scholarly journals Assessing the blood-host plasticity and dispersal rate of the malaria vector Anopheles coluzzii

2018 ◽  
Author(s):  
James Orsborne ◽  
Luis Furuya-Kanamori ◽  
Claire L. Jeffries ◽  
Mojca Kristan ◽  
Abdul Rahim Mohammed ◽  
...  
Keyword(s):  
Blood Meal ◽  
Disease Transmission ◽  
Blood Feeding ◽  
Host Choice ◽  
Anopheles Coluzzii ◽  
Dispersal Rate ◽  
Blood Digestion ◽  
Novel Method ◽  
Blood Meal Digestion ◽  
Blood Meals

AbstractDifficulties with observing the dispersal of insect vectors in the field have hampered understanding of several aspects of their behaviour linked to disease transmission. Here, a novel method based on detection of blood-meal sources is introduced to inform two critical and understudied mosquito behaviours: plasticity in the malaria vector’s blood-host choice and vector dispersal. Strategically located collections of Anopheles coluzzii from a malaria-endemic village of southern Ghana showed statistically significant variation in host species composition of mosquito blood-meals. Trialling a new sampling approach gave the first estimates for the remarkably local spatial scale across which host choice is plastic. Using quantitative PCR, the blood-meal digestion was then quantified for field-caught mosquitoes and calibrated according to timed blood digestion in colony mosquitoes. We demonstrate how this new ‘molecular Sella score’ approach can be used to estimate the dispersal rate of blood-feeding vectors caught in the field.

scholarly journals Understanding mosquito host-choice behaviour: a new and low-cost method of identifying the sex of human hosts from mosquito blood meals

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Fiona Teltscher ◽  
Sophie Bouvaine ◽  
Gabriella Gibson ◽  
Paul Dyer ◽  
Jennifer Guest ◽  
...  
Keyword(s):  
Blood Meal ◽  
Host Species ◽  
Disease Transmission ◽  
Low Cost ◽  
Host Choice ◽  
Epidemiological Models ◽  
Choice Behaviour ◽  
Vector Borne ◽  
Transmission Models ◽  
Blood Meals

Abstract Background Mosquito-borne diseases are a global health problem, causing hundreds of thousands of deaths per year. Pathogens are transmitted by mosquitoes feeding on the blood of an infected host and then feeding on a new host. Monitoring mosquito host-choice behaviour can help in many aspects of vector-borne disease control. Currently, it is possible to determine the host species and an individual human host from the blood meal of a mosquito by using genotyping to match the blood profile of local inhabitants. Epidemiological models generally assume that mosquito biting behaviour is random; however, numerous studies have shown that certain characteristics, e.g. genetic makeup and skin microbiota, make some individuals more attractive to mosquitoes than others. Analysing blood meals and illuminating host-choice behaviour will help re-evaluate and optimise disease transmission models. Methods We describe a new blood meal assay that identifies the sex of the person that a mosquito has bitten. The amelogenin locus (AMEL), a sex marker located on both X and Y chromosomes, was amplified by polymerase chain reaction in DNA extracted from blood-fed Aedes aegypti and Anopheles coluzzii. Results AMEL could be successfully amplified up to 24 h after a blood meal in 100% of An. coluzzii and 96.6% of Ae. aegypti, revealing the sex of humans that were fed on by individual mosquitoes. Conclusions The method described here, developed using mosquitoes fed on volunteers, can be applied to field-caught mosquitoes to determine the host species and the biological sex of human hosts on which they have blood fed. Two important vector species were tested successfully in our laboratory experiments, demonstrating the potential of this technique to improve epidemiological models of vector-borne diseases. This viable and low-cost approach has the capacity to improve our understanding of vector-borne disease transmission, specifically gender differences in exposure and attractiveness to mosquitoes. The data gathered from field studies using our method can be used to shape new transmission models and aid in the implementation of more effective and targeted vector control strategies by enabling a better understanding of the drivers of vector-host interactions.

scholarly journals Assessing the blood meal hosts of Culex quinquefasciatus and Aedes taeniorhynchus in Isla Santa Cruz, Galápagos

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Samoa Asigau ◽  
Sawsan Salah ◽  
Patricia G. Parker
Keyword(s):  
Feeding Behavior ◽  
Culex Quinquefasciatus ◽  
Blood Meal ◽  
Disease Transmission ◽  
Avian Malaria ◽  
Mosquito Species ◽  
Blood Feeding ◽  
Santa Cruz ◽  
Aedes Taeniorhynchus ◽  
Blood Meals

