scholarly journals Implications of Sublethal Insecticide Exposure and the Development of Resistance on Mosquito Physiology, Behavior, and Pathogen Transmission

Insects ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 917
Author(s):  
Felipe Andreazza ◽  
Eugênio E. Oliveira ◽  
Gustavo Ferreira Martins
Keyword(s):  
Population Genetics ◽  
Sublethal Effects ◽  
Pathogen Transmission ◽  
Development Of Resistance ◽  
Insecticide Exposure ◽  
Complex Interactions ◽  
Population Sizes ◽  
Sublethal Doses ◽  
Vertebrate Hosts ◽  
And Behavior

For many decades, insecticides have been used to control mosquito populations in their larval and adult stages. Although changes in the population genetics, physiology, and behavior of mosquitoes exposed to lethal and sublethal doses of insecticides are expected, the relationships between these changes and their abilities to transmit pathogens remain unclear. Thus, we conducted a comprehensive review on the sublethal effects of insecticides and their contributions to insecticide resistance in mosquitoes, with the main focus on pyrethroids. We discuss the direct and acute effects of sublethal concentrations on individuals and populations, the changes in population genetics caused by the selection for resistance after insecticide exposure, and the major mechanisms underlying such resistance. Sublethal exposures negatively impact the individual’s performance by affecting their physiology and behavior and leaving them at a disadvantage when compared to unexposed organisms. How these sublethal effects could change mosquito population sizes and diversity so that pathogen transmission risks can be affected is less clear. Furthermore, despite the beneficial and acute aspects of lethality, exposure to higher insecticide concentrations clearly impacts the population genetics by selecting resistant individuals, which may bring further and complex interactions for mosquitoes, vertebrate hosts, and pathogens. Finally, we raise several hypotheses concerning how the here revised impacts of insecticides on mosquitoes could interplay with vector-mediated pathogens’ transmission.

scholarly journals Brook trout passage performance through culverts

2016 ◽  
Vol 73 (1) ◽  
pp. 94-104 ◽  
Author(s):  
Elsa Goerig ◽  
Theodore Castro-Santos ◽  
Normand Émile Bergeron
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Structural Characteristics ◽  
Passive Integrated Transponder ◽  
Complex Interactions ◽  
Factors Influencing ◽  
Several Variables ◽  
And Behavior ◽  
Steep Slopes ◽  
Corrugated Metal

Culverts can restrict access to habitat for stream-dwelling fishes. We used passive integrated transponder telemetry to quantify passage performance of >1000 wild brook trout (Salvelinus fontinalis) attempting to pass 13 culverts in Quebec under a range of hydraulic and environmental conditions. Several variables influenced passage success, including complex interactions between physiology and behavior, hydraulics, and structural characteristics. The probability of successful passage was greater through corrugated metal culverts than through smooth ones, particularly among smaller fish. Trout were also more likely to pass at warmer temperatures, but this effect diminished above 15 °C. Passage was impeded at higher flows, through culverts with steep slopes, and those with deep downstream pools. This study provides insight on factors influencing brook trout capacity to pass culverts as well as a model to estimate passage success under various conditions, with an improved resolution and accuracy over existing approaches. It also presents methods that could be used to investigate passage success of other species, with implications for connectivity of the riverscape.

scholarly journals Modeling human temperament and character on the basis of combined theoretical approaches

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Konstantinos N. Fountoulakis ◽  
Xenia Gonda
Keyword(s):  
Cognitive Control ◽  
Cognitive Processes ◽  
Personal Space ◽  
Environment Interaction ◽  
Ego Strength ◽  
Complex Interactions ◽  
Theoretical Approaches ◽  
Forward Stepwise ◽  
And Behavior ◽  
Single Approach

