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- Emami, S. Noushin, et al.
(author)
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Can Plasmodium's tricks for enhancing its transmission be turned against the parasite? New hopes for vector control
- 2019
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In: Pathogens and Global Health. - : Informa UK Limited. - 2047-7724 .- 2047-7732. ; 113:8, s. 325-335
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Research review (peer-reviewed)abstract
- Approximately 120 years ago the link between mosquito and the malaria transmission was discovered. However, even today it remains an open question whether the parasite is able to direct the blood-seeking and feeding behavior of its mosquito vector to maximize the probability of transmission. If the parasite has this ability, could it occur only through the alteration of the vertebrate host's volatile organic compounds (VOCs) and/or the parasite alteration of the behavior of the infected vector in a manner that favors its transmission? Although some recent empirical evidence supports the hypothesis regarding the parasite ability in alteration of the vertebrate host's VOCs, the role of parasite alteration and behavioral differences between infected and uninfected female mosquitoes toward infected and uninfected hosts has not yet been considered in the implementation of control measures. This review will discuss the current evidence, which shows 1. Plasmodium can direct uninfected mosquito blood-seeking and feeding behavior via alteration of vertebrate-host odor profiles and production of phagostimulants and 2. Plasmodium also manipulates its vector during the sporogony cycle to increase transmission. Briefly, we also consider the next generation of methods for moving the empirical laboratory evidence to potential application in future integrated malaria control programs.
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| 2. |
- Hajkazemian, Melika, et al.
(author)
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Battleground midgut : The cost to the mosquito for hosting the malaria parasite
- 2021
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In: Biology of the Cell. - : Wiley. - 0248-4900 .- 1768-322X. ; 113:2, s. 79-94
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Research review (peer-reviewed)abstract
- In eco-evolutionary studies of parasite-host interactions, virulence is defined as a reduction in host fitness as a result of infection relative to an uninfected host. Pathogen virulence may either promote parasite transmission, when correlated with higher parasite replication rate, or decrease the transmission rate if the pathogen quickly kills the host. This evolutionary mechanism, referred to as 'trade-off' theory, proposes that pathogen virulence evolves towards a level that most benefits the transmission. It has been generally predicted that pathogens evolve towards low virulence in their insect vectors, mainly due to the high dependence of parasite transmission on their vector survival. Therefore, the degree of virulence which malaria parasites impose on mosquito vectors may depend on several external and internal factors. Here, we review briefly (i) the role of mosquito in parasite development, with a particular focus on mosquito midgut as the battleground between Plasmodium and the mosquito host. We aim to point out (ii) the histology of the mosquito midgut epithelium and its role in host defence against parasite's countermeasures in the three main battle sites, namely (a) the lumen (microbiota and biochemical environment), (b) the peritrophic membrane (physical barrier) and (c) the tubular epithelium including the basal membrane (physical and biochemical barrier). Lastly, (iii) we describe the impact which malaria parasite and its virulence factors have on mosquito fitness.
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| 3. |
- Hajkazemian, Melika, 1988-
(author)
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Decoding the language of transmission among vector-pathogen-host
- 2023
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Doctoral thesis (other academic/artistic)abstract
- Vector-borne diseases account for over 17 percent of all infectious diseases and lead to more than 700,000 mortalities annually. Importantly, there is a complex interaction between infectious organisms and their host. Vectors spread pathogens, which have a significant negative health effect on humans and animals and therefore detrimental economic and environmental impacts. Only 2% of the more than 3,600 mosquito species are blood feeders, primarily; the Anopheles, Culex, and Aedes which spread the Malaria parasite, Zika, Chikungunya, West Nile, and Dengue viruses. Therefore, understanding the complex chemical signaling and the molecular mechanisms that mediate pathogen and vector interaction, and allow the pathogen to survive and spread, are the subjects of this thesis.In project I, we determined the production and release of Anopheles male aggregation Volatile Organic Compounds (VOCs) that initiate swarming, and enhance mating success. In addition, we compared the RNA-sequencing libraries of swarming to flag for chemosensory and circadian genes. The goal was to identify the molecular mechanisms of swarming and metabolite roles in mating success.In project II, we evaluated the phagostimulant effects of (E)-4-Hydroxy-3-methyl-but-2-enyl pyrophosphate (HMBPP) on an artificial feeding system for some important vectors (Anopheles coluzzii, An. arabiensis, An. gambiae s.s., Culex pipiens/Culex torrentium, and Aedes aegypti). We showed that our toxic plant-based solution can kill the five lethal vectors.In project III, we studied the alteration of An. gambiae behavior by the Plasmodium falciparum at infected (oocyst-carrying, 7 days post-infection) and infective (sporozoite-carrying, 14 days post-infection) stages. To discover whether antennal chemosensory genes expression changes at different stages of infection, we performed RNA-seq and examined the candidate olfactory genes’ abundance to provide a possible molecular mechanism for manipulating the parasite-carrying mosquitoes' behavior.Finally, in project IV, we presented the results of RNA-seq analysis that revealed the network connection between developmental genes and the physiological plasticity in male mosquitoes of An. funestus. We identified the transcripts that associated with the male An. funestus sexual maturation and mating success.In summary, this thesis focuses on understanding how vector-pathogen interaction manipulates the vector’s transcriptome, physiology, and behavior to enhance transmission success and thereby identify novel targets for vector-borne disease control.