Abstract Background Blood meal host selection by mosquito vectors is an important component in understanding disease dynamics of pathogens that threaten endemic fauna in isolated islands such as Galápagos. Research on the feeding behavior of mosquitoes can provide clues to the hosts and vectors involved in disease transmission. This information is particularly critical for endemic wildlife fauna in island systems that have evolved without resistance to novel diseases such as avian malaria. The aims of this study were to determine the blood-feeding patterns of two species of mosquitoes found in Galápagos and discuss how their feeding behavior may influence the transmission of pathogens such as avian malaria. Methods In the summer of 2015, we sampled two mosquito species (Aedes taeniorhynchus and Culex quinquefasciatus) across 18 different sites on Isla Santa Cruz, which is the second largest island in Galápagos and has the largest human population. We trapped mosquitoes using CDC light traps and CDC gravid traps and identified sources of blood meals for engorged mosquitoes by sequencing a portion of the vertebrate mitochondrial cytochrome b gene. Results Out of 947 female mosquitoes captured, 320 were blood-fed, and PCR amplifications were successful for 301 of the blood meals. Results revealed that both Aedes taeniorhynchus and Culex quinquefasciatus feed from a variety of vertebrate taxa, numerically dominated by humans on Isla Santa Cruz. Conclusions The high proportion of mammalian blood meals could represent locally available and abundant hosts on Santa Cruz. However, host surveys and estimates of relative abundances of vertebrate species will need to accompany mosquito trapping studies on non-inhabited and inhabited islands in Galápagos to further validate this.

scholarly journals Haematophagous arthropod saliva and host defense system: a tale of tear and blood

2005 ◽  
Vol 77 (4) ◽  
pp. 665-693 ◽  
Author(s):  
Bruno B. Andrade ◽  
Clarissa R. Teixeira ◽  
Aldina Barral ◽  
Manoel Barral-Netto
Keyword(s):  
Immune Response ◽  
Immune Responses ◽  
Host Defense ◽  
Blood Meal ◽  
Disease Transmission ◽  
Blood Feeding ◽  
Defense System ◽  
Current Information ◽  
System A ◽  
Host Defense System

The saliva from blood-feeding arthropod vectors is enriched with molecules that display diverse functions that mediate a successful blood meal. They function not only as weapons against host's haemostatic, inflammatory and immune responses but also as important tools to pathogen establishment. Parasites, virus and bacteria taking advantage of vectors' armament have adapted to facilitate their entry in the host. Today, many salivary molecules have been identified and characterized as new targets to the development of future vaccines. Here we focus on current information on vector's saliva and the molecules responsible to modify host's hemostasis and immune response, also regarding their role in disease transmission.

scholarly journals Blood Digestion by Trypsin-Like Serine Proteases in the Replete Lyme Disease Vector Tick, Ixodes scapularis

Insects ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 201
Author(s):  
Jeremiah Reyes ◽  
Cuauhtemoc Ayala-Chavez ◽  
Arvind Sharma ◽  
Michael Pham ◽  
Andrew B. Nuss ◽  
...  
Keyword(s):  
Lyme Disease ◽  
Blood Meal ◽  
Serine Proteases ◽  
Ixodes Scapularis ◽  
Life Stage ◽  
Blood Feeding ◽  
Eastern United States ◽  
Blood Digestion ◽  
Hemoglobin Degradation

Ixodes scapularis is the major vector of Lyme disease in the Eastern United States. Each active life stage (larva, nymph, and adult) takes a blood meal either for developing and molting to the next stage (larvae and nymphs) or for oviposition (adult females). This protein-rich blood meal is the only food taken by Ixodes ticks and therefore efficient blood digestion is critical for survival. Studies in partially engorged ticks have shown that the initial stages of digestion are carried out by cathepsin proteases within acidic digestive cells. In this study, we investigated the potential role of serine proteases in blood digestion in replete ticks. RNA interference was used for functional analysis and a trypsin-benzoyl-D, L-arginine 4-nitoanilide assay was used to measure active trypsin levels. Hemoglobinolytic activity was determined in vitro, with or without a serine protease inhibitor. Our data suggest that trypsin levels increase significantly after repletion. Knockdown of serine proteases negatively impacted blood feeding, survival, fecundity, levels of active trypsin in the midgut, and resulted in lower hemoglobin degradation. Incubation of midgut extract with a trypsin inhibitor resulted in 65% lower hemoglobin degradation. We provide evidence of the serine proteases as digestive enzymes in fully engorged, replete females. Understanding the digestive profile of trypsin during blood meal digestion in I. scapularis improves our understanding of the basic biology of ticks and may lead to new methods for tick control.

