scholarly journals Sugar feeding protects against arboviral infection by enhancing gut immunity in the mosquito vector Aedes aegypti

2021 ◽  
Vol 17 (9) ◽  
pp. e1009870
Author(s):  
Floriane Almire ◽  
Selim Terhzaz ◽  
Sandra Terry ◽  
Melanie McFarlane ◽  
Rommel J. Gestuveo ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Blood Meal ◽  
Vector Competence ◽  
Antiviral Immunity ◽  
Infection Prevalence ◽  
Sugar Intake ◽  
Sugar Feeding ◽  
Induced Immunity ◽  
Mosquito Females

As mosquito females require a blood meal to reproduce, they can act as vectors of numerous pathogens, such as arboviruses (e.g. Zika, dengue and chikungunya viruses), which constitute a substantial worldwide public health burden. In addition to blood meals, mosquito females can also take sugar meals to get carbohydrates for their energy reserves. It is now recognised that diet is a key regulator of health and disease outcome through interactions with the immune system. However, this has been mostly studied in humans and model organisms. So far, the impact of sugar feeding on mosquito immunity and in turn, how this could affect vector competence for arboviruses has not been explored. Here, we show that sugar feeding increases and maintains antiviral immunity in the digestive tract of the main arbovirus vector Aedes aegypti. Our data demonstrate that the gut microbiota does not mediate the sugar-induced immunity but partly inhibits it. Importantly, sugar intake prior to an arbovirus-infected blood meal further protects females against infection with arboviruses from different families. Sugar feeding blocks arbovirus initial infection and dissemination from the gut and lowers infection prevalence and intensity, thereby decreasing the transmission potential of female mosquitoes. Finally, we show that the antiviral role of sugar is mediated by sugar-induced immunity. Overall, our findings uncover a crucial role of sugar feeding in mosquito antiviral immunity which in turn decreases vector competence for arboviruses. Since Ae. aegypti almost exclusively feed on blood in some natural settings, our findings suggest that this lack of sugar intake could increase the spread of mosquito-borne arboviral diseases.

scholarly journals Sugar feeding enhances gut immunity and protects against arboviral infection in the mosquito vector Aedes aegypti

2021 ◽  
Author(s):  
Floriane Almire ◽  
Sandra Terry ◽  
Melanie McFarlane ◽  
Agnieszka M. Sziemel ◽  
Selim Terhzaz ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Blood Meal ◽  
Vector Competence ◽  
Antiviral Immunity ◽  
Model Organisms ◽  
Infection Prevalence ◽  
Mosquito Vector ◽  
Sugar Feeding ◽  
The Impact ◽  
Mosquito Females

AbstractAs mosquito females require a blood meal to reproduce, they can act as vectors of numerous pathogens, such as arboviruses (e.g. Zika, dengue and chikungunya viruses), which constitute a substantial worldwide public health burden. In addition to blood meals, mosquito females can also take sugar meals to get carbohydrates for their energy reserves. It is now recognised that diet is a key regulator of health and disease outcome through interactions with the immune system. However, it has been mostly studied in humans and model organisms. So far, the impact of sugar feeding on mosquito immunity and in turn, how this could affect vector competence for arboviruses has not been analysed. Here, we show that sugar feeding increases and maintains antiviral immunity in the digestive tract of the main arbovirus vector Aedes aegypti. Our data demonstrate that the gut microbiota does not mediate the sugar-induced immunity but partly inhibits it. Importantly, sugar intake prior to an arbovirus-infected blood meal further protects females against infection with arboviruses from different families, highlighting a broad antiviral action of sugar. Sugar feeding blocks arbovirus initial infection and dissemination from the gut, lowers infection prevalence and intensity, thereby decreasing transmission potential of female mosquitoes. Overall, our findings uncover a crucial role of sugar feeding in mosquito antiviral immunity and vector competence for arboviruses. Since Ae. aegypti almost exclusively feed on blood in some natural settings, our findings suggest that this could increase the spread of mosquito-borne arboviral diseases.

