Changing pattern of circulating dengue serotypes in the endemic region: An alarming risk to the healthcare system during the pandemic

Phuleria H, Bhowmick IP. Spatio-temporal distribution of dengue cases and vectors along with the interrelationship of environmental and climatic factors in the metropolitan city, Kolkata, India, for 2017-2022: calling implications for vector control

We studied the spatio-temporal distribution of dengue at the micro-scale, along with other important factors for disease transmission, like vector prevalence, seasonality, breeding behaviour, entomological indices, and its relation with environmental and climatic factors in Kolkata, one of the most populous metropolitan cities in India, facing dengue upsurge in recent years. We analysed dengue data from 144 wards, city-level meteorological data for 6 years (2017-2022), Land Use Land Cover (LULC) data for 2022, and entomological surveillance data from 7 wards in 2022. Dengue showed high spatial heterogeneity and clustering at the micro-level, with a yearly post-monsoon peak (August-November) accounting for ∼90% of cases and representing a 2-3 month lag between high rainfall, temperature, and relative humidity (RH). Both Ae. aegypti and Ae. albopictus were prevalent, with distinct spatio-temporal distributions and instances of mixed breeding. Ae. aegypti primarily breeds indoors and peri-domestically, showing a strong correlation with rainfall (R² = 0.78, p-value = 0.0003) in indoor habitats and had a perennial presence. In contrast, Ae. albopictus was the more common outdoor breeder, strongly correlating with rainfall (R² = 0.75, p-value = 0.0003) in outdoor habitats. This is the first study from Kolkata, India, highlighting the spatio-temporal distribution of dengue and its links to vector behaviour, climate, and environmental factors. The findings will help identify recent dengue hotspots in Kolkata, which will help in developing targeted vector control strategies.

Spatial patterns and clustering of dengue incidence in Mexico: Analysis of Moran's index across 2,471 municipalities from 2022 to 2024

Dengue is an increasing public health challenge, with rising cases and expanding distribution. Its complex epidemiology is influenced by climate change, urbanization, and the circulation of multiple viral serotypes. This study aimed to characterize the spatial and temporal (2022-2024) patterns of dengue incidence across 2,471 municipalities in Mexico. Weekly case counts, obtained through the normative epidemiological surveillance system for vector-borne diseases, were used to calculate incidence rates per 100,000 population. Geographic Information Systems were employed to analyze spatial patterns, while Local Moran's I statistic and a k-nearest neighbors spatial weights matrix identified spatial clusters. A total of 622,689 dengue cases were analyzed, with incidence rates rising from 29.4 in 2022 to 279.0 per 100,000 in 2024. Dengue transmission expanded, affecting 38.0% of municipalities in 2022 and 68.6% by 2024 ([Formula: see text] < 0.001). Spatial clustering also increased, with positive clusters increasing from 28 municipalities in 2022-98 in both 2023 and 2024. Moran's I values indicated a peak in spatial autocorrelation in 2023 (I = 0.57). While DENV-2 was the predominant serotype in 2022, DENV-3 became dominant in 2023 and 2024. Over time, high-incidence areas shifted from southern and central regions to the southeast and Pacific coast. These findings suggest the growing burden of dengue in Mexico, driven by rising incidence, expanding geographic distribution, and evolving spatial patterns. A coordinated public health response is needed to mitigate the impact of dengue and prevent its spread to newly affected areas.

Dengue Investigation Research in Bangladesh: Insights From a Scoping Review

Background and Aims

A more accurate assessment of the disease's incidence and fatality rate over the previous years could help with future outbreak detection and containment. Therefore, this scoping review was conducted to compile the results of research on dengue investigation in Bangladesh in terms of knowledge, attitudes, and practices; risk factors; clinical presentations; and stereotypes of dengue.

Methods

The final analysis included 27 studies that satisfied the inclusion criteria. The PRISMA 2020 guidelines served as the basis for data extraction. All included articles were retrieved from PubMed, BanglaJOL, Google Scholar, Embase, Web Sciences, Cochrane Library, and other databases up to October, 2024. The quality of included studies in terms of relevance, reliability, validity, and applicability was also evaluated.

Results

The present study recorded a moderate understanding of dengue infection among slum dwellers and people in rural areas due to a lack of knowledge about it. Insufficient practices regarding dengue fever were also found among them. However, the differences in perception regarding dengue infection were observed in different parts of Dhaka city. Additionally, between 2017 and 2022, different dengue serotypes were the most common at various times. The potential risk factors included monsoon sessions (July to September), static water, scrapyards, and indoor plants; urbanization; population density; being outside in the morning and evening; sleeping during the day; and so forth. Along with the common symptoms of dengue, hematological abnormalities such as thrombocytopenia and leukopenia, as well as elevated levels of ALT and AST, were observed in Bangladeshi dengue patients.

Conclusions

Knowledge gap, moderate understanding, insufficient practices regarding dengue infection among slum dwellers and rural people, and varieties in dengue serotypes are the main obstacles to control the dengue outbreak. Therefore, it is essential to undertake several preventive measures to reduce the dengue infection and also understand the dengue serotypes.

Diagnostic challenges of arboviral infections and dengue virus serotype distribution in febrile patients in East Java, Indonesia

Objectives

Arboviruses pose significant public health threats worldwide, with Southeast Asia being a hotspot for these infections. This study aimed to reassess the incidence of dengue, Zika, and chikungunya viruses in patients clinically diagnosed with dengue in East Java, Indonesia in 2023.

Methods

The study included 108 patients admitted to hospitals in Jember, with blood samples collected on admission. Multiplex reverse transcription-polymerase chain reaction was used to detect viral RNA for dengue, Zika, and chikungunya, whereas dengue serotypes were identified using real-time polymerase chain reaction.

Results

A total of 67 of 108 (62%) patients tested positive for dengue virus (DENV), one patient tested positive for chikungunya, and no cases of Zika were detected. Differences in laboratory parameters between patients who were DENV RNA-negative and confirmed dengue cases suggest possible misdiagnosis of dengue. Serotyping of DENV-positive samples revealed DENV serotype 3 as the predominant serotype in Jember, accounting for 34% of cases (n = 23 of 67), followed by DENV serotype 1 and DENV serotype 2 at 19% each (n = 13 of 67) and 6% for DENV-4 (n = 4 of 67), whereas 21% (n = 14 of 67) remained untyped.

Conclusions

This study highlights the nature of the dengue outbreak in Jember in 2023, where all four DENV serotypes were in circulation, and underlines the need for serological or nucleic acid-based methods to improve arbovirus diagnosis in the region.

Serotype and genotype shift detection over two consecutive periods of dengue virus infection in a tertiary care hospital

PURPOSE

Dengue virus infection in humans can also lead to severe complications like dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). The World Health Organization (WHO) estimates around 50 to 100 million dengue infections annually, with approximately 500,000 cases of DHF and 22,000 deaths, predominantly among children. The present study aimed at identifying circulating serotypes of dengue virus in patients by molecular techniques. Serotypes detected were correlated with the clinical profiles, complications, and outcomes in these patients.

METHODS

This study was conducted between October 2019 to September 2022. Institute Ethics Committee approval was obtained (Reference no. IEC: RC/18/59). Serum from patients who tested positive for dengue NS1 antigen (NS1Ag) or anti-dengue immunoglobulin M (IgM) were serotyped by dengue reverse transcriptase polymerase chain reaction (RT-PCR). Clinical data was documented in case report forms and transferred to an Excel spreadsheet, and subsequently analyzed to correlate the dengue virus (DENV) serotype with clinical profile and outcome.

RESULTS

The study population included 416 patients, confirmed by Dengue NS1Ag and or anti-Dengue IgM ELISA. Young adults (18-29 yrs) constituted the majority (56 %) of patients. About 85 % of all patients presented with fever, 10.6 % with hemorrhagic fever, and 4.4 % with shock syndrome. Thrombocytopenia with multiple bleeding manifestations was observed in 6.5 % of the patients. The predominant dengue serotype identified was serotype 3 from October 2019 to March 2021, and serotype 2 from April 2021 to September 2022, showing a shift in the serotypes affecting the patients.

CONCLUSION

Continuous sero- and molecular surveillance plays a crucial role in predicting dengue outbreaks and identifying shifts in circulating serotypes during the early phase of the dengue season. It may also play a role in vaccine preparedness for the control of dengue.

