Climate Change and Aedes Mosquito Vector: A Projection towards Future Scenario of Disease Transmission

The ecology and environmental conditions of a habitat have profound influences on mosquito population abundance. As a result, mosquito species vary in their associations with particular habitat types, yet long-term studies showing how mosquito populations shift in a changing ecological landscape are lacking. To better understand how land use changes influence mosquito populations, we examined mosquito surveillance data over a thirty-four-year period for two contrasting sites in central Iowa. One site displayed increasing levels of urbanization over time and a dramatic decline in Culex pipiens group (an informal grouping of Culex restuans, Culex pipiens, and Culex salinarius, referred to as CPG), the primary vectors of West Nile virus in central Iowa. Similar effects were also shown for other mosquito vector populations, yet the abundance of Aedes vexans remained constant during the study period. This is in contrast to a second site, which reflected an established urban landscape. At this location, there were no significant changes in land use and CPG populations remained constant. Climate data (temperature, total precipitation) were compiled for each location to see if these changes could account for altered population dynamics, but neither significantly influence CPG abundance at the respective site locations. Taken together, our data suggest that increased landscape development can have negative impacts on Culex vector populations, and we argue that long-term surveillance paired with satellite imagery analysis are useful methods for measuring the impacts of rapid human development on mosquito vector communities. As a result, we believe that land use changes can have important implications for mosquito management practices, population modeling, and disease transmission dynamics.

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Impact of recent climate extremes on mosquito-borne disease transmission in Kenya

PLoS Neglected Tropical Diseases ◽

10.1371/journal.pntd.0009182 ◽

2021 ◽

Vol 15 (3) ◽

pp. e0009182

Author(s):

Cameron Nosrat ◽

Jonathan Altamirano ◽

Assaf Anyamba ◽

Jamie M. Caldwell ◽

Richard Damoah ◽

...

Keyword(s):

Climate Change ◽

Disease Transmission ◽

Enzyme Linked Immunosorbent Assay ◽

Mosquito Abundance ◽

Targeted Interventions ◽

Extreme Climate Events ◽

Extreme Climate ◽

Recent Climate ◽

Climate Events ◽

The Impact

Climate change and variability influence temperature and rainfall, which impact vector abundance and the dynamics of vector-borne disease transmission. Climate change is projected to increase the frequency and intensity of extreme climate events. Mosquito-borne diseases, such as dengue fever, are primarily transmitted by Aedes aegypti mosquitoes. Freshwater availability and temperature affect dengue vector populations via a variety of biological processes and thus influence the ability of mosquitoes to effectively transmit disease. However, the effect of droughts, floods, heat waves, and cold waves is not well understood. Using vector, climate, and dengue disease data collected between 2013 and 2019 in Kenya, this retrospective cohort study aims to elucidate the impact of extreme rainfall and temperature on mosquito abundance and the risk of arboviral infections. To define extreme periods of rainfall and land surface temperature (LST), we calculated monthly anomalies as deviations from long-term means (1983–2019 for rainfall, 2000–2019 for LST) across four study locations in Kenya. We classified extreme climate events as the upper and lower 10% of these calculated LST or rainfall deviations. Monthly Ae. aegypti abundance was recorded in Kenya using four trapping methods. Blood samples were also collected from children with febrile illness presenting to four field sites and tested for dengue virus using an IgG enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR). We found that mosquito eggs and adults were significantly more abundant one month following an abnormally wet month. The relationship between mosquito abundance and dengue risk follows a non-linear association. Our findings suggest that early warnings and targeted interventions during periods of abnormal rainfall and temperature, especially flooding, can potentially contribute to reductions in risk of viral transmission.

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Population dynamics modelling : Impact of climate change on tick populations

Revue Africaine de la Recherche en Informatique et Mathématiques Appliquées ◽

10.46298/arima.2553 ◽

2016 ◽

Vol Volume 22 - 2016-2018 ◽

Author(s):

Leila Khouaja ◽

Slimane Ben Miled ◽

Hassan Hbid

Keyword(s):

