Dengue Cases Research Articles

LEVANTAMENTO DE PERFIL EPIDEMIOLÓGICO DA DENGUE EM ARAGUAÍNA NO ESTADO DO TOCANTINS

Analyzing the epidemiology of dengue in Brazil, focusing on the city of Araguaína in Tocantins, exploring the characteristics of the different virus serotypes, their clinical implications, and the importance of early diagnosis. A quantitative study was conducted with a time series analysis covering the period from 2014 to 2023. Using data from the Notification Diseases Information System (Sinan), the research correlated the number of dengue cases in Araguaína with variables such as sex, age, and months of the year. The objective was to ensure the accuracy of the results, avoiding distortions in interpretation. The research aims to provide information on the seasonality of the infection and identify more vulnerable groups, contributing to preventive actions. The analyzed data from SINAN indicate a significant increase in the incidence of dengue in Araguaína TO, especially during the months of higher rainfall, when conditions for the proliferation of Aedes aegypti are ideal. The research confirmed that the lack of adherence by the population to prophylactic measures contributes to this increase, reflecting the need to intensify awareness campaigns. It was also observed that the majority of reported cases are among women, suggesting a greater tendency to seek care in health units. Early identification of symptoms is crucial for effective treatment, helping to reduce mortality. Thus, the importance of continuous and appropriate preventive actions for dengue control is reinforced.

Geographic Information System for Mapping Deployment Areas Dengue Fever in Umalulu District

Dengue fever is a disease caused by the dangue virus, causing serious health problems, especially in Umalulu sub-district, East Sumba Regency which has an area of 307.90 km2 and consists of 10 villages, each of which has an impact on dengue cases. This study aims to map the area of the spread of dengue fever in real time in Umalulu sub-district using a Geographic Information System (GIS), which is currently experiencing the problem of an increase in the number of dangue hemorrhagic fever cases and assistance that has not been targeted. The research method used is Waterfall, which follows the stages of planning, data collection, system analysis and design, implementation, and maintenance. Based on black box testing, this research succeeded in producing a web-based GIS that maps the dengue fever distribution areas in showing that the Lumbukore village is the area that has the highest number of cases with 12 and the Ngarukanoru village with the lowest area with 0 cases, with an average of many cases occurring in March and April of 2024 in Umalulu District, allowing users to analyze dengue disease distribution patterns provide recommendations for prevention and control measures for dengue disease more accurately and on target.

Rapid review: effectiveness of the Wolbachia strategy for arbovirus controlRevisión sistemática rápida: efectividad de la estrategia de control con Wolbachia en la lucha contra las arbovirosis

To identify and synthesize evidence of the effectiveness and cost-effectiveness of the Wolbachia-Aedes methodology for reducing cases of arboviral infection. Rapid systematic review. A search of five online portals and bibliographic databases was conducted in February 2022. Two reviewers conducted the selection stages, with any disagreements resolved by a third investigator. Data were extracted by one reviewer and subsequently checked by another. The inclusion criteria were studies describing the cost-effectiveness and effectiveness of the Wolbachia-Aedes methodology, based on field interventions, published in Portuguese, English, and Spanish, with no restrictions on date of publication. Four studies were included: one cluster randomized trial, two quasi-experimental studies, and one pre-post study, published between 2019 and 2021 in four countries. The included studies reported effectiveness for some of the outcomes of interest, such as a reduction in the incidence of dengue, Zika, and chikungunya cases. Although no experimental studies addressing the cost-effectiveness of the Wolbachia-Aedes strategy were identified, some modeling studies have demonstrated potential cost-benefit of this methodology. Considering the results of the included studies, Wolbachia has the potential to be an economically effective strategy that leads to reductions in the incidence of dengue, Zika, and chikungunya. Nevertheless, this strategy cannot yet be recommended as a public policy; additional large-scale studies with high methodological quality are still needed to inform political decision-making.

