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Liu W, Yang L, Di C, Sun J, Liu P, Liu H. Nonstructural Protein A238L of the African Swine Fever Virus (ASFV) Enhances Antiviral Immune Responses by Activating the TBK1-IRF3 Pathway. Vet Sci 2024; 11:252. [PMID: 38921999 PMCID: PMC11209439 DOI: 10.3390/vetsci11060252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Revised: 05/26/2024] [Accepted: 05/29/2024] [Indexed: 06/27/2024] Open
Abstract
African swine fever virus (ASFV) is a double-stranded DNA virus with an envelope. ASFV has almost the largest genome among all DNA viruses, and its mechanisms of immune evasion are complex. Better understanding of the molecular mechanisms of ASFV genes will improve vaccine design. A238L, a nonstructural protein of ASFV, inhibits NF-κB activation by suppressing the HAT activity of p300. Whether A238L also affects the transcriptional activity of IRF3 remains unexplored. Here we first confirmed the ability of A238L to suppress NF-κB-activity in L929 cells. A238L inhibits the expression of proinflammatory cytokine genes. In contrast, A238L increased the phosphorylation levels of TBK1 and IRF3 in three different cell lines. A238L increases the IRF3-driven promoter activity and induces IRF3 nuclear translocation. Furthermore, A238L enhanced innate antiviral immunity in the absence or presence of poly d (A:T) or poly (I:C) stimulation, or herpes simplex virus type 1 (HSV-1) or Sendai virus (SeV) infection. This study reveals a previously unrecognized role of A238L in promoting antiviral immune responses by TBK1-IRF3 pathway activation.
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Affiliation(s)
- Wei Liu
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China; (W.L.)
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonosis, Yangzhou University, Yangzhou 225009, China
| | - Lanlan Yang
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China; (W.L.)
| | - Chuanyuan Di
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China; (W.L.)
| | - Jing Sun
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China; (W.L.)
| | - Penggang Liu
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China; (W.L.)
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonosis, Yangzhou University, Yangzhou 225009, China
| | - Huisheng Liu
- Institute of Comparative Medicine, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China; (W.L.)
- State Key Laboratory for Animal Disease Control and Prevention, Lanzhou Veterinary Research Institute, College of Veterinary Medicine, Chinese Academy of Agricultural Sciences, Lanzhