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

2018 ◽  
Vol 285 (1884) ◽  
pp. 20180795 ◽  
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

Temperature 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 towards the predicted thermal optimum (29°C) owing to climate change, urbanization or seasonality, Zika could expand north and into longer seasons. By 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.

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.

scholarly journals Sequential Infection of Aedes aegypti Mosquitoes with Chikungunya Virus and Zika Virus Enhances Early Zika Virus Transmission

Insects ◽  
2018 ◽  
Vol 9 (4) ◽  
pp. 177 ◽  
Author(s):  
Tereza Magalhaes ◽  
Alexis Robison ◽  
Michael Young ◽  
William Black ◽  
Brian Foy ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Blood Meal ◽  
Zika Virus ◽  
Chikungunya Virus ◽  
Vector Competence ◽  
Virus Transmission ◽  
Mosquito Vector ◽  
Molecular Aspects ◽  
Virus Interactions ◽  
Sequential Infection

In urban settings, chikungunya, Zika, and dengue viruses are transmitted by Aedes aegypti mosquitoes. Since these viruses co-circulate in several regions, coinfection in humans and vectors may occur, and human coinfections have been frequently reported. Yet, little is known about the molecular aspects of virus interactions within hosts and how they contribute to arbovirus transmission dynamics. We have previously shown that Aedes aegypti exposed to chikungunya and Zika viruses in the same blood meal can become coinfected and transmit both viruses simultaneously. However, mosquitoes may also become coinfected by multiple, sequential feeds on single infected hosts. Therefore, we tested whether sequential infection with chikungunya and Zika viruses impacts mosquito vector competence. We exposed Ae. aegypti mosquitoes first to one virus and 7 days later to the other virus and compared infection, dissemination, and transmission rates between sequentially and single infected groups. We found that coinfection rates were high after sequential exposure and that mosquitoes were able to co-transmit both viruses. Surprisingly, chikungunya virus coinfection enhanced Zika virus transmission 7 days after the second blood meal. Our data demonstrate heterologous arbovirus synergism within mosquitoes, by unknown mechanisms, leading to enhancement of transmission under certain conditions.

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.

Ecosystem Services-Climate-Health Associations

2019 ◽  
pp. 280-290 ◽  
Author(s):  
Ahmed Karmaoui ◽  
Siham Zerouali ◽  
Ashfaq Ahmad Shah ◽  
Mohammed Yacoubi-Khebiza ◽  
Fadoua El Qorchi
Keyword(s):  
Ecosystem Services ◽  
Water Availability ◽  
Disease Transmission ◽  
Strong Correlation ◽  
Groundwater Availability ◽  
Zoonotic Cutaneous Leishmaniasis ◽  
Vector Borne ◽  
Dam Inflow ◽  
The Relationship ◽  
Vegetation Cover Change

Water is the main ecosystem service that supports the oasis system. Middle Draa Valley is an oasis zone located in the south of Morocco. The water availability in this area is the key element of vegetation cover change. This change added to other factors can cause some parasitic diseases. The zoonotic cutaneous leishmaniasis is one of these diseases. In this chapter, an analysis of the interaction between some key risk factors and the disease transmission was carried out. The outputs of this work rivaled that there is a very strong correlation between this disease and ecosystem services such as water stored and the dam outflow (directed to the oasis for the irrigation), and the groundwater availability. Regarding the correlation between this vector-borne disease and the cropping area, a strong correlation was recorded. However, for the relationship between leishmaniasis and the precipitation and the dam inflow, average correlations were found. Basically, in MDV, the water availability is the first element that affects an ensemble of processes that cause the disease infection.

scholarly journals Temperature explains broad patterns of Ross River virus transmission

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Marta Strecker Shocket ◽  
Sadie J Ryan ◽  
Erin A Mordecai
Keyword(s):  
Disease Transmission ◽  
Pacific Islands ◽  
Nonlinear Models ◽  
Mechanistic Model ◽  
Virus Transmission ◽  
Thermal Response ◽  
Ross River Virus ◽  
Vector Borne ◽  
High And Low Temperatures ◽  
The Tropics

