scholarly journals Identify and Predict Environmental Change Effects On Tiger Mosquitos, Aedes Polynesiensis

2018 ◽  
Author(s):  
Florian Grziwotz ◽  
Jakob Friedrich Strauß ◽  
Chih-hao Hsieh ◽  
Arndt Telschow
Keyword(s):  
Environmental Variables ◽  
Dynamic Modelling ◽  
Dew Point ◽  
Vector Ecology ◽  
Vector Borne Diseases ◽  
Natural Systems ◽  
Close Proximity ◽  
Vector Borne ◽  
Aedes Polynesiensis ◽  
New Framework

SummaryTo control mosquito populations for managing vector-borne diseases, a critical need is to identify and predict their response to causal environmental variables. However, most existing attempts rely on linear approaches based on correlation, which cannot apply in complex, nonlinear natural systems, because correlation is neither a necessary nor sufficient condition for causation. Appling empirical dynamic modelling that acknowledges nonlinear dynamics on nine subpopulations of tiger mosquitos from three neighbouring reef islets of the Raiatea atoll, we identified temperature, precipitation, dew point, air pressure, and mean tide level as causal environmental variables. Interestingly, responses of subpopulations in close proximity (100-500 m) differed with respect to their causal environmental variables and the time delay of effect, highlighting complexity in mosquito-environment causality network. Moreover, we demonstrated how to explore the effects of changing environmental variables on number and strength of mosquito outbreaks, providing a new framework for pest control and disease vector ecology.

Incorporating Vector Ecology and Life History into Disease Transmission Models: Insights from Tsetse (Glossina spp.)

2020 ◽  
pp. 175-188
Author(s):  
Sinead English ◽  
Antoine M.G. Barreaux ◽  
Michael B. Bonsall ◽  
John W. Hargrove ◽  
Matt J. Keeling ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Laboratory Data ◽  
Maternal Investment ◽  
Disease Spread ◽  
Vector Ecology ◽  
Vector Borne Diseases ◽  
Extensive Field ◽  
Survival And Reproduction ◽  
Vector Borne ◽  
And Control

Accurate models are crucial for predicting the spread of vector-borne diseases, and for developing appropriate control policies. Simple models often ignore finer details of vector biology, commonly due to lack of pertinent field data. However, for tsetse (Glossina spp), vectors of the parasites causing debilitating human and livestock trypanosomiasis in Africa, extensive field and laboratory data facilitate improved models and predictions of vector control outcomes. We review studies on the effects of environmental temperature, and fly age and sex, on survival and reproduction in tsetse, savannah species particularly–emphasizing the extreme maternal investment and sensitivity of early life stages to high temperatures. We consider implications of these results for predictive models of tsetse populations, and of the transmission and control of African trypanosomiasis. We discuss how further research on vectors, and improved models of vector populations and disease dynamics, can lead to improved predictions of vector abundance and disease spread.

scholarly journals The ecological and epidemiological consequences of reproductive interference between the vectors Aedes aegypti and Aedes albopictus

2019 ◽  
Vol 16 (156) ◽  
pp. 20190270 ◽  
Author(s):  
Robert S. Paton ◽  
Michael B. Bonsall
Keyword(s):  
Aedes Aegypti ◽  
Aedes Albopictus ◽  
Reproductive Interference ◽  
Larval Competition ◽  
Vector Ecology ◽  
Vector Borne Diseases ◽  
Behavioural Responses ◽  
Competitive Mechanisms ◽  
Vector Borne ◽  
Mosquito Population Dynamics

Vector ecology is integral to understanding the transmission of vector-borne diseases, with processes such as reproduction and competition pivotal in determining vector presence and abundance. The arbovirus vectors Aedes aegypti and Aedes albopictus compete as larvae, but this mechanism is insufficient to explain patterns of coexistence and exclusion. Inviable interspecies matings—known as reproductive interference—is another candidate mechanism. Here, we analyse mathematical models of mosquito population dynamics and epidemiology which include two Aedes -specific features of reproductive interference. First, as these mosquitoes use hosts to find mates, reproductive interference will only occur if the same host is visited. Host choice will, in turn, be determined by behavioural responses to host availability. Second, females can become sterilized after mis-mating with heterospecifics. We find that a species with an affinity for a shared host will suffer more from reproductive interference than a less selective competitor. Costs from reproductive interference can be ‘traded-off’ against costs from larval competition, leading to competitive outcomes that are difficult to predict from empirical evidence. Sterilizations of a self-limiting species can counterintuitively lead to higher densities than a competitor suffering less sterilization. We identify that behavioural responses and reproductive interference mediate a concomitant relationship between vector ecological dynamics and epidemiology. Competitors with opposite behavioural responses can maintain disease where human hosts are rare, due to vector coexistence facilitated by a reduced cost from reproductive interference. Our work elucidates the relative roles of the competitive mechanisms governing Aedes populations and the associated epidemiological consequences.