Abstract Background Although there are several models on the structure of human temperament, character and personality, the majority follow a single approach, providing a unilateral and overly theoretical construct which is unsuitable for clinical application. The current study aimed to develop a complex and comprehensive model of temperament and character by empirically combining relevant existing theories. Methods The study included 734 healthy general population subjects aged 40.80 ± 11.48 years, who completed the TEMPS-A, TCI and NEO-PI-3 questionnaires. Data were analyzed in a multistep approach using Exploratory Factor analysis and forward stepwise linear regression. Results The results yielded two highest order factors (Self and Self–Environment Interaction), six middle order factors (Emotional Self, Cognitive Self, Social Emotionality, Emotional and Cognitive Control, Ethical Emotionality and Behavior, Social Emotionality and Behavior) and 12 factors at the bottom (Ego Resiliency, Ego Strength, Intrapersonal Emotion, Personal Space Cognition, Interpersonal Cognition, Emotional Creativity, Externalized Interpersonal Emotion, Internalized Interpersonal Emotion, Emotional Motivation, Self-Discipline, Ethical Values and Ethical Behavior). Conclusions The current study developed a complex hierarchical model of temperament and character on the basis of empirical data from several temperament theories. An important feature of the new temperamental model is the frequent admixture of emotional and cognitive processes within the same module. This model expands the field to include elements probably corresponding to meta-cognition mechanisms and complex interactions between affective and cognitive control, which may provide useful in understanding and treating affective disorders as well.

Dealing with antimicrobial resistance – the Danish experience

2000 ◽  
Vol 80 (2) ◽  
pp. 223-228 ◽  
Author(s):  
F. Bager ◽  
F. M. Aarestrup ◽  
H. C. Wegener
Keyword(s):  
Antimicrobial Resistance ◽  
Growth Promotion ◽  
Steering Committee ◽  
Eu Member States ◽  
Development Of Resistance ◽  
Complex Interactions ◽  
Resistant Strains ◽  
Food Animals ◽  
Clonal Spread ◽  
Practical Recommendations

Following the discovery in 1994 and 1995 that use of the glycopeptide antimicrobial avoparcin for growth promotion was associated with the occurrence of vancomycin resistant Enterococcus faecium in food animals and in food, the Danish Minister of Food, Agriculture and Fisheries banned the use of avoparcin in May 1995. The ban was later extended by the European Commission to include all EU member states. In May 1999, the EU Scientific Steering Committee recommended that use for growth promotion of antimicrobials, which are or may be used in human or veterinary medicine should be phased out as soon as possible and ultimately abolished. During the first half of the 1990s the consumption of tetracyclines, mainly in pig production, increased markedly. This was countered by severely reducing through legal means the financial enticement for veterinarians to prescribe medicines and by restricting the availability of tetracycline as non-registered speciality products. The focus on consumption of antimicrobials and on resistance prompted a number of initiatives by Danish authorities to limit the increase in antimicrobial resistance. One such initiative was the implementation of an integrated programme (DANMAP), which monitors resistance among bacteria from food animals, food and humans. A programme to monitor all use of prescription medicine in food animals at the herd level is presently being implemented. Another initiative was the elaboration of a series of practical recommendations to veterinarians on the prudent use of antimicrobials in order to reduce the development of resistance without compromising therapeutic efficacy. Our experience with avoparcin shows that a restrictive policy on the use of antimicrobials can curb the development of resistance. However, the occurrence and persistence of specific resistance phenotypes is the end-result of complex interactions of, among others, antimicrobial co-selection, clonal spread of resistant strains and various herd management factors. Key words: Antimicrobial resistance, Denmark, avoparcin, tetracycline

scholarly journals Sublethal and transgenerational effects of alphamethrin on life history traits of Anopheles stephensi (Diptera: Culicidae), a malaria mosquito

2017 ◽  
Vol 149 (2) ◽  
pp. 251-264 ◽  
Author(s):  
T.P.N. Hariprasad ◽  
N.J. Shetty
Keyword(s):  
Sex Ratio ◽  
Disease Transmission ◽  
Anopheles Stephensi ◽  
Sublethal Effects ◽  
Adult Emergence ◽  
Negative Effects ◽  
Egg Hatchability ◽  
Fitness Parameters ◽  
Sublethal Doses ◽  
Sublethal Concentrations

