scholarly journals Tick extracellular vesicles enable arthropod feeding and promote distinct outcomes of bacterial infection

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Adela S. Oliva Chávez ◽  
Xiaowei Wang ◽  
Liron Marnin ◽  
Nathan K. Archer ◽  
Holly L. Hammond ◽  
...  

AbstractExtracellular vesicles are thought to facilitate pathogen transmission from arthropods to humans and other animals. Here, we reveal that pathogen spreading from arthropods to the mammalian host is multifaceted. Extracellular vesicles from Ixodes scapularis enable tick feeding and promote infection of the mildly virulent rickettsial agent Anaplasma phagocytophilum through the SNARE proteins Vamp33 and Synaptobrevin 2 and dendritic epidermal T cells. However, extracellular vesicles from the tick Dermacentor andersoni mitigate microbial spreading caused by the lethal pathogen Francisella tularensis. Collectively, we establish that tick extracellular vesicles foster distinct outcomes of bacterial infection and assist in vector feeding by acting on skin immunity. Thus, the biology of arthropods should be taken into consideration when developing strategies to control vector-borne diseases.

2018 ◽  
Author(s):  
Mabel L. Taracena ◽  
Vanessa Bottino-Rojas ◽  
Octavio A.C. Talyuli ◽  
Ana Beatriz Walter-Nuno ◽  
José Henrique M. Oliveira ◽  
...  

AbstractAedes aegypti is the vector of some of the most important vector-borne diseases like Dengue, Chikungunya, Zika and Yellow fever, affecting millions of people worldwide. The cellular processes that follow a blood meal in the mosquito midgut are directly associated with pathogen transmission. We studied the homeostatic response of the midgut against oxidative stress, as well as bacterial and dengue virus (DENV) infections, focusing on the proliferative ability of the intestinal stem cells (ISC). Inhibition of the peritrophic matrix (PM) formation led to an increase in ROS production by the epithelial cells in response to contact with the resident microbiota, suggesting that maintenance of low levels of ROS in the intestinal lumen is key to keep ISCs division in balance. We show that dengue virus infection induces midgut cell division in both DENV susceptible (Rockefeller) and refractory (Orlando) mosquito strains. However, the susceptible strain delays the activation of the regeneration process compared with the refractory strain. Impairment of the Delta/Notch signaling, by silencing the Notch ligand Delta using RNAi, significantly increased the susceptibility of the refractory strains to DENV infection of the midgut. We propose that this cell replenishment is essential to control viral infection in the mosquito. Our study demonstrates that the intestinal epithelium of the blood fed mosquito is able to respond and defend against different challenges, including virus infection. In addition, we provide unprecedented evidence that the activation of a cellular regenerative program in the midgut is important for the determination of the mosquito vectorial competence.