IMPACTO DAS MUDANÇAS CLIMÁTICAS NA DISTRIBUIÇÃO E INCIDÊNCIA DE DENGUE NA REGIÃO AMAZÔNICA

This study addresses the impact of climate change on the distribution and incidence of dengue in the Amazon region, examining how changes in temperature, precipitation, and humidity patterns influence the proliferation of the Aedes aegypti mosquito, the disease vector. Evidence suggests that global warming and extreme weather events, such as heavy rainfall and drought periods, create favorable conditions for mosquito breeding, leading to a geographical expansion of risk areas and an increase in dengue cases.

Insecticide resistance status and mechanisms in Aedes aegypti and Aedes albopictus from different dengue endemic regions of Panama

BackgroundDengue is a serious public health problem worldwide, including Panama. During the last years, the number of dengue cases has increased. This may be due to the presence of mosquito populations resistant to insecticides. The aim of this study was to characterize the resistance status, its enzymatic mechanisms and Kdr mutations in wild populations of Aedes aegypti and Aedes albopictus.MethodsStandard WHO bioassays were performed using insecticide-treated filter papers to determine resistance in populations Ae. aegypti and Ae. albopictus to pyrethroids insecticides, organophosphates, to the carbamate propoxur and to the organochlorine DDT. Biochemical assays were conducted to detect metabolic resistance mechanisms and real-time PCR was performed to determine the frequencies of the Kdr mutations Val1016IIe and F1534C.ResultsThe strains Ae. aegypti El Coco showed confirmed resistance to deltamethrin (78.5% mortality) and lambda-cyhalothrin (81%), Aguadulce to deltamethrin (79.3%), David to deltamethrin (74.8%) and lambda-cyhalothrin (87.5%) and Puerto Armuelles to permethrin (83%). Aedes aegypti El Empalme showed confirmed resistance to pirimiphos-methyl (62.3% mortality), chlorpyrifos-methyl (55.5%) and propoxur (85.3%). All strains of Ae. albopictus showed possible resistance to PYs and five strains to DDT. Only Ae. albopictus Canto del Llano showed confirmed resistance to pirimiphos-methyl (70% mortality) and malathion (62%). Esterase activity was variable across sites with the most frequent expression of α-EST compared to β-EST in Ae. aegypti populations. In Ae. Albopictus, the expressed enzymes were β-EST and MFOs. Through ANOVA, significant differences were established in the levels of enzymatic activity of α- and β-EST, MFOs and GST, with p < 0.001 in the Ae. aegypti and Ae. albopictus. The Kdr Val1016IIe mutation was detected in Ae. aegypti Aguadulce, El Coco and David. The odds ratio for the Val1016Ile mutation ranged from 0.8 to 20.8 in resistant mosquitoes, indicating the association between pyrethroid phenotypic resistance and the kdr mutation.ConclusionThe presence of a varied and generalized resistance, enzymatic mechanisms and the Val1016IIe mutation may be associated with the intensive use and possibly misuse of the different insecticides applied to control Aedes populations. These results highlight the need to develop a program for resistance management. Also, alternative approaches to mosquito control that do not involve insecticides should be explored.

Global burden of viral infectious diseases of poverty based on Global Burden of Diseases Study 2021.

