scholarly journals Understanding the effect of temperature on Bluetongue disease risk in livestock

2019 ◽  
Author(s):  
Fadoua El Moustaid ◽  
Zorian Thronton ◽  
Hani Slamani ◽  
Sadie J. Ryan ◽  
Leah R. Johnson
Keyword(s):  
Disease Risk ◽  
Vector Competence ◽  
Basic Reproductive Number ◽  
Effect Of Temperature ◽  
Reproductive Number ◽  
Temperature Sensitive ◽  
Modeling Tools ◽  
Vector Borne Diseases ◽  
Thermal Range ◽  
Vector Borne

AbstractThe transmission of vector-borne diseases is governed by complex factors including pathogen characteristics, vector-host interactions, and environmental conditions. Temperature is a major driver for many vector-borne diseases including Bluetongue viral (BTV) disease, a midge-borne febrile disease of ruminants, notably livestock, whose etiology ranges from mild or asymptomatic to rapidly fatal, thus threatening animal agriculture and the economy of affected countries. Using modeling tools, we seek to predict where transmission can occur based on suitable temperatures for BTV. We fit thermal performance curves to temperature sensitive midge life history traits, using a Bayesian approach. Then, we incorporated these into a new formula for the disease basic reproductive number, R0, to include trait responses, for two species of key midge vectors, Culicoides sonorensis and Culicoides variipennis. Our results show that outbreaks of BTV are more likely between 15°C and 33°C with predicted peak transmission at 26°C. The greatest uncertainty in R0 is associated with the uncertainty in: mortality and fecundity of midges near optimal temperature for transmission; midges’ probability of becoming infectious post infection at the lower edge of the thermal range; and the biting rate together with vector competence at the higher edge of the thermal range. We compare our R0 to two other R0 formulations and show that incorporating thermal curves into all three leads to similar BTV risk predictions. To demonstrate the utility of this model approach, we created global suitability maps indicating the areas at high and long-term risk of BTV transmission, to assess risk, and anticipate potential locations of establishment.

scholarly journals Predicting temperature-dependent transmission suitability of bluetongue virus in livestock

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Fadoua El Moustaid ◽  
Zorian Thornton ◽  
Hani Slamani ◽  
Sadie J. Ryan ◽  
Leah R. Johnson
Keyword(s):  
Vector Competence ◽  
Transmission Risk ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Temperature Sensitive ◽  
Temperature Dependent ◽  
Modeling Tools ◽  
Vector Borne Diseases ◽  
Thermal Range ◽  
Vector Borne

AbstractThe transmission of vector-borne diseases is governed by complex factors including pathogen characteristics, vector–host interactions, and environmental conditions. Temperature is a major driver for many vector-borne diseases including Bluetongue viral (BTV) disease, a midge-borne febrile disease of ruminants, notably livestock, whose etiology ranges from mild or asymptomatic to rapidly fatal, thus threatening animal agriculture and the economy of affected countries. Using modeling tools, we seek to predict where the transmission can occur based on suitable temperatures for BTV. We fit thermal performance curves to temperature-sensitive midge life-history traits, using a Bayesian approach. We incorporate these curves into S(T), a transmission suitability metric derived from the disease’s basic reproductive number, $$R_0.$$ R 0 . This suitability metric encompasses all components that are known to be temperature-dependent. We use trait responses for two species of key midge vectors, Culicoides sonorensis and Culicoides variipennis present in North America. Our results show that outbreaks of BTV are more likely between 15$$^{\circ }$$ ∘ C and $$34^{\circ }\hbox { C}$$ 34 ∘ C , with predicted peak transmission risk at 26 $$^\circ$$ ∘  C. The greatest uncertainty in S(T) is associated with the following: the uncertainty in mortality and fecundity of midges near optimal temperature for transmission; midges’ probability of becoming infectious post-infection at the lower edge of the thermal range; and the biting rate together with vector competence at the higher edge of the thermal range. We compare three model formulations and show that incorporating thermal curves into all three leads to similar BTV risk predictions. To demonstrate the utility of this modeling approach, we created global suitability maps indicating the areas at high and long-term risk of BTV transmission, to assess risk and to anticipate potential locations of disease establishment.