2016 ◽  
Vol 13 (2) ◽  
pp. 1-14
Author(s):  
MAHNA Khan

Vector-borne diseases (VBDs) of zoonotic importance are the global threat in the human life and on animal welfare as well. Many vector-borne pathogens (VBPs) have appeared in new regions in the past two decades, while many endemic diseases have increased in incidence. Although introductions and emergence of endemic pathogens are often considered to be distinct processes, many endemic pathogens are actually spreading at a local scale coincident with habitat change. Key differences between dynamics and diseases burden result from increased pathogen transmission following habitat change, deforestation and introduction life into new regions. Local emergence of VBPs are commonly driven by changing in ecology (deforestation, massive natural calamities, civil wares etc.), altered human behavior, enhanced enzootic cycles, pathogen invasion from anthropogenic trade and travel, genomic changes of pathogens to coup up with the new hosts, vectors, and climatic conditions and adaptability in wildlife reservoirs. Once a pathogen is established, ecological factors related to vector and host characteristics can shape the evolutionary selective pressure and result in increased use of people as transmission hosts. West Nile virus (WNV), Nipah virus and Chikungunya virus (CHIKV) are among the best-understood zoonotic vector-borne pathogens (VBPs) to have emerged in the last two decades and showed just how explosive epidemics can be in new regions. Zoonotic VBPs that are likely introduced into new regions include Rift Valley Fever and Japanese Encephalitis viruses (JEV) in the Americas, Venezuelan equine encephalitis virus in Eurasia or Africa, Crimean-Congo Hemorrhagic Fever virus (CCHFV) in new parts of Eurasia. Vector-borne diseases currently impose global burden on public health and animal welfare including widespread formerly zoonotic human diseases, such as malaria, leishmania and dengue fever, as well as zoonotic diseases for which humans are dead end hosts, such as Lyme disease, WNV and CCHF. It requires highly equipped laboratory facilities and technical manpower to address emergence and re-emergence of vector-borne zoonotic diseases. Financial and technological hurdles persist in developing countries, making diagnosis and control facility difficult where these diseases are stubbornly most prevalent. Development of technological and highly knowledgeable manpower is the key to protect public health and eco-health. An awareness building about the changing risk of VBPs to prevent introduction foreign pathogens is far more difficult because this is commonly an inevitable consequence of the globalization of trade and travel and in most cases is accidental. Designing of active surveillance of the deadly infectious pathogens by combining the expertise of veterinary and human health could play pivotal roles towards reducing burden of VBPs. History suggests that successful control of VBPs requires prompt identification, swift action, mobilization of fund for developing technical expertise and occasionally by using draconian social measures.DOI: http://dx.doi.org/10.3329/bjvm.v13i2.26614Bangl. J. Vet. Med. (2015). 13 (2): 1-14


Author(s):  
Maria A. Diuk-Wasser ◽  
Maria del Pilar Fernandez ◽  
Stephen Davis

Tick-borne pathogens pose the greatest vector-borne disease burden in temperate areas of Europe and North America. We synthesize key aspects of tick life history that enable ticks to persist, spread and impact human health, including a two-year life cycle, multiple transmission pathways and dependence on hosts for tick feeding, movement and pathogen transmission. We discuss modeling advances that incorporate these traits in the context of climate-driven variation in tick feeding phenology. For established pathogens, such as the Lyme disease agent in the United States, we disentangle the linkages between land use change, habitat fragmentation and host diversity influencing human risk of infection along an urbanization gradient. We propose a coupled natural-human system framework for tick-borne pathogens that accounts for nonlinear effects and feedbacks between the enzootic cycle and human spillover. A deeper understanding of the eco-bio-social determinants of these diseases is required to develop more effective public health interventions.


2020 ◽  
Vol 70 (2) ◽  
pp. 147-169
Author(s):  
Leschnik Michael

AbstractVector-borne diseases are one of the main causes of morbidity and mortality in small animals in Europe. Many of these diseases are well-known among veterinary practitioners and some of them are called emerging diseases as prevalence, temporal and spatial distribution seem to increase in Europe. The number of newly recognized pathogens, transmitted by a variety of arthropod vectors, that are relevant for dogs and cats, is also increasing every year. The prevalence among infected vectors and hosts is a hot topic in veterinary science throughout the entire continent, as well as the development of efficient diagnostic procedures, therapy and prophylactic measures. Companion animal vector-borne diseases comprise a large group of pathogens including viruses, bacteria, protozoa and helminths. These pathogens are mainly transmitted by bloodsucking arthropods (ticks, fleas, mosquitos, sand flies), and more seldom by direct transmission between vertebrate hosts. Vector prevalence and activity is influenced by local climate conditions, host species density, changes in landscape and land use. Human parameters such as poverty and migration affect the use of prophylactic measures against pathogen transmission and infection as well as increasing the zoonotic risk to introducing pathogens by infected humans. Small animal associated factors such as pet trade and pet travel spread infection and certain vectors such as ticks and fleas. All these factors pose several complex and significant challenges for veterinarians in clinical practice to decide on efficient laboratory work-up and constructive diagnostic procedures.


