Dengue Incidence Research Articles

Dengue incidence forecasting model in Magalang, Pampanga using time series analysis

This study aimed to provide an Auto-Regressive Integrated Moving Average (ARIMA) model that can predict dengue incidence in Magalang, Pampanga based on the past dengue incidences & climate variables from 2016 to 2019 and identify significant predictor/predictors among the climate variables. Weekly dengue incidence and climatological data from January 2016 to December 2019 were gathered and considered as the dependent and independent variables, respectively. Then, the Expert Modeler in IBM SPSS 22 automatically selected and estimated the best fitting ARIMA model for one dependent variable series. The created model was then used to forecast dengue incidence for the 52-week period of 2020, employing quarterly, semi-annual, and annual forecasting. A one-way ANOVA was conducted to evaluate differences among the four groups, followed by a post hoc Scheffe test to determine which groups differed from each other. Additionally, the Diebold-Mariano (DM) test was utilized to validate the forecasting performance of the ARIMA model. The non-seasonal ARIMA (0,1,6) model, with the sum of rainfall as the sole predictor from seven candidate predictors, was identified as the best fit. Model fit statistics indicated a stationary R-squared value of 0.739. The Ljung-Box statistics test value of 0.344, deemed not significant, confirmed correct model specification. One-way ANOVA analysis revealed a significant difference among the four groups, with an F value of 34.37 and a p-value approaching zero. Post hoc Scheffe tests further indicated a significant difference between the observed dataset and both semi-annual and annual forecasting, with p-values of 0.014 and approaching zero, respectively. However, no significant difference was observed between the observed dataset and quarterly forecasting, with a p-value of 0.281. Moreover, DM test statistics revealed that quarterly forecasting outperformed both annual and semi-annual forecasting. This suggests that the non-seasonal ARIMA (0,1,6) model, with the sum of rainfall as a predictor, effectively predicts future dengue incidences using quarterly forecasting.

Silent spread of DENV-3 in Brazil: autochthonous outbreak in São Paulo after 15years.

The high incidence of dengue in Brazil and re-emergence of DENV-3 in São Paulo after a 15-year absence, coupled with the potential risk for DENV-4, may be the results from changing climate patterns favouring Aedes mosquito proliferation, allied by the resuming of domestic and international travels.

School and community driven dengue vector control and monitoring in Myanmar: Study protocol for a cluster randomized controlled trial.

Dengue is the most common and widespread mosquito-borne arboviral disease globally estimated to cause >390 million infections and >20,000 deaths annually. There are no effective preventive drugs and the newly introduced vaccines are not yet available. Control of dengue transmission still relies primarily on mosquito vector control. Although most vector control methods currently used by national dengue control programs may temporarily reduce mosquito populations, there is little evidence that they affect transmission. There is an urgent need for innovative, participatory, effective, and locally adapted approaches for sustainable vector control and monitoring in which students can be particularly relevant contributors and to demonstrate a clear link between vector reduction and dengue transmission reduction, using tools that are inexpensive and easy to use by local communities in a sustainable manner. Here we describe a cluster randomized controlled trial to be conducted in 46 school catchment areas in two townships in Yangon, Myanmar. The outcome measures are dengue cases confirmed by rapid diagnostic test in the townships, dengue incidence in schools, entomological indices, knowledge, attitudes and practice, behavior, and engagement. The trial involves middle school students that positions them to become actors in dengue knowledge transfer to their communities and take a leadership role in the delivery of vector control interventions and monitoring methods. Following this rationale, we believe that students can become change agents of decentralized vector surveillance and sustainable disease control in line with recent new paradigms in integrated and participatory vector surveillance and control. This provides an opportunity to operationalize transdisciplinary research towards sustainable health development. Due to the COVID-19 pandemic and political instability in Myanmar the project has been terminated by the donor, but the protocol will be helpful for potential future implementation of the project in Myanmar and/or elsewhere.Registration: This trial was registered in the ISRCTN Registry on 31 May 2022 ( https://doi.org/10.1186/ISRCTN78254298).