scholarly journals Evolutionary transition from blood feeding to obligate nonbiting in a mosquito

2017 ◽  
Vol 115 (5) ◽  
pp. 1009-1014 ◽  
Author(s):  
William E. Bradshaw ◽  
Joshua Burkhart ◽  
John K. Colbourne ◽  
Rudyard Borowczak ◽  
Jacqueline Lopez ◽  
...  
Keyword(s):  
Blood Meal ◽  
Disease Transmission ◽  
Blood Feeding ◽  
Evolutionary Transition ◽  
Genetic Changes ◽  
Wyeomyia Smithii ◽  
Extant Species ◽  
Starting Point ◽  
Differential Gene ◽  
Vector Borne

The spread of blood-borne pathogens by mosquitoes relies on their taking a blood meal; if there is no bite, there is no disease transmission. Although many species of mosquitoes never take a blood meal, identifying genes that distinguish blood feeding from obligate nonbiting is hampered by the fact that these different lifestyles occur in separate, genetically incompatible species. There is, however, one unique extant species with populations that share a common genetic background but blood feed in one region and are obligate nonbiters in the rest of their range: Wyeomyia smithii. Contemporary blood-feeding and obligate nonbiting populations represent end points of divergence between fully interfertile southern and northern populations. This divergence has undoubtedly resulted in genetic changes that are unrelated to blood feeding, and the challenge is to winnow out the unrelated genetic factors to identify those related specifically to the evolutionary transition from blood feeding to obligate nonbiting. Herein, we determine differential gene expression resulting from directional selection on blood feeding within a polymorphic population to isolate genetic differences between blood feeding and obligate nonbiting. We show that the evolution of nonbiting has resulted in a greatly reduced metabolic investment compared with biting populations, a greater reliance on opportunistic metabolic pathways, and greater reliance on visual rather than olfactory sensory input. W. smithii provides a unique starting point to determine if there are universal nonbiting genes in mosquitoes that could be manipulated as a means to control vector-borne disease.

scholarly journals BiteOscope: an open platform to study mosquito blood-feeding behavior

2020 ◽  
Author(s):  
Felix JH Hol ◽  
Louis Lambrechts ◽  
Manu Prakash
Keyword(s):  
Blood Meal ◽  
Human Subjects ◽  
Blood Feeding ◽  
Anopheles Coluzzii ◽  
Open Platform ◽  
Essential Nutrient ◽  
Resolution Imaging ◽  
The Common ◽  
New Perspective

AbstractFemale mosquitoes need a blood meal to reproduce, and in obtaining this essential nutrient they transmit deadly pathogens. Although crucial for the spread of mosquito-borne diseases, our understanding of skin exploration, probing, and engorgement, is limited due to a lack of quantitative tools. Indeed, studies often expose human subjects to assess biting behavior. Here, we present the biteOscope, a device that attracts mosquitoes to a host mimic which they bite to obtain an artificial blood meal. The host mimic is transparent, allowing high-resolution imaging of the feeding mosquito. Using machine learning we extract detailed behavioral statistics describing the locomotion, pose, biting, and feeding dynamics of Aedes aegypti, Aedes albopictus, Anopheles stephensi, and Anopheles coluzzii. In addition to characterizing behavioral patterns, we discover that the common insect repellent DEET repels Anopheles coluzzii upon contact with their legs. The biteOscope provides a new perspective on mosquito blood feeding, enabling high-throughput quantitative characterization of the effects physiological and environmental factors have on this lethal behavior.

scholarly journals Malaria parasite immune evasion and adaptation to its mosquito host is influenced by the acquisition of multiple blood meals

2019 ◽  
Author(s):  
Hyeogsun Kwon ◽  
Rebekah A. Reynolds ◽  
Maria L. Simões ◽  
George Dimopoulos ◽  
Ryan C. Smith
Keyword(s):  
Blood Meal ◽  
Blood Feeding ◽  
Parasite Development ◽  
Protein Meal ◽  
Infected Blood ◽  
Adult Lifespan ◽  
Multiple Blood ◽  
The Impact ◽  
Immune Detection ◽  
Blood Meals