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| 4. |
- Hajkazemian, Melika, et al.
(author)
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Mosquito host-seeking diel rhythm and chemosensory gene expression is affected by age and Plasmodium stages
- 2022
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 12
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Journal article (peer-reviewed)abstract
- Malaria parasites can affect vector-related behaviours, increasing transmission success. Using Anopheles gambiae and Plasmodium falciparum, we consider the effect of interaction between infection stage and vector age on diel locomotion in response to human odour and the expression of antennal chemosensory genes. We identified age-dependent behavioural diel compartmentalisation by uninfected females post-blood meal. Infection disrupts overall and diel activity patterns compared with age-matched controls. In this study, mosquitoes carrying transmissible sporozoites were more active, shifting activity periods which corresponded with human host availability, in response to human odour. Older, uninfected, blood-fed females displayed reduced activity during their peak host-seeking period in response to human odour. Age- and infection stage-specific changes in odour-mediated locomotion coincide with altered transcript abundance of select chemosensory genes suggesting a possible molecular mechanism regulating the behaviour. We hypothesize that vector-related behaviours of female mosquitoes are altered by infection stage and further modulated by the age post-blood meal of the vector. Findings may have important implications for malaria transmission and disease dynamics.
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| 5. |
- Koekemoer, L. L., et al.
(author)
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Data-driven networking of global transcriptomics and male sexual development in the main malaria vector, Anopheles funestus
- 2023
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In: Scientific Reports. - 2045-2322. ; 13
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Journal article (peer-reviewed)abstract
- Deaths from malaria remain staggering despite global support that drives research into new territories. One major gap is our understanding of the sexual biological aspects of the male mosquito, which maintain the vector population solidity. Although Anopheles funestus s.s. is an extremely efficient African vector, little is known about the network between its sexual physiology and gene expression. The Culicidae male’s sexual maturity involves a suite of physiological changes, such as genitalia rotation that is necessary for successful mating to occur. We show that mating success is guided by genes and physiological plasticity. Transcriptome analysis between newly emerged males (immature) versus males with rotating genitalia (maturing) provides insight into possible molecular mechanisms regulating male sexual behaviour. Putative transcripts that were associated with male sexual maturation were identified and validated. The discovery of the functions of these transcripts could lead to identifying potential targets for innovative vector control interventions, and mosquito population suppression.
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| 6. |
- Mozūraitis, Raimondas, et al.
(author)
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Male swarming aggregation pheromones increase female attraction and mating success among multiple African malaria vector mosquito species
- 2020
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In: Nature Ecology & Evolution. - : Nature Research. - 2397-334X. ; 4:10, s. 1395-1401
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Journal article (peer-reviewed)abstract
- Accumulating behavioural data indicate that aggregation pheromones may mediate the formation and maintenance of mosquito swarms. However, chemical cues possibly luring mosquitoes to swarms have not been adequately investigated, and the likely molecular incitants of these complex reproductive behaviours remain unknown. Here we show that males of the important malaria vector species Anopheles arabiensis and An. gambiae produce and release aggregation pheromones that attract individuals to the swarm and enhance mating success. We found that males of both species released significantly higher amounts of 3-hydroxy-2-butanone (acetoin), 6-methyl-5-hepten-2-one (sulcatone), octanal, nonanal and decanal during swarming in the laboratory. Feeding males with stable-isotope-labelled glucose revealed that the males produced these five compounds. A blend composed of synthetic analogues to these swarming odours proved highly attractive to virgin males and females of both species under laboratory conditions and substantially increased mating in five African malaria vectors (An. gambiae,An. coluzzii,An. arabiensis,An. merus and An. funestus) in semi-field experiments. Our results not only narrow a conspicuous gap in understanding a vital aspect of the chemical ecology of male mosquitoes but also demonstrate fundamental roles of rhythmic and metabolic genes in the physiology and behavioural regulation of these vectors. These identified aggregation pheromones have great potential for exploitation against these highly dangerous insects. Manipulating such pheromones could increase the efficacy of malaria-vector control programmes.
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| 7. |
- Stromsky, Viktoria E., et al.
(author)
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Plasmodium metabolite HMBPP stimulates feeding of main mosquito vectors on blood and artificial toxic sources
- 2021
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In: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 4:1
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Journal article (peer-reviewed)abstract
- Recent data show that parasites manipulate the physiology of mosquitoes and human hosts to increase the probability of transmission. Here, we investigate phagostimulant activity of Plasmodium-metabolite, (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMBPP), in the primary vectors of multiple human diseases, Anopheles coluzzii, An. arabiensis, An. gambiae s.s., Aedes aegypti, and Culex pipiens/Culex torrentium complex species. The addition of 10 µM HMBPP to blood meals significantly increased feeding in all the species investigated. Moreover, HMBPP also exhibited a phagostimulant property in plant-based-artificial-feeding-solution made of beetroot juice adjusted to neutral pH similar to that of blood. The addition of AlbuMAXTM as a lipid/protein source significantly improved the feeding rate of An. gambiae s.l. females providing optimised plant-based-artificial-feeding-solution for delivery toxins to control vector populations. Among natural and synthetic toxins tested, only fipronil sulfone did not reduce feeding. Overall, the toxic-plant-based-artificial-feeding-solution showed potential as an effector in environmentally friendly vector-control strategies.
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