Turkey tick news: A molecular investigation into the presence of tick-borne pathogens in host-seeking ticks in Anatolia; Initial evidence of putative vectors and pathogens, and footsteps of a secretly rising vector tick, Haemaphysalis parva

Abstract The northern distributional limit of Dermacentor variabilis Say, the American dog tick, is expanding in Saskatchewan and Manitoba (western Canada). The ability of D. variabilis to continue to expand its range northwards will depend upon the ability of individuals within populations at the species distributional edge to withstand very low temperatures during winter. One component of cold hardiness is the supercooling point (SCP), the temperature below 0°C at which an individual freezes. In this study, the SCP was determined for 94 questing D. variabilis adults (44 females and 50 males) from an established population near Blackstrap Provincial Park in Saskatchewan. SCP values ranged from −18.2 to −6.7°C, with a median of −13.3°C. This suggests that host-seeking D. variabilis adults differ in their ability to survive exposure to subzero temperatures, for at least a short period of time, without freezing. The distribution of SCPs was bimodal, but there was no significant difference in SCP values between female and male ticks, and no relationship between SCP and tick body weight. It remains to be determined what factors contribute to the variation in SCP values among questing D. variabilis adults.

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Aphid–Plant–Phytovirus Pathosystems: Influencing Factors from Vector Behaviour to Virus Spread

Agriculture ◽

10.3390/agriculture11060502 ◽

2021 ◽

Vol 11 (6) ◽

pp. 502

Author(s):

Junior Corneille Fingu-Mabola ◽

Frédéric Francis

Keyword(s):

Influencing Factors ◽

Virus Transmission ◽

Physical Factors ◽

Factors Affecting ◽

Vector Borne Diseases ◽

Vector Behaviour ◽

Crop Fields ◽

Host Seeking ◽

The Impact ◽

Vector Efficiency

Aphids are responsible for the spread of more than half of the known phytovirus species. Virus transmission within the plant–aphid–phytovirus pathosystem depends on vector mobility which allows the aphid to reach its host plant and on vector efficiency in terms of ability to transmit phytoviruses. However, several other factors can influence the phytoviruses transmission process and have significant epidemiological consequences. In this review, we aimed to analyse the aphid behaviours and influencing factors affecting phytovirus spread. We discussed the impact of vector host-seeking and dispersal behaviours mostly involved in aphid-born phytovirus spread but also the effect of feeding behaviours and life history traits involved in plant–aphid–phytovirus relationships on vector performances. We also noted that these behaviours are influenced by factors inherent to the interactions between pathosystem components (mode of transmission of phytoviruses, vector efficiency, plant resistance, …) and several biological, biochemical, chemical or physical factors related to the environment of these pathosystem components, most of them being manipulated as means to control vector-borne diseases in the crop fields.

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Gonoactivity of Culex (Culex) (Diptera: Culicidae) Mosquitoes During Winter in Temperate Argentina

Journal of Medical Entomology ◽

10.1093/jme/tjaa295 ◽

2021 ◽

Author(s):

María Florencia Branda ◽

Magdalena Laurito ◽

Andrés Mario Visintin ◽

Walter Ricardo Almirón

Keyword(s):

Developmental Stage ◽

Culex Quinquefasciatus ◽

Culex Pipiens ◽

Life Cycles ◽

Morphological Identification ◽

Dry Ice ◽

Culex Pipiens Pipiens ◽

Host Seeking ◽

Baited Traps ◽

The City

Abstract The subgenus Culex L. includes species involved in summer–autumn arbovirus transmission but studies during winter are scarce in temperate Argentina. Female specimens were collected host-seeking at dry-ice-baited traps during autumn–winter–spring at two sites in Córdoba City during 2016 and 2017. The specimens were morphologically identified and dissected to determine the follicular developmental stage (gonotrophic activity). Females with advanced follicular stages (≥III) were subjected to molecular procedures to confirm or re-identify previous morphological identification. Five species (Culex apicinus Philippi (Diptera: Culicidae), Culex dolosus (Lynch-Arribálzaga) (Diptera: Culicidae), Culex maxi Dyar (Diptera: Culicidae), Culex pipiens pipiens L. (Diptera: Culicidae), and Culex quinquefasciatus Say (Diptera: Culicidae)) were collected and found gonoactive during winter; showing that a high proportion of Culex (Culex) females remain reproductively active during the unfavorable season for mosquito populations. Among them, it is worth noting the collection of Cx. quinquefasciatus, vector of the St. Louis encephalitis virus (endemic in the city), a specimen of Cx. p. pipiens, and a hybrid of Cx. p. pipiens/Cx. quinquefasciatus (during autumn). The study of this community during winter should continue because a high gonoactive female proportion with advanced follicular stages was found: 29.12 and 13.07% in 2016 and 2017, respectively. Local studies such as this one provide evidence about ornithophilic Culex species with active year-round life cycles, species that could favor arbovirus overwintering.