Viral infectious diseases of poverty (vIDPs) remain a significant global health challenge. Despite their profound impact, the burden of these diseases is not comprehensively quantified. This study aims to analyze the global burden of six major vIDPs, including coronavirus disease 2019 (COVID-19), HIV/AIDS, acute hepatitis, dengue, rabies, and Ebola virus disease (EVD), using data from the Global Burden of Diseases, Injuries, and Risk Factors Study 2021 (GBD 2021). Following the GBD 2021 framework, we analyzed the incidence, mortality, and disability-adjusted life years (DALYs) of the six vIDPs across 204 countries and territories from 1990 to 2021. We examined the association between the Socio-Demographic Index (SDI) and the burden of vIDPs. All estimates were reported as numbers and rates per 100,000 population, calculated using the Bayesian statistical model employed by GBD 2021, with 95% uncertainty intervals (UI). In 2021, vIDPs caused approximately 8.7 million deaths and 259.2 million DALYs, accounting for 12.8% and 9.0% of the global all-cause totals, respectively. Globally, the burden of vIDPs varied significantly: COVID-19 caused around 7.9 million (95% UI: 7.5, 8.4) deaths and 212.0 million (95% UI 197.9, 234.7) DALYs in 2021. Acute hepatitis had the second-highest age-standardized incidence rate, with 3411.5 (95% UI: 3201.8, 3631.3) per 100,000 population, while HIV/AIDS had a high age-standardized prevalence rate, with 483.1 (95% UI: 459.0, 511.4) per 100,000 population. Dengue incidence cases rose from 26.5 million (95% UI: 3.9, 51.9) in 1990 to 59.0 million (95% UI: 15.5, 106.9) in 2021. Rabies, although reduced in prevalence, continued to pose a significant mortality risk. EVD had the lowest overall burden but significant outbreak impacts. Age-standardized DALY rates for vIDPs were significantly negatively correlated with SDI: acute hepatitis (r = -0.8, P < 0.0001), rabies (r = -0.7, P < 0.0001), HIV/AIDS (r = -0.6, P < 0.0001), COVID-19 (r = -0.5, P < 0.0001), dengue (r = -0.4, P < 0.0001), and EVD (r = -0.2, P < 0.005). VIDPs pose major public health challenges worldwide, with significant regional, age, and gender disparities. The results underscore the need for targeted interventions and international cooperation to mitigate the burden of these diseases. Policymakers can use these findings to implement cost-effective interventions and improve health outcomes, particularly in regions with high or increasing burdens.

Dengue Outbreak Caused by Multiple Virus Serotypes and Lineages, Colombia, 2023-2024.

Dengue cases rose to record levels during 2023-2024. We investigated dengue in Valle del Cauca, Colombia, to determine if specific virus serotypes or lineages caused its large outbreak. We detected all 4 serotypes and multiple lineages, suggesting that factors such as climatic conditions were likely responsible for increased dengue in Colombia.

A clinicoepidemiological study of serologically diagnosed acute febrile illness in a teaching hospital, Kolkata

ABSTRACT Introduction: Similar presenting manifestations in early phase and lack of awareness of aetiology of acute febrile illness (AFI) are major challenges in management of AFI. Material and Methods: This was a retrospective observational cross-sectional study conducted in the Department of Microbiology, NRS Medical College, from 1 July 2022 to 30 June 2023 in serologically diagnosed febrile patients attending the outpatient department or admitted. Clinical and epidemiological data and laboratory parameters were recorded in a pretested structured questionnaire study tool, and collected data were analysed on MS-Excel sheets with various charts and tables. Results: A total of 1711 serologically diagnosed febrile patients showed preponderance of dengue (38.3%), followed by leptospirosis (25%), scrub typhus (23.9%), malaria (12.6%), and enteric fever (1.92%). A majority of cases were male, less than 40 years of age, and from the rural population (73.2%), except in malaria (urban = 79.6%). The mean duration of fever was 9 days. Febrile cases were recorded maximum during the monsoon and postmonsoon periods (66.5%). The common manifestations are fever, headache (46.2%), pain abdomen (7.8%), nausea, and vomiting (9.4%). Thrombocytopenia with bleeding manifestation was higher in dengue (18%) cases. Mortality in dengue cases was recorded with multiorgan dysfunction syndrome (MODS). Scrub typhus cases showed seizure (8.3%) and altered sensorium (5%) due to fatal meningoencephalitis. Fatality in leptospirosis was mostly due to acute kidney injury (29.5%) and Weil’s disease (4.4%). Conclusion: Misdiagnosis or incorrect diagnosis and delay in initiation of appropriate treatment results in increased morbidity and mortality in AFI. Determination of epidemiological features and clinical manifestations of AFI along with timely correct diagnosis will benefit clinicians in proper treatment initiation, thereby reducing morbidity and mortality.

Dengue outbreak 2023 in Bangladesh: From a local concern to a global public health issue.

