scholarly journals An Experimental Murine Model to Study Acquisition Dynamics of Tick-Borne Langat Virus in Ixodes Scapularis

2021 ◽  
Author(s):  
Kundave V. Rajendran ◽  
Waqas Ahmed ◽  
Ashkan Roozitalab ◽  
Girish Neelakanta ◽  
Hameeda Sultana
Keyword(s):  
Murine Model ◽  
Ixodes Scapularis ◽  
Blood Feeding ◽  
Complex Nature ◽  
Nymphal Stage ◽  
Feeding Method ◽  
Viral Loads ◽  
Langat Virus ◽  
Vertebrate Hosts ◽  
Set Up

Abstract Ixodes scapularis ticks acquire several pathogens from reservoir animals and transmit them to humans. Development of an animal model to study acquisition and transmission dynamics of these pathogens into and from ticks, respectively, is challenging due to the fact that in nature ticks feed for a longer duration and on multiple vertebrate hosts. To understand the complex nature of pathogen acquisition/transmission, it is essential to set up a successful tick blood feeding method on a suitable vertebrate host. In this study, we provide an evidence that murine model can be successfully used to study acquisition dynamics of Langat virus (LGTV), a member of tick-borne flaviviruses. Mice were inoculated intraperitoneally with LGTV that showed detectable viral loads in murine blood, skin and other tissues including brain. Both larval and nymphal ticks that were allowed to feed on murine host successfully acquired LGTV loads. Also, we found that after molting LGTV was transstadially transmitted from larval to nymphal stage. In addition, we noted that, LGTV down-regulated IsSMase expression in all group of ticks possibly for its survival in its vector host. Taken together, we provide an evidence on the use of murine model to not only study acquisition dynamics of LGTV but also to study changes in tick gene expression during acquisition of arboviruses into ticks.

scholarly journals Immune factor of bacterial origin protects ticks against host skin microbes

2020 ◽  
Author(s):  
Beth M. Hayes ◽  
Atanas D. Radkov ◽  
Fauna Yarza ◽  
Sebastian Flores ◽  
Jungyun Kim ◽  
...  
Keyword(s):  
Lyme Disease ◽  
Ixodes Scapularis ◽  
Blood Feeding ◽  
Toxin Gene ◽  
Opportunistic Pathogens ◽  
Tick Vector ◽  
Immune Factor ◽  
Skin Commensals ◽  
Tick Borne Disease ◽  
Vertebrate Hosts

SummaryHard ticks are blood-feeding arthropods that carry and transmit microbes to their vertebrate hosts1. Tick-borne disease cases have been on the rise over the last several decades, drawing much-needed attention to the molecular interplay between transmitted pathogens and their human hosts. However, far less is known about how ticks control their own microbes, which is critical for understanding how zoonotic transmission cycles persist. We previously found that ticks horizontally acquired an antimicrobial toxin gene from bacteria known as domesticated amidase effector 2 (dae2)2. Here we show that this effector from the tick vector Ixodes scapularis (Dae2Is) has structurally and biochemically diverged from ancestral bacterial representatives, expanding its antibacterial targeting range to include host skin microbes. Disruption of dae2Is increases the burden of skin-associated staphylococci within I. scapularis and adversely affects tick fitness, suggesting resistance of host microbes may be important for the parasitic blood-feeding lifestyle. In contrast, Dae2Is has no intrinsic ability to kill Borrelia burgdorferi, the tick-borne bacterium of Lyme disease. Our observations suggest that ticks have evolved to tolerate their own symbionts while resisting host skin commensals, which we discover are natural opportunistic pathogens of ticks. This work moves our understanding of vector biology beyond a human-centric view: just as tick commensals are pathogenic to humans, so too do our commensals pose a threat to ticks. These observations illuminate how a complex and mirrored set of interkingdom interactions between blood-feeding vectors, their hosts, and associated microbes can ultimately lead to disease.

