1
|
Grabowski JM, Tsetsarkin KA, Long D, Scott DP, Rosenke R, Schwan TG, Mlera L, Offerdahl DK, Pletnev AG, Bloom ME. Flavivirus Infection of Ixodes scapularis (Black-Legged Tick) Ex Vivo Organotypic Cultures and Applications for Disease Control. mBio 2017; 8:e01255-17. [PMID: 28830948 PMCID: PMC5565970 DOI: 10.1128/mbio.01255-17] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 07/25/2017] [Indexed: 12/21/2022] Open
Abstract
Ixodes scapularis ticks transmit many infectious agents that cause disease, including tick-borne flaviviruses (TBFVs). TBFV infections cause thousands of human encephalitis cases worldwide annually. In the United States, human TBFV infections with Powassan virus (POWV) are increasing and have a fatality rate of 10 to 30%. Additionally, Langat virus (LGTV) is a TBFV of low neurovirulence and is used as a model TBFV. TBFV replication and dissemination within I. scapularis organs are poorly characterized, and a deeper understanding of virus biology in this vector may inform effective countermeasures to reduce TBFV transmission. Here, we describe short-term, I. scapularis organ culture models of TBFV infection. Ex vivo organs were metabolically active for 9 to 10 days and were permissive to LGTV and POWV replication. Imaging and videography demonstrated replication and spread of green fluorescent protein-expressing LGTV in the organs. Immunohistochemical staining confirmed LGTV envelope and POWV protein synthesis within the infected organs. LGTV- and POWV-infected organs produced infectious LGTV and POWV; thus, the ex vivo cultures were suitable for study of virus replication in individual organs. LGTV- and POWV-infected midgut and salivary glands were subjected to double-stranded RNA (dsRNA) transfection with dsRNA to the LGTV 3' untranslated region (UTR), which reduced infectious LGTV and POWV replication, providing a proof-of-concept use of RNA interference in I. scapularis organ cultures to study the effects on TBFV replication. The results contribute important information on TBFV localization within ex vivo I. scapularis organs and provide a significant translational tool for evaluating recombinant, live vaccine candidates and potential tick transcripts and proteins for possible therapeutic use and vaccine development to reduce TBFV transmission.IMPORTANCE Tick-borne flavivirus (TBFV) infections cause neurological and/or hemorrhagic disease in humans worldwide. There are currently no licensed therapeutics or vaccines against Powassan virus (POWV), the only TBFV known to circulate in North America. Evaluating tick vector targets for antitick vaccines directed at reducing TBFV infection within the arthropod vector is a critical step in identifying efficient approaches to controlling TBFV transmission. This study characterized infection of female Ixodes scapularis tick organ cultures of midgut, salivary glands, and synganglion with the low-neurovirulence Langat virus (LGTV) and the more pathogenic POWV. Cell types of specific organs were susceptible to TBFV infection, and a difference in LGTV and POWV replication was noted in TBFV-infected organs. This tick organ culture model of TBFV infection will be useful for various applications, such as screening of tick endogenous dsRNA corresponding to potential control targets within midgut and salivary glands to confirm restriction of TBFV infection.
Collapse
Affiliation(s)
- Jeffrey M Grabowski
- Biology of Vector-Borne Viruses Section, Laboratory of Virology, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, Montana, USA
| | - Konstantin A Tsetsarkin
- Neurotropic Flaviviruses Section, Laboratory of Infectious Diseases, NIAID, NIH, Bethesda, Maryland, USA
| | - Dan Long
- Rocky Mountain Veterinary Branch, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, Montana, USA
| | - Dana P Scott
- Rocky Mountain Veterinary Branch, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, Montana, USA
| | - Rebecca Rosenke
- Rocky Mountain Veterinary Branch, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, Montana, USA
| | - Tom G Schwan
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, Montana, USA
| | - Luwanika Mlera
- Biology of Vector-Borne Viruses Section, Laboratory of Virology, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, Montana, USA
| | - Danielle K Offerdahl
- Biology of Vector-Borne Viruses Section, Laboratory of Virology, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, Montana, USA
| | - Alexander G Pletnev
- Neurotropic Flaviviruses Section, Laboratory of Infectious Diseases, NIAID, NIH, Bethesda, Maryland, USA
| | - Marshall E Bloom
- Biology of Vector-Borne Viruses Section, Laboratory of Virology, Rocky Mountain Laboratories, NIAID, NIH, Hamilton, Montana, USA
| |
Collapse
|
2
|
Xia H, Beck AS, Gargili A, Forrester N, Barrett ADT, Bente DA. Transstadial Transmission and Long-term Association of Crimean-Congo Hemorrhagic Fever Virus in Ticks Shapes Genome Plasticity. Sci Rep 2016; 6:35819. [PMID: 27775001 PMCID: PMC5075774 DOI: 10.1038/srep35819] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 10/04/2016] [Indexed: 02/05/2023] Open
Abstract
The trade-off hypothesis, the current paradigm of arbovirus evolution, proposes that cycling between vertebrate and invertebrate hosts presents significant constraints on genetic change of arboviruses. Studying these constraints in mosquito-borne viruses has led to a new understanding of epizootics. The trade-off hypothesis is assumed to be applicable to tick-borne viruses too, although studies are lacking. Tick-borne Crimean-Congo hemorrhagic fever virus (CCHFV), a member of the family Bunyaviridae, is a major cause of severe human disease worldwide and shows an extraordinary amount of genetic diversity compared to other arboviruses, which has been linked to increased virulence and emergence in new environments. Using a transmission model for CCHFV, utilizing the main vector tick species and mice plus next generation sequencing, we detected a substantial number of consensus-level mutations in CCHFV recovered from ticks after only a single transstadial transmission, whereas none were detected in CCHFV obtained from the mammalian host. Furthermore, greater viral intra-host diversity was detected in the tick compared to the vertebrate host. Long-term association of CCHFV with its tick host for 1 year demonstrated mutations in the viral genome become fixed over time. These findings suggest that the trade-off hypothesis may not be accurate for all arboviruses.
