17 research outputs found
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Landing behaviour of the host seeking malaria vector anopheles coluzzii in response to host associated cues
v ABSTRACT Female mosquitoes of the genus Anopheles transmit the parasites responsible for malaria, one of the most serious vector-borne diseases, which affects one-fifth of the world population. Current malaria prevention relies heavily on vector control interventions, which are most effective and sustainable when based on mosquito behaviour. Although much research has focussed on host-seeking behaviour, less is known about the close-range phase, including landing and post-landing behaviour. Thus, this research aimed to 1) quantify the relative effect that host-associated stimuli have on landing response, 2) quantify the effect that physical target characteristics have on flight behaviour and landing response, and 3) characterise pre- and post-landing behaviour and feeding success in relation to variations of target temperatures. Using behavioural assays, this project firstly quantified the relative role of three host-associated stimuli (thermal, visual, and olfactory) in driving landing and found that they act synergically to increase landing response, that host odour is an essential cue in this phase, and that the landing response is the result of a flexible yet accurate stimuli integration. Secondly, mosquitoes were offered targets with different physical characteristics, and it was found that more mosquitoes landed on the target when at least half of its surface was heated, which suggests a basis for more cost-effective trap designs. Furthermore, more mosquitoes landed on large targets, although small targets caught a greater density of mosquitoes per unit area; however, no effect on landing was observed when targets were oriented vertically or horizontally. Thirdly, it was demonstrated that the surface temperature of a target strongly influenced the feeding success, with mosquitoes being equally successful in feeding on blood at temperatures that ranged from normal human physiological to febrile conditions. Surface temperature also influenced post-landing behaviour, as mosquitoes displayed few foraging events and fed promptly on blood at 36 °C, whilst behaved radically different when presented with blood at 30 °C and 48 °C. Altogether, these results indicate that mosquitoes respond with distinct behaviours depending on the set of cues encountered during host-seeking. The results presented here could be used to improve vector surveillance and control tools by incorporating specific stimuli that are known to elicit specific behavioural responses. Thus, this research aids the cause of reducing the global burden of mosquito-transmitted diseases
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Papillomavirus (HPV) in low-income countries: which perspectives?
Human Papillomavirus (HPV) is agent of the most common sexually transmitted diseases that can infect both females and males. In most cases HPV is asymptomatic and transient, but it may persist giving a variety of mucosal manifestations, genital and not, such as warts and cancers and playing a role in infertility. In low-income countries, despite the high incidence, to date, do not exist effective prevention strategies, neither acceptable diagnostic and therapeutic procedures. In this paper we suggest an operational research approach in order to assess HPV burden and taylor the best solution for HPV infection in low-resources settings
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Short- and long-range dispersal by members of the Simulium damnosum complex (Diptera: Simuliidae), vectors of onchocerciasis: a review
Blackfly members of the Simulium damnosum complex are major vectors of the parasite that causes onchocerciasis in Africa and Yemen, with other vector species involved in a few localized areas of Africa and in the Neotropics. Although the life cycle of these blackflies is linked to fast-flowing rivers, they can travel long distances (up to at least 500 km), calling into question how transmission zones are defined. Knowledge of the short- and long-range dispersal of these vectors could inform where control interventions and monitoring are necessary if targets for onchocerciasis elimination are to be met. Yet, research on blackfly dispersal has been limited and fragmented over the last 70 years. Here, we review the literature on the dispersal of onchocerciasis vectors, and we show the need for further research to establish how far larvae can travel downstream; the extent to which adults invade transmission zones; and whether adults migrate in a series of successive short movements or in single long-distance shifts, or use both methods
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Multimodal synergisms in host stimuli drive landing response in malaria mosquitoes
Anopheles mosquitoes transmit malaria, which affects one-fifth of the world population. A comprehensive understanding of mosquito behaviour is essential for the development of novel tools for vector control and surveillance. Despite abundant research on mosquito behaviour, little is known on the stimuli that drive malaria vectors during the landing phase of host-seeking. Using behavioural assays with a multimodal step approach we quantified both the individual and the combined effect of three host-associated stimuli in eliciting landing in Anopheles coluzzii females. We demonstrated that visual, olfactory and thermal sensory stimuli interact synergistically to increase the landing response. Furthermore, if considering only the fnal outcome (i.e. landing response), our insect model can bypass the absence of either a thermal or a visual stimulus, provided that at least one of these is presented simultaneously with the olfactory stimuli, suggesting that landing is the result of a flexible but accurate stimuli integration. These results have important implications for the development of mosquito control and surveillance tools
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Tolerance to extreme hot and cold temperatures in the EU-protected terrestrial slug Geomalacus maculosus
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Visual and thermal stimuli modulate mosquito-host contact with implications for improving malaria vector control tools
Malaria prevention relies on mosquito control interventions that use insecticides and exploit mosquito behavior. The rise of insecticide resistance and changing transmission dynamics urgently demand vector control innovation. To identify behavioral traits that could be incorporated into such tools, we investigated the flight and landing response of Anopheles coluzzii to human-like host cues. We show that landing rate is directly proportional to the surface area of thermal stimulus, whereas close-range orientation is modulated by both thermal and visual inputs. We modeled anopheline eye optics to theorize the distance at which visual targets can be detected under a range of conditions, and experimentally established mosquito preference for landing on larger targets, although landing density is greater on small targets. Target orientation does not affect landing rate; however, vertical targets can be resolved at greater distance than horizontal targets of the same size. Mosquito traps for vector control could be significantly enhanced by incorporating these features
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Protocol for rearing and using mosquitoes for flight path tracking and behavioral characterization in wind tunnel bioassays
Mosquito behavioral assays are an important component in vector research and control tool development. Here, we present a protocol for rearing Anopheles mosquitoes, performing host-seeking behavioral bioassays, and collecting 3D flight tracks in a large wind tunnel.We describe steps for setting up host-seeking landing assays, both as a non-choice and as a dual-choice assay, and analyzing flight tracks. This protocol can be applied in the research of several behavioral traits, including nectar seeking, resting, mating, and oviposition behavior. For complete details on the use and execution of this protocol, please refer to Carnaghi et al
Nematode associates and susceptibility of a protected slug (Geomalacus maculosus) to four biocontrol nematodes
The impact of selected entomopathogenic nematodes and Phasmarhabditis hermaphrodita on the European-Union-protected slug Geomalacus maculosus and the sympatric Lehmannia marginata was investigated. There was no significant difference in mortality between slugs treated with nematodes and their controls. The presence of P. hermaphrodita in two G. maculosus cadavers may be the result of necromenic behaviour. This study constitutes the first record of P. californica in Europe
Grand challenges in entomology: Priorities for action in the coming decades
Entomology is key to understanding terrestrial and freshwater ecosystems at a time of unprecedented anthropogenic environmental change and offers substantial untapped potential to benefit humanity in a variety of ways, from improving agricultural practices to managing vector-borne diseases and inspiring technological advances. We identified high priority challenges for entomology using an inclusive, open, and democratic four-stage prioritisation approach, conducted among the membership and affiliates (hereafter âmembersâ) of the UK-based Royal Entomological Society (RES). A list of 710 challenges was gathered from 189 RES members. Thematic analysis was used to group suggestions, followed by an online vote to determine initial priorities, which were subsequently ranked during an online workshop involving 37 participants. The outcome was a set of 61 priority challenges within four groupings of related themes: (i) âFundamental Researchâ (themes: Taxonomy, âBlue Skiesâ [defined as research ideas without immediate practical application], Methods and Techniques); (ii) âAnthropogenic Impacts and Conservationâ (themes: Anthropogenic Impacts, Conservation Options); (iii) âUses, Ecosystem Services and Disservicesâ (themes: Ecosystem Benefits, Technology and Resources [use of insects as a resource, or as inspiration], Pests); (iv) âCollaboration, Engagement and Trainingâ (themes: Knowledge Access, Training and Collaboration, Societal Engagement). Priority challenges encompass research questions, funding objectives, new technologies, and priorities for outreach and engagement. Examples include training taxonomists, establishing a global network of insect monitoring sites, understanding the extent of insect declines, exploring roles of cultivated insects in food supply chains, and connecting professional with amateur entomologists. Responses to different challenges could be led by amateur and professional entomologists, at all career stages. Overall, the challenges provide a diverse array of options to inspire and initiate entomological activities and reveal the potential of entomology to contribute to addressing global challenges related to human health and well-being, and environmental change
Grand challenges in entomology: priorities for action in the coming decades
1. Entomology is key to understanding terrestrial and freshwater ecosystems at a time of unprecedented anthropogenic environmental change and offers substantial untapped potential to benefit humanity in a variety of ways, from improving agricultural practices to managing vector-borne diseases and inspiring technological advances.
2. We identified high priority challenges for entomology using an inclusive, open, and democratic four-stage prioritisation approach, conducted among the membership and affiliates (hereafter âmembersâ) of the UK-based Royal Entomological Society (RES).
3. A list of 710 challenges was gathered from 189 RES members. Thematic analysis was used to group suggestions, followed by an online vote to determine initial priorities, which were subsequently ranked during an online workshop involving 37 participants.
4. The outcome was a set of 61 priority challenges within four groupings of related themes: (i) âFundamental Researchâ (themes: Taxonomy, âBlue Skiesâ [defined as research ideas without immediate practical application], Methods and Techniques); (ii) âAnthropogenic Impacts and Conservationâ (themes: Anthropogenic Impacts, Conservation Options); (iii) âUses, Ecosystem Services and Disservicesâ (themes: Ecosystem Benefits, Technology and Resources [use of insects as a resource, or as inspiration], Pests); (iv) âCollaboration, Engagement and Trainingâ (themes: Knowledge Access, Training and Collaboration, Societal Engagement).
5. Priority challenges encompass research questions, funding objectives, new technologies, and priorities for outreach and engagement. Examples include training taxonomists, establishing a global network of insect monitoring sites, understanding the extent of insect declines, exploring roles of cultivated insects in food supply chains, and connecting professional with amateur entomologists. Responses to different challenges could be led by amateur and professional entomologists, at all career stages.
6. Overall, the challenges provide a diverse array of options to inspire and initiate entomological activities and reveal the potential of entomology to contribute to addressing global challenges related to human health and well-being, and environmental change