Identification of Bloodmeals from Sand Flies (Diptera: Psychodidae) Collected in the Parque Nacional do Viruá, State of Roraima, Brazil

2021 ◽  
Author(s):  
Bruno Leite Rodrigues ◽  
Glaucilene da Silva Costa ◽  
Paloma Helena Fernandes Shimabukuro
Keyword(s):  
Blood Feeding ◽  
Sand Flies ◽  
Feeding Preferences ◽  
Light Traps ◽  
Dasypus Novemcinctus ◽  
Search Tool ◽  
Vertebrate Hosts ◽  
Host Blood ◽  
Clustering Pattern ◽  
Species Being

Abstract The transmission of pathogens that cause leishmaniases occurs by the bite of female sand flies (Diptera: Psychodidae) in their vertebrate hosts, which makes the identification of their bloodmeal sources an important step for the control and epidemiology of these diseases. In Brazil, the state of Roraima has a great diversity of sand flies, vertebrate hosts, and protozoan Leishmania, but little is known about the host blood-feeding preferences of sand flies. Thus, we evaluated the bloodmeal sources of sand flies collected from their sylvatic habitats in Parque Nacional do Viruá, Roraima. Fieldwork was carried-out between 13th and 18th August 2019 using CDC light traps. Sand flies were slide-mounted and morphologically identified using the head and last segments of the abdomen. Engorged females had their DNA extracted, followed by amplification and sequencing of the cytochrome b (cytb) molecular marker for vertebrates. Sequences were analyzed and compared with those from GenBank using the BLASTn search tool, in addition to the reconstruction of a phylogenetic tree to demonstrate the clustering pattern of these sequences. A total of 1,209 sand flies were identified, comprising 20 species, in which the most abundant were Psychodopygus ayrozai (Barretto and Coutinho) (42.10%) and Psychodopygus chagasi (Costa Lima) (26.22%). Bloodmeal source identification was successfully performed for 34 sand flies, that confirm four vertebrate species, being the most abundant the armadillo Dasypus novemcinctus Linnaeus, 1758 (Cingulata: Dasypodidae).

scholarly journals An efficient microinjection method to generate human anaplasmosis agent Anaplasma phagocytophilum-infected ticks

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Vikas Taank ◽  
Ellango Ramasamy ◽  
Hameeda Sultana ◽  
Girish Neelakanta
Keyword(s):  
Anaplasma Phagocytophilum ◽  
Ixodes Scapularis ◽  
In Vitro Cultures ◽  
Transmission Dynamics ◽  
Tick Feeding ◽  
Nymphal Stage ◽  
Bacterial Colony ◽  
Obligate Intracellular ◽  
Transstadial Transmission

Abstract Ticks are important vectors that transmit several pathogens including human anaplasmosis agent, Anaplasma phagocytophilum. This bacterium is an obligate intracellular rickettsial pathogen. An infected reservoir animal host is often required for maintenance of this bacterial colony and as a source for blood to perform needle inoculations in naïve animals for tick feeding studies. In this study, we report an efficient microinjection method to generate A. phagocytophilum-infected ticks in laboratory conditions. The dense-core (DC) form of A. phagocytophilum was isolated from in vitro cultures and injected into the anal pore of unfed uninfected Ixodes scapularis nymphal ticks. These ticks successfully transmitted A. phagocytophilum to the murine host. The bacterial loads were detected in murine blood, spleen, and liver tissues. In addition, larval ticks successfully acquired A. phagocytophilum from mice that were previously infected by feeding with DC-microinjected nymphal ticks. Transstadial transmission of A. phagocytophilum from larvae to nymphal stage was also evident in these ticks. Taken together, our study provides a timely, rapid, and an efficient method not only to generate A. phagocytophilum-infected ticks but also provides a tool to understand acquisition and transmission dynamics of this bacterium and perhaps other rickettsial pathogens from medically important vectors.

scholarly journals A Protective Role for Interleukin-1 Signaling during Mouse Adenovirus Type 1-Induced Encephalitis

2016 ◽  
Vol 91 (4) ◽  
Author(s):  
Luiza A. Castro-Jorge ◽  
Carla D. Pretto ◽  
Asa B. Smith ◽  
Oded Foreman ◽  
Kelly E. Carnahan ◽  
...  
Keyword(s):  
Inflammatory Cytokine ◽  
Time Course ◽  
Interleukin 1 ◽  
Adenovirus Type ◽  
Mouse Strains ◽  
Complex Nature ◽  
Type I ◽  
Viral Loads ◽  
The Brain