Impact of climate factors on contact rate of vector-borne diseases: Case study of malaria

2016 ◽  
Vol 10 (01) ◽  
pp. 1750005 ◽  
Author(s):  
Ezekiel Dangbé ◽  
Antoine Perasso ◽  
Damakoa Irépran ◽  
David Békollé
Keyword(s):  
Environmental Changes ◽  
Temporal Distribution ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Contact Rate ◽  
Vector Borne Diseases ◽  
Transmission Period ◽  
Vector Borne ◽  
The Stability ◽  
The Impact

Climate change influences more and more of our activities. These changes led to environmental changes which has in turn affected the spatial and temporal distribution of the incidence of vector-borne diseases. To establish the impact of climate on contact rate of vector-borne diseases, we examine the variation of prevalence of diseases according to season. In this paper, the goal is to establish that the basic reproductive number [Formula: see text] depends on the duration of transmission period and the date of the first conta-mination case that was declared ([Formula: see text]) in the specific case of malaria. We described the dynamics of transmission of malaria by using non-autonomous differential equations. We analyzed the stability of endemic equilibrium (EE) and disease-free equilibrium (DFE). We prove that the persistence of disease depends on minimum and maximum values of contact rate of vector-borne diseases.

scholarly journals Huanglongbing Model under the Control Strategy of Discontinuous Removal of Infected Trees

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1164
Author(s):  
Weiwei Ling ◽  
Pinxia Wu ◽  
Xiumei Li ◽  
Liangjin Xie
Keyword(s):  
Infectious Disease ◽  
Global Stability ◽  
Control Strategy ◽  
Theoretical Basis ◽  
Dynamic Properties ◽  
Transmission Mechanism ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Vector Borne ◽  
Citrus Trees

By using differential equations with discontinuous right-hand sides, a dynamic model for vector-borne infectious disease under the discontinuous removal of infected trees was established after understanding the transmission mechanism of Huanglongbing (HLB) disease in citrus trees. Through calculation, the basic reproductive number of the model can be attained and the properties of the model are discussed. On this basis, the existence and global stability of the calculated equilibria are verified. Moreover, it was found that different I0 in the control strategy cannot change the dynamic properties of HLB disease. However, the lower the value of I0, the fewer HLB-infected citrus trees, which provides a theoretical basis for controlling HLB disease and reducing expenditure.

scholarly journals Stability and Hopf Bifurcation of a Vector-Borne Disease Model with Saturated Infection Rate and Reinfection

2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Zhixing Hu ◽  
Shanshan Yin ◽  
Hui Wang
Keyword(s):  
Hopf Bifurcation ◽  
Infection Rate ◽  
Disease Model ◽  
Endemic Equilibrium ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Cure Rate ◽  
Vector Borne Disease ◽  
Vector Borne ◽  
The Stability

This paper established a delayed vector-borne disease model with saturated infection rate and cure rate. First of all, according to the basic reproductive number R0, we determined the disease-free equilibrium E0 and the endemic equilibrium E1. Through the analysis of the characteristic equation, we consider the stability of two equilibriums. Furthermore, the effect on the stability of the endemic equilibrium E1 by delay was studied, the existence of Hopf bifurcations of this system in E1 was analyzed, and the length of delay to preserve stability was estimated. The direction and stability of the Hopf bifurcation were also been determined. Finally, we performed some numerical simulation to illustrate our main results.

scholarly journals Mosquito diversity and dog heartworm prevalence in suburban areas

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Meredith R. Spence Beaulieu ◽  
Jennifer L. Federico ◽  
Michael H. Reiskind
Keyword(s):  
Disease Transmission ◽  
Disease Risk ◽  
Mosquito Species ◽  
Negative Relationship ◽  
Global Scale ◽  
Vector Borne Diseases ◽  
Suburban Areas ◽  
Host Seeking ◽  
Vector Borne ◽  
Wake County

Abstract Background Urbanization is occurring rapidly on a global scale and is altering mosquito communities, creating assemblages that are characteristically less diverse. Despite high rates of urbanization and ample examples of vector-borne diseases transmitted by multiple species, the effects of urbanization-driven mosquito diversity losses on disease transmission has not been well explored. We investigated this question using the dog heartworm, a filarial parasite vectored by numerous mosquito species. Methods We trapped host-seeking mosquitoes in undeveloped areas and neighborhoods of different ages in Wake County, North Carolina, USA, analyzing captured mosquitoes for heartworm DNA. We compared within-mosquito heartworm infection across land-use types by Kruskal–Wallis and likelihood ratio tests. Using zip code level data acquired from dogs in a local shelter, we performed linear regressions of within-host heartworm prevalence by within-mosquito heartworm prevalence as well as by three mosquito diversity measures. We also determined the best predictor of host-level prevalence among models including within-mosquito infection, mosquito diversity and abundance, and socioeconomic status as variables. Results Suburban areas had lower within-mosquito heartworm prevalence and lower likelihood of heartworm-positive mosquitoes than did undeveloped field sites, although no differences were seen between suburban and undeveloped wooded sites. No relationships were noted between within-mosquito and within-host heartworm prevalence. However, mosquito diversity metrics were positively correlated with host heartworm prevalence. Model selection revealed within-host prevalence was best predicted by a positive relationship with mosquito Shannon–Wiener diversity and a negative relationship with household income. Conclusions Our results demonstrate that decreases in mosquito diversity due to urbanization alter vector-borne disease risk. With regard to dog heartworm disease, this loss of mosquito diversity is associated with decreased heartworm prevalence within both the vector and the host. Although the response is likely different for diseases transmitted by one or few species, mosquito diversity losses leading to decreased transmission could be generalizable to other pathogens with multiple vectors. This study contributes to better understanding of the effects of urbanization and the role of vector diversity in multi-vectored pathosystems.