Collapse
Affiliation(s)
- Han Xia
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, USA.,Galveston National Laboratory, Galveston TX, USA.,Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Andrew S Beck
- Department of Pathology, and Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, TX, USA
| | | | - Naomi Forrester
- Department of Pathology, and Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, TX, USA
| | - Alan D T Barrett
- Department of Pathology, and Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, TX, USA
| | - Dennis A Bente
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, USA.,Galveston National Laboratory, Galveston TX, USA
| |
Collapse
|
3
|
Kliot A, Ghanim M. The role of bacterial chaperones in the circulative transmission of plant viruses by insect vectors. Viruses 2013; 5:1516-35. [PMID: 23783810 PMCID: PMC3717719 DOI: 10.3390/v5061516] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 06/01/2013] [Accepted: 06/04/2013] [Indexed: 11/22/2022] Open
Abstract
Persistent circulative transmission of plant viruses involves complex interactions between the transmitted virus and its insect vector. Several studies have shown that insect vector proteins are involved in the passage and the transmission of the virus. Interestingly, proteins expressed by bacterial endosymbionts that reside in the insect vector, were also shown to influence the transmission of these viruses. Thus far, the transmission of two plant viruses that belong to different virus genera was shown to be facilitated by a bacterial chaperone protein called GroEL. This protein was shown to be implicated in the transmission of Potato leafroll virus (PLRV) by the green peach aphid Myzus persicae, and the transmission of Tomato yellow leaf curl virus (TYLCV) by the sweetpotato whitefly Bemisia tabaci. These tri-trophic levels of interactions and their possible evolutionary implications are reviewed.
Collapse
Affiliation(s)
- Adi Kliot
- Department of Entomology, The Volcani Center, Bet Dagan, 50250, Israel; E-Mail:
- Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, POB 12, Rehovot, 76100, Israel
| | - Murad Ghanim
- Department of Entomology, The Volcani Center, Bet Dagan, 50250, Israel; E-Mail:
| |
Collapse
|
4
|
Mitzel DN, Best SM, Masnick MF, Porcella SF, Wolfinbarger JB, Bloom ME. Identification of genetic determinants of a tick-borne flavivirus associated with host-specific adaptation and pathogenicity. Virology 2008; 381:268-76. [PMID: 18823640 DOI: 10.1016/j.virol.2008.08.030] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Revised: 08/05/2008] [Accepted: 08/19/2008] [Indexed: 01/12/2023]
Abstract
Tick-borne flaviviruses are maintained in nature in an enzootic cycle involving a tick vector and a vertebrate host. Thus, the virus replicates in two disparate hosts, each providing selective pressures that can influence virus replication and pathogenicity. To identify viral determinants associated with replication in the individual hosts, plaque purified Langat virus (TP21pp) was adapted to growth in mouse or tick cell lines to generate two virus variants, MNBp20 and ISEp20, respectively. Virus adaptation to mouse cells resulted in four amino acid changes in MNBp20 relative to TP21pp, occurring in E, NS4A and NS4B. A comparison between TP21pp and ISEp20 revealed three amino acid modifications in M, NS3 and NS4A of ISEp20. ISEp20, but not MNBp20, was attenuated following intraperitoneal inoculation of mice. Following isolation from mice brains, additional mutations reproducibly emerged in E and NS3 of ISEp20 that were possibly compensatory for the initial adaptation to tick cells. Thus, our data implicate a role for E, M, NS3, NS4A and NS4B in host adaptation and pathogenicity of tick-borne flaviviruses.