scholarly journals Predicting the effect of climate change on African trypanosomiasis: integrating epidemiology with parasite and vector biology

2011 ◽  
Vol 9 (70) ◽  
pp. 817-830 ◽  
Author(s):  
Sean Moore ◽  
Sourya Shrestha ◽  
Kyle W. Tomlinson ◽  
Holly Vuong
Keyword(s):  
Climate Change ◽  
Disease Transmission ◽  
Transmission Model ◽  
Future Research ◽  
African Trypanosomiasis ◽  
Vector Biology ◽  
Vector Ecology ◽  
Large Shift ◽  
Vector Borne Diseases ◽  
Vector Borne

Climate warming over the next century is expected to have a large impact on the interactions between pathogens and their animal and human hosts. Vector-borne diseases are particularly sensitive to warming because temperature changes can alter vector development rates, shift their geographical distribution and alter transmission dynamics. For this reason, African trypanosomiasis (sleeping sickness), a vector-borne disease of humans and animals, was recently identified as one of the 12 infectious diseases likely to spread owing to climate change. We combine a variety of direct effects of temperature on vector ecology, vector biology and vector–parasite interactions via a disease transmission model and extrapolate the potential compounding effects of projected warming on the epidemiology of African trypanosomiasis. The model predicts that epidemics can occur when mean temperatures are between 20.7°C and 26.1°C. Our model does not predict a large-range expansion, but rather a large shift of up to 60 per cent in the geographical extent of the range. The model also predicts that 46–77 million additional people may be at risk of exposure by 2090. Future research could expand our analysis to include other environmental factors that influence tsetse populations and disease transmission such as humidity, as well as changes to human, livestock and wildlife distributions. The modelling approach presented here provides a framework for using the climate-sensitive aspects of vector and pathogen biology to predict changes in disease prevalence and risk owing to climate change.

scholarly journals The ecological and epidemiological consequences of reproductive interference between the vectors Aedes aegypti and Aedes albopictus

2019 ◽  
Author(s):  
Robert S Paton ◽  
Michael B Bonsall
Keyword(s):  
Aedes Aegypti ◽  
Aedes Albopictus ◽  
Reproductive Interference ◽  
Larval Competition ◽  
Vector Ecology ◽  
Functional Responses ◽  
Vector Borne Diseases ◽  
Competitive Mechanisms ◽  
Vector Borne ◽  
Mosquito Population Dynamics

AbstractVector ecology is integral to understanding the transmission of vector-borne diseases, with processes such as reproduction and competition pivotal in determining vector presence and abundance. The arbovirus vectors Aedes aegypti and Aedes albopictus compete as larvae, but this mechanism is insufficient to explain patterns of coexistence and exclusion. Inviable interspecies matings - known as reproductive interference - is another candidate mechanism. Here, we analyse mathematical models of mosquito population dynamics and epidemiology which include two Aedes-specific features of reproductive interference. First, as these mosquitoes use hosts to find mates, reproductive interference will only occur if the same host is visited. Host choice will, in turn, be determined by functional responses to host availability. Second, females can become sterilised after mis-mating with heterospecifics. We find that a species with an affinity for a shared host will suffer more from reproductive interference than a less selective competitor. Costs from reproductive interference can be “traded-off” against costs from larval competition, leading to competitive outcomes difficult to predict from empirical evidence. Sterilisations of a self-limiting species can counter-intuitively lead to higher densities than a competitor suffering less sterilisation. We identify that functional responses and reproductive interference mediate a concomitant relationship between vector ecological dynamics and epidemiology. Competitors with opposite functional responses can maintain disease where human hosts are rare, due to vector coexistence facilitated by a reduced cost from reproductive interference. Our work elucidates the relative roles of the competitive mechanisms governing Aedes populations and the associated epidemiological consequences.

The Spread of Mosquito Borne Disease – Is Climate Change Beginning to Bite?