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 Lufenuron can be transferred by gravid Aedes aegypti females to breeding sites and can affect its fertility, fertility and blood intake capacity

2020 ◽  
Author(s):  
Paula V Gonzalez ◽  
Laura Harburguer
Keyword(s):  
Aedes Aegypti ◽  
Blood Meal ◽  
Adult Emergence ◽  
Chitin Synthesis ◽  
Synthesis Inhibitor ◽  
Breeding Sites ◽  
Resting Sites ◽  
Test Kit ◽  
Gravid Females ◽  
Mosquito Females

Abstract BACKGROUND Aedes aegypti (L.) is the main vector of dengue, yellow fever, Zika and chikungunya viruses. A new method for controlling this mosquito has been developed based on the possibility that wild adult mosquitoes exposed to artificial resting sites contaminated with a larvicide, can disseminate it to larval breeding sites, is named ‘‘autodissemination’’. The present study was undertaken to evaluate if a chitin synthesis inhibitor like lufenuron can by disseminated to larval breeding sites and prevent adult emergence and also if forced contact of Ae. aegypti females with treated surfaces can affect its fertility, fecundity and blood in take capaity.METHODSLarval susceptibility to lufenuron was measured through EI50 and EI90. On the other hand gravid females were exposed by tarsal contact to lufenuron-treated papers, we used the WHO susceptibility test kit tube to line the papers, and 1, 3 or 5 females for the transference. We also evaluate if the exposure of mosquito females to lufenuron-treated papers (0.4 and 1 mg a.i./cm 2 ) has an effect on their fecundity, fertility or in the ability to feed on blood. In each assay 12-15 mosquito females were exposed to lufenuron for 1 hour; 24 h before (before blood meal - BBM) or 24 h after a blood meal (ABM).RESULTSLufenuron proved to be very active against Ae. aegypti larvae with an EI 50 of 0.164 ppb and EI 95 of 1.26 ppb. We also found that lufenuron can be transferred by females from treated surfaces to clean containers causing the inhibition of emergence of the larvae (between 30 and 50%). This effect was dependent on the concentration applied on the paper and also the number of females added to each cage.CONCLUSIONSThis paper introduces an innovation by first exploring the possibility that an IGR belonging to the group of benzoylphenyl ureas, such as lufenuron, can be transferred by gravid females to breeding sites and that at the same time can have an effect on fertility, fertility and blood intake capacity of adult mosquitoes.

scholarly journals The impact of mating and sugar feeding on blood-feeding physiology and behavior in the arbovirus vector mosquito Aedes aegypti

2021 ◽  
Vol 15 (9) ◽  
pp. e0009815
Author(s):  
Garrett P. League ◽  
Ethan C. Degner ◽  
Sylvie A. Pitcher ◽  
Yassi Hafezi ◽  
Erica Tennant ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Blood Meal ◽  
Egg Production ◽  
Control Strategies ◽  
Blood Feeding ◽  
Female Behavior ◽  
Sugar Feeding ◽  
And Behavior ◽  
The Impact ◽  
Initial Blood

Background Aedes aegypti mosquitoes are globally distributed vectors of viruses that impact the health of hundreds of millions of people annually. Mating and blood feeding represent fundamental aspects of mosquito life history that carry important implications for vectorial capacity and for control strategies. Females transmit pathogens to vertebrate hosts and obtain essential nutrients for eggs during blood feeding. Further, because host-seeking Ae. aegypti females mate with males swarming near hosts, biological crosstalk between these behaviors could be important. Although mating influences nutritional intake in other insects, prior studies examining mating effects on mosquito blood feeding have yielded conflicting results. Methodology/Principal findings To resolve these discrepancies, we examined blood-feeding physiology and behavior in virgin and mated females and in virgins injected with male accessory gland extracts (MAG), which induce post-mating changes in female behavior. We controlled adult nutritional status prior to blood feeding by using water- and sugar-fed controls. Our data show that neither mating nor injection with MAG affect Ae. aegypti blood intake, digestion, or feeding avidity for an initial blood meal. However, sugar feeding, a common supplement in laboratory settings but relatively rare in nature, significantly affected all aspects of feeding and may have contributed to conflicting results among previous studies. Further, mating, MAG injection, and sugar intake induced declines in subsequent feedings after an initial blood meal, correlating with egg production and laying. Taking our evaluation to the field, virgin and mated mosquitoes collected in Colombia were equally likely to contain blood at the time of collection. Conclusions/Significance Mating, MAG, and sugar feeding impact a mosquito’s estimated ability to transmit pathogens through both direct and indirect effects on multiple aspects of mosquito biology. Our results highlight the need to consider natural mosquito ecology, including diet, when assessing their physiology and behavior in the laboratory.