Collapse
Affiliation(s)
- Dana N Mitzel
- Laboratory of Virology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 903 South Fourth Street, Hamilton, MT 59840, USA.
| | | | | | | | | | | |
Collapse
|
5
|
Mitzel DN, Wolfinbarger JB, Daniel Long R, Masnick M, Best SM, Bloom ME. Tick-borne flavivirus infection in Ixodes scapularis larvae: development of a novel method for synchronous viral infection of ticks. Virology 2007; 365:410-8. [PMID: 17490700 PMCID: PMC2032017 DOI: 10.1016/j.virol.2007.03.057] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2007] [Revised: 03/28/2007] [Accepted: 03/30/2007] [Indexed: 11/15/2022]
Abstract
Following a bite from an infected tick, tick-borne flaviviruses cause encephalitis, meningitis and hemorrhagic fever in humans. Although these viruses spend most of their time in the tick, little is known regarding the virus-vector interactions. We developed a simple method for synchronously infecting Ixodes scapularis larvae with Langat virus (LGTV) by immersion in media containing the virus. This technique resulted in approximately 96% of ticks becoming infected. LGTV infection and replication were demonstrated by both viral antigen expression and the accumulation of viral RNA. Furthermore, ticks transmitted LGTV to 100% of the mice and maintained the virus through molting into the next life stage. This technique circumvents limitations present in the current methods by mimicking the natural route of infection and by using attenuated virus strains to infect ticks, thereby making this technique a powerful tool to study both virus and tick determinants of replication, pathogenesis and transmission.
Collapse
Affiliation(s)
- Dana N. Mitzel
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, NIAID, NIH. 903 S. Fourth St., Hamilton MT USA 59840
| | - James B. Wolfinbarger
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, NIAID, NIH. 903 S. Fourth St., Hamilton MT USA 59840
| | - R. Daniel Long
- Rocky Mountain Veterinary Branch, Rocky Mountain Laboratories, NIAID, NIH. 903 S. Fourth St., Hamilton MT USA 59840
| | - Max Masnick
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, NIAID, NIH. 903 S. Fourth St., Hamilton MT USA 59840
| | - Sonja M. Best
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, NIAID, NIH. 903 S. Fourth St., Hamilton MT USA 59840
| | - Marshall E. Bloom
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, NIAID, NIH. 903 S. Fourth St., Hamilton MT USA 59840
| |
Collapse
|
6
|
Abstract
A majority of the plant-infecting viruses and many of the animal-infecting viruses are dependent upon arthropod vectors for transmission between hosts and/or as alternative hosts. The viruses have evolved specific associations with their vectors, and we are beginning to understand the underlying mechanisms that regulate the virus transmission process. A majority of plant viruses are carried on the cuticle lining of a vector's mouthparts or foregut. This initially appeared to be simple mechanical contamination, but it is now known to be a biologically complex interaction between specific virus proteins and as yet unidentified vector cuticle-associated compounds. Numerous other plant viruses and the majority of animal viruses are carried within the body of the vector. These viruses have evolved specific mechanisms to enable them to be transported through multiple tissues and to evade vector defenses. In response, vector species have evolved so that not all individuals within a species are susceptible to virus infection or can serve as a competent vector. Not only are the virus components of the transmission process being identified, but also the genetic and physiological components of the vectors which determine their ability to be used successfully by the virus are being elucidated. The mechanisms of arthropod-virus associations are many and complex, but common themes are beginning to emerge which may allow the development of novel strategies to ultimately control epidemics caused by arthropod-borne viruses.
Collapse
Affiliation(s)
- S M Gray
- Plant Protection Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Ithaca, New York 14853, USA.