Climate Change ◽

Disease Transmission ◽

Physiological State ◽

Good Prediction ◽

Disease Evolution ◽

Vector Borne Diseases ◽

Host Interaction ◽

Animaux Domestiques ◽

Vector Borne ◽

Dynamics Modelling

Epidemiology had an important development these last years allowing the resolution of a large number of problems and had good prediction on disease evolution. However, the transmission of several vector-borne diseases is closely connected to environmental protagonists, specially in the parasite-host interaction. Moreover, understanding the disease transmission is related to studying the ecology of all protagonists. These two levels of complexity(epidemiology and ecology) cannot be separated and have to be studied as a whole in a systematic way. Our goal is to understand the interaction of climate change on the evolution of a disease when the vector has ecological niche that depends on physiological state of development. We are particularly interested in tick vector diseases which are serious health problem affecting humans as well as domestic animals in many parts of the world. These infections are transmitted through a bite of an infected tick, and it appears that most of these infections are widely present in some wildlife species. L'épidémiologie a connu un développement important ces dernières années. Cette discipline a permis une meilleure compréhension del'évolution de maladies. Cependant, plusieurs maladies à transmission vectorielle sont étroitement liées aux protagonistes environnementaux. Ce constat est particulièrement vrai dans le contexte des interactions du parasite avec son hôte. De plus, comprendre la transmission de maladie est lié à l'étude de l'écologie de tous les protagonistes. Notre objectif est de comprendre l'influence du changement climatique sur l'évolution des maladies lorsque la niche écologique du vecteur dépend de l'état de développement physiologique de son hôte. Nous sommes particulièrement intéressés par les maladies vectorielles à tiques qui constituent un grave problème de santé touchant l'être humain et les animaux domestiques dans de nombreuses régions du monde. Ces infections sont généralement transmises par la piqûre d'une tique infectée et il apparaît que la plupart de ces infections sont largement présentées dans certaines espèces fauniques

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Waterborne Diseases and Climate Change: Impact and Implications

Climate Change and Environmental Concerns ◽

10.4018/978-1-5225-5487-5.ch024 ◽

2018 ◽

pp. 469-484

Author(s):

Maha Bouzid

Keyword(s):

Climate Change ◽

Developing Countries ◽

Disease Transmission ◽

Waterborne Diseases ◽

Vector Borne Diseases ◽

Significant Burden ◽

Change Impact ◽

Vector Borne ◽

The Impact ◽

Adaptation Options

Waterborne diseases are caused by a multitude of pathogens and associated with a significant burden in both developed and developing countries. While the assessment of the adverse impacts of climate change on human heath from infectious diseases has mainly focused on vector-borne diseases, waterborne diseases prevalence and transmission patterns are also likely to be impacted by environmental change. This chapter will outline relevant waterborne pathogens, summarise the impact of climate change on disease transmission and explore climate change adaptation options in order to reduce the increased burden of waterborne diseases.

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Waterborne Diseases and Climate Change

Natural Resources Management ◽

10.4018/978-1-5225-0803-8.ch049 ◽

2017 ◽

pp. 1041-1055

Author(s):

Maha Bouzid

Keyword(s):

Climate Change ◽

Developing Countries ◽

Disease Transmission ◽

Waterborne Diseases ◽

Waterborne Pathogens ◽

Vector Borne Diseases ◽

Significant Burden ◽

Vector Borne ◽

The Impact ◽

Adaptation Options

Waterborne diseases are caused by a multitude of pathogens and associated with a significant burden in both developed and developing countries. While the assessment of the adverse impacts of climate change on human heath from infectious diseases has mainly focused on vector-borne diseases, waterborne diseases prevalence and transmission patterns are also likely to be impacted by environmental change. This chapter will outline relevant waterborne pathogens, summarise the impact of climate change on disease transmission and explore climate change adaptation options in order to reduce the increased burden of waterborne diseases.

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Using Gene Drive Technologies to Control Vector-Borne Infectious Diseases

Sustainability ◽

10.3390/su10124789 ◽

2018 ◽

Vol 10 (12) ◽

pp. 4789 ◽

Cited By ~ 1

Author(s):

Stephanie James ◽

Karen Tountas

Keyword(s):

Disease Transmission ◽

Sub Saharan Africa ◽

Reproductive Capacity ◽

World Health ◽

Mosquito Vector ◽

Gene Drive ◽

African Region ◽

Safety Testing ◽

Malaria Burden ◽

Health Organization

After years of success in reducing the global malaria burden, the World Health Organization (WHO) recently reported that progress has stalled. Over 90% of malaria deaths world-wide occurred in the WHO African Region. New tools are needed to regain momentum and further decrease the burden of malaria. Gene drive, an emerging technology that can enhance the inheritance of beneficial genes, offers potentially transformative solutions for overcoming these challenges. Gene drives may decrease disease transmission by interfering with the growth of the malaria parasite in the mosquito vector or reducing mosquito reproductive capacity. Like other emerging technologies, development of gene drive products faces technical and non-technical challenges and uncertainties. In 2018, to begin addressing such challenges, a multidisciplinary group of international experts published comprehensive recommendations for responsible testing and implementation of gene drive-modified mosquitoes to combat malaria in Sub-Saharan Africa. Considering requirements for containment, efficacy and safety testing, monitoring, stakeholder engagement and authorization, as well as policy and regulatory issues, the group concluded that gene drive products for malaria can be tested safely and ethically, but that this will require substantial coordination, planning, and capacity development. The group emphasized the importance of co-development and co-ownership of products by in-country scientists.

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The influence of climate change on waterborne disease and Legionella: a review

Perspectives in Public Health ◽

10.1177/1757913918791198 ◽

2018 ◽

Vol 138 (5) ◽

pp. 282-286 ◽

Cited By ~ 17

Author(s):

JT Walker

Keyword(s):

Climate Change ◽

Disease Transmission ◽

Local Level ◽

Extreme Weather ◽

Extreme Weather Events ◽

Waterborne Diseases ◽

Sea Levels ◽

The Earth ◽

Weather Events ◽

Rising Sea Levels

Climate change is predicted to have a major impact on people’s lives with the recent extreme weather events and varying abnormal temperature profiles across the world raising concerns. The impacts of global warming are already being observed, from rising sea levels and melting snow and ice to changing weather patterns. Scientists state unequivocally that these trends cannot be explained by natural variability in climate alone. Human activities, especially the burning of fossil fuels, have warmed the earth by dramatically increasing concentrations of heat-trapping gases in the atmosphere; as these concentrations increase, the more the earth will warm. Climate change and related extreme weather events are being exacerbated sooner than has previously been considered and are already adversely affecting ecosystems and human health by increasing the burden and type of disease at a local level. Changes to the marine environment and freshwater supplies already affect significant parts of the world’s population and warmer temperatures, especially in more temperate regions, may see an increased spread and transmission of diseases usually associated with warmer climes including, for example, cholera and malaria; these impacts are likely to become more severe in a greater number of countries. This review discusses the impacts of climate change including changes in infectious disease transmission, patterns of waterborne diseases and the likely consequences of climate change due to warmer water, drought, higher rainfall, rising sea levels and flooding.

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Climate, environmental and socio-economic change: weighing up the balance in vector-borne disease transmission

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2013.0551 ◽

2015 ◽

Vol 370 (1665) ◽

pp. 20130551 ◽

Cited By ~ 114

Author(s):

Paul E. Parham ◽

Joanna Waldock ◽

George K. Christophides ◽

Deborah Hemming ◽

Folashade Agusto ◽

...

Keyword(s):

Climate Change ◽

Disease Transmission ◽

Disease Burden ◽

Current Knowledge ◽

Vector Borne Diseases ◽

Data Limitations ◽

Vector Borne ◽

Research Questions ◽

Potential Impact ◽

Socio Economic Factors

Arguably one of the most important effects of climate change is the potential impact on human health. While this is likely to take many forms, the implications for future transmission of vector-borne diseases (VBDs), given their ongoing contribution to global disease burden, are both extremely important and highly uncertain. In part, this is owing not only to data limitations and methodological challenges when integrating climate-driven VBD models and climate change projections, but also, perhaps most crucially, to the multitude of epidemiological, ecological and socio-economic factors that drive VBD transmission, and this complexity has generated considerable debate over the past 10–15 years. In this review, we seek to elucidate current knowledge around this topic, identify key themes and uncertainties, evaluate ongoing challenges and open research questions and, crucially, offer some solutions for the field. Although many of these challenges are ubiquitous across multiple VBDs, more specific issues also arise in different vector–pathogen systems.