Lufenuron can be transferred by gravid Aedes aegypti females to breeding sites and can affect its fertility, fecundity and blood intake capacity

2020 ◽  
Author(s):  
Paula V Gonzalez ◽  
Laura Harburguer
Keyword(s):  
Aedes Aegypti ◽  
Blood Meal ◽  
Adult Emergence ◽  
Chitin Synthesis ◽  
Synthesis Inhibitor ◽  
Breeding Sites ◽  
Resting Sites ◽  
Test Kit ◽  
Gravid Females ◽  
Mosquito Females

Abstract Background: Aedes aegypti (L.) is the main vector of dengue, yellow fever, Zika and chikungunya viruses. A new method for controlling this mosquito has been developed based on the possibility that wild adult mosquitoes exposed to artificial resting sites contaminated with a larvicide, can disseminate it to larval breeding sites, is named ‘‘auto-dissemination’’. The present study was undertaken to evaluate if a chitin synthesis inhibitor like lufenuron can by disseminated to larval breeding sites and prevent adult emergence and also if forced contact of Ae. aegypti females with treated surfaces can affect its fertility, fecundity and blood intake capacity. Methods: Larval susceptibility to lufenuron was measured through EI 50 and EI 90 . On the other hand gravid females were exposed by tarsal contact to lufenuron-treated papers, we used the WHO susceptibility test kit tube to line the papers, and 1, 3 or 5 females for the transference. We also evaluated if the exposure of mosquito females to lufenuron-treated papers (0.4 and 1 mg a.i./cm 2 ) has an effect on their fertility, fecundity or in the ability to feed on blood. In each assay 12-15 mosquito females were exposed to lufenuron for 1 hour; 24 h before (before blood meal - BBM) or 24 h after a blood meal (ABM). Results: Lufenuron proved to be very active against Ae. aegypti larvae with an EI 50 of 0.164 ppb and EI 90 of 0.81 ppb. We also found that lufenuron can be transferred by females from treated surfaces to clean containers causing the inhibition of emergence of the larvae (between 30 and 50%). This effect was dependent on the concentration applied on the paper and also the number of females added to each cage. Conclusions: This paper introduces an innovation by first exploring the possibility that an IGR belonging to the group of benzoylphenyl ureas, such as lufenuron, can be transferred by gravid females to breeding sites and that at the same time can have an effect on fertility, fecundity and blood intake capacity of adult mosquitoes. Keywords: Aedes aegypti , lufenuron, auto-disemination, fertility, fecundity.

On the Role of Blood in Ovulation in Aëdes aegypti, Linn

1936 ◽  
Vol 27 (3) ◽  
pp. 423-429 ◽  
Author(s):  
D. N. Roy
Keyword(s):  
Aedes Aegypti ◽  
Blood Meal ◽  
Ovarian Follicles ◽  
Chemical Stimulus ◽  
Physico Chemical ◽  
Intimate Association

The intimate association between a blood meal and ovulation in all female mosquitos, with the exception of a few (de Buck, Roubaud) has been clearly recognised; but the peculiar manner in which the presence of blood in the stomach can influence the formation of eggs is not understood. Two explanations may be suggested: it may either act as a physico-chemical stimulus to the ovarian follicles, or certain constituents in the blood may furnish some nutrient material for the development of the eggs.

scholarly journals Starvation at the larval stage increases the vector competence of Aedes aegypti females for Zika virus