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Molecular investigation of modified β-cyclodextrin and cholesterol inclusion complexes through molecular docking simulations

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/902/1/012017 ◽

2020 ◽

Vol 902 ◽

pp. 012017

Author(s):

M A F Nasution ◽

H G Riyanto ◽

E Saepudin ◽

T A Ivandini

Keyword(s):

Molecular Docking ◽

Inclusion Complexes ◽

Docking Simulations ◽

Molecular Investigation

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Molecular characterization of Polychromophilus parasites of Scotophilus kuhlii bats in Thailand

Parasitology ◽

10.1017/s003118202000222x ◽

2020 ◽

pp. 1-5

Author(s):

Chatree Chumnandee ◽

Nawarat Pha-obnga ◽

Oskar Werb ◽

Kai Matuschewski ◽

Juliane Schaer

Keyword(s):

Blood Cells ◽

Clinical Symptoms ◽

Temperate Climate ◽

Diverse Group ◽

Malaria Parasites ◽

Climate Zones ◽

Haemosporidian Parasites ◽

South And Southeast Asia ◽

Molecular Investigation

Abstract Parasites of the haemosporidian genus Polychromophilus have exclusively been described in bats. These parasites belong to the diverse group of malaria parasites, and Polychromophilus presents the only haemosporidian taxon that infects mammalian hosts in tropical as well as in temperate climate zones. This study provides the first information of Polychromophilus parasites in the lesser Asiatic yellow bat (Scotophilus kuhlii) in Thailand, a common vespertilionid bat species distributed in South and Southeast Asia. The gametocyte blood stages of the parasites could not be assigned to a described morphospecies and molecular analysis revealed that these parasites might represent a distinct Polychromophilus species. In contrast to Plasmodium species, Polychromophilus parasites do not multiply in red blood cells and, thus, do not cause the clinical symptoms of malaria. Parasitological and molecular investigation of haemosporidian parasites of wildlife, such as the neglected genus Polychromophilus, will contribute to a better understanding of the evolution of malaria parasites.

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Modulation of odour-guided behaviour in mosquitoes

Cell and Tissue Research ◽

10.1007/s00441-020-03368-6 ◽

2021 ◽

Vol 383 (1) ◽

pp. 195-206

Author(s):

Sharon R. Hill ◽

Rickard Ignell

Keyword(s):

Functional Genomics ◽

Life Stage ◽

Blood Feeding ◽

Model Systems ◽

Extrinsic Factors ◽

Intrinsic Factors ◽

Host Seeking ◽

Enhancing Resources ◽

Maturation Age ◽

Behavioural Repertoire

AbstractMosquitoes are emerging as model systems with which to study innate behaviours through neuroethology and functional genomics. Decades of work on these disease vectors have provided a solid behavioural framework describing the distinct repertoire of predominantly odour-mediated behaviours of female mosquitoes, and their dependence on life stage (intrinsic factors) and environmental cues (extrinsic factors). The purpose of this review is to provide an overview of how intrinsic factors, including adult maturation, age, nutritional status, and infection, affect the attraction to plants and feeding on plant fluids, host seeking, blood feeding, supplemental feeding behaviours, pre-oviposition behaviour, and oviposition in female mosquitoes. With the technological advancements in the recent two decades, we have gained a better understanding of which volatile organic compounds are used by mosquitoes to recognise and discriminate among various fitness-enhancing resources, and characterised their neural and molecular correlates. In this review, we present the state of the art of the peripheral olfactory system as described by the neural physiology, functional genomics, and genetics underlying the demonstrated changes in the behavioural repertoire in female mosquitoes. The review is meant as a summary introduction to the current conceptual thinking in the field.

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A minimal 3D model of mosquito flight behaviour around the human baited bed net

Malaria Journal ◽

10.1186/s12936-020-03546-5 ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Jeff Jones ◽

Gregory P D Murray ◽

Philip J McCall

Keyword(s):

Spatial Scales ◽

Video Tracking ◽

Sub Saharan Africa ◽

Bed Nets ◽

State Transitions ◽

Bed Net ◽

Flight Behaviour ◽

Individual Agent ◽

Host Seeking ◽

Mosquito Behaviour

Abstract Background Advances in digitized video-tracking and behavioural analysis have enabled accurate recording and quantification of mosquito flight and host-seeking behaviours, facilitating development of individual (agent) based models at much finer spatial scales than previously possible. Methods Quantified behavioural parameters were used to create a novel virtual testing model, capable of accurately simulating indoor flight behaviour by a virtual population of host-seeking mosquitoes as they interact with and respond to simulated stimuli from a human-occupied bed net. The model is described, including base mosquito behaviour, state transitions, environmental representation and host stimulus representation. Results In the absence of a bed net and human host bait, flight distribution of the model population was relatively uniform throughout the arena. Introducing an unbaited untreated bed net induced a change in distribution with an increase in landing events on the net surface, predominantly on the sides of the net. Adding the presence of a simulated human bait dramatically impacted flight distribution patterns, exploratory foraging and, the number and distribution of landing positions on the net, which were determined largely by the orientation of the human within. The model replicates experimental results with free-flying living mosquitoes at human-occupied bed nets, where contact occurs predominantly on the top surface of the net. This accuracy is important as it quantifies exposure to the lethal insecticide residues that may be unique to the net roof (or theoretically any other surface). Number of net contacts and height of contacts decreased with increasing attractant dispersal noise. Conclusions Results generated by the model are an accurate representation of actual mosquito behaviour recorded at and around a human-occupied bed net in untreated and insecticide-treated nets. This fine-grained model is highly flexible and has significant potential for in silico screening of novel bed net designs, potentially reducing time and cost and accelerating the deployment of new and more effective tools for protecting against malaria in sub-Saharan Africa.

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