scholarly journals Early determination of the reproductive number for vector-borne diseases: the case of dengue in Brazil

2006 ◽  
Vol 11 (3) ◽  
pp. 332-340 ◽  
Author(s):  
C. Favier ◽  
N. Degallier ◽  
M. G. Rosa-Freitas ◽  
J. P. Boulanger ◽  
J. R. Costa Lima ◽  
...  
Keyword(s):  
Reproductive Number ◽  
Vector Borne Diseases ◽  
Vector Borne

scholarly journals Successive Bloodmeals Enhance Virus Dissemination Within Mosquitoes And Increase Transmission Potential

2018 ◽  
Author(s):  
Philip M. Armstrong ◽  
Hanna Ehrlich ◽  
Angela Bransfield ◽  
Joshua L. Warren ◽  
Virginia E. Pitzer ◽  
...  
Keyword(s):  
Vector Competence ◽  
Basic Reproductive Number ◽  
Reproductive Number ◽  
Transmission Potential ◽  
The Public ◽  
Virus Dissemination ◽  
Virus Escape ◽  
Extrinsic Incubation Period ◽  
And Behavior ◽  
Transmission Status

SUMMARY PARAGRAPHThe recent Zika virus (ZIKV) and chikungunya virus (CHIKV) epidemics highlight the explosive nature of arthropod-borne (arbo) viruses transmitted by Aedes aegypti mosquitoes1,2. Vector competence and the extrinsic incubation period (EIP) are two key entomological parameters used to assess the public health risk posed by arboviruses3. These are typically measured empirically by offering mosquitoes an infectious bloodmeal and temporally sampling mosquitoes to determine infection and transmission status. This approach has been used for the better part of a century; however, it does not accurately capture the biology and behavior of many mosquito vectors which refeed frequently (every 2-3 days)4. Here we demonstrate that administration of a second non-infectious bloodmeal significantly shortens the EIP of ZIKV-infected Ae. aegypti by enhancing virus escape from the mosquito midgut. Similarly, a second bloodmeal increased the competence of this species for dengue virus and CHIKV. This effect was also observed for ZIKV in Aedes albopictus, suggesting that this species might be a more important vector than once thought and that this phenomenon may be common among other virus-vector pairings. Modeling of these findings reveals that a shortened EIP would result in a significant increase in the basic reproductive number, R0. This increase helps explain how Ae.aegypti can sustain an explosive epidemic like ZIKV despite its relatively poor vector competence in single-feed laboratory trials. Together, these data demonstrate a direct and unrecognized link between mosquito feeding behavior, EIP, and vector competence.

scholarly journals Borrelia infection in rodent host has dramatic effects on the microbiome of ticks

2021 ◽  
Author(s):  
Phineas T. Hamilton ◽  
Elodie Maluenda ◽  
Anouk Sarr ◽  
Alessandro Belli ◽  
Georgia Hurry ◽  
...  
Keyword(s):  
Large Scale ◽  
Vector Competence ◽  
Bacterial Community Composition ◽  
Blood Feeding ◽  
Rodent Host ◽  
Vector Borne Diseases ◽  
Bacterial Microbiome ◽  
Vector Borne ◽  
Scale Experiment ◽  
Tick Microbiome