2021 ◽  
Vol 15 (11) ◽  
pp. e0010003
Author(s):  
Christie S. Herd ◽  
DeAna G. Grant ◽  
Jingyi Lin ◽  
Alexander W. E. Franz
Keyword(s):  
Aedes Aegypti ◽  
Salivary Glands ◽  
Blood Meal ◽  
Zika Virus ◽  
Vector Competence ◽  
Transmission Cycle ◽  
Physical Evidence ◽  
Transmission Electron ◽  
Primary Vector ◽  
Blood Meal Digestion

Aedes aegypti is the primary vector of Zika virus (ZIKV), a flavivirus which typically presents itself as febrile-like symptoms in humans but can also cause neurological and pregnancy complications. The transmission cycle of mosquito-borne arboviruses such as ZIKV requires that various key tissues in the female mosquito including the salivary glands get productively infected with the virus before the mosquito can transmit the virus to another vertebrate host. Following ingestion of a viremic blood-meal from a vertebrate, ZIKV initially infects the midgut epithelium before exiting the midgut after blood-meal digestion to disseminate to secondary tissues including the salivary glands. Here we investigated whether smaller Ae. aegypti females resulting from food deprivation as larvae exhibited an altered vector competence for blood-meal acquired ZIKV relative to larger mosquitoes. Midguts from small ‘Starve’ and large ‘Control’ Ae. aegypti were dissected to visualize by transmission electron microscopy (TEM) the midgut basal lamina (BL) as physical evidence for the midgut escape barrier showing Starve mosquitoes with a significantly thinner midgut BL than Control mosquitoes at two timepoints. ZIKV replication was inhibited in Starve mosquitoes following intrathoracic injection of virus, however, Starve mosquitoes exhibited a significantly higher midgut escape and population dissemination rate at 9 days post-infection (dpi) via blood-meal, with more virus present in saliva and head tissue than Control by 10 dpi and 14 dpi, respectively. These results indicate that Ae. aegypti developing under stressful conditions potentially exhibit higher midgut infection and dissemination rates for ZIKV as adults, Thus, variation in food intake as larvae is potentially a source for variable vector competence levels of the emerged adults for the virus.

scholarly journals Microbial composition in larval water enhances Aedes aegypti development but reduces transmissibility of Zika virus

2021 ◽  
Author(s):  
Lark L. Coffey ◽  
Will Louie
Keyword(s):  
Aedes Aegypti ◽  
Zika Virus ◽  
Tap Water ◽  
Vector Competence ◽  
Environmental Water ◽  
Water Type ◽  
Microbial Composition ◽  
Experimental Protocols ◽  
Laboratory Water

Arthropod-borne viruses comprise a significant global disease burden. Surveillance and mitigation of arboviruses like Zika virus (ZIKV) require accurate estimates of transmissibility by vector mosquitoes. Although Aedes spp.mosquitoes are established as competent ZIKV vectors, differences in experimental protocols across studies prevent direct comparisons of relative transmissibility. An understudied factor complicating these comparisons is differential environmental microbiota exposures, where most vector competence studies use mosquitoes reared in laboratory tap water, which does not represent the microbial complexity of environmental water where wild larvae develop. We simulated natural larval development by rearing Californian Aedes aegypti with microbes obtained from cemetery headstone water compared to conventional tap water. Ae. aegypti larvae reared in environmental cemetery water pupated 3 days faster and at higher rates. Female adult mosquitoes reared in environmental water were less competent vectors of ZIKV compared to laboratory water-reared Ae. aegypti, as evidenced by significantly reduced infection and transmission rates. Microbiome comparisons of laboratory- and environment-water reared mosquitoes and their rearing water showed significantly higher bacterial diversity in environment water; despite this pattern, corresponding differences in diversity were not consistently detected in adult mosquitoes reared in different water sources. We also detected more significant associations between the microbial composition of adult mosquitoes and whether they ingested a bloodmeal than larval water type. Together, these results highlight the role of transient microbes in the larval environment in modulating vector competence. Laboratory vector competence likely overestimates true transmissibility of arboviruses like ZIKV when conventional laboratory water is used for rearing.

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