Rapid spread of the emerging cosmopolitan genotype of dengue virus serotype 2, and expansion of dengue virus serotype 1 genotype V in Peru

BACKGROUND

Motivation for the study. This study aimed to analyze the prevalence and distribution of the V genotypes of dengue virus type 1 (DENV-1) and the cosmopolitan genotype DENV-2 in Peru, in order to understand their expansion in different regions; since these viruses can cause important outbreaks in the country. Main findings. A rapid spread and wide distribution of the cosmopolitan DENV-2 genotype was reported in Peru in 2022, following its initial introduction in 2019. DENV-1 genotype V, present in Peru since the 1990s, has now expanded to new Peruvian regions, after previously being restricted to rural and jungle areas in the north of the country. Implications. The results highlight the urgent need to strengthen epidemiological and genomic surveillance systems to monitor and control the spread of these genotypes in Peru, allowing a more rapid response and controlling their potential spread to other regions of the Americas.

OBJECTIVES.

This study aimed to evaluate the prevalence and distribution of dengue virus genotype V serotype 1 (DENV-1) and cosmopolitan genotype serotype 2 (DENV-2) in Peru between 2019 and 2022.

MATERIALS AND METHODS.

The envelope (E) gene region was amplified from 79 serum samples by polymerase chain reaction (PCR) and sequenced by next-generation sequencing (NGS) technology. The obtained sequences were subsequently analyzed with bioinformatics tools.

RESULTS.

The study generated envelope gene sequences of DENV-1 and DENV-2 serotypes. Our study revealed a rapid dispersal and wide distribution of the cosmopolitan DENV-2 genotype in several regions of Peru in 2022, as well as the spread of DENV-1 genotype V to new Peruvian regions, along with the cosmopolitan DENV-2 genotype.

CONCLUSIONS.

Our findings suggest the urgent need to strengthen epidemiological and genomic surveillance systems to understand and control the spread of circulating DENV genotypes in Peru. This will allow a more rapid response, as well as the monitoring of its potential dissemination to other countries in the Americas.

Risk of cognitive decline among patients with dengue virus infection: a systematic review

Dengue fever, caused by the dengue virus and transmitted through Aedes mosquitoes, is a growing public health concern, particularly in tropical and subtropical regions. Traditionally associated with febrile and hemorrhagic symptoms, recent research suggests a potential link between dengue and cognitive impairments. This systematic review assessed existing research to understand the association between dengue virus infection and cognitive impairments, including dementia, Alzheimer disease, memory loss, and confusion. This systematic review followed preferred reporting items for systematic reviews and meta-analyses guidelines. A comprehensive literature search was conducted in PubMed, EMBASE, and Web of Science up to January 18, 2024. Studies examining the prevalence and association of cognitive impairments in dengue patients were included. Data extraction and quality assessment were performed using Nested Knowledge software and the Newcastle-Ottawa Scale. Of the 1129 articles identified, 5 were included in the review, covering a total of 200 873 participants from Taiwan, Brazil, and France. Evidence from population-based cohort studies indicated short-term cognitive impairments, including confusion and memory loss, in some dengue patients. Additionally, long-term risks of dementia, including Alzheimer disease and vascular dementia, were observed, particularly among older adults. Although the findings suggest there might be an association between dengue infection and cognitive decline, the mechanisms underlying this link remain unclear. This systematic review suggests that dengue virus infection may affect cognitive function in both acute and long-term contexts. However, the current evidence is not strong enough to establish a conclusive link. Further research with larger sample sizes and longitudinal studies is essential to confirm the impact of dengue virus on cognitive health.

Cryptic transmission and novel introduction of Dengue 1 and 2 genotypes in Colombia