Arbovirus Detection of Adult Female <i>Aedes aegypti</i> for Dengue Surveillance: a Cohort Study in Bandung City, Indonesia

Dengue surveillance is an important activity to prevent dengue outbreaks. This activity becomes a significant challenge for the region with limited logistic capabilities. Developing a simple mathematical model to predict the possibility of dengue incidence provides a reliable early warning system. This study compared the correlation between vector (adult female Aedes aegypti) and arbovirus detection on a vector to dengue incidence, which generalized linear mixed models tested. The incidence of adult female Aedes aegypti and dengue fever cases were interpolated through third-power inverse distance weighting (IDW). A spatial correlation between female Aedes aegypti incidence and dengue incidence was obtained from polynomial regression. Collection sites were 16 villages in Bandung city, one of the significant dengue endemic areas in January–December 2017. A total of 8,402 mosquitoes of Aedes aegypti, Aedes albopictus, and Culex sp., with 17% belonging to Aedes aegypti as the subject of the dengue virus (DENV) infection test. Data analysis only showed a weak correlation between the numbers of adult female Aedes aegypti and dengue incidence. On the other hand, there is no correlation between positive dengue infection of vector and dengue incidence. This study highlights the importance of constant arbovirus surveillance and integrated surveillance methods on all possible dengue vectors to develop an early warning system for dengue incidence.

Evaluation of the effectiveness of LIRAa as an instrument to monitor Dengue

Objectives: We investigated whether the application of the LIRAa monitoring tool (Aedes aegypti Fast Infestation Survey) had an impact on lowering the Dengue incidence rate in the municipalities of the country. Methods: Two methods were all used, the first was difference in differences (DiD) and Event Study, being both estimated by balanced panel data. The study was carried out considering the 2001-2016 period. The National Information and Injuries System (SINAN), National Sanitation Information System (SNIS), National Institute of Space Research (INPE) and the Brazilian Institute of Geography and Statistics (IBGE) were the main data sources. Results: By using the method of difference in differences, the municipalities that accounted for the LIRAa presented a significant decrease in the rate of Dengue incidence of approximately 144 cases in a universe of 100,000 inhabitants during the period (b3 = -143.73; IC95% -320.51 – 13.12). For the Event Study, the results behaved similarly, with a result of 274 cases in average (j9 = -274.02; IC95% -430.93 - 117.12). Conclusion: It was concluded that LIRAa in an important tool for monitoring Dengue, since it provides data capable to guide the public policies in a community.

Facing the escalating burden of dengue: Challenges and perspectives.

Dengue is the most rapidly emerging mosquito-borne infection and, due to climate change and unplanned urbanization, it is predicted that the global burden of dengue will rise further as the infection spreads to new geographical locations. Dengue-endemic countries are often unable to cope with such increases, with health care facilities becoming overwhelmed during each dengue season. Furthermore, although dengue has been predominantly a childhood illness in the past, it currently mostly affects adults in many countries, with higher incidence of severe disease and mortality rates in pregnant women and in those with comorbidities. As there is currently no specific treatment for dengue and no early biomarker to identify those who will progress to develop vascular leakage, all individuals with dengue are closely monitored in case they need fluid management. Furthermore, diagnosing patients with acute dengue is challenging due to the similarity of clinical symptoms during early illness and poor sensitivity and specificity of point-of-care diagnostic tests. Novel vector control methods, such as the release of Wolbachia-infected mosquitoes, have shown promising results by reducing vector density and dengue incidence in clinical trial settings. A new dengue vaccine, TAK-003, had an efficacy of 61.2% against virologically confirmed dengue, 84.1% efficacy against hospitalizations and a 70% efficacy against development of dengue haemorrhagic fever (DHF) at 54 months. While vaccines and mosquito control methods are welcome, they alone are unlikely to fully reduce the burden of dengue, and a treatment for dengue is therefore essential. Several novel antiviral drugs are currently being evaluated along with drugs that inhibit host mediators, such as mast cell products. Although viral proteins such as NS1 contribute to the vascular leak observed in severe dengue, the host immune response to the viral infection also plays a significant role in progression to severe disease. There is an urgent need to discover safe and effective treatments for dengue to prevent disease progression.

