scholarly journals Controlling Geminiviruses before Transmission: Prospects

Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1556
Author(s):  
Muhammad Salman Mubarik ◽  
Sultan Habibullah Khan ◽  
Aftab Ahmad ◽  
Ali Raza ◽  
Zulqurnain Khan ◽  
...  
Keyword(s):  
Virus Transmission ◽  
Viral Disease ◽  
Life Cycles ◽  
Crop Plants ◽  
Insect Vector ◽  
Vector Species ◽  
Tropical Regions ◽  
Virus Particles ◽  
Bacterial Endosymbionts ◽  
Microbial Symbionts

Whitefly (Bemisia tabaci)-transmitted Geminiviruses cause serious diseases of crop plants in tropical and sub-tropical regions. Plants, animals, and their microbial symbionts have evolved complex ways to interact with each other that impact their life cycles. Blocking virus transmission by altering the biology of vector species, such as the whitefly, can be a potential approach to manage these devastating diseases. Virus transmission by insect vectors to plant hosts often involves bacterial endosymbionts. Molecular chaperonins of bacterial endosymbionts bind with virus particles and have a key role in the transmission of Geminiviruses. Hence, devising new approaches to obstruct virus transmission by manipulating bacterial endosymbionts before infection opens new avenues for viral disease control. The exploitation of bacterial endosymbiont within the insect vector would disrupt interactions among viruses, insects, and their bacterial endosymbionts. The study of this cooperating web could potentially decrease virus transmission and possibly represent an effective solution to control viral diseases in crop plants.

scholarly journals Vesicular Stomatitis Virus Transmission: A Comparison of Incriminated Vectors

Insects ◽  
2018 ◽  
Vol 9 (4) ◽  
pp. 190 ◽  
Author(s):  
Paula Rozo-Lopez ◽  
Barbara Drolet ◽  
Berlin Londoño-Renteria
Keyword(s):  
Virus Transmission ◽  
Viral Disease ◽  
Economic Losses ◽  
Vector Species ◽  
Biting Midges ◽  
Virus Serotype ◽  
Multiple Routes ◽  
Veterinary Importance ◽  
Vesicular Stomatitis ◽  
Occurrence Pattern

Vesicular stomatitis (VS) is a viral disease of veterinary importance, enzootic in tropical and subtropical regions of the Americas. In the U.S., VS produces devastating economic losses, particularly in the southwestern states where the outbreaks display an occurrence pattern of 10-year intervals. To date, the mechanisms of the geographic spread and maintenance cycles during epizootics remain unclear. This is due, in part, to the fact that VS epidemiology has a complex of variables to consider, including a broad range of vertebrate hosts, multiple routes of transmission, and an extensive diversity of suspected vector species acting as both mechanical and biological vectors. Infection and viral progression within vector species are highly influenced by virus serotype, as well as environmental factors, including temperature and seasonality; however, the mechanisms of viral transmission, including non-conventional pathways, are yet to be fully studied. Here, we review VS epidemiology and transmission mechanisms, with comparisons of transmission evidence for the four most incriminated hematophagous dipteran taxa: Aedes mosquitoes, Lutzomyia sand flies, Simulium black flies, and Culicoides biting midges.

scholarly journals Unresolved advantages of multipartitism in spatially structured environments

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Mark P Zwart ◽  
Stéphane Blanc ◽  
Marcelle Johnson ◽  
Susanna Manrubia ◽  
Yannis Michalakis ◽  
...  
Keyword(s):  
Genome Organization ◽  
Latent Infection ◽  
Virus Transmission ◽  
Plant Viruses ◽  
Epidemic Spread ◽  
Virus Particles ◽  
Distinct Virus ◽  
Network Epidemiology ◽  
Short Commentary ◽  
Animal Hosts