Dengue, a viral infection transmitted by mosquitoes, has become a substantial public health issue in Bangladesh. The high population density and subtropical-tropical climate of the nation create conducive environments for the transmission of the virus. The recent increase in dengue cases in Bangladesh prompts an inquiry into the potential for the virus to progress into an epidemic manifestation. Bangladesh is prone to dengue outbreaks due to a multitude of contributing factors. To commence, the virus is endemic to tropical and subtropical regions, and climate change is contributing to the expansion of its range. Additionally, the high population density in Bangladesh amplifies the vulnerability to dengue transmission. Intimate human proximity elevates the probability of contracting mosquito stings and transmitting viruses. The escalating incidence of dengue in Bangladesh is substantiated by the growing count of documented cases. The emergence of severe dengue is a contributing aspect that raises concerns about the potential worldwide consequences of the disease. It could potentially head from Bangladesh to neighboring nations via an infected individual. There exist apprehensions due to the substantial employment of Bangladeshi laborers overseas, compounded by the presence of foreign laborers within Bangladesh. The endeavor to control dengue in Bangladesh continues to face ongoing challenges. This review addresses the complexities of dengue transmission, assesses Bangladesh's readiness for managing epidemics, analyzes risk factors associated with dengue, and suggests preventive measures to mitigate the possibility of worldwide consequences of dengue originating within the nation.

Correlation between CRP and ferritin in dengue patients: A hospital-based prospective observational study

ABSTRACT Background: In India, dengue is one of the health challenges and a leading cause of hospitalization, especially during the monsoon. C-reactive protein (CRP) is an independent marker for dengue severity. The present study aimed to analyze the correlation between CRP and ferritin and with other hematological markers in dengue fever (DF). Methods: A hospital-based prospective study was conducted over one year. With the patient’s consent, A total of 189 dengue-diagnosed hospitalized patients aged more than 18 years were included in the study group. Demographic features, total leukocytes, total platelet counts, packed cell volume, CRP, and ferritin were monitored in both severe and non-severe cases. Significant univariate parameters were correlated and significant associations were analyzed from the correlation coefficient and P value respectively. Result: A total of 189 dengue-diagnosed, hospitalized patients were recruited, among them 30 patients were diagnosed as severe and 159 patients were diagnosed as non-severe. The mean age ranged between 41 ± 16.7 and 42 ± 15.9 years. In univariate analysis, total leucocytes, CRP, and ferritin were significantly higher in dengue severe cases in comparison to non-severe dengue cases. The association between CRP and ferritin revealed a positive correlation whereas, the association between ferritin and total platelet count showed a negative correlation. Conclusion: A significant positive correlation between CRP and ferritin indicates that ferritin can be an additional biomarker along with CRP for the hospitalization of dengue patients and may be useful for severity prediction at an early stage of infection.

Detection of dengue virus serotype 4 in Panama after 23 years without circulation.

Panama is a country with endemic Dengue virus (DENV) transmission since its reintroduction in 1993. The four serotypes have circulated in the country and the region of the Americas, however, DENV-4 confirmed autochthonous cases have not been identified since 2000, despite its circulation in neighboring countries. Here, we report DENV-4 detection in Panama in the last four-month period of 2023 with co-circulation of the other serotypes, this was associated with a peak of dengue cases during the dry season even though most dengue outbreaks are described in the rainy season. Complete genomes of DENV-4 allowed us to determine that cases were caused by DENV-4 genotype IIb, the same genotype as 23 years ago, with high similarity to DENV-4 sequences circulating in Nicaragua and El Salvador during 2023. This report shows the importance of maintaining serotype and genotype surveillance for early detection of new variants circulating in the country.

Impact of COVID-19 on dengue: a twofold challenge to public health in Sabah, Malaysia.