Thermal biology predicts that vector-borne disease transmission peaks at intermediate temperatures and declines at high and low temperatures. However, thermal optima and limits remain unknown for most vector-borne pathogens. We built a mechanistic model for the thermal response of Ross River virus, an important mosquito-borne pathogen in Australia, Pacific Islands, and potentially at risk of emerging worldwide. Transmission peaks at moderate temperatures (26.4°C) and declines to zero at thermal limits (17.0 and 31.5°C). The model accurately predicts that transmission is year-round endemic in the tropics but seasonal in temperate areas, resulting in the nationwide seasonal peak in human cases. Climate warming will likely increase transmission in temperate areas (where most Australians live) but decrease transmission in tropical areas where mean temperatures are already near the thermal optimum. These results illustrate the importance of nonlinear models for inferring the role of temperature in disease dynamics and predicting responses to climate change.

scholarly journals ESTIMATE OF VIRUS ZIKA SPREAD RISK IN THE REPUBLIC OF ABKHAZIA ASSOCIATING THE LOCAL POPULATION OF MOSQUITOES AEDES AEGYPTI AND AEDES ALBOPICTUS

2017 ◽  
pp. 10-15
Author(s):  
O. V. Maletskaya ◽  
V. M. Dubyansky ◽  
A. I. Belyaeva ◽  
L. I. Shaposhnikova ◽  
D. S. Agapitov ◽  
...  
Keyword(s):  
Zika Virus ◽  
Vector Competence ◽  
Local Population ◽  
Virus Transmission ◽  
The Black Sea ◽  
Control Methods ◽  
Black Sea Coast ◽  
The Russian Federation ◽  
The Republic ◽  
Virus Zika

Aim. Chracteristic of number and distribution of mosquitoes Ae. aegypti and Ae. albopictus in the Republic of Abkhazia and a risk assessment of virus Zika spread. Materials and methods. The accounting of mosquitoes number was made by the method «on the observer» in 20 minutes at the 70 nature landscapes points in april-oktober 2016. Results. The Black sea coast of the Republic of Abkhazia has favorable ecological conditions for the mosquitoes ingrowth of Ae. aegypti and Ae. albopictus. At 2016 the mosquitoes Ae. albopictus having vector competence to spread a Zika virus, has been revealed in the open stations in the territory from Ochamchirsky district to border with the Russian Federation. Their number is correlated with the air temperature in the region. The control of efficiency of the insecticidal works showed that in the open stations Ae. albopictus were not found within 3 - 7 days after the disinsection actions. However, their number of recovered as a result of settling from nearby natural biotopes. Conclusion. The risk of local Zika virus transmission has estimated as a low. Considering the gravity of the disease caused by the Zika virus carrying out a wider complex of the control methods of the mosquitoes number in areas of their dwelling, especially on the epidemiologically significant objects is necessary. The most effective of the population protection action is riddance of the reproduction mosquitoes places and sanitation of territory.

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.

scholarly journals Vector competence ofAnophelesandCulexmosquitoes for Zika virus

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3096 ◽  
Author(s):  
Brittany L. Dodson ◽  
Jason L. Rasgon
Keyword(s):  
Anopheles Gambiae ◽  
Culex Quinquefasciatus ◽  
Zika Virus ◽  
Anopheles Stephensi ◽  
Vector Competence ◽  
Mosquito Species ◽  
Plaque Assay ◽  
Virus Transmission ◽  
Serious Disease ◽  
Blood Meals

Zika virus is a newly emergent mosquito-borne flavivirus that has caused recent large outbreaks in the new world, leading to dramatic increases in serious disease pathology including Guillain-Barre syndrome, newborn microcephaly, and infant brain damage. AlthoughAedesmosquitoes are thought to be the primary mosquito species driving infection, the virus has been isolated from dozens of mosquito species, includingCulexandAnophelesspecies, and we lack a thorough understanding of which mosquito species to target for vector control. We exposedAnopheles gambiae,Anopheles stephensi, andCulex quinquefasciatusmosquitoes to blood meals supplemented with two Zika virus strains. Mosquito bodies, legs, and saliva were collected five, seven, and 14 days post blood meal and tested for infectious virus by plaque assay. Regardless of titer, virus strain, or timepoint,Anopheles gambiae,Anopheles stephensi, andCulex quinquefasciatusmosquitoes were refractory to Zika virus infection. We conclude thatAnopheles gambiae,Anopheles stephensi, andCulex quinquefasciatusmosquitoes likely do not contribute significantly to Zika virus transmission to humans. However, future studies should continue to explore the potential for other novel potential vectors to transmit the virus.