Author(s):  
Patrick Mavingui ◽  
Claire Valiente Mor ◽  
Pablo Tortosa

Arthropods transmit a variety of diseases to humans and animals, including arboviruses, bacteria and parasites. No efficient treatments or control methods are available for many vector-borne diseases, especially for emerging diseases. Therefore, the development of alternative strategies aiming at controlling disease transmission is encouraged worldwide. Although transmission phenomenon is a result of complex interactions involving several actors evolving in a changing environment, the biotic relationship between pathogens and their vectors represents a key step in successful disease transmission. Recent studies highlighted a strong impact of microbiomes on the life-history traits of arthropod hosts. This chapter emphasizes those biotic interactions having an impact on adaptive traits influencing disease transmission. Evidence in behavioral alterations of vector populations/individuals with relevance to vector-pathogen transmission mitigation is reviewed. Opportunities to take advantage of such biotic processes in the control of vector-borne diseases in different epidemiological, entomological and environmental settings are explored.


2020 ◽  
Vol 11 ◽  
Author(s):  
María José Ruiz-López

The microbiota is increasingly recognized for its ability to influence host health and individual fitness through multiple pathways, such as nutrient synthesis, immune system development, and even behavioral processes. Most of these studies though focus on the direct effects microbiota has on its host, but they do not consider possible interactions with other individuals. However, host microbiota can change not only host behavior but also the behavior of other individuals or species toward the host. For example, microbes can have an effect on animal chemistry, influencing animal behaviors mediated by chemical communication, such as mosquito attraction. We know that host skin microbes play a major role in odor production and thus can affect the behavior of mosquitoes leading to differences in attraction to their hosts. Ultimately, the vector feeding preference of mosquitoes conditions the risk of vertebrates of coming into contact with a vector-borne pathogen, affecting its transmission, and thus epidemiology of vector-borne diseases. In this mini review, I provide an overview of the current status of research on the interaction between mosquito behavior and host skin microbiota, both in humans and other vertebrates. I consider as well the factors that influence vertebrate skin microbiota composition, such as sex, genetic makeup, and infection status, and discuss the implications for pathogen transmission.


2019 ◽  
Vol 57 (1) ◽  
pp. 8-16
Author(s):  
Christina E Thomas ◽  
Emily S Burton ◽  
Jesse L Brunner

Abstract Vector feeding behavior can have a profound influence on the transmission of vector-borne diseases. In the case of black-legged ticks, Ixodes scapularis Say, which vectors the agents of Lyme disease, babesiosis, and other pathogens, the timing and propensity of questing can determine which hosts are fed upon as well as the risk of contact with humans. Yet we know little about the controls and constraints on tick host-finding behavior under natural conditions. Ticks must balance the need to quest for blood meal hosts with the risk of desiccation, all on a fixed energy budget. Prior research, primarily in the laboratory, has shown that questing activity varies with conditions (e.g., temperature, relative humidity), light-dark cycles, and energy reserves, but the findings have been idiosyncratic and the dominant factor(s) in nature remains unknown. We measured questing activity of nymphs and larvae throughout the day and night and over several weeks in enclosures across a range of suitable tick habitats within a site in the Northeast. Activity of nymphs increased slightly during dawn and dusk, opposite of larvae, and declined slightly with air temperature and rain, but these patterns were weak and inconsistent among replicate sites. Rather it appears a fraction of ticks were questing most of the time, regardless of conditions. Our study suggests neither climatic conditions or light-dark cycles have appreciable influence on tick questing behavior.


2019 ◽  
Vol 13 ◽  
pp. 117863021985900 ◽  
Author(s):  
Craig A Stoops ◽  
Whitney A Qualls ◽  
Thuy-Vi T Nguyen ◽  
Stephanie L Richards