Spatial correlation of dengue with socioeconomic status and land temperature in northwest Mexico

Objective. To characterize the geographic distribution of dengue and to evaluate the spatial autocorrelation with social and climatic determinants at the census-tract level in two medium sized cities in northwestern Mexico. Methods. In this work we apply spatial analysis ecological tools, such as the Moran’s Index and the Local Indicator of Spatial Association (LISA) method, to examine global and local spatial correlation between incidence of dengue, and socioeconomic and climatic factors at the census tract-level. For the analysis of the spatial clustering, the Getis-Ord method was used to find statistically significant hot spots in each city. Results. Overall, a global spatial autocorrelation could not be identified, although local clusters of a high dengue incidence, soil surface temperature ≤ 31 °C and high degree of social marginalization coincide. Discussion. We found that at the census-tract level in urban settings, socially disadvantaged populations showed higher clusters of dengue when compared to areas with better socioeconomic conditions. In the two study sites, a similar spatial pattern was observed when considering public health conditions and its aggregation with physical attributes using spatial analysis techniques, supporting the application of this technique for a better understanding about the dengue distribution in urban areas.

Dengue virus infection and neurological manifestations: an update.

Dengue virus is a flavivirus transmitted by the mosquitoes, Aedes aegypti and Aedes albopictus. Dengue infection by all four serotypes (DEN 1 to 4) is endemic globally in regions with tropical and subtropical climates, with an estimated 100-400 million infections annually. Among those hospitalized, the mortality is about 1%. Neurological involvement has been reported to be about 5%. The spectrum of neurological manifestations spans both the peripheral and central nervous systems. These manifestations could possibly be categorized into those directly related to dengue infection, i.e. acute and chronic encephalitis, indirect complications leading to dengue encephalopathy, and post-infectious syndrome due to immune-mediated reactions, and manifestations with uncertain mechanisms, such as acute transverse myelitis, acute cerebellitis and myositis. The rising trend in global dengue incidence calls for attention to a more explicit definition of each neurological manifestation for more accurate epidemiological data. The actual global burden of dengue infection with neurological manifestation is essential for future planning and execution of strategies, especially in the development of effective antivirals and vaccines against the dengue virus. In this article, we discuss the recent findings of different spectrums of neurological manifestations in dengue infection and provide an update on antiviral and vaccine development and their challenges.

Interactions between climate change, urban infrastructure and mobility are driving dengue emergence in Vietnam

Dengue is expanding globally, but how dengue emergence is shaped locally by interactions between climatic and socio-environmental factors is not well understood. Here, we investigate the drivers of dengue incidence and emergence in Vietnam, through analysing 23 years of district-level case data spanning a period of significant socioeconomic change (1998-2020). We show that urban infrastructure factors (sanitation, water supply, long-term urban growth) predict local spatial patterns of dengue incidence, while human mobility is a more influential driver in subtropical northern regions than the endemic south. Temperature is the dominant factor shaping dengue’s distribution and dynamics, and using long-term reanalysis temperature data we show that warming since 1950 has expanded transmission risk throughout Vietnam, and most strongly in current dengue emergence hotspots (e.g., southern central regions, Ha Noi). In contrast, effects of hydrometeorology are complex, multi-scalar and dependent on local context: risk increases under either short-term precipitation excess or long-term drought, but improvements in water supply mitigate drought-associated risks except under extreme conditions. Our findings challenge the assumption that dengue is an urban disease, instead suggesting that incidence peaks in transitional landscapes with intermediate infrastructure provision, and provide evidence that interactions between recent climate change and mobility are contributing to dengue’s expansion throughout Vietnam.

EPH47 Modeling the Impact of the Vaccine Candidate TAK-003 on the Incidence of Dengue in French Overseas Territories

EPH47 Modeling the Impact of the Vaccine Candidate TAK-003 on the Incidence of Dengue in French Overseas Territories

Reduced dengue incidence following city-wide wMel Wolbachia mosquito releases throughout three Colombian cities: Interrupted time series analysis and a prospective case-control study.