scholarly journals Impact of Mosquito Age and Insecticide Exposure on Susceptibility of Aedes albopictus (Diptera: Culicidae) to Infection with Zika Virus

Pathogens ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 67 ◽  
Author(s):  
Heidi Knecht ◽  
Stephanie Richards ◽  
Jo Balanay ◽  
Avian White
Keyword(s):  
Zika Virus ◽  
Vector Competence ◽  
Virus Transmission ◽  
Sublethal Dose ◽  
Oral Exposure ◽  
Chronological Age ◽  
Control Group ◽  
Source Reduction ◽  
Time Of Infection ◽  
Virus Interactions

Zika virus (ZIKV) is primarily transmitted to humans by Aedes aegypti and Ae. albopictus. Vector–virus interactions influencing vector competence vary and depend on biological and environmental factors. A mosquito’s chronological age may impact its immune response against virus infection. Insecticides, source reduction, and/or public education are currently the best defense against mosquitoes that transmit ZIKV. This study assessed the effects of a mosquito’s chronological age at time of infection on its response to ZIKV infection. We exposed young (6–7 d post-emergence) and old (11–12 d post-emergence) Ae. albopictus to a sublethal dose of bifenthrin prior to oral exposure to blood meals containing ZIKV (7-day incubation period). Old mosquitoes experienced a significantly (p < 0.01) higher rate of mortality than young mosquitoes. Significantly higher ZIKV body titers (p < 0.01) were observed in the old control group compared to the young control group. Significantly higher (p < 0.01) ZIKV dissemination rates and leg titers (p < 0.01) were observed in old bifenthrin-exposed mosquitoes compared to old control mosquitoes or young bifenthrin-exposed or control mosquitoes. Hence, bifenthrin exposure may increase the potential for virus transmission; however, the degree of these impacts varies with mosquito age. Impacts of insecticides should be considered in risk assessments of potential vector populations.

scholarly journals Mosquito Trilogy: Microbiota, Immunity and Pathogens, and Their Implications for the Control of Disease Transmission

2021 ◽  
Vol 12 ◽  
Author(s):  
Paolo Gabrieli ◽  
Silvia Caccia ◽  
Ilaria Varotto-Boccazzi ◽  
Irene Arnoldi ◽  
Giulia Barbieri ◽  
...  
Keyword(s):  
Immune System ◽  
Disease Transmission ◽  
Current Knowledge ◽  
Control Strategies ◽  
Vector Competence ◽  
Complex Interaction ◽  
Level Ii ◽  
The Relationship ◽  
Mosquito Females ◽  
Review Current

In mosquitoes, the interaction between the gut microbiota, the immune system, and the pathogens that these insects transmit to humans and animals is regarded as a key component toward the development of control strategies, aimed at reducing the burden of severe diseases, such as malaria and dengue fever. Indeed, different microorganisms from the mosquito microbiota have been investigated for their ability to affect important traits of the biology of the host insect, related with its survival, development and reproduction. Furthermore, some microorganisms have been shown to modulate the immune response of mosquito females, significantly shaping their vector competence. Here, we will review current knowledge in this field, focusing on i) the complex interaction between the intestinal microbiota and mosquito females defenses, both in the gut and at humoral level; ii) how knowledge on these issues contributes to the development of novel and targeted strategies for the control of mosquito-borne diseases such as the use of paratransgenesis or taking advantage of the relationship between Wolbachia and mosquito hosts. We conclude by providing a brief overview of available knowledge on microbiota-immune system interplay in major insect vectors.

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