Abstract Multipartite viruses have segmented genomes and package each of their genome segments individually into distinct virus particles. Multipartitism is common among plant viruses, but why this apparently costly genome organization and packaging has evolved remains unclear. Recently Zhang and colleagues developed network epidemiology models to study the epidemic spread of multipartite viruses and their distribution over plant and animal hosts (Phys. Rev. Lett. 2019, 123, 138101). In this short commentary, we call into question the relevance of these results because of key model assumptions. First, the model of plant hosts assumes virus transmission only occurs between adjacent plants. This assumption overlooks the basic but imperative fact that most multipartite viruses are transmitted over variable distances by mobile animal vectors, rendering the model results irrelevant to differences between plant and animal hosts. Second, when not all genome segments of a multipartite virus are transmitted to a host, the model assumes an incessant latent infection occurs. This is a bold assumption for which there is no evidence to date, making the relevance of these results to understanding multipartitism questionable.

scholarly journals Vector distribution and transmission risk of the Zika virus in South and Central America

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7920
Author(s):  
Sarah Cunze ◽  
Judith Kochmann ◽  
Lisa K. Koch ◽  
Elisa Genthner ◽  
Sven Klimpel
Keyword(s):  
South America ◽  
Central America ◽  
Zika Virus ◽  
Habitat Suitability ◽  
Virus Transmission ◽  
Transmission Risk ◽  
Eastern Coast ◽  
Suitable Habitat ◽  
Virus Infections ◽  
Vector Species

Background Zika is of great medical relevance due to its rapid geographical spread in 2015 and 2016 in South America and its serious implications, for example, certain birth defects. Recent epidemics urgently require a better understanding of geographic patterns of the Zika virus transmission risk. This study aims to map the Zika virus transmission risk in South and Central America. We applied the maximum entropy approach, which is common for species distribution modelling, but is now also widely in use for estimating the geographical distribution of infectious diseases. Methods As predictor variables we used a set of variables considered to be potential drivers of both direct and indirect effects on the emergence of Zika. Specifically, we considered (a) the modelled habitat suitability for the two main vector species Aedes aegypti and Ae. albopictus as a proxy of vector species distributions; (b) temperature, as it has a great influence on virus transmission; (c) commonly called evidence consensus maps (ECM) of human Zika virus infections on a regional scale as a proxy for virus distribution; (d) ECM of human dengue virus infections and, (e) as possibly relevant socio-economic factors, population density and the gross domestic product. Results The highest values for the Zika transmission risk were modelled for the eastern coast of Brazil as well as in Central America, moderate values for the Amazon basin and low values for southern parts of South America. The following countries were modelled to be particularly affected: Brazil, Colombia, Cuba, Dominican Republic, El Salvador, Guatemala, Haiti, Honduras, Jamaica, Mexico, Puerto Rico and Venezuela. While modelled vector habitat suitability as predictor variable showed the highest contribution to the transmission risk model, temperature of the warmest quarter contributed only comparatively little. Areas with optimal temperature conditions for virus transmission overlapped only little with areas of suitable habitat conditions for the two main vector species. Instead, areas with the highest transmission risk were characterised as areas with temperatures below the optimum of the virus, but high habitat suitability modelled for the two main vector species. Conclusion Modelling approaches can help estimating the spatial and temporal dynamics of a disease. We focused on the key drivers relevant in the Zika transmission cycle (vector, pathogen, and hosts) and integrated each single component into the model. Despite the uncertainties generally associated with modelling, the approach applied in this study can be used as a tool and assist decision making and managing the spread of Zika.

scholarly journals Favipiravir at high doses has potent antiviral activity in SARS-CoV-2−infected hamsters, whereas hydroxychloroquine lacks activity

2020 ◽  
Vol 117 (43) ◽  
pp. 26955-26965 ◽  
Author(s):  
Suzanne J. F. Kaptein ◽  
Sofie Jacobs ◽  
Lana Langendries ◽  
Laura Seldeslachts ◽  
Sebastiaan ter Horst ◽  
...  
Keyword(s):  
Antiviral Drug ◽  
Virus Transmission ◽  
Small Animal ◽  
Antiviral Effect ◽  
Viral Disease ◽  
Scientific Basis ◽  
Infection Model ◽  
High Dose ◽  
High Doses