Dengue fever remains as a public health challenge in Colombia, standing as the most prevalent infectious disease in the country. The cyclic nature of dengue epidemics, occurring approximately every 3 years, is intricately linked to meteorological events like El Niño Southern Oscillation (ENSO). Therefore, the Colombian system faces challenges in genomic surveillance. This study aimed to evaluate local dengue virus (DENV) transmission and genetic diversity in four Colombian departments with heterogeneous incidence patterns (department is first-level territorial units in Colombia). For this study, we processed 266 serum samples to identify DENV. Subsequently, we obtained 118 genome sequences by sequencing DENV genomes from serum samples of 134 patients infected with DENV-1 and DENV-2 serotypes. The predominant serotype was DENV-2 (108/143), with the Asian-American (AA) genotype (91/118) being the most prevalent one. Phylogenetic analysis revealed concurrent circulation of two lineages of both DENV-2 AA and DENV-1 V, suggesting ongoing genetic exchange with sequences from Venezuela and Cuba. The continuous migration of Venezuelan citizens into Colombia can contribute to this exchange, emphasizing the need for strengthened prevention measures in border areas. Notably, the time to most recent common ancestor analysis identified cryptic transmission of DENV-2 AA since approximately 2015, leading to the recent epidemic. This challenges the notion that major outbreaks are solely triggered by recent virus introductions, emphasizing the importance of active genomic surveillance. The study also highlighted the contrasting selection pressures on DENV-1 V and DENV-2 AA, with the latter experiencing positive selection, possibly influencing its transmissibility. The presence of a cosmopolitan genotype in Colombia, previously reported in Brazil and Peru, raises concerns about transmission routes, emphasizing the necessity for thorough DENV evolution studies. Despite limitations, the study underscores genomic epidemiology's crucial role in early detection and comprehension of DENV genotypes, recommending the use of advanced sequencing techniques as an early warning system to help prevent and control dengue outbreaks in Colombia and worldwide.

The COVID-19 Pandemic Affected Hepatitis C Virus Circulation and Genotypic Frequencies-Implications for Hepatitis C Prevention, Treatment and Research

Hepatitis C is regarded as a global health issue caused by hepatitis C virus (HCV) infection. HCV is targeted for elimination by 2030 as a global public health goal. However, the COVID-19 pandemic has changed human circulation and prevented access to diagnostics and treatment to many other diseases, including hepatitis C. COVID-19 impacted HCV global elimination efforts with implications not fully comprehended yet. The high genetic variability in HCV makes the development of vaccines and pan-genotypic drug therapies a difficult task. Changes in the dynamics of HCV impose new challenges for public health and opportunities for future research. Meta-analysis, the follow up of new cases and sampling of HCV patients compared with previously available data are options for investigating the possible changes. The determination of HCV genotypes and subtypes is important for understanding viral dynamics and treatment; therefore, the changes in genotype and subtype prevalences can directly affect such processes. Recent results in the literature already suggest changes in HCV dynamics during the COVID-19 pandemic, both considering viral circulation and differential genotypic frequencies in distinct geographic areas. In this context, we propose a further examination of these trends using different approaches to provide support for the hypothesis that the COVID-19 pandemic affected HCV circulation, since these findings would have important implications for hepatitis C prevention, treatment and research.

Investigating the Clinico-Demographic Characteristics of Dengue Fever and Its Seroprevalence at a Tertiary Care Hospital in Northern India

Background and objective Dengue virus (DENV) is a major global health threat, causing over 50,000 deaths annually. The state of Uttar Pradesh (UP) in India faces significant challenges due to the increasing number of dengue cases detected. This study aimed to assess DENV seropositivity in the Raebareli district of UP, to offer crucial insights into the region's effective control and management strategies. Materials and methods This study, after obtaining approval from the ethics committee, analyzed blood samples of individuals suspected of having dengue at a teaching hospital in rural UP between January and December 2022. To determine the disease's seroprevalence, both dengue NS1 antigen ELISA and dengue IgM Microlisa were conducted. Furthermore, RT-PCR was performed on NS1-positive samples to confirm the serotypes. The collected data were analyzed using Epi Info 7.0. Results Of the 589 suspected dengue cases, 86 (14.60%) tested positive for dengue NS1 and/or IgM. Our findings showed that males (n=330, 56.03%) and adolescents and young adults (n=301, 51.1%) from rural areas (n=523, 88.4%) were predominantly affected. Cases peaked post-monsoon, and platelet levels were notably low in NS1-positive cases. Dengue serotype 2 (DEN-2) was found in all RT-PCR-positive samples. Our results revealed a dengue seroprevalence of 14.60% (n=86), which peaked in post-monsoon months. The higher incidence among males and young adults from rural areas attending the outpatient department highlights the importance of targeted interventions and community surveillance. RT-PCR confirmed the circulation of a single serotype in the region. Conclusions This study contributes crucial insights into dengue's epidemiology and clinical profile and its findings are all the more significant now as India prepares for phase 3 trials of a quadrivalent dengue-virus vaccine in 2024. Adolescent and young adult males have an increased likelihood of acquiring the virus, and this demographic can be prioritized for vaccine trials.