The introduction of Wolbachia (wMel strain) into Aedes aegypti mosquitoes reduces their capacity to transmit dengue and other arboviruses. Randomised and non-randomised studies in multiple countries have shown significant reductions in dengue incidence following field releases of wMel-infected Ae. aegypti. We report the public health outcomes from phased, large-scale releases of wMel-Ae. aegypti mosquitoes throughout three contiguous cities in the Aburrá Valley, Colombia. Following pilot releases in 2015-2016, staged city-wide wMel-Ae. aegypti deployments were undertaken in the cities of Bello, Medellín and Itagüí (3.3 million people) between October 2016 and April 2022. The impact of the Wolbachia intervention on dengue incidence was evaluated in two parallel studies. A quasi-experimental study using interrupted time series analysis showed notified dengue case incidence was reduced by 95% in Bello and Medellín and 97% in Itagüí, following establishment of wMel at ≥60% prevalence, compared to the pre-intervention period and after adjusting for seasonal trends. A concurrent clinic-based case-control study with a test-negative design was unable to attain the target sample size of 63 enrolled virologically-confirmed dengue (VCD) cases between May 2019 and December 2021, consistent with low dengue incidence throughout the Aburrá Valley following wMel deployments. Nevertheless, VCD incidence was 45% lower (OR 0.55 [95% CI 0.25, 1.17]) and combined VCD/presumptive dengue incidence was 47% lower (OR 0.53 [95% CI 0.30, 0.93]) among participants resident in wMel-treated versus untreated neighbourhoods. Stable introduction of wMel into local Ae. aegypti populations was associated with a significant and sustained reduction in dengue incidence across three Colombian cities. These results from the largest contiguous Wolbachia releases to-date demonstrate the real-world effectiveness of the method across large urban populations and, alongside previously published results, support the reproducibility of this effectiveness across different ecological settings. NCT03631719.

Stagnant Cleaning Affects Dengue Hemorrhagic Fever Incidence: A Rapid Survey

DHF is still a serious health problem and a threat in a number of areas in Indonesia. The purpose of this study was to intervene regarding the disease and reduce the number of dengue cases and to implement the jumantik program in Bandar Setia Village. After going through these stages the data is analyzed descriptively, namely percentage and frequency, chi square and multiple logistic regression. The results obtained that >50% of people were fogging, the results of statistical tests showed that overall factors had a significant relationship with the implementation of the DHF prevention program with risks ranging from 1.19 to 5.23 times, the results of the multivariate test stated that the category of cleaning puddles was the highest risk. in influencing the implementation of dengue prevention programs. This study concludes that at this time DHF has an attempt to go down and someday it could rise again. The results of the multivariate test stated that the category of cleaning puddles was the highest risk in influencing the implementation of the DHF prevention program. This study concludes that at this time DHF has an attempt to go down and someday it could rise again. The results of the multivariate test stated that the category of cleaning puddles was the highest risk in influencing the implementation of the DHF prevention program. This study concludes that at this time DHF has an attempt to go down and someday it could rise again.

Natural vertical transmission of dengue virus in Latin America and the Caribbean: highlighting its detection limitations and potential significance.

Dengue continues to be a major public health concern in Latin America and the Caribbean with many countries in the region having experienced drastic increases in the incidence of dengue over the past few years. Dengue virus is predominantly transmitted by the bite of an infected female Aedes aegypti mosquito via a process called horizontal transmission. However, the virus may also be transmitted from an infected female mosquito to her offspring by vertical transmission, which occurs via viral invasion of the ovary either at the time of fertilization or during oviposition. In this way, mosquitoes may become dengue virus infected before ever encountering a human host. While some researchers have reported this phenomenon and suggested it may serve as a reservoir for the dengue virus in nature, others have questioned its epidemiological significance because of the low frequency at which it has been observed. Several researchers have either altogether failed to detect it or observed its occurrence at low frequencies. However, some studies have attributed these failures to small sample sizes as well as poor sensitivities of screening methods employed. Therefore, an overview of the occurrence, significance and limitations of detection of vertical transmission of dengue virus in Aedes mosquitoes in nature within Latin America and the Caribbean will be the focus of this review.

