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Global maps of dengue epidemic potential () for the highest three consecutive months of the year. A) Present (1980–2009) (same as Fig. 2B). B) Future (2070–2099) under RCP8.5 from five global climate models. In A) and B), DTR was included. The color bar describes the values of the .
Source publication
Dengue is a mosquito-borne viral disease that occurs mainly in the tropics and subtropics but has a high potential to spread to new areas. Dengue infections are climate sensitive, so it is important to better understand how changing climate factors affect the potential for geographic spread and future dengue epidemics. Vectorial capacity (VC) descr...
Contexts in source publication
Context 1
... the main effect of DTR is to increase (by a relatively large percentage) the overall dengue epidemic potential in temperate climates and reduce (by a relatively small percentage) the dengue epidemic potential in the tropical regions. Figure 3 shows the dengue epidemic potential for the highest three consecutive months of the year where DTR was included in the present rVc estimates ( Figure 3A) and the projected rVc estimates for the future ) time period ( Figure 3B) under a high greenhouse emission scenario (RCP8.5, see Methods section for definition) [27][28][29]. It is apparent from Figure 3B that the majority of the Northern Hemsphere is projected to have a higher epidemic potential in this period. ...
Context 2
... the main effect of DTR is to increase (by a relatively large percentage) the overall dengue epidemic potential in temperate climates and reduce (by a relatively small percentage) the dengue epidemic potential in the tropical regions. Figure 3 shows the dengue epidemic potential for the highest three consecutive months of the year where DTR was included in the present rVc estimates ( Figure 3A) and the projected rVc estimates for the future ) time period ( Figure 3B) under a high greenhouse emission scenario (RCP8.5, see Methods section for definition) [27][28][29]. It is apparent from Figure 3B that the majority of the Northern Hemsphere is projected to have a higher epidemic potential in this period. ...
Context 3
... the main effect of DTR is to increase (by a relatively large percentage) the overall dengue epidemic potential in temperate climates and reduce (by a relatively small percentage) the dengue epidemic potential in the tropical regions. Figure 3 shows the dengue epidemic potential for the highest three consecutive months of the year where DTR was included in the present rVc estimates ( Figure 3A) and the projected rVc estimates for the future ) time period ( Figure 3B) under a high greenhouse emission scenario (RCP8.5, see Methods section for definition) [27][28][29]. It is apparent from Figure 3B that the majority of the Northern Hemsphere is projected to have a higher epidemic potential in this period. ...
Context 4
... 3 shows the dengue epidemic potential for the highest three consecutive months of the year where DTR was included in the present rVc estimates ( Figure 3A) and the projected rVc estimates for the future ) time period ( Figure 3B) under a high greenhouse emission scenario (RCP8.5, see Methods section for definition) [27][28][29]. It is apparent from Figure 3B that the majority of the Northern Hemsphere is projected to have a higher epidemic potential in this period. This effect of temperature on the dengue epidemic potential is projected to occur in most parts of Europe, Asia, and North America including parts of Sweden, Finland, Russia, Alaska, and Canada. ...
Context 5
... to the comparison of the high rVc period (Fig. 3), Figure 4 shows the dengue epidemic potential based on annual average of rVc for the present (Figure 4A) and future (Figure 4B) time periods. Using the annually averagedrVc, we show the same trend as for the highest three consecutive month average although with less magnitude and smaller geographic areas affected. There is an obvious ...
Context 6
... DTR included and using projected (30 year average) temperature under a high greenhouse emission scenario (RCP8.5) at the end of this century, a large increase of dengue epidemic potential in both intensity and areas is observed as shown in Figure 3 and Figure 4 -especially in the Northern Hemisphere -compared to the estimate based on the present temperature. The change in dengue epidemic potential has been more dramatic in this century than the last century as shown in Figure 5 and Figure 6. ...
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Citations
... Considering the population density and the cases of malaria, it can be stated that out of the total population, 1.1% are projected to be pretentious by malaria on average every year, putting Mizoram at the second most malaria affected State in Northeast India 26 . The increase and decrease in the cases of malaria incidents can be hold responsible for many multifactorial such as temperature, rainfall, humidity, measures for vector borne controls, altitude of a geographical location, urbanization, host immunity, all these can determine the effects of vector disease transmissions 9,16,17 . ...
Malaria (P. falciparum, P. vivax) is a major vector borne disease in Mizoram. Since the extreme weather conditions and changing climate have a major role in the spread of vector borne illnesses, the purpose of this study aimed to examine the changing trend of climate and the relationship between climatic variables and epidemiological malaria situation in Mizoram. The Mann-Kendall and Sen's slope test were employed to analyze the changing trend on rainfall and humidity, the climatic data were collected from Indian Meteorological Department, Aizawl (1986-2019) and multiple regression model has been utilized to observe the correlation between instances of malaria and climatic factors (2000-2019). The data on epidemiological malaria cases were obtained from Health and Family Welfare Department, Govt. of Mizoram. The Mann-Kendall results show declining trend in rainfall with-4.58 magnitude of rainfall annually and an increase in the annual relative humidity with 0.19% (p <0.1). The regression model shows a highly significant association between the climatic variables and the malaria situation showing p<0.05.
... Moreover, we identified key parameters, like transmission and recovery rates, that drive the proportion of individuals with insecticide resistance 37 . For example, the results of sensitivity analysis of the model revealed that perturbation of model parameters (the natural birth rate of mosquitoes ( r ), the natural rate of resistance ( γ ), the transmission rate ( β ), the natural death rate of mosquitoes ( µ ), insecticide-induced mortality rate ( µi ), and the mortality rate due to offspring of resistant mosquitoes that do not inherit resistance ( α )) mirrored variations in R 0 , confirming their importance in proportion of the number of individuals within the mosquito population with insecticide resistance and the transmission dynamics 42 . ...
The control of arthropod disease vectors using chemical insecticides is vital in combating malaria, however the increasing insecticide resistance (IR) poses a challenge. Furthermore, climate variability affects mosquito population dynamics and subsequently IR propagation. We present a mathematical model to decipher the relationship between IR in Anopheles gambiae populations and climate variability. By adapting the susceptible-infected-resistant (SIR) framework and integrating temperature and rainfall data, our model examines the connection between mosquito dynamics, IR, and climate. Model validation using field data achieved 92% accuracy, and the sensitivity of model parameters on the transmission potential of IR was elucidated (e.g. μPRCC = 0.85958, p-value < 0.001). In this study, the integration of high-resolution covariates with the SIR model had a significant impact on the spatial and temporal variation of IR among mosquito populations across Africa. Importantly, we demonstrated a clear association between climatic variability and increased IR (width = [0–3.78], α = 0.05). Regions with high IR variability, such as western Africa, also had high malaria incidences thereby corroborating the World Health Organization Malaria Report 2021. More importantly, this study seeks to bolster global malaria combat strategies by highlighting potential IR ‘hotspots’ for targeted intervention by National malria control programmes.
... The extreme temperature could also be linked with the lower number of cases in such regions which could affect the propagation of vectors responsible for dengue transmission. Previous studies have reported that climate variation can potentially increase the dengue transmission via the alteration in vector's prevalence as well as changes in human behavior [28,29]. Dengue outbreaks have been observed to be associated with climate change globally [30]. ...
Background
Dengue fever caused by dengue virus is a tropical disease and is among the deadliest vector-borne diseases. The humid and hot summers of Pakistan support the probation of the vectors responsible for the transmission of viral and other parasitic diseases.
Methodology
A retrospective study, from 2012- 2019, of dengue infected individuals from the Punjab province of Pakistan was carried out to analyze epidemiology, clinical and laboratory findings of subjects with dengue virus infection. Data was derived from National Institute of Health (NIH) followed by Dengue control program of Pakistan, covering the incidence rate in 36 districts of Punjab and Islamabad Capital Territory (ICT) respectively. Patients data including the presence of dengue specific antigen or/and antibodies such as NS1 and IgG/IgM were observed. The study also included the analysis of demographic data, geographic data, and the month-wise distribution of dengue cases to examine seasonal trends.
Results
We analyzed 25,682 dengue infected individuals. The statistical analysis revealed a significant association between genders in which male population was more affected by dengue than females. It was also noted that the middle age group was the most affected age group while the highest number of cases were reported in October. Rawalpindi and Lahore were the most affected cities in Punjab province while Islamabad represented the highest number of cases during the recent outbreak in 2019. The IgM and IgG antibodies were highly prevalent among the infected patients.
Conclusion
Dengue is endemic in Pakistan, circulating throughout the year. Highest number of cases were observed in the month of October, September and November respectively. Association between climate change and vector-borne diseases need to be investigated in Pakistan as they significantly influence the timing and intensity of dengue and other disease outbreaks. Further exploration of hematological parameters is required to better diagnose and treat the disease. For the effective control of dengue outbreaks, awareness campaigns on sewage management and vector control along with social factors are strongly recommended for better control and eradication of the disease.
... Temperature, another important determinant of vector-borne transmission, can also vary within cities because of the urban heat island effect (UHI). Temperature influences the demographic parameters of mosquitoes, as well as transmission parameters, ultimately determining vectorial capacity [20][21][22]. Importantly, land surface modifications make urban areas warmer than their surrounding peri-urban or rural landscapes [3]. Although the local cause of the UHI can vary, several high-resolution remote sensing studies have shown that the intensity of UHI tends to positively correlate with human population density [23][24][25]. ...
The role of climate factors on transmission of mosquito-borne infections within urban landscapes must be considered in the context of the pronounced spatial heterogeneity of such environments. Socio-demographic and environmental variation challenge control efforts for emergent arboviruses transmitted via the urban mosquito Aedes aegypti. We address at high resolution, the spatial heterogeneity of dengue transmission risk in the megacity of Delhi, India, as a function of both temperature and the carrying-capacity of the human environment for the mosquito. Based on previous results predicting maximum mosquitoes per human for different socioeconomic typologies, and on remote sensing temperature data, we produce a map of the reproductive number of dengue at a resolution of 250m by 250m. We focus on dengue risk hotspots during inter-epidemic periods, places where chains of transmission can persist for longer. We assess the resulting high-resolution risk map of dengue with reported cases for three consecutive boreal winters. We find that both temperature and vector carrying capacity per human co-vary in space because of their respective dependence on population density. The synergistic action of these two factors results in larger variation of dengue's reproductive number than when considered separately, with poor and dense locations experiencing the warmest conditions and becoming the most likely reservoirs off-season. The location of observed winter cases is accurately predicted for different risk threshold criteria. Results underscore the inequity of risk across a complex urban landscape, whereby individuals in dense poor neighborhoods face the compounded effect of higher temperatures and mosquito carrying capacity. Targeting chains of transmission in inter-epidemic periods at these locations should be a priority of control efforts. A better mapping is needed of the interplay between climate factors that are dominant determinants of the seasonality of vector-borne infections and the socioeconomic conditions behind unequal exposure.
... Therefore, the vector population significantly impact the dengue transmission within human populations. Environmental conditions directly impact the mosquito population density and therefore can create high sensitivity in dengue transmission 7,[11][12][13][14][15] . The warmer and humid environments, typically between 25 − 30 0 C (77 − 86 0 F) of temperatures and above 60% of humidity levels provide a highly favorable environment for the Aedes mosquitoes causing rapid transmission [16][17][18] . ...
... These favorable conditions create large number of Aedes breeding sites [19][20][21] . Specifically, Sri Lanka falls within the highest-risk category for epidemic potential according to the projected climate change in 11 . Apart from these two consistent favorable conditions throughout the year, rainfall from the two monsoons experienced by Sri Lanka adds an additional level of favorability, generating high risk of dengue [22][23][24] . ...
Dengue is a vector-borne disease transmitted to humans by vectors of genus Aedes causing a global threat to health, social, and economic sectors in many of the tropical countries including Sri Lanka. In Sri Lanka, the tropical climate, marked by seasonal weather primarily influenced by monsoons, fosters optimal conditions for the virus to spread efficiently, especially during monsoon periods. This heightened transmission results in increased per-capita vector density. In this work, we investigate the dynamic influence of environmental conditions on dengue emergence in Colombo district- the geographical region with the highest recorded dengue threat in Sri Lanka. An iterative approach is employed to estimate dengue cases dynamically leveraging the Markov chain Monte Carlo simulations, utilizing the dynamics of weather patterns governing in the region. The developed algorithm allows to estimate the risk of dengue outbreaks with high precision, facilitating accurate forecasts of upcoming disease emergence patterns for better preparedness. The uncertainty quantification not only validated the accuracy of outbreak estimates but also showcased the model's capacity to capture extreme cases and revealed undisclosed external factors that might affect dengue transmission.
... This is attributed to the negative impact of the diurnal temperature range on vector competence and survival, both of which are critical components of vectorial capacity 12,40 . Thus, larger fluctuations in temperate regions with lower overall temperatures may also increase the potential for dengue epidemics, which suggests greater risk for outbreaks in temperate regions than typically recognized 41 . In addition to the extrinsic incubation temperature, the temperature at which larval and pupal development occurs also affects vector competence. ...
Vector-borne diseases are transmitted by haematophagous arthropods (for example, mosquitoes, ticks and sandflies) to humans and wild and domestic animals, with the largest burden on global public health disproportionately affecting people in tropical and subtropical areas. Because vectors are ectothermic, climate and weather alterations (for example, temperature, rainfall and humidity) can affect their reproduction, survival, geographic distribution and, consequently, ability to transmit pathogens. However, the effects of climate change on vector-borne diseases can be multifaceted and complex, sometimes with ambiguous consequences. In this Review, we discuss the potential effects of climate change, weather and other anthropogenic factors, including land use, human mobility and behaviour, as possible contributors to the redistribution of vectors and spread of vector-borne diseases worldwide.
... In particular, dengue is a climate-sensitive, tropical and subtropical disease caused by a flavivirus (DENV) primarily transmitted by female Aedes aegypti mosquitoes; it causes 100-400 million cases every year [32] and cases have been increasing dramatically both regionally and globally over the last three decades [33]. Notably, since mosquitoes and the pathogens they harbor are ectotherms, temperature can influence multiple stages of the mosquito life cycle and pathogen transmission cycle, affecting the distribution and dynamics of disease [10,[34][35][36]. Previous research has used a combination of constant-temperature laboratory experiments and mathematical modeling to first isolate the effects of temperature on different mosquito and pathogen traits (e.g., DENV development rate within the mosquito, mosquito lifespan and fecundity) and then combine these processes to understand how potential transmission rates vary across temperature [34,[36][37][38][39]. ...
... Notably, since mosquitoes and the pathogens they harbor are ectotherms, temperature can influence multiple stages of the mosquito life cycle and pathogen transmission cycle, affecting the distribution and dynamics of disease [10,[34][35][36]. Previous research has used a combination of constant-temperature laboratory experiments and mathematical modeling to first isolate the effects of temperature on different mosquito and pathogen traits (e.g., DENV development rate within the mosquito, mosquito lifespan and fecundity) and then combine these processes to understand how potential transmission rates vary across temperature [34,[36][37][38][39]. This has provided specific predictions for how temperature affects dengue transmission in the field: small increases in temperature should increase transmission up to the optimal temperature of 29˚C, after which increases in temperature should decrease transmission [10]. ...
Temperature can influence mosquito-borne diseases like dengue. These effects are expected to vary geographically and over time in both magnitude and direction and may interact with other environmental variables, making it difficult to anticipate changes in response to climate change. Here, we investigate global variation in temperature–dengue relationship by analyzing published correlations between temperature and dengue and matching them with remotely sensed climatic and socioeconomic data. We found that the correlation between temperature and dengue was most positive at intermediate (near 24°C) temperatures, as predicted from an independent mechanistic model. Positive temperature–dengue associations were strongest when temperature variation and population density were high and decreased with infection burden and rainfall mean and variation, suggesting alternative limiting factors on transmission. Our results show that while climate effects on diseases are context-dependent they are also predictable from the thermal biology of transmission and its environmental and social mediators.
... Although the South-East Asia region remains a region of concern regarding dengue, the virus has a high potential to spread to new areas. Some studies indicated that in addition to the influence of mean temperature values, the effect of the diurnal temperature range on the behavior of Aedes aegypti should be taken into account, while climate change projections suggest that large increases are expected by the end of this century in temperate Northern Hemisphere regions [37,38]. In 2022, and as of 23 August, in the Americas region there were 2,141,240 reported dengue cases, while the country reporting the most cases was Brazil (1,910,657) [7]. ...
Background and Objectives: Dengue is an important public health concern that warrants an examination of the longer-term global trends of its disease burden. The aim of this study was to assess the trends in dengue incidence and mortality worldwide over the last three decades. Materials and Methods: A descriptive epidemiological study was carried out, investigating the trends in the incidence and mortality of dengue from 1990 to 2019. The dengue incidence and mortality data were obtained from the Global Burden of Disease study database. Trends were examined using joinpoint regression analysis. Results: Globally, there were 56.7 million new cases of dengue reported in 2019: the disease was diagnosed in 27.4 million males and 29.3 million females. A total of 36,055 (18,993 males and 17,032 females) related deaths were reported worldwide in 2019. In both sexes, about 60% of new cases were recorded in the South-East Asia region (16.3 million in males and 17.4 million in females). Globally, the incidence of dengue exhibited an increasing tendency from 1990 to 2019 in both sexes (equally, by 1.2% per year). A significantly decreasing trend in the mortality of dengue was recorded only in females (by −0.5% per year), while an increasing trend was observed in males (by +0.6% per year). Conclusions: The rise in the number of new dengue cases and deaths in the world in the last several decades suggests a need for implementing more effective prevention and management measures.
... Here, we assumed an equal proportion of mosquitos per human (m = 1), a common assumption for models of vector-borne disease transmission [38]. We found evidence of a temperature dependence of Ae. aegypti biting behavior [39,40], which we assumed is independent from treatment but needs to be confirmed in future experimental studies. We also gathered information on the temperature dependence of DENV's EIP [41]; since there is little information for MAYV, we extrapolated this information from CHIKV as it is the closest representative with temperature dependencies available [42]. ...
Background
Increasing global temperatures and unpredictable climatic extremes have contributed to the spread of vector-borne diseases. The mosquito Aedes aegypti is the main vector of multiple arboviruses that negatively impact human health, mostly in low socioeconomic areas of the world. Co-circulation and co-infection of these viruses in humans have been increasingly reported; however, how vectors contribute to this alarming trend remains unclear.
Methods
Here, we examine single and co-infection of Mayaro virus (D strain, Alphavirus) and dengue virus (serotype 2, Flavivirus) in Ae. aegypti adults and cell lines at two constant temperatures, moderate (27 °C) and hot (32 °C), to quantify vector competence and the effect of temperature on infection, dissemination and transmission, including on the degree of interaction between the two viruses.
Results
Both viruses were primarily affected by temperature but there was a partial interaction with co-infection. Dengue virus quickly replicates in adult mosquitoes with a tendency for higher titers in co-infected mosquitoes at both temperatures, and mosquito mortality was more severe at higher temperatures in all conditions. For dengue, and to a lesser extent Mayaro, vector competence and vectorial capacity were higher at hotter temperature in co- vs. single infections and was more evident at earlier time points (7 vs. 14 days post infection) for Mayaro. The temperature-dependent phenotype was confirmed in vitro by faster cellular infection and initial replication at higher temperatures for dengue but not for Mayaro virus.
Conclusions
Our study suggests that contrasting kinetics of the two viruses could be related to their intrinsic thermal requirements, where alphaviruses thrive better at lower temperatures compared to flaviviruses. However, more studies are necessary to clarify the role of co-infection at different temperature regimes, including under more natural temperature settings.
Graphical Abstract
... In recent decades, there have been multiple occurrences in which alphavirus, ZIKV, and flavivirus, CHIKV, outbreaks have been documented across various regions worldwide, specifically in urban settings with tropical/subtropical climates [70,72,[76][77][78][79][80][81][82][83][84][85][86][87][88]. The global distribution and ongoing global expansion of the vectors, namely Aedes aegypti and Aedes albopictus, have a significant impact on the disease burden [89][90][91]. ...
Zika virus (ZIKV) and chikungunya virus (CHIKV) are arthropod-borne viruses with significant pathogenicity, posing a substantial health and economic burden on a global scale. Moreover, ZIKV-CHIKV coinfection imposes additional therapeutic challenges as there is no specific treatment for ZIKV or CHIKV infection. While a growing number of studies have documented the ZIKV-CHIKV coinfection, there is currently a lack of conclusive reports on this coinfection. Therefore, we performed a systematic review and meta-analysis to determine the true statistics of ZIKV-CHIKV coinfection in the global human population. Relevant studies were searched for in PubMed, Scopus, and Google Scholar without limitation in terms of language or publication date. A total of 33 studies containing 41,460 participants were included in this meta-analysis. The study protocol was registered with PROSPERO under the registration number CRD42020176409. The pooled prevalence and confidence intervals of ZIKV-CHIKV coinfection were computed using a random-effects model. The study estimated a combined global prevalence rate of 1.0% [95% CI: 0.7–1.2] for the occurrence of ZIKV-CHIKV coinfection. The region of North America (Mexico, Haiti, and Nicaragua) and the country of Haiti demonstrated maximum prevalence rates of 2.8% [95% CI: 1.5–4.1] and 3.5% [95% CI: 0.2–6.8], respectively. Moreover, the prevalence of coinfection was found to be higher in the paediatric group (2.1% [95% CI: 0.0–4.2]) in comparison with the adult group (0.7% [95% CI: 0.2–1.1]). These findings suggest that the occurrence of ZIKV-CHIKV coinfection varies geographically and by age group. The results of this meta-analysis will guide future investigations seeking to understand the underlying reasons for these variations and the causes of coinfection and to develop targeted prevention and control strategies.