AbstractA minimum of two blood meals are required for a mosquito to acquire and transmit malaria, yet Anopheles mosquitoes frequently obtain additional blood meals during their adult lifespan. To determine the impact of subsequent blood-feeding on parasite development in Anopheles gambiae, we examined rodent and human Plasmodium parasite infection with or without an additional non-infected blood meal. We find that an additional blood meal significantly reduces P. berghei immature oocyst numbers, yet does not influence mature oocysts that have already begun sporogony. This is in contrast to experiments performed with the human parasite, P. falciparum, where an additional blood meal does not affect oocyst numbers. These observations are reproduced when mosquitoes were similarly challenged with an artificial protein meal, suggesting that parasite losses are due to the physical distension of the mosquito midgut. We provide evidence that feeding compromises the integrity of the midgut basal lamina, enabling the recognition and lysis of immature P. berghei oocysts by the mosquito complement system. Moreover, we demonstrate that additional feeding promotes P. falciparum oocyst growth, suggesting that human malaria parasites exploit host resources provided with blood-feeding to accelerate their growth. This contrasts experiments with P. berghei, where the size of surviving oocysts is independent of an additional blood meal. Together, these data demonstrate differences in the ability of Plasmodium species to evade immune detection and adapt to utilize host resources at the oocyst stage, representing an additional, yet unexplored component of vectorial capacity that has important implications for transmission of malaria.

Rhodnius prolixus and its symbiotic actinomycete: a microbiological, physiological and behavioural study

1976 ◽  
Vol 194 (1117) ◽  
pp. 501-525 ◽  
Keyword(s):  
Blood Meal ◽  
De Novo ◽  
Wild Type ◽  
Glucose Levels ◽  
Blood Sucking ◽  
Developmental Disturbance ◽  
Novel Method ◽  
Blood Meal Digestion ◽  
Lactate Levels

The rôle of the symbiont in this blood-sucking insect has been reinvestigated by a novel method: the substitution of wild-type symbionts by auxotrophic mutants produced in vitro , unable to synthesize particular B-group vitamins namely nicotinamide, thiamin, pyridoxine, riboflavin, p -aminobenzoic acid or biotin. Symbiont-free instar IV insects infected with a mutant of any one of these phenotypes moulted to instar V essentially as though infected with wild-type symbionts and did not exhibit the substantial developmental disturbance shown by symbiont-free controls. Though occasional overgrowth of auxotrophs by prototrophic revertants occurred it was not a significant problem. Continued growth of the nicotinamide, thiamin or pyridoxine auxotroph- and wild-type-infected instar V insects was comparable. With the remaining auxotroph-infected insects results varied between experiments, possibly because of disjunction of pre- and post-ecdysial changes in the insect’s pharyngeal pump. Overall, the results are interpreted as disproving the hypothesis that the de novo synthesis of B-vitamins by the symbiont is the sine qua non of the relationship. This contrasts with the conclusions of previous workers. It is suggested that these differences might be accounted for by the more precise experimental framework adopted here. Variations on the ‘traditional’ vitamin hypothesis are suggested: these involve the ‘conversion of metabolites’ rather than the de novo synthesis of vitamins and may help reconcile conflicting results. The symbiont showed unexpected carbon source utilization in vitro and from this it is inferred that erythrocyte-mediated glycolysis within the insect’s blood-meal continues, thus converting to lactate glucose present in the insect. As blood-meal digestion progresses glycolysis would cease, leading to a possible increase in glucose levels within the gut. Cyclical changes in glucose/lactate levels might influence the development of Trypanosoma cruzi the aetiological agent of Chagas’ disease, which undergoes part of its life cycle in the triatomid gut. Peak populations of about 10 8 symbionts per instar IV insects were found, corresponding to about 5 % of the dry increase of the instar. Symbionts survived well in the insect’s faeces and this, in conjunction with the demonstrated coprophilic behaviour of the insect, which would lead to a high probability of contact with faeces, may be of critical importance in the establishment of the symbiotic relationship.

scholarly journals Blood meal sources of Anopheles vectors of human malaria in Malawi: Implications for malaria transmission and effectiveness of interventions