Association between environmental factors and dengue incidence in Lao People’s Democratic Republic: a nationwide time-series study

BackgroundDengue fever is a vector-borne disease of global public health concern, with an increasing number of cases and a widening area of endemicity in recent years. Meteorological factors influence dengue transmission. This study aimed to estimate the association between meteorological factors (i.e., temperature and rainfall) and dengue incidence and the effect of altitude on this association in the Lao People’s Democratic Republic (Lao PDR).MethodsWe used weekly dengue incidence and meteorological data, including temperature and rainfall, from 18 jurisdictions in Lao PDR from 2015 to 2019. A two-stage distributed lag nonlinear model with a quasi-Poisson distribution was used to account for the nonlinear and delayed associations between dengue incidence and meteorological variables, adjusting for long-term time trends and autocorrelation.ResultsA total of 55,561 cases were reported in Lao PDR from 2015 to 2019. The cumulative relative risk for the 90th percentile of weekly mean temperature (29 °C) over 22 weeks was estimated at 4.21 (95% confidence interval: 2.00–8.84), relative to the 25th percentile (24 °C). The cumulative relative risk for the weekly total rainfall over 12 weeks peaked at 82 mm (relative risk = 1.76, 95% confidence interval: 0.91–3.40) relative to no rain. However, the risk decreased significantly when heavy rain exceeded 200 mm. We found no evidence that altitude modified these associations.ConclusionsWe found a lagged nonlinear relationship between meteorological factors and dengue incidence in Lao PDR. These findings can be used to develop climate-based early warning systems and provide insights for improving vector control in the country.

Alarming Trends in Dengue Incidence and Mortality in Bangladesh.

Bangladesh is currently experiencing the country's largest and deadliest dengue outbreak on record. This year's outbreak has been characterized by an early seasonal surge in cases, rapid geographic spread, and a high fatality rate. The alarming trends in dengue incidence and mortality this year is an urgent wake-up call for public health policymakers and researchers to pay closer attention to dengue dynamics in South Asia, to strengthen the surveillance system and diagnostic capabilities, and to develop tools and methods for guiding strategic resource allocation and control efforts.

Effects of boosting and waning in highly exposed populations on dengue epidemic dynamics.

Sequential infection with multiple dengue virus (DENV) serotypes is thought to induce enduring protection against dengue disease. However, long-term antibody waning has been observed after repeated DENV infection. Here, we provide evidence that highly immune Nicaraguan children and adults (n = 4478) experience boosting and waning of antibodies during and after major Zika and dengue epidemics. We develop a susceptible-infected-recovered-susceptible (SIRS-type) model that tracks immunity by titer rather than number of infections to show that boosts in highly immune individuals can contribute to herd immunity, delaying their susceptibility to transmissible infection. In contrast, our model of lifelong immunity in highly immune individuals, as previously assumed, results in complete disease eradication after introduction. Periodic epidemics under this scenario can only be sustained with a constant influx of infected individuals into the population or a high basic reproductive number. We also find that Zika virus infection can boost DENV immunity and produce delays and then surges in dengue epidemics, as observed with real epidemiological data. This work provides insight into factors shaping periodicity in dengue incidence and may inform vaccine efforts to maintain population immunity.

Effectiveness of Eupatorium perfoliatum 30C in Prevention of Dengue Fever and Acute Febrile Illness during 2017 Dengue Outbreak in Urban Slums of Delhi: A Prospective, Open-Label, Community-Based, Parallel Cohort Study