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rapidly spread around the globe after its emergence in Wuhan in December 2019. With no specific therapeutic and prophylactic options available, the virus has infected millions of people of which more than half a million succumbed to the viral disease, COVID-19. The urgent need for an effective treatment together with a lack of small animal infection models has led to clinical trials using repurposed drugs without preclinical evidence of their in vivo efficacy. We established an infection model in Syrian hamsters to evaluate the efficacy of small molecules on both infection and transmission. Treatment of SARS-CoV-2−infected hamsters with a low dose of favipiravir or hydroxychloroquine with(out) azithromycin resulted in, respectively, a mild or no reduction in virus levels. However, high doses of favipiravir significantly reduced infectious virus titers in the lungs and markedly improved lung histopathology. Moreover, a high dose of favipiravir decreased virus transmission by direct contact, whereas hydroxychloroquine failed as prophylaxis. Pharmacokinetic modeling of hydroxychloroquine suggested that the total lung exposure to the drug did not cause the failure. Our data on hydroxychloroquine (together with previous reports in macaques and ferrets) thus provide no scientific basis for the use of this drug in COVID-19 patients. In contrast, the results with favipiravir demonstrate that an antiviral drug at nontoxic doses exhibits a marked protective effect against SARS-CoV-2 in a small animal model. Clinical studies are required to assess whether a similar antiviral effect is achievable in humans without toxic effects.

scholarly journals Structural Insights into the Molecular Mechanisms of Cauliflower Mosaic Virus Transmission by Its Insect Vector

2010 ◽  
Vol 84 (9) ◽  
pp. 4706-4713 ◽  
Author(s):  
François Hoh ◽  
Marilyne Uzest ◽  
Martin Drucker ◽  
Célia Plisson-Chastang ◽  
Patrick Bron ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Molecular Mechanisms ◽  
Structural Model ◽  
Coiled Coil ◽  
Virus Transmission ◽  
Cauliflower Mosaic Virus ◽  
Insect Vector ◽  
Virus Surface ◽  
X Ray Crystallography ◽  
Coil Structure

ABSTRACT Cauliflower mosaic virus (CaMV) is transmitted from plant to plant through a seemingly simple interaction with insect vectors. This process involves an aphid receptor and two viral proteins, P2 and P3. P2 binds to both the aphid receptor and P3, itself tightly associated with the virus particle, with the ensemble forming a transmissible viral complex. Here, we describe the conformations of both unliganded CaMV P3 protein and its virion-associated form. X-ray crystallography revealed that the N-terminal domain of unliganded P3 is a tetrameric parallel coiled coil with a unique organization showing two successive four-stranded subdomains with opposite supercoiling handedness stabilized by a ring of interchain disulfide bridges. A structural model of virus-liganded P3 proteins, folding as an antiparallel coiled-coil network coating the virus surface, was derived from molecular modeling. Our results highlight the structural and biological versatility of this coiled-coil structure and provide new insights into the molecular mechanisms involved in CaMV acquisition and transmission by the insect vector.

scholarly journals A protein key to plant virus transmission at the tip of the insect vector stylet

2007 ◽  
Vol 104 (46) ◽  
pp. 17959-17964 ◽  
Author(s):  
M. Uzest ◽  
D. Gargani ◽  
M. Drucker ◽  
E. Hebrard ◽  
E. Garzo ◽  
...  
Keyword(s):  
Plant Virus ◽  
Virus Transmission ◽  
Insect Vector

Detection of thiol-based redox switch processes in parasites – facts and future

2015 ◽  
Vol 396 (5) ◽  
pp. 445-463 ◽  
Author(s):  
Mahsa Rahbari ◽  
Kathrin Diederich ◽  
Katja Becker ◽  
R. Luise Krauth-Siegel ◽  
Esther Jortzik
Keyword(s):  
Fluorescent Dyes ◽  
Redox Homeostasis ◽  
Life Cycles ◽  
Detection Methods ◽  
Mammalian Host ◽  
Host Immune System ◽  
Insect Vector ◽  
Comprehensive Overview ◽  
Specificity And Sensitivity ◽  
Antiparasitic Drugs