AbstractBackgroundVector-borne diseases remain major causes of human morbidity and mortality. It is increasingly recognized that the community of microbes inhabiting arthropods can strongly affect their vector competence, but the role of the tick microbiome in Borrelia transmission – the cause of Lyme disease – remains unclear.ResultsHere, we use a large-scale experiment to clarify the reciprocal interactions between Borrelia afzelii and the microbiome of Ixodes ricinus, its primary vector. In contrast to other reports, we find that depletion of the bacterial microbiome in larval ticks has no effect on their subsequent acquisition of B. afzelii during blood feeding on infected mice. Rather, exposure to B. afzelii-infected hosts drives pervasive changes to the tick microbiome, decreasing overall bacterial abundance, shifting bacterial community composition, and increasing bacterial diversity. These effects appear to be independent of the acquisition of B. afzelii by ticks, suggesting they are mediated by physiological or immunological aspects of B. afzelii infection in the rodent host.ConclusionsManipulation of the microbiome of I. ricinus larvae had no effect on their ability to acquire B. afzelii. In contrast, B. afzelii infection in the mouse had dramatic effects on the composition of the gut microbiome in I. ricinus nymphs. Our study demonstrates that vector-borne infections in the vertebrate host shape the microbiome of the arthropod vector.

scholarly journals Are Temperature Suitability and Socioeconomic Factors Reliable Predictors of Dengue Transmission in Brazil?

2021 ◽  
Vol 2 ◽  
Author(s):  
Lorena M. Simon ◽  
Thiago F. Rangel
Keyword(s):  
Socioeconomic Factors ◽  
Disease Transmission ◽  
Effect Of Temperature ◽  
Relative Role ◽  
Transmission Potential ◽  
Vector Borne Diseases ◽  
Dengue Transmission ◽  
Significant Proxy ◽  
Vector Borne ◽  
Temperature Suitability

Dengue is an ongoing problem, especially in tropical countries. Like many other vector-borne diseases, the spread of dengue is driven by a myriad of climate and socioeconomic factors. Within developing countries, heterogeneities on socioeconomic factors are expected to create variable conditions for dengue transmission. However, the relative role of socioeconomic characteristics and their association with climate in determining dengue prevalence are poorly understood. Here we assembled essential socioeconomic factors over 5570 municipalities across Brazil and assessed their effect on dengue prevalence jointly with a previously predicted temperature suitability for transmission. Using a simultaneous autoregressive approach (SAR), we showed that the variability in the prevalence of dengue cases across Brazil is primarily explained by the combined effect of climate and socioeconomic factors. At some dengue seasons, the effect of temperature on transmission potential showed to be a more significant proxy of dengue cases. Still, socioeconomic factors explained the later increase in dengue prevalence over Brazil. In a heterogeneous country such as Brazil, recognizing the transmission drivers by vectors is a fundamental issue in effectively predicting and combating tropical diseases like dengue. Ultimately, it indicates that not considering socioeconomic factors in disease transmission predictions might compromise efficient surveillance strategies. Our study shows that sanitation, urbanization, and GDP are regional indicators that should be considered along with temperature suitability on dengue transmission, setting effective directions to mosquito-borne disease control.

scholarly journals Temperature drives Zika virus transmission: evidence from empirical and mathematical models

2018 ◽  
Author(s):  
Blanka Tesla ◽  
Leah R. Demakovsky ◽  
Erin A. Mordecai ◽  
Sadie J. Ryan ◽  
Matthew H. Bonds ◽  
...  
Keyword(s):  
Zika Virus ◽  
Disease Transmission ◽  
Vector Competence ◽  
Virus Transmission ◽  
Thermal Range ◽  
Environmental Suitability ◽  
Dependent Model ◽  
Vector Borne ◽  
Temperature Dependent Model ◽  
The Relationship

AbstractTemperature is a strong driver of vector-borne disease transmission. Yet, for emerging arboviruses we lack fundamental knowledge on the relationship between transmission and temperature. Current models rely on the untested assumption that Zika virus responds similarly to dengue virus, potentially limiting our ability to accurately predict the spread of Zika. We conducted experiments to estimate the thermal performance of Zika virus (ZIKV) in field-derived Aedes aegypti across eight constant temperatures. We observed strong, unimodal effects of temperature on vector competence, extrinsic incubation period, and mosquito survival. We used thermal responses of these traits to update an existing temperature-dependent model to infer temperature effects on ZIKV transmission. ZIKV transmission was optimized at 29°C, and had a thermal range of 22.7°C - 34.7°C. Thus, as temperatures move toward the predicted thermal optimum (29°C) due to climate change, urbanization, or seasonally, Zika could expand north and into longer seasons. In contrast, areas that are near the thermal optimum were predicted to experience a decrease in overall environmental suitability. We also demonstrate that the predicted thermal minimum for Zika transmission is 5°C warmer than that of dengue, and current global estimates on the environmental suitability for Zika are greatly over-predicting its possible range.

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