Objective: This study was undertaken to assess the effectiveness of Eupatorium perfoliatum (EP) 30C on the incidence of dengue fever and acute febrile illness (AFI) during the 2017 dengue outbreak. Methods: We conducted a prospective, open-label, community-based parallel cohort study involving apparently healthy individuals residing in 06 urban slums (JJ colony) of Delhi. The participants were enrolled in two cohorts – the medicine cohort (MC) and the control cohort (CC). Participants in MC were given weekly one dose of EP 30C for 10 weeks along with Information, Education and Communication (IEC) material regarding dengue. Participants in the CC were provided with the IEC material only. The primary outcome measure was the incidence of dengue fever as per case definitions notified in the national guidelines for clinical management of dengue fever by the Government of India during the 10 weeks follow-up period. The secondary outcome measures were the incidence of AFI and the hospitalization of confirmed dengue cases. Results: The analysis included 40,769 participants residing in 06 slum clusters of Delhi out of which 28,321 participants were in MC and 12,448 participants were in CC. The incidence of laboratory-confirmed dengue in the MC was 2.57 per 10,000 person-weeks (95% confidence interval [CI], 2.02–3.22) in comparison with 7.55 per 10,000 person-weeks (95% CI, 6.12–9.21) in the CC. The incidence of AFI in the MC was 19.66 per 10,000 person-weeks (95% CI, 18.07–21.36) in comparison with 40.96 per 10,000 person-weeks (95% CI, 37.48–44.67) in the CC. The overall protective effect of EP against laboratory-confirmed dengue was 65.77% (95% CI, 53.37–74.87; p = 0.0001) and against AFI was 52.58% (95% CI, 46.37–58.07; p = 0.0001). Hospitalization reported in the MC was nil as against 4.35% in the CC. No dengue-related case fatalities were reported from either cohort. None of the participants from the MC reported any adverse events owing to the prophylactic intervention. Conclusion: The study concludes that EP 30C was able to prevent dengue significantly. Randomized controlled trials are needed to confirm or refute our findings.

Dengue and climate changes: Increase of DENV-1 in São Paulo/Brazil – 2023

Dengue is a vector borne disease caused by virus serotypes DENV-1, DENV-2, DENV-3, and DENV-4, representing a significant public health concern in the Region of the Americas (2,997,097 cases in 2023). This study explores the relationship between dengue incidence and climate changes in the city of São Paulo-Brazil. During the first semester of 2023, Brazil reported the highest number of dengue cases in Americas’ Region. Our data reveals a correlation between the high temperature and rainfall season persistence and the extension of dengue incidence into the winter season. The findings highlight the importance of understanding the relationship between climate change and disease transmission patterns to develop effective strategies for prevention and control.

Utility of surveillance data for planning for dengue elimination in Yogyakarta, Indonesia: a scenario-tree modelling approach

IntroductionField trials and modelling studies suggest that elimination of dengue transmission may be possible through widespread release of Aedes aegypti mosquitoes infected with the insect bacterium Wolbachia pipientis (wMel strain),...

A non-integer order model for Zika and Dengue co-dynamics with cross-enhancement

A novel fractional derivative model with nine compartments is formulated to investigate the transmission dynamics of zika and dengue co-infection. The Atangana–Baleanu fractional derivative in the Caputo sense was employed. The conditions for a unique solution are identified, and the solutions’ positivity and boundedness are demonstrated. The disease-free equilibrium point (DFE) and basic reproduction number, R0, were obtained. The DFE was shown to be locally asymptotically stable when the basic reproduction number is less than one. Zika-associated reproduction number, R0z, and dengue-associated reproduction number, R0d, were estimated to be 1.0144 and 1.1724, respectively. The system was shown to be generalized Ulam Hyers–Rassias stable, and the Adam–Bashforth method was used to provide its’ numerical solution. Sensitivity analysis using the Latin Hyper-cube Sampling (LHS) and Partial Rank Correlation Coefficient (PRCC) (|PRCC|> 0.45) with 200 runs was carried out using various variables as response functions per time. The most significant parameters were found to be zika human-to-human transmission rate, βhz1, vector death rate, μv, zika recovery rate, γhz1 and dengue vector-to-human transmission rate, βhd. Real data from Espirito Santo in Brazil is used to validate the model and fit needed parameter values. Numerical simulations illustrated the impact of varying the fractional order derivative, recovery rates, transmission rates, and cross-enhancement parameters on the infected human compartments. The zika Human-to-human transmission rate, βhz1, was found to be a very significant parameter in the control of zika disease transmission. Increasing the vector death rate, μv, was more important in curbing dengue prevalence and incidence than the attainment of recovery from the dengue disease, and the absence of the zika Vector-to-human transmission rate, βhz3, was almost insignificant in the presence of the zika Human-to-human transmission rate, βhz1, for disease eradication. This study suggested control measures and strategies to decrease the dengue and zika human-to-human transmission rates.