The dengue epidemic poses a significant public health challenge in Malaysia, and the concurrent presence of dengue and SARS-CoV-2 infections has further strained its healthcare system. Sabah, the second largest state in Malaysia, located in the northern part of Borneo Island, has been particularly hard-hit by both dengue and SARS-CoV-2 outbreaks. This study aims to analyze the status of dengue infections in Sabah over the past decade and understand the impact of the COVID-19 pandemic on dengue virus transmission. This study compared the annual dengue cases and associated deaths in Sabah from 2012 to 2022. Systematic data and information were collected from PubMed, the World Health Organization, the Centers for Disease Control and Prevention, and the official government reporting system of Malaysia. Dengue cases in Sabah increased overall with slight fluctuations over the years, marked by new outbreaks approximately every 3-5 years. The number of deaths did not consistently correlate with reported dengue cases. Early in the COVID-19 pandemic in 2020, dengue cases remained high; however, as COVID-19 cases surged, dengue cases experienced a significant decline. Conversely, from mid-2022, dengue cases surged in Sabah despite COVID-19 cases remaining relatively low and well-controlled. Particularly noteworthy is the 99% increase in dengue cases in Sabah, contrasting sharply with Malaysia's overall 36% decrease in 2022 compared to 2015 to 2019. Monitoring and prioritizing efforts to prevent COVID-19 and control dengue transmission is crucial. The dual challenges posed by these diseases offer valuable lessons that should be incorporated into future pandemic-preparedness strategies.

Dengue Fever in Fiji:epidemiological Insights and Strategic Control Approaches

The incidence of dengue has grown dramatically around the world in recent decades, with cases reported to WHO increasing from 505 430 cases in 2000 to 5.2 million in 2019. A vast majority of cases are asymptomatic or mild and self-managed, and hence the actual numbers of dengue cases are under-reported. Many cases are also misdiagnosed as other febrile illnesses . Dengue fever is most common in tropical and subtropical regions of the world and is arguably one of the most devastating diseases in countries like Fiji. This paper attempts to evaluate the disease, focusing on the Fijian case in the last 15 years, explaining the degenerative processes of the disease, and present-day approaches to controlling the disease, as well as newer methods of diagnosis and therapies. The intended outcome is to broaden knowledge and enhance approaches to address one of the most persistent health risks in one of the highly affected regions of the globe.

Utilizing the '5 in 1 Magic Touch' CCRTV method for early detection of severe dengue warning signs in pediatric patients: A case study from a Type C Hospital in Indonesia

Background: Dengue fever, prevalent in tropical and subtropical regions, is recognized by WHO as a significant global health threat. Early detection of severe dengue symptoms, especially in resource-limited settings, is critical for patient outcomes. The "5 in 1 Magic Touch - CCRTV" method, which evaluates Color, Capillary Refill Time, Temperature, Pulse Rate, and Pulse Volume, provides a simple yet effective approach to monitor hemodynamics and identify early warning signs of severe dengue. Case Description: In a case study, a 3-year-old boy was admitted with fever, shortness of breath, weakness, nausea, vomiting, and epigastric pain. On the third day, he entered a critical phase with symptoms of pale extremities, delayed capillary refill time, high fever, and a weak, rapid pulse. Thorax examination revealed severe plasma leakage, pulmonary edema, and right pleural effusion, indicating a pre-shock state. The patient required close clinical monitoring, regular fluid balance management, and frequent blood tests to guide treatment. Conclusion:The CCRTV assessment method allowed for the early identification of the pre-shock condition, facilitating timely and appropriate intervention. This case highlights the potential of the CCRTV method for improving prognosis in severe dengue cases. The effectiveness of this method warrants further research, particularly in its ability to predict outcomes and improve recovery rates in children with severe dengue.