Background and Purpose: Barrier insecticide treatments have a long history in mosquito control programs but have been used more frequently in the United States in recent years for control of invasive “backyard” species (eg, Aedes albopictus) and increases in incidence of vector-borne diseases (eg, Zika). Methods: We reviewed the published literature for studies investigating barrier treatments for mosquito control during the last 74 years (1944-2018). We searched databases such as PubMed, Web of Science, and Google Scholar to retrieve worldwide literature on barrier treatments. Results: Forty-four studies that evaluated 20 active ingredients (AIs) and 21 formulated products against multiple mosquito species are included. Insecticides investigated for efficacy included organochlorines (dichlorodiphenyltrichloroethane [DDT], β-hexachlorocyclohexane [BHC]), organophosphates (malathion), and pyrethroids (bifenthrin, deltamethrin, permethrin, lambda-cyhalothrin) as AIs. Study design varied with multiple methods used to evaluate effectiveness of barrier treatments. Barrier treatments were effective at lowering mosquito populations although there was variation between studies and for different mosquito species. Factors other than AI, such as exposure to rainfall and application equipment used, also influenced control efficacy. Conclusions: Many of the basic questions on the effectiveness of barrier insecticide applications have been answered, but several important details still must be investigated to improve precision and impact on vector-borne pathogen transmission. Recommendations are made to assist future evaluations of barrier treatments for mosquito control and to limit the potential development of insecticide resistance.


2020 ◽  
Vol 57 (4) ◽  
pp. 1069-1076
Author(s):  
Ana María Ayala ◽  
Noelia Soledad Vera ◽  
Marina Beatriz Chiappero ◽  
Walter Ricardo Almirón ◽  
Cristina Noemí Gardenal

Abstract Aedes aegypti (L.), the main vector of dengue and other arboviruses, was declared eradicated from Argentina in 1964; however, in 1987, it was detected again and nowadays it occurs in most of the country territory. To understand the transmission of vector-borne diseases, knowledge of the dispersal of vector populations is essential to evaluate the risk of pathogen transmission. We conducted a population genetic analysis of Ae. aegypti in 20 neighborhoods from Córdoba, the second largest city in Argentina, using 10 microsatellite loci. High genetic differentiation and the absence of an isolation by distance pattern was found using Weir and Cockerham’s θ. Bayesian and multivariate clustering analyses showed that the studied sites included individuals with high membership coefficients (Q) in their populations, individuals with membership in another cluster, and admixed individuals. Individuals with high Q in clusters different from the population in which they were collected strongly suggests that passive transport is important in shaping the Ae. aegypti dispersal pattern in Córdoba city. Knowing the genetic structure of Ae. aegypti populations and their dispersal patterns would contribute to the implementation of vector control programs.


2001 ◽  
Vol 69 (10) ◽  
pp. 6456-6462 ◽  
Author(s):  
Alexia A. Belperron ◽  
Linda K. Bockenstedt

ABSTRACT Natural antibodies are those immunoglobulin molecules found in mammalian serum that arise in the absence of exposure to environmental pathogens and may comprise an early host defense against invading pathogens. The spirochete Borrelia burgdorferi first encounters natural antibodies when its arthropod vector, Ixodes scapularis, begins feeding on a mammalian host. Natural antibodies may therefore have an impact on pathogens within blood-sucking vectors, prior to pathogen transmission to the mammal. In this study, we investigated whether natural antibodies influenced the number and/or phenotype of B. burgdorferi organisms within feeding I. scapularis nymphs. Using a competitive PCR, we found that ticks ingesting a blood meal from B-cell-deficient mice, which lack all immunoglobulins, contained fivefold more spirochete DNA than ticks feeding on control mice. Spirochete DNA levels could be reduced to that of controls with passive transfer of normal mouse serum or polyclonal immunoglobulin M (IgM), but not IgG, into B-cell-deficient mice prior to placement of infected ticks. At 48 h of tick feeding, 90% of spirochetes within salivary glands of ticks removed from B-cell-deficient mice were found by confocal immunofluorescence microscopy to express outer surface protein A (OspA), compared to only 5% of salivary gland spirochetes from ticks detached from control mice. Taken together, these results show that ingestion of natural antibodies limits the spirochete burden within feeding ticks. Because OspA is normally downregulated when spirochetes moved from the tick midgut to the salivary gland, our findings suggest that OspA-expressing midgut spirochetes may be particularly susceptible to the borrelicidal effects of these molecules.


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