ABSTRACT Interleukin-1β (IL-1β), an inflammatory cytokine and IL-1 receptor ligand, has diverse activities in the brain. We examined whether IL-1 signaling contributes to the encephalitis observed in mouse adenovirus type 1 (MAV-1) infection, using mice lacking the IL-1 receptor (Il1r1 −/− mice). Il1r1 −/− mice demonstrated reduced survival, greater disruption of the blood-brain barrier (BBB), higher brain viral loads, and higher brain inflammatory cytokine and chemokine levels than control C57BL/6J mice. We also examined infections of mice defective in IL-1β production (Pycard −/− mice) and mice defective in trafficking of Toll-like receptors to the endosome (Unc93b1 −/− mice). Pycard −/− and Unc93b1 −/− mice showed lower survival (similar to Il1r1 −/− mice) than control mice but, unlike Il1r1 −/− mice, did not have increased brain viral loads or BBB disruption. Based on the brain cytokine levels, MAV-1-infected Unc93b1 −/− mice had a very different inflammatory profile from infected Il1r1 −/− and Pycard −/− mice. Histological examination demonstrated pathological findings consistent with encephalitis in control and knockout mice; however, intranuclear viral inclusions were seen only in Il1r1 −/− mice. A time course of infection of control and Il1r1 −/− mice evaluating the kinetics of viral replication and cytokine production revealed differences between the mouse strains primarily at 7 to 8 days after infection, when mice began succumbing to MAV-1 infection. In the absence of IL-1 signaling, we noted an increase in the transcription of type I interferon (IFN)-stimulated genes. Together, these results indicate that IL-1 signaling is important during MAV-1 infection and suggest that, in its absence, increased IFN-β signaling may result in increased neuroinflammation. IMPORTANCE The investigation of encephalitis pathogenesis produced by different viruses is needed to characterize virus and host-specific factors that contribute to disease. MAV-1 produces viral encephalitis in its natural host, providing a good model for studying factors involved in encephalitis development. We investigated the role of IL-1 signaling during MAV-1-induced encephalitis. Unexpectedly, the lack of IL-1 signaling increased the mortality and inflammation in mice infected with MAV-1. Also, there was an increase in the transcription of type I IFN-stimulated genes that correlated with the observed increased mortality and inflammation. The findings highlight the complex nature of encephalitis and suggests that IL-1 has a protective effect for the development of MAV-1-induced encephalitis.

scholarly journals Ixodes scapularis Tick Saliva Proteins Sequentially Secreted Every 24 h during Blood Feeding

2016 ◽  
Vol 10 (1) ◽  
pp. e0004323 ◽  
Author(s):  
Tae Kwon Kim ◽  
Lucas Tirloni ◽  
Antônio F. M. Pinto ◽  
James Moresco ◽  
John R. Yates ◽  
...  
Keyword(s):  
Ixodes Scapularis ◽  
Blood Feeding ◽  
Tick Saliva

scholarly journals Extending access to care across the rural US south: Preliminary results from the Alabama eHealth programme

2018 ◽  
Vol 25 (5) ◽  
pp. 301-309
Author(s):  
Kriti M Jain ◽  
Prashanth Bhat ◽  
Cathy Maulsby ◽  
Alexandria Andersen ◽  
Tomas Soto ◽  
...  
Keyword(s):  
Missing Data ◽  
Antiretroviral Therapy ◽  
Rural Areas ◽  
Formative Evaluation ◽  
Social Innovation ◽  
People Living With Hiv ◽  
Viral Loads ◽  
Innovation Fund ◽  
Set Up ◽  
Hiv Continuum Of Care

Purpose Using a mixed-methods formative evaluation, the purpose of this study was to provide a broad overview of the Alabama eHealth programme set-up and initial patient outcomes. The Alabama eHealth programme uses telemedicine to provide medical care to people living with HIV in rural Alabama. It was led by a community-based organisation, Medical Advocacy and Outreach (MAO), and supported by AIDS United and the Corporation for National Community Service’s Social Innovation Fund with matching support from non-federal donors. Methods We conducted and transcribed in-depth interviews with Alabama eHealth staff and then performed directed content analysis. We also tracked patients’ ( n = 240) appointment attendance, CD4 counts, and viral loads. Findings Staff described the steps taken to establish the programme, associated challenges (e.g., costly, inadequate broadband in rural areas), and technology enabling this programme (electronic medical records, telemedicine equipment). Of all enrolled patients, 76% were retained in care, 88% had antiretroviral therapy and 75% had a suppressed viral load. Among patients without missing data, 96% were retained in care, 97% used antiretroviral therapy and 93% had suppressed viral loads. There were no statistically significant demographic differences between those with and without missing data. Conclusions Patients enrolled in a telemedicine programme evaluation successfully moved through the HIV continuum of care.