Space-time dynamics of the dengue epidemic in Brazil, 2024: an insight for decision making

BackgroundDengue is a vector-borne viral infection caused by the dengue virus transmitted to humans primarily by Aedes aegypti. The year 2024 has been a historic year for dengue in Brazil, with the highest number of probable cases ever registered. Herein, we analyze the temporal trend and spatio-temporal dynamics of dengue cases in Brazil during the first nine epidemiological weeks (EW) of 2024.MethodsThis is an ecological study, including all probable cases of dengue in Brazil during the period, carried out in two steps: time series analysis to assess the temporal trend and spatial analysis to identify high-risk clusters.Results1,345,801 probable cases of dengue were reported. The regions with the highest increasing trend were the Northeast with an average epidemiologic week percent change (AEPC) of 52.4 (95% CI: 45.5–59.7; p < 0.001) and the South with 35.9 (95% CI: 27.7–44.5; p < 0.001). There was a statistically significant increasing trend in all states, except Acre (AEPC = -4.1; 95% CI: -16.3–10; p = 0.55), Amapá (AEPC = 1.3; 95% CI: -16.2–22.3; p = 0.9) and Espírito Santo (AEPC = 8.9; 95% CI: -15.7–40.6; p = 0.5). The retrospective space-time analysis showed a cluster within the Northeast, Central-West and Southeast regions, with a radius of 515.3 km, in which 1,267 municipalities and 525,324 of the cases were concentrated (RR = 6.3; p < 0.001). Regarding the spatial variation of the temporal trend, 21 risk areas were found, all of them located in Southeast or Central-West states. The area with the highest relative risk was Minas Gerais state, where 5,748 cases were concentrated (RR = 8.1; p < 0.001). Finally, a purely spatial analysis revealed 25 clusters, the one with the highest relative risk being composed of two municipalities in Acre (RR = 6.9; p < 0.001).ConclusionsWe described a detailed temporal-spatial analysis of dengue cases in the first EWs of 2024 in Brazil, which were mainly concentrated in the Southeast and Central-West regions. Overall, it is recommended that governments adopt public policies to control the the vector population in high-risk areas, as well as to prevent the spread of dengue fever to other areas of Brazil.

Global landmark: 2023 marks the worst year for dengue cases with millions infected and thousands of deaths reported

ObjectivesIn 2023, the world experienced the worst dengue virus (DENV) outbreak on record. The study aimed to identify global regions and continents with high burden of dengue in 2023. DesignWe collected data on the number of DENV cases and deaths reported by various countries to the World Health Organization and World Health Organization regional offices. We estimated DENV cases per million population and case fatality ratio (CFR) among the confirmed cases reported by each country. ResultsOverall, in 2023 more than 6.5 million cases and over 6,800 deaths attributed to DENV were recorded globally, marking a historic milestone. Two distinct hotspots of DENV circulation emerged: South America and South and Southeast Asian regions. South America reported the highest number of cases (3,924,992), and 1,946 deaths, with a CFR of 0.05. In Asia, 1,622,405 cases and 3,637 deaths were reported, with a CFR of 0.22. We observed a statistically significant difference in the number of cases and deaths per million across different continents (P-value <0.001). However, the CFR did not differ significantly across continents (P-value = 0.123). ConclusionsThe increased cases and mortality highlight the urgent need for a comprehensive global approach aimed at DENV infection control, including vaccine development, vector control, public health initiatives, and improved clinical management.

Resurgence of dengue in the Philippines.

The coronavirus disease 2019 (COVID-19) pandemic has significantly influenced the epidemiological landscape of various infectious diseases such as dengue. Dengue is an endemic disease in the Philippines, which showed a significant decline in the number of cases beginning in March 2020 due to the stringent public health measures implemented to curb COVID-19 cases. However, the easing of these restrictions subsequently led to a resurgence in dengue cases, as reported by the World Health Organization, with a notable increase compared to previous years. As the country navigates towards a post-pandemic phase, addressing the resurgence of dengue requires sustained efforts in vector control, surveillance, and healthcare preparedness. This article underscores the critical need for collaborative efforts among stakeholders to mitigate the resurgence of dengue while managing the ongoing recovery from the COVID-19 pandemic.

