for IgG antibodies, we observed a prevalence of 77.4% for secondary Dengue during this outbreak. IgM/IgG ratio of 1.59 delivered a sensitivity of 100% and specificity of 90.8%. Comparison of clinical characteristics revealed significant differences in rigors (p ​= ​0.04) and haemorrhagic manifestations (p ​= ​0.01) between the two types of infection.

CONCLUSIONS

This study revealed an overwhelming predominance of secondary Dengue during the reported outbreak, which hints at increasing endemicity in this region and raises the risk of severe clinical manifestations. An optimal IgM/IgG cut-off ratio, tailored according to the endemicity of this geographical region, is therefore suggested in this study.

Invasive Fungal Infections in Dengue Recovered Patients: A New Phenomenon in the Covid-19 Era

Invasive fungal rhinosinusitis was seen to rise to epidemic levels after the 2nd wave of ongoing Covid pandemic, especially in tropical countries, maximally in India. A similar trend is being observed for cases who have recently recovered from dengue virus infection. Post dengue invasive fungal infection is a new presentation and any associations between it and Covid pandemic need to be studied in detail to help prepare for any complications. 3 patients presented to the out-patient department of E.N.T at a tertiary level teaching hospital in East India with complains similar to rhinosinusitis. These patients were then evaluated and diagnosed to be infected from Mucormycosis and Aspergillosis fungal sinusitis after which they were managed with surgical debridement and systemic antifungal therapy. All had a recent history of recovery from Dengue virus infection and a possible association could be suspected. 3 patients presented with complains of pain over upper jaw with orbital swelling and loss of vision developing over a period of 24 days. Two of them had ulceration of hard palate. They were then subjected to Contrast MRI along with CT scan of the Paranasal sinuses which depicted pansinus involvement with intracranial extension in two patients. These were then planned for diagnostic nasal endoscopies along with biopsies which turned out to be Invasive fungal sinusitis in the form of Aspergillosis and Mucormycosis. All the 3 patients had recent history of recovery from Dengue virus infection and did not have any other co-morbidities. Covid Associated Mucormycosis (CAM) is a well-known entity now but no reports of Dengue associated Invasive fungal sinusitis are yet reported. Whether this new phenomenon has anything to do with the interactions between dengue virus and coronavirus is not known at present and needs to be studied in detail so appropriate management protocols can be formulated.

Economic burden estimation associated with dengue and chikungunya in Gujarat, India

Background

Dengue and chikungunya have been emerging as major vector-borne diseases. The global burden of the diseases is rising as a public health problem. The complexity of disease is governed by multiple constraints including only symptomatic treatment and inflicts heavy social and economic burden on society. The present study is designed to assess the economic burden of dengue and chikungunya infection by calculating cost per patient in Gujarat, India.

Methods

A total of 210 patients were enrolled in the study from Ahmedabad and Kheda district of Gujarat from May 2018 to December 2019 of which 150 had dengue and 60 chikungunya infections, subject to the willingness of participation in the survey. Information on wage loss days, cost associated with medicines, diagnosis, special food and travel cost, etc., for the calculation of the direct and indirect costs associated with dengue and chikungunya were collected from these participants using a structured questionnaire. Informed consent was taken before including any participant in the study.

Results

In the dengue sample, 86 were males (57.3%) and the rest were females, and in the chikungunya sample, 31 were males (51.7%) and the rest females. The median age of the participants with dengue and chikungunya was 18 (p25 to p75: 8 to 26) and 30 (p25 to p75: 21 to 45) years respectively. Median family income was recorded as Rs 15,000 (p25 to p75: 9000 to 25500) and Rs 12,000 (p25 to p75: 9000 to 18500) for the dengue and chikungunya cases, respectively. The average duration of the illness was observed to be higher in chikungunya (median days (P25 to p75): 15 (7-45)) than dengue (median days (P25 to p75): 10 (5-15)). The median indirect cost in the case of dengue was Rs 1,931 (p25 to p75: 300 to 4500) while Rs 2,550 (p25 to p75: 0 to 5250) was observed for chikungunya cases. Two types of direct cost, namely, direct cost related to medical expenses and direct cost related to other expenses were calculated. Direct cost related to medical expenses was observed to be higher in dengue (Md (P25 to p75): Rs 2,450 (400-5000)) than chikungunya (Md (P25 to p75): Rs 1,500 (150-5200)) while indirect cost related to other expenses were comparable between dengue (Md (P25 to p75): Rs 1,575 (1300-2600)) and chikungunya (Md (P25 to p75): Rs 1500 (850-2850)). The average total cost for one dengue episode was estimated to be Rs 6,860 (3700-12525) whereas it was Rs 7,000 (2550-14000) for one episode of Chikungunya.

Conclusions

Overall, patients have to bear high costs while suffering from dengue and chikungunya infections. Furthermore, the duration of illness while suffering from viral diseases also contributes to the substantial economic burden. Improved knowledge about the impact of the cost and the economic burden associated with dengue and chikungunya will help policymakers allocate and appropriate resources accordingly.