Purification and cloning of the salivary nitrophorin from the hemipteran Cimex lectularius.

1998 ◽  
Vol 201 (18) ◽  
pp. 2659-2664 ◽  
Author(s):  
J G Valenzuela ◽  
J M Ribeiro
Keyword(s):  
Molecular Mass ◽  
High Performance ◽  
Blood Feeding ◽  
Protein Sequencing ◽  
Cimex Lectularius ◽  
Base Pairs ◽  
Clone Sequence ◽  
Internal Peptide ◽  
Vertebrate Hosts ◽  
Inositol Phosphatases

Cimex lectularius and Rhodnius prolixus contain salivary nitric oxide (NO) that may help them to feed on their vertebrate hosts by promoting vasodilation and inhibiting platelet aggregation. Salivary NO is associated with heme proteins (nitrophorins) that store and transport NO from the insect salivary glands to the skin of the host. In this study, the salivary nitrophorin of Cimex lectularius was purified by DEAE chromatography and reverse-phase high-performance liquid chromatography. The purified nitrophorin had a molecular mass of 32.9 kDa. The DEAE-purified hemoprotein was able to bind NO, and this binding shifted the absorption maximum from 388 nm to 438 nm. The ratio of heme to apoprotein was estimated to be of 1:1. A cDNA clone of 1079 base pairs was sequenced and was found to code for a protein with a molecular mass of 31.7 kDa. The clone sequence was in agreement with the internal peptide sequences obtained from the purified protein. Sequencing of the isolated clone indicates high similarity to several inositol phosphatases; however, no significant similarities emerged when the sequence of C. lectularius nitrophorin was compared with that of R. prolixus nitrophorin, the only other nitrophorin known in insect saliva. Because C. lectularius and R. prolixus belong to two different families of Hemiptera that evolved independently to blood feeding, a case is made for the convergent evolution of these two insect nitrophorins.

E-justice evaluation factors: The case of Smart Court of China

2020 ◽  
pp. 026666692096738
Author(s):  
Jia Yu ◽  
Jun Xia
Keyword(s):  
Information And Communication Technologies ◽  
Relevant Literature ◽  
Policy Issue ◽  
Modern Society ◽  
Evaluation Framework ◽  
Complex Nature ◽  
Trial Management ◽  
Information And Communication ◽  
Set Up ◽  
Justice Evaluation

As information and communication technologies (ICT) continue to impact and shape modern society, and e-justice has gained momentum in recent years. China’s Supreme People’s Court (SPC) set up a trial management information system that connects all courts in China. Designed to be online, transparent, and intelligent, China’s Smart Court development began in 2016. In practice, SPC promoted modernization of the trial systems to improve the flow of information between courts throughout China. However, significant investments in ICT e-justice services have caused some to question whether these investments have achieved the expected ends. Thus, how to evaluate e-justice services becomes an urgent theoretical and policy issue in the process of e-justice construction in China. E-justice value is not clearly defined in theory in China, nor is easy to measure in practice. Because of the sensitive and complex nature of such evaluation, little research has been conducted in this regard. The objective of this paper is to fill this gap. Relevant literature is reviewed before the article moves on to describe various approaches withe regard to e-government and e-justice evaluation, as well as the characteristics of China’s Smart Court. Evaluation factors and constructs are found based on the Chinese circumstances. This study contributes to the development of a holistic evaluation framework for e-justice system. It also adds the Chinese case to the existing literature. Evaluation factors found in this article can also serve as a foundation for future development and study of e-justice services.

scholarly journals Wide Dispersal and Possible Multiple Origins of Low-Copy-Number Plasmids in Rickettsia Species Associated with Blood-Feeding Arthropods