| | | |
Collapse
|
7
|
Labuda M, Jiang WR, Kaluzova M, Kozuch O, Nuttall PA, Weismann P, Elĕckova E, Zuffová E, Gould EA. Change in phenotype of tick-borne encephalitis virus following passage in Ixodes ricinus ticks and associated amino acid substitution in the envelope protein. Virus Res 1994; 31:305-15. [PMID: 8191785 DOI: 10.1016/0168-1702(94)90024-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Serial passage of an uncloned tick-borne encephalitis virus (strain 4387 isolated from the liver and lungs of a bank vole) in Ixodes ricinus ticks, was accompanied by gradual reduction in virulence of the virus, as indicated by transmission of virus by infected ticks feeding on laboratory mice. After the 7th serial passage in ticks (strain 4387/7), 95% of mice survived the bite of infected ticks. The surviving infected mice showed either no or only low viraemia although virus could be isolated from the brains of some mice 14 and 30 days after commencement of tick feeding, implying that the tick passaged virus might have established a persistent infection in the mice. Tests for haemagglutinating capacity were positive with TBE strain 4387 but strain 4387/7 exhibited no haemagglutinating activity over a wide pH range, suggesting that phenotypic changes, resulting from selection, had affected the site on the viral envelope protein that binds red blood cell receptors. Sequencing of the envelope protein gene of the virulent TBE strain 4387 showed 3 amino acid codon differences from western European TBE virus strain Neudorfl, which is also virulent for mice. The attenuated virus 4387/7, had an amino acid substitution that was different from 4387 and Neudorfl TBE virus (amino acid 84, E to K) and a second substitution different from 4387 but identical to Neudorfl virus (amino acid 319, I to T). Thus, the phenotypic change from virulence to attenuation was associated with a single amino acid codon change in the viral envelope gene of TBE virus. It is recognised, however, that amino acid substitutions in other parts of the viral genome have not been ruled out.
Collapse
Affiliation(s)
- M Labuda
- Institute of Virology, Slovak Academy of Sciences, Bratislava
| | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Randolph SE, Nuttall PA. Nearly right or precisely wrong? Natural versus laboratory studies of vector-borne diseases. ACTA ACUST UNITED AC 1994; 10:458-62. [PMID: 15275510 DOI: 10.1016/0169-4758(94)90154-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Recent studies that compare experimental vector-borne disease systems incorporating elements of natural pathogen-vector-host interactions with model systems using unnatural associations have highlighted quantitative, and even qualitative, differences in the results. Here, Sarah Randolph and Pat Nuttall argue that the use of mathematical models to explore epidemiological processes and patterns depends on accurate parameter values obtained from natural systems.
Collapse
Affiliation(s)
- S E Randolph
- Department of Zoology, South Parks Road, Oxford, UK OX1 3PS
| | | |
Collapse
|
9
|
Uspensky I. Ability of successful attack in two species of ixodid ticks (Acari: Ixodidae) as a manifestation of their aggressiveness. EXPERIMENTAL & APPLIED ACAROLOGY 1993; 17:673-683. [PMID: 7628239 DOI: 10.1007/bf00058507] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Patterns of attacking hosts by two closely related species of ixodid ticks (Ixodes persulcatus and I. ricinus) were compared in parallel field tests. The ability of active unfed adults of both sexes to adhere to a flannel flag dragged over grass vegetation and to remain on the flag during this process were estimated. The tests were conducted under two temperature conditions, 6-10 degrees C and 17-22 degrees C. In all test versions, adults of I. persulcatus were more successful both in adhering to the flag and in remaining on it. There were no consistent differences between males and females of the same species. The results demonstrated a differing ability of successful attack in both tick species. This ability is a complex derivative of the tick activity and aggressiveness. An attempt is made to analyse the latter phenomenon, which is considered as a general one for all bloodsucking arthropods. The aggressiveness of arthropods should be taken into account as one of the leading factors influencing the sampling results.
Collapse
Affiliation(s)
- I Uspensky
- Department of Biological Chemistry, Hebrew University of Jerusalem, Givat Ram, Israel
| |
Collapse
|
10
|
Abstract
Three lines of observation demonstrate the role of arthropods in transmission and evolution of viruses. a) Recent outbreaks of viruses from their niches took place and insects have played a major role in propagating the viruses. b) Examination of the list of viral families and their hosts shows that many infect invertebrates (I) and vertebrates (V) or (I) and plants (P) or all kingdoms (VIPs). This notion holds true irrespective of the genome type. At first glance the argument seems to be weak in the case of enveloped and non-enveloped RNA viruses with single-stranded (ss) segmented or non-segmented genomes of positive (+) or negative polarity. Here, there are several families infecting V or P only; no systematic relation to arthropods is found. c) In the non-enveloped plant viruses with ss RNA genomes there is a strong tendency for segmentation and individual packaging of the genome pieces. This is in contrast to ss+ RNA animal viruses and can only be explained by massive transmission by seed or insects or both, because individual packaging necessitates a multihit infection. Comparisons demonstrate relationships in the nonstructural proteins of double-stranded and ss+ RNA viruses irrespective of host range, segmentation, and envelope. Similar conclusions apply for the negative-stranded RNA viruses. Thus, viral supergroups can be created that infect V or P and exploit arthropods for infection or transmission or both. Examples of such relationships and explanations for viral evolution are reviewed and the arthropod orders important for cell culture are given.
Collapse
Affiliation(s)
- H Koblet
- Institute for Medical Microbiology, University of Berne, Switzerland
| |
Collapse
|