Exploring variations in dengue symptoms: a comparative study of 2013, 2019, and 2023 in a tertiary care hospital of Bangladesh

Background: Dengue fever remains a major public health issue in Bangladesh, with repeated outbreaks. This study compares dengue symptoms in a tertiary care hospital during 2013, 2019, and 2023. The purpose of this study is to evaluate the variations in dengue symptoms among Bangladeshi dengue patients from 2013 and 2019 to 2023. Methods: This was a cross-sectional study, conducted on 100 dengue positive patients, admitted between 1st January to 7th August 2023, to the Medicine Department, Holy Family Red Crescent Medical College and Hospital, Dhaka. Demographic data, sign and symptoms and laboratory investigation reports were collected. These data were compared with a previously published study from the same institute comparing dengue symptoms between 2013 and 2019 among admitted dengue patients. The study employed a convenience sampling method for participant selection, and data analysis was carried out using SPSS version 26. Results: Analysis of 100 sero-positive dengue cases reveals a predominant occurrence in the 20 to 40 age group (51%), with the mean age of patients being 34.5 years. Among these cases, a higher prevalence is observed in males (62%) compared to females (38%). Symptomatology exhibits variations over time, with fever being consistently present. Other symptoms such as headache (90%, 23% and 12%), retroorbital pain (45%, 3% and 16%), skin rash (16%, 4% and 1%) and constipation (32%, 1% and 5%) showing fluctuations, respectively in 2013, 2019 and 2023. Notably, a significant proportion of patients in 2023 exhibit normal ultrasound findings (53%). Conclusions: In conclusion, our study provides a comprehensive analysis of Dengue infection dynamics over a decade, highlighting significant variations in clinical manifestations, laboratory findings, and abdominal ultrasound results among Bangladeshi patients. The findings suggest that Dengue remains a considerable public health concern, with fluctuations observed in symptomatology, including fever and other associated symptoms, and changes in laboratory parameters over time. BIRDEM Med J 2024; 14(3): 131-136

Mapping dengue in Brazil: an epidemiological, geospatial and climate correlation

Brazil has been suffering for many years from an extensive dengue epidemic. The objective of this study was to map dengue cases in Brazil between 2007 and 2022, correlating their epidemiology, geospatial distribution, and relationship to climatic and social data. An epidemiological survey was conducted based on data available in the Notifiable Diseases Information System, calculating incidence rates (IR), mortality rates (MR), case fatality rates (CFR), and the distribution of epidemiological characteristics, allowing the geolocation of cases and the creation of maps for each year and Brazilian states. Finally, the ecological determinants were correlated with IR and MR. We observed that IR and MR remained high throughout the analyzed period, with a slight decrease in IR in 2017 and 2018. Cases occurring in female individuals were higher, however, with a similar percentage of deaths. A decrease in the average mortality was observed, during the evaluation period, in children and adolescents; however, an increase in the average mortality among elderly was correlated with the presence of comorbidities. The states located in the Midwest region were the most affected, followed by the states in the Northern region. In addition, we observed a significant, but weak, correlation between ecological determinants (maximum temperature and humidity) and IR, GDP per capita and HDI (Human Development Index) with MR. Due to the hyperendemic scenario, it is necessary to take efficient control and constant epidemiological surveillance.

Epidemiological characteristics and transmission dynamics of dengue fever in China

China has experienced successive waves of dengue epidemics over the past decade. Nationwide data on 95,339 dengue cases, 89 surveillance sites for mosquito density and population mobility between 337 cities during 2013-20 were extracted. Weekly dengue time series including time trends and harmonic terms were fitted using seasonal regression models, and the amplitude and peak timing of the annual and semiannual cycles were estimated. A data-driven model-inference approach was used to simulate the epidemic at city-scale and estimate time-evolving epidemiological parameters. We found that the geographical distribution of dengue cases was expanding, and the main imported areas as well as external sources of imported cases changed. Dengue cases were predominantly concentrated in southern China and it exhibited an annual peak of activity, typically peaking in September. The annual amplitude of dengue epidemic varied with latitude (F = 19.62, P = 0.0001), mainly characterizing by large in southern cities and small in northern cities. The effective reproduction number Reff across cities is commonly greater than 1 in several specific months from July to November, further confirming the seasonal fluctuations and spatial heterogeneity of dengue epidemics. The results of this national study help to better informing interventions for future dengue epidemics in China.