2010 ◽  
Vol 76 (6) ◽  
pp. 1718-1731 ◽  
Author(s):  
Gerald D. Baldridge ◽  
Nicole Y. Burkhardt ◽  
Marcelo B. Labruna ◽  
Richard C. Pacheco ◽  
Christopher D. Paddock ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Ixodes Scapularis ◽  
Blood Feeding ◽  
Adaptive Traits ◽  
Phylogenetic Groups ◽  
Plasmid Copy ◽  
Rickettsia Species ◽  
Real Time Quantitative Pcr ◽  
Rickettsia Amblyommii ◽  
Obligate Intracellular Bacteria

ABSTRACT Plasmids are mobile genetic elements of bacteria that can impart important adaptive traits, such as increased virulence or antibiotic resistance. We report the existence of plasmids in Rickettsia (Rickettsiales; Rickettsiaceae) species, including Rickettsia akari, “Candidatus Rickettsia amblyommii,” R. bellii, R. rhipicephali, and REIS, the rickettsial endosymbiont of Ixodes scapularis. All of the rickettsiae were isolated from humans or North and South American ticks. R. parkeri isolates from both continents did not possess plasmids. We have now demonstrated plasmids in nearly all Rickettsia species that we have surveyed from three continents, which represent three of the four major proposed phylogenetic groups associated with blood-feeding arthropods. Gel-based evidence consistent with the existence of multiple plasmids in some species was confirmed by cloning plasmids with very different sequences from each of two “Ca. Rickettsia amblyommii” isolates. Phylogenetic analysis of rickettsial ParA plasmid partitioning proteins indicated multiple parA gene origins and plasmid incompatibility groups, consistent with possible multiple plasmid origins. Phylogenetic analysis of potentially host-adaptive rickettsial small heat shock proteins showed that hsp2 genes were plasmid specific and that hsp1 genes, found only on plasmids of “Ca. Rickettsia amblyommii,” R. felis, R. monacensis, and R. peacockii, were probably acquired independently of the hsp2 genes. Plasmid copy numbers in seven Rickettsia species ranged from 2.4 to 9.2 per chromosomal equivalent, as determined by real-time quantitative PCR. Plasmids may be of significance in rickettsial evolution and epidemiology by conferring genetic plasticity and host-adaptive traits via horizontal gene transfer that counteracts the reductive genome evolution typical of obligate intracellular bacteria.

scholarly journals Blood Digestion by Trypsin-Like Serine Proteases in the Replete Lyme Disease Vector Tick, Ixodes scapularis

Insects ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 201
Author(s):  
Jeremiah Reyes ◽  
Cuauhtemoc Ayala-Chavez ◽  
Arvind Sharma ◽  
Michael Pham ◽  
Andrew B. Nuss ◽  
...  
Keyword(s):  
Lyme Disease ◽  
Blood Meal ◽  
Serine Proteases ◽  
Ixodes Scapularis ◽  
Life Stage ◽  
Blood Feeding ◽  
Eastern United States ◽  
Blood Digestion ◽  
Hemoglobin Degradation

Ixodes scapularis is the major vector of Lyme disease in the Eastern United States. Each active life stage (larva, nymph, and adult) takes a blood meal either for developing and molting to the next stage (larvae and nymphs) or for oviposition (adult females). This protein-rich blood meal is the only food taken by Ixodes ticks and therefore efficient blood digestion is critical for survival. Studies in partially engorged ticks have shown that the initial stages of digestion are carried out by cathepsin proteases within acidic digestive cells. In this study, we investigated the potential role of serine proteases in blood digestion in replete ticks. RNA interference was used for functional analysis and a trypsin-benzoyl-D, L-arginine 4-nitoanilide assay was used to measure active trypsin levels. Hemoglobinolytic activity was determined in vitro, with or without a serine protease inhibitor. Our data suggest that trypsin levels increase significantly after repletion. Knockdown of serine proteases negatively impacted blood feeding, survival, fecundity, levels of active trypsin in the midgut, and resulted in lower hemoglobin degradation. Incubation of midgut extract with a trypsin inhibitor resulted in 65% lower hemoglobin degradation. We provide evidence of the serine proteases as digestive enzymes in fully engorged, replete females. Understanding the digestive profile of trypsin during blood meal digestion in I. scapularis improves our understanding of the basic biology of ticks and may lead to new methods for tick control.

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