Abstract Malaria and African trypanosomiasis are tropical diseases caused by the protozoa Plasmodium and Trypanosoma, respectively. The parasites undergo complex life cycles in the mammalian host and insect vector, during which they are exposed to oxidative and nitrosative challenges induced by the host immune system and endogenous processes. Attacking the parasite’s redox metabolism is a target mechanism of several known antiparasitic drugs and a promising approach to novel drug development. Apart from this aspect, oxidation of cysteine residues plays a key role in protein-protein interaction, metabolic responses to redox events, and signaling. Understanding the role and dynamics of reactive oxygen species and thiol switches in regulating cellular redox homeostasis is crucial for both basic and applied biomedical approaches. Numerous techniques have therefore been established to detect redox changes in parasites including biochemical methods, fluorescent dyes, and genetically encoded probes. In this review, we aim to give an insight into the characteristics of redox networks in the pathogens Plasmodium and Trypanosoma, including a comprehensive overview of the consequences of specific deletions of redox-associated genes. Furthermore, we summarize mechanisms and detection methods of thiol switches in both parasites and discuss their specificity and sensitivity.

scholarly journals Role of the major antigenic membrane protein in phytoplasma transmission by two insect vector species

2015 ◽  
Vol 15 (1) ◽  
Author(s):  
Mahnaz Rashidi ◽  
Luciana Galetto ◽  
Domenico Bosco ◽  
Andrea Bulgarelli ◽  
Marta Vallino ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Insect Vector ◽  
Vector Species

scholarly journals Tenuivirususes a molecular bridge strategy to overcome insect midgut barriers for virus persistent transmission

2018 ◽  
Author(s):  
Gang Lu ◽  
Shuo Li ◽  
Changwei Zhou ◽  
Xin Qian ◽  
Qing Xiang ◽  
...  
Keyword(s):  
Brown Planthopper ◽  
Specific Interaction ◽  
Virus Transmission ◽  
Plant Viruses ◽  
Insect Vector ◽  
Terminal Protein ◽  
Insect Midgut ◽  
Helper Component ◽  
Vector Interaction ◽  
Molecular Bridge

AbstractMany persistent transmitted plant viruses, includingRice stripe tenuivirus(RSV), cause serious damages to crop productions in China and worldwide. Although many reports have indicated that successful insect-mediated virus transmission depends on proper virus–insect vector interactions, the mechanism(s) controlling interactions between viruses and insect vectors for virus persistent transmission remained poorly understood. In this study, we used RSV and its small brown planthopper (SBPH) vector as a working model to elucidate the molecular mechanism controlling RSV virion entrance into SBPH midgut for persistent transmission. We have now demonstrated that this non-envelopedTenuivirususes its non-structural glycoprotein NSvc2 as a helper component to bridge the specific interaction between virion and SBPH midgut cells, leading to overcome SBPH midgut barriers for virus persistent transmission. In the absence of this glycoprotein, purified RSV virion is not capable of entering SBPH midgut cells. In RSV-infected cells, glycoprotein NSvc2 is processed into two mature proteins: an amino-terminal protein NSvc2-N and a carboxyl-terminal protein NSvc2-C. We determined that NSvc2-N interacted with RSV virion and bound directly to midgut lumen surface via its N-glycosylation sites. Upon recognition by midgut cells, the midgut cells underwent endocytosis followed by compartmentalizing RSV virion and NSvc2 into early and then late endosomes. The acidic condition inside the late endosome triggered conformation change of NSvc2-C and caused cell membrane fusion via its highly conserved fusion loop motifs, leading to the release of RSV virion from endosome into cytosol. In summary, our results showed for the first time that a riceTenuivirususes a molecular bridge strategy to ensure proper interactions between virus and insect midgut for successful persistent transmission.Author summaryOver 75% of the known plant viruses are insect transmitted. Understanding how plant viruses interacted with their insect vectors during virus transmission is one of the key steps to manage virus diseases worldwide. Both the direct and indirect virus–insect vector interaction models have been proposed for virus non-persistent and semi-persistent transmission. However, the indirect virus–vector interaction mechanism during virus persistent transmission has not been reported previously. In this study, we developed a new reverse genetics technology and demonstrated that the circulative and propagative transmittedRice stripe tenuivirusutilizes a glycoprotein NSvc2 as a helper component to ensure a specific interaction betweenTenuivirusvirion and midgut cells of small brown planthopper (SBPH), leading to conquering the midgut barrier of SBPH. This is the first report of a helper component mediated-molecular bridge mechanism for virus persistent transmission. These new findings and our new model on persistent transmission expand our understanding of molecular mechanism(s) controlling virus–insect vector interactions during virus transmission in nature.

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