AbstractAnopheles stephensi Liston (Diptera: Culicidae), an urban malaria vector in India, is controlled by insecticides. Sublethal concentrations can be effective in reducing mosquito populations and disease transmission by reducing its reproductive fitness. In this study, sublethal effects of alphamethrin, a synthetic pyrethroid, were assessed on selected fitness parameters. Late third instars of the Goraguntepalya strain, Bangalore, were exposed to three sublethal doses, LC10 – 0.00006, LC30 – 0.0004, and LC50 – 0.0014 mg/L and their effects on fecundity, egg hatchability, sex ratio, and longevity in parental, F1 and F2 generations. The morphology of gonads, pattern of pupation, and adult emergence were also assessed. We found a significant reduction in fecundity and hatchability among the sublethal concentrations as well as across generations. Survival analysis showed significant reduction in lifespan of exposed groups. Delay in pupation, eclosion, and no distortion in sex ratio was observed. The results suggest that sublethal concentrations of alphamethrin may have negative effects on exposed individuals and subsequent generations.

scholarly journals Exploring the Interactions Between Neurophysiology and Cognitive and Behavioral Changes Induced by a Non-pharmacological Treatment: A Network Approach

2021 ◽  
Vol 13 ◽  
Author(s):  
Víctor Rodríguez-González ◽  
Carlos Gómez ◽  
Hideyuki Hoshi ◽  
Yoshihito Shigihara ◽  
Roberto Hornero ◽  
...  
Keyword(s):  
Behavioral Changes ◽  
Pharmacological Intervention ◽  
Functional Impairments ◽  
Complex Interactions ◽  
Before And After ◽  
Neurophysiological Data ◽  
Behavior Disturbance ◽  
And Behavior ◽  
State Examination ◽  
Personalized Intervention

Dementia due to Alzheimer’s disease (AD) is a neurological syndrome which has an increasing impact on society, provoking behavioral, cognitive, and functional impairments. AD lacks an effective pharmacological intervention; thereby, non-pharmacological treatments (NPTs) play an important role, as they have been proven to ameliorate AD symptoms. Nevertheless, results associated with NPTs are patient-dependent, and new tools are needed to predict their outcome and to improve their effectiveness. In the present study, 19 patients with AD underwent an NPT for 83.1 ± 38.9 days (mean ± standard deviation). The NPT was a personalized intervention with physical, cognitive, and memory stimulation. The magnetoencephalographic activity was recorded at the beginning and at the end of the NPT to evaluate the neurophysiological state of each patient. Additionally, the cognitive (assessed by means of the Mini-Mental State Examination, MMSE) and behavioral (assessed in terms of the Dementia Behavior Disturbance Scale, DBD-13) status were collected before and after the NPT. We analyzed the interactions between cognitive, behavioral, and neurophysiological data by generating diverse association networks, able to intuitively characterize the relationships between variables of a different nature. Our results suggest that the NPT remarkably changed the structure of the association network, reinforcing the interactions between the DBD-13 and the neurophysiological parameters. We also found that the changes in cognition and behavior are related to the changes in spectral-based neurophysiological parameters. Furthermore, our results support the idea that MEG-derived parameters can predict NPT outcome; specifically, a lesser degree of AD neurophysiological alterations (i.e., neural oscillatory slowing, decreased variety of spectral components, and increased neural signal regularity) predicts a better NPT prognosis. This study provides deeper insights into the relationships between neurophysiology and both, cognitive and behavioral status, proving the potential of network-based methodology as a tool to further understand the complex interactions elicited by NPTs.

scholarly journals Predators affect a plant virus through direct and trait-mediated indirect effects on vectors

2021 ◽  
Author(s):  
Benjamin W. Lee ◽  
Robert E. Clark ◽  
Saumik Basu ◽  
David W. Crowder
Keyword(s):  
Plant Pathogens ◽  
Virus Transmission ◽  
Pathogen Transmission ◽  
Risk Of Predation ◽  
Predation Effects ◽  
Antipredator Behaviors ◽  
Vector Borne ◽  
Predator Risk ◽  
Aphid Movement ◽  
And Behavior