2021 ◽  
Author(s):  
Rex B Mbewe ◽  
John Keven ◽  
Themba Mzilahowa ◽  
Lauren Cohee ◽  
Miriam K Laufer ◽  
...  
Keyword(s):  
Human Blood ◽  
Blood Meal ◽  
Light Trap ◽  
Blood Feeding ◽  
Malaria Vectors ◽  
Rural Villages ◽  
Human Malaria ◽  
Anopheles Vectors ◽  
Wide Availability ◽  
Blood Meals

Abstract BackgroundSelection of blood meal hosts by mosquitoes is a key variable in the vectorial capacity of Anopheles mosquitoes for human malaria. Blood feeding on humans is likely to be modulated by use of different types of long-lasting insecticidal nets (LLINs) and the effectiveness of LLINs is impacted by the relative intensity of insecticide resistance. The aim of this study was to test the hypothesis that LLINs containing pyrethroid and the synergist piperonyl butoxide (PBO) would lead to a reduction of human host utilization than LLINs containing only pyrethroid and that blood feeding patterns of Anopheles in Malawi compromise malaria interventions.MethodsFemale Anopheles mosquitoes were sampled indoors from May 2019 through April 2020 by aspiration, pyrethrum spray catch, and CDC light trap in rural villages of Namanolo (conventional nets) and Ntaja (PBO nets) in Balaka and Machinga districts respectively. Anopheles species, blood meal sources, and infection with Plasmodium falciparum in the head and thorax of individual mosquitoes were determined with PCR.ResultsOf a total of 6,585 Anopheles females sampled indoors in 203 houses, 633 (9.6%) were blood-fed and consisted of An. arabiensis (44.1% (n = 279)), An. gambiae s.s (16.2% (n = 103)), An. funestus s.s (33.5% (n = 212)), An. parensis 0.3% (n = 2), and unidentified Anopheles spp (5.8% (n = 37)). Of the 541 mosquitoes (85.5%) successfully identified blood meals, 436 (81.0%) were solely human, 28 (5.2%) goat, 11 (2.0%) dog, 60 (11.1%) mixed goat-human, 5 (0.9%) dog-human, and 1 dog-goat. Human blood index and EIR was high in Namanolo than Ntaja (0.96 vs 0.89 (p = 0.001) and 0.11 vs 0.06 infective bites per person per year respectively) despite high net ownership (92%) and nightly use (75%) rates. Relative to host availability, non-human hosts were over selected in the two sites.ConclusionThe use of PBO nets was associated with lower HBI and EIR, however, the wide availability of LLINs was still associated with extensive successful human blood meals by the main malaria vectors in Malawi. The presence of a small fraction of mixed blood meals indicates constrained plasticity of Anopheles vectors to switch to non-human hosts and circumvent malaria control interventions.

scholarly journals Novel small molecule agonists of an Aedes aegypti neuropeptide Y receptor block mosquito biting behavior

2018 ◽  
Author(s):  
Laura B. Duvall ◽  
Lavoisier Ramos-Espiritu ◽  
Kyrollos E. Barsoum ◽  
J. Fraser Glickman ◽  
Leslie B. Vosshall
Keyword(s):  
Aedes Aegypti ◽  
Neuropeptide Y ◽  
Small Molecule ◽  
Blood Meal ◽  
Disease Transmission ◽  
Blood Feeding ◽  
Behavioral Suppression ◽  
Host Seeking ◽  
Novel Approach ◽  
Seeking Behavior

AbstractFemale Aedes aegypti mosquitoes bite humans to obtain a blood-meal to develop their eggs. Remarkably, strong attraction to humans is suppressed for several days after the blood-meal by an unknown mechanism. We investigated a role for neuropeptide Y (NPY)-related signaling in this long-term behavioral suppression, and discovered that drugs targeting human NPY receptors modulate mosquito host-seeking behavior. In a screen of all 49 predicted Ae. aegypti peptide receptors, we identified NPY-like receptor 7 (NPYLR7) as the sole target of these human drugs. To obtain small molecule agonists selective for NPYLR7, we carried out a high-throughput cell-based assay of 265,211 compounds, and isolated 6 highly selective NPYLR7 agonists that inhibit mosquito attraction to humans. NPYLR7 CRISPR-Cas9 null mutants are defective in behavioral suppression, and resistant to these drugs. Finally, we show that these drugs are capable of inhibiting biting and blood-feeding on a live host, suggesting a novel approach to control infectious disease transmission by controlling mosquito behavior.

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