Studies on the fitness characteristics of wMel- and wAlbB-introgressed Aedes aegypti (Pud) lines in comparison with wMel- and wAlbB-transinfected Aedes aegypti (Aus) and wild-type Aedes aegypti (Pud) lines

Wolbachia, an intracellular maternally transmitted endosymbiont, has been shown to interfere with the replication of dengue virus in Aedes aegypti mosquitoes. The Wolbachia-transinfected Ae. aegypti has been currently released in many countries to test its effectiveness in preventing the transmission of dengue virus. ICMR-Vector Control Research Centre in collaboration with World Mosquito Program Monash University, Australia, has generated two new Wolbachia-introgressed Ae. aegypti Puducherry (Pud) lines via backcrossing Ae. aegypti females of Australian (Aus) strains, infected with wMel and wAlbB Wolbachia with wild-type Ae. aegypti Puducherry (Pud) males. Wolbachia infections are known to induce a fitness cost and confer benefit on the host mosquito populations that will influence spread of the Wolbachia into native wild mosquito populations during the field release. Hence, the induced fitness cost or benefit/advantage in the two newly generated Ae. aegypti (Pud) lines was assessed in the laboratory in comparison with the wild-type Ae. aegypti (Pud) strain. In addition, maternal transmission (MT) efficiency, induced cytoplasmic incompatibility (CI), and insecticide resistance status of the two (Pud) lines were determined to assess the likely frequency of wMel and wAlbB infections in the native wild population after field invasion. The study shows that wMel and wAlbB infections did not induce any fitness cost on the two newly generated (Pud) lines. Rather, in terms of wing length, fecundity, egg hatch rate, and adult survival, the Wolbachia introgression conferred fitness benefits on the (Pud) lines compared to uninfected Wolbachia free wild Ae. aegypti population. wMel and wAlbB exhibited a high maternal transmission (99–100%) and induced nearly complete (98–100%) cytoplasmic incompatibility. Both the (Pud) lines were resistant to deltamethrin, malathion, DDT, and temephos, and the level of resistance was almost the same between the two lines as in the wild type. Overall, the stable association of wMel and wAlbB established with Ae. aegypti and the reproductive advantages of the (Pud) lines encourage a pilot release in the field for population replacement potential.

Uncovering of Anti-dengue Molecules from Plants Prescribed for Dengue: A Computational Investigation

Dengue fever is a tropical disease spread worldwide, transmitted by the mosquito Aedes aegypti. It affects 100 million people worldwide every year and half a million cases of dengue hemorrhagic fever are registered. At present, it poses sever health burden as combined infections of COVID-19. Currently, as a combined infection with COVID-19, it is becoming a serious health burden. To identify the active molecule, Maestro V12.7 was used with different tools including LigPrep, Grid Generation, SiteMap, Glide XP Docking, Pharmachophores and MM-GBSA. The UNRESS tool was also used to assess the protein stability with this dengue protein. The docking result showed that all examined phytocomponents except berberine and -(+)-l-alliin had good docking scores of -8.577 (azadirachtin), -8.112 (curcumin), -7.348 (apigenin) and -6.028 (andrographolide). However, berberine and -(+)-l-alliin possessed good hydrogen-bonding interactions with RdRp. In addition, molecular dynamic simulations demonstrate that the complex of azadirachtin and dengue protein has a solid understanding of the precise interactions. As per the research results, the present research suggests that this is the first statement of azadirachtin against NS5 RNA-dependent RNA polymerase domain (RdRp), despite extensive research on this molecule in previous investigations. Furthermore, we anticipate that molecules such as curcumin, apigenin, and andrographolide would show beneficial effects while in vitro and in vivo studies are conducted on virally related objects. Since we performed ADMET and pharmacokinetic properties in this research, we feel that the phytochemicals of the screened anti-dengue molecules may not need to be evaluated for toxicological effects.

Global prevalence of dengue and chikungunya coinfection: A systematic review and meta-analysis of 43,341 participants

Dengue and chikungunya virus are important arboviruses of public health concern. In the past decades, they have accounted for numerous outbreaks of dengue and chikungunya in different parts of the world. Several cases of concurrent infection of dengue and chikungunya have been documented. However, the true burden of this concurrent infection is unknown. Here, a systematic review and meta-analysis of published data on the prevalence of dengue and chikungunya coinfection in the human population was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis. Six electronic databases (Web of science, Embase, PubMed, ScienceDirect, Scopus, and Google Scholar) were searched without year or language restrictions for relevant studies. The study protocol was registered with PROSPERO (CRD42020175344). Eighty-three studies involving a total of 43,341 participants were included. The random-effects model was employed to calculate the summary estimates. A pooled global prevalence of 2.5% (95% CI: 1.8-3.4) was obtained for dengue and chikungunya coinfection. Males and females appear to be coinfected at a fairly similar rate. Among the regions, Asia accounted for the highest prevalence (3.3%, 95% CI: 2.3-4.6) while North America was the least (0.8%, 95% CI: 0.3-2.4). The prevalence estimates varied across different countries. A much higher prevalence rates were obtained for Colombia (37.4%, 95% CI: 9.1-78.1), Madagascar (18.2%, 95% CI: 10.1-30.6), Laos (12.5%, 95% CI: 5.3-26.7), Maldives (4.5%, 95% CI: 1.5-13.0) and Thailand (3.7%, 95% CI: 0.4-26.3). This first extensive systematic review and meta-analysis reveals dengue and chikungunya coinfection as a global problem worthy of consideration. It is therefore pertinent that both infections be assessed during diagnosis, mosquito vector control practices be implemented, and vaccine development strides be supported globally.