AbstractArthropods that vector plant pathogens often interact with predators within food webs. Predators affect vectors by eating them (consumptive effects) and by inducing antipredator behaviors (non-consumptive effects), and these interactions may affect transmission of vector-borne pathogens. However, it has proven difficult to experimentally tease apart the effects of predators on vector fitness and behavior as they are often correlated. We addressed this problem by assessing how both aphids and an aphid-borne pathogen were affected by variable predation risk. Specifically, we experimentally manipulated ladybeetle predators’ mouthparts to isolate consumptive, and non-consumptive, effects of predators on aphid fitness, movement, and virus transmission. We show that although lethal predators decreased aphid vector abundance, they increased pathogen transmission by increasing aphid movement among hosts. Moreover, aphids responded to risk of predation by moving to younger plant tissue that was more susceptible to the pathogen. Aphids also responded to predator risk through compensatory reproduction, which offset direct consumptive effects. Our results support predictions of disease models showing alterations of vector movement due to predators can have greater effects on transmission of pathogens than vector consumption. Broadly, our study shows isolating direct and indirect predation effects can reveal novel pathways by which predators affect vector-borne pathogens.

scholarly journals Landscape-level toxicant exposure mediates infection impacts on wildlife populations

2020 ◽  
Vol 16 (11) ◽  
pp. 20200559
Author(s):  
Cecilia A. Sánchez ◽  
Sonia Altizer ◽  
Richard J. Hall
Keyword(s):  
Sublethal Effects ◽  
Mechanistic Model ◽  
Host Population ◽  
Pathogen Transmission ◽  
Population Declines ◽  
Wildlife Diseases ◽  
Toxicant Exposure ◽  
Landscape Modification ◽  
Wildlife Populations ◽  
Landscape Level

Anthropogenic landscape modification such as urbanization can expose wildlife to toxicants, with profound behavioural and health effects. Toxicant exposure can alter the local transmission of wildlife diseases by reducing survival or altering immune defence. However, predicting the impacts of pathogens on wildlife across their ranges is complicated by heterogeneity in toxicant exposure across the landscape, especially if toxicants alter wildlife movement from toxicant-contaminated to uncontaminated habitats. We developed a mechanistic model to explore how toxicant effects on host health and movement propensity influence range-wide pathogen transmission, and zoonotic exposure risk, as an increasing fraction of the landscape is toxicant-contaminated. When toxicant-contaminated habitat is scarce on the landscape, costs to movement and survival from toxicant exposure can trap infected animals in contaminated habitat and reduce landscape-level transmission. Increasing the proportion of contaminated habitat causes host population declines from combined effects of toxicants and infection. The onset of host declines precedes an increase in the density of infected hosts in contaminated habitat and thus may serve as an early warning of increasing potential for zoonotic spillover in urbanizing landscapes. These results highlight how sublethal effects of toxicants can determine pathogen impacts on wildlife populations that may not manifest until landscape contamination is widespread.

scholarly journals Effects of Lethal Bronzing Disease, Palm Height, and Temperature on Abundance and Monitoring of Haplaxius crudus

Insects ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 748
Author(s):  
De-Fen Mou ◽  
Chih-Chung Lee ◽  
Philip G. Hahn ◽  
Noemi Soto ◽  
Alessandra R. Humphries ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Disease Management ◽  
Low Temperature ◽  
Feeding Preference ◽  
Pathogen Transmission ◽  
Interactive Effects ◽  
Insect Vector ◽  
Cumulative Number ◽  
Sticky Traps ◽  
And Behavior

Insect vector feeding preference and behavior play important roles in pathogen transmission, especially for pathogens that solely rely on insect vector transmission. This study aims to examine the effects of the 16SrIV-D phytoplasma, the causal agent of lethal bronzing (LB) disease of palms, on associated auchenorrhynchan insects. The numbers of auchenorrhynchans collected during weekly surveys during a yearlong study using yellow sticky traps were analyzed. The cumulative number of H. crudus was 4.5 times greater on phytoplasma-infected relative to non-infected palms. Other auchenorrhynchans showed no difference between phytoplasma-infected and non-infected palms or were greater on non-infected rather than on infected palms. Furthermore, we examined the effects of LB, palm height, temperature, and the interactive effects of these factors on H. crudus abundance. When the palms were infected with LB, at low temperature, H. crudus was more abundant on shorter than taller palms; however, H. crudus was more abundant on taller than shorter palms at the median and higher temperatures. These results may indicate that H. crudus prefers LB-infected palms over non-infected palms. The interactive effects of LB, palm heights, and temperature further suggest that vector monitoring and disease management should be optimized according to seasonal variation in temperature.

scholarly journals Retroviral Restriction Factors and Their Viral Targets: Restriction Strategies and Evolutionary Adaptations

2020 ◽  
Vol 8 (12) ◽  
pp. 1965
Author(s):  
Guney Boso ◽  
Christine A. Kozak
Keyword(s):  
Adaptive Evolution ◽  
Restriction Factors ◽  
Complex Interactions ◽  
Evolutionary Conflict ◽  
Accelerated Evolution ◽  
Multiple Virus ◽  
Vertebrate Hosts ◽  
Cellular Pathways ◽  
Retroviral Replication ◽  
Viral Antagonists

The evolutionary conflict between retroviruses and their vertebrate hosts over millions of years has led to the emergence of cellular innate immune proteins termed restriction factors as well as their viral antagonists. Evidence accumulated in the last two decades has substantially increased our understanding of the elaborate mechanisms utilized by these restriction factors to inhibit retroviral replication, mechanisms that either directly block viral proteins or interfere with the cellular pathways hijacked by the viruses. Analyses of these complex interactions describe patterns of accelerated evolution for these restriction factors as well as the acquisition and evolution of their virus-encoded antagonists. Evidence is also mounting that many restriction factors identified for their inhibition of specific retroviruses have broader antiviral activity against additional retroviruses as well as against other viruses, and that exposure to these multiple virus challenges has shaped their adaptive evolution. In this review, we provide an overview of the restriction factors that interfere with different steps of the retroviral life cycle, describing their mechanisms of action, adaptive evolution, viral targets and the viral antagonists that evolved to counter these factors.

scholarly journals Insights into Oropharyngeal Microbiota, Biofilms and Associated Diseases from Metagenomics and Transcriptomic Approaches

2021 ◽  
Author(s):  
Richa Priyadarshini ◽  
Karthik Krishnan ◽  
Rashmi Niranjan
Keyword(s):  
Gene Expression ◽  
Microbial Community ◽  
Oral Cavity ◽  
Pathogenic Bacteria ◽  
Microbial Biofilms ◽  
Complex Interactions ◽  
Microbial Associations ◽  
And Behavior ◽  
Fine Tune ◽  
Diverse Microbial Community

Oral cavity is an ecologically complex environment and hosts a diverse microbial community. Most of these organisms are commensals, however, on occasion, some have the potential to become pathogenic causing damage to the human host. Complex interactions between pathogenic bacteria, the microbiota, and the host can modify pathogen physiology and behavior. Most bacteria in the environment do not exist in free-living state but are found as complex matrix enclosed aggregates known as biofilms. There has been research interest in microbial biofilms because of their importance in industrial and biomedical settings. Bacteria respond to environmental cues to fine-tune the transition from planktonic growth to biofilm by directing gene expression changes favorable for sessile community establishment. Meta-approaches have been used to identify complex microbial associations within human oral cavity leading to important insights. Comparative gene expression analysis using deep sequencing of RNA and metagenomics studies done under varying conditions have been successfully used in understanding and identifying possible triggers of pathogenicity and biofilm formation in oral commensals.

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