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The impact of temperature changes on vector-borne disease transmission: Culicoides midges and bluetongue virus

Journal of The Royal Society Interface ◽

10.1098/rsif.2016.0481 ◽

2017 ◽

Vol 14 (128) ◽

pp. 20160481 ◽

Cited By ~ 19

Author(s):

Samuel P. C. Brand ◽

Matt J. Keeling

Keyword(s):

Climate Change ◽

Life Expectancy ◽

Disease Transmission ◽

Bluetongue Virus ◽

Optimal Temperature ◽

Climatic Fluctuations ◽

Transmission Potential ◽

Vector Borne ◽

The Uk ◽

The Impact

It is a long recognized fact that climatic variations, especially temperature, affect the life history of biting insects. This is particularly important when considering vector-borne diseases, especially in temperate regions where climatic fluctuations are large. In general, it has been found that most biological processes occur at a faster rate at higher temperatures, although not all processes change in the same manner. This differential response to temperature, often considered as a trade-off between onward transmission and vector life expectancy, leads to the total transmission potential of an infected vector being maximized at intermediate temperatures. Here we go beyond the concept of a static optimal temperature, and mathematically model how realistic temperature variation impacts transmission dynamics. We use bluetongue virus (BTV), under UK temperatures and transmitted by Culicoides midges, as a well-studied example where temperature fluctuations play a major role. We first consider an optimal temperature profile that maximizes transmission, and show that this is characterized by a warm day to maximize biting followed by cooler weather to maximize vector life expectancy. This understanding can then be related to recorded representative temperature patterns for England, the UK region which has experienced BTV cases, allowing us to infer historical transmissibility of BTV, as well as using forecasts of climate change to predict future transmissibility. Our results show that when BTV first invaded northern Europe in 2006 the cumulative transmission intensity was higher than any point in the last 50 years, although with climate change such high risks are the expected norm by 2050. Such predictions would indicate that regular BTV epizootics should be expected in the UK in the future.

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Effect of wall type, delayed mortality and mosquito age on the residual efficacy of a clothianidin-based indoor residual spray formulation (SumiShield™ 50WG) in southern Mozambique

PLoS ONE ◽

10.1371/journal.pone.0248604 ◽

2021 ◽

Vol 16 (8) ◽

pp. e0248604

Author(s):

Helena Marti-Soler ◽

Mara Máquina ◽

Mercy Opiyo ◽

Celso Alafo ◽

Ellie Sherrard-Smith ◽

...

Keyword(s):

Vector Control ◽

Disease Transmission ◽

Indoor Residual Spraying ◽

World Health ◽

Malaria Vector Control ◽

Mosquito Vector ◽

Post Exposure ◽

Mosquito Mortality ◽

Residual Efficacy ◽

Delayed Mortality

Indoor residual spraying (IRS) is one of the main malaria vector control strategies in Mozambique alongside the distribution of insecticide treated nets. As part of the national insecticide resistance management strategy, Mozambique introduced SumiShield™ 50WG, a third generation IRS product, in 2018. Its residual efficacy was assessed in southern Mozambique during the 2018–2019 malaria season. Using a susceptible Anopheles arabiensis strain, residual efficacy was assessed on two different wall surfaces, cement and mud-plastered walls, using standard WHO (World Health Organization) cone bioassay tests at three different heights. Female mosquitoes of two age groups (2–5 and 13–26 day old) were exposed for 30 minutes, after which mortality was observed 24h, 48h, 72h, and 96h and 120h post-exposure to assess (delayed) mortality. Lethal times (LT) 90, LT50 and LT10 were estimated using Bayesian models. Mortality 24h post exposure was consistently below 80%, the current WHO threshold value for effective IRS, in both young and old mosquitoes, regardless of wall surface type. Considering delayed mortality, residual efficacies (mosquito mortality equal or greater than 80%) ranged from 1.5 to ≥12.5 months, with the duration depending on mortality time post exposure, wall type and mosquito age. Looking at mortality 72h after exposure, residual efficacy was between 6.5 and 9.5 months, depending on wall type and mosquito age. The LT50 and LT10 (i.e. 90% of the mosquitoes survive exposure to the insecticides) values were consistently higher for older mosquitoes (except for LT10 values for 48h and 72h post-exposure mortality) and ranged from 0.9 to 5.8 months and 0.2 to 7.8 months for LT50 and LT10, respectively. The present study highlights the need for assessing mosquito mortality beyond the currently recommended 24h post exposure. Failure to do so may lead to underestimation of the residual efficacy of IRS products, as delayed mortality will lead to a further reduction in mosquito vector populations and potentially negatively impact disease transmission. Monitoring residual efficacy on relevant wall surfaces, including old mosquitoes that are ultimately responsible for malaria transmission, and assessing delayed mortalities are critical to provide accurate and actionable data to guide vector control programmes.

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