2019 ◽  
Vol 30 (5) ◽  
pp. 192-194
Author(s):  
John (Luke) Lucas
Keyword(s):  
Climate Change ◽  
Vector Borne Diseases ◽  
Vector Borne

The author considers the threat to vector-borne diseases in the light of climate change.

The Scientific Basis for the Prevention of Zooanthroponoze Vector-Borne Diseases Spread by Parasitic Arthropods of the Center of the East European Plain

2020 ◽  
Vol 14 (1) ◽  
pp. 81-88
Author(s):  
Fedor I. Vasilevich ◽  
Anna M. Nikanorova
Keyword(s):  
Mathematical Models ◽  
Culex Pipiens ◽  
Preventive Measures ◽  
Mosquito Species ◽  
Natural Habitat ◽  
Piperonyl Butoxide ◽  
East European Plain ◽  
Vector Borne Diseases ◽  
Vector Borne ◽  
Kaluga Region

The purpose of the research is development of preventive measures against zooanthroponoze vector-borne diseases spread by parasitic arthropods in the Kaluga Region. Materials and methods. The subject of the research was Ixodidae, mosquitoes, and small mammals inhabiting the Kaluga Region. The census of parasitic arthropods was carried out on the territory of all districts of the Kaluga Region and the city of Kaluga. Open natural habitat and human settlements were investigated. Weather conditions from 2013 to 2018 were also taken into account. For the purposes of the study, we used standard methods for capturing and counting arthropods and mouse-like rodents. In order to obtain mathematical models of small mammal populations, a full factorial experiment was conducted using the collected statistical data. In-process testing of the drug based on s-fenvalerate and piperonyl butoxide were carried out under the conditions of the agricultural collective farm “Niva” of the Kozelsky District, the Kaluga Region, and LLC “Angus Center of Genetics” of the Babyninsky District, the Kaluga Region. Results and discussion. In the Kaluga Region, two species of ixodic ticks are found, namely, Ixodes ricinus and Dermacentor reticulatus, which have two activity peaks. Mosquito may have 3-4 generations in a year in the Kaluga region. The most common mosquito species in the Kaluga Region are Aedes communis, Ae. (Och.) togoi and Ae. (Och.) diantaeus, Culex pipiens Culex Linnaeus, 1758 (Diptera, Culicidae) (Culex pipiens): Cx. pipiens f. pipiens L. (non-autogenic form) and Cx. p. f. molestus Fors. (autogenic form), which interbreed, and reproductively isolated in the Region. The developed mathematical models make it possible to quantify the risks of outbreaks of zooanthroponoze vector-borne diseases without the cost of field research, and allow for rational, timely and effective preventive measures. Medications based on s-fenvalerate and piperonyl butoxide and based on cyfluthrin showed high insecto-acaricidal efficacy and safety.

Current Challenges in the Development of Vaccines and Drugs Against Emerging Vector-borne Diseases

2019 ◽  
Vol 26 (16) ◽  
pp. 2974-2986 ◽  
Author(s):  
Kwang-sun Kim
Keyword(s):  
New Host ◽  
In Vivo Models ◽  
Vector Borne Diseases ◽  
Novel Drugs ◽  
Huge Impact ◽  
Tick Borne Disease ◽  
Vector Borne ◽  
Living Organisms

Vectors are living organisms that transmit infectious diseases from an infected animal to humans or another animal. Biological vectors such as mosquitoes, ticks, and sand flies carry pathogens that multiply within their bodies prior to delivery to a new host. The increased prevalence of Vector-Borne Diseases (VBDs) such as Aedes-borne dengue, Chikungunya (CHIKV), Zika (ZIKV), malaria, Tick-Borne Disease (TBD), and scrub typhus has a huge impact on the health of both humans and livestock worldwide. In particular, zoonotic diseases transmitted by mosquitoes and ticks place a considerable burden on public health. Vaccines, drugs, and vector control methods have been developed to prevent and treat VBDs and have prevented millions of deaths. However, development of such strategies is falling behind the rapid emergence of VBDs. Therefore, a comprehensive approach to fighting VBDs must be considered immediately. In this review, I focus on the challenges posed by emerging outbreaks of VBDs and discuss available drugs and vaccines designed to overcome this burden. Research into promising drugs needs to be upgraded and fast-tracked, and novel drugs or vaccines being tested in in vitro and in vivo models need to be moved into human clinical trials. Active preventive tactics, as well as new and upgraded diagnostics, surveillance, treatments, and vaccination strategies, need to be monitored constantly if we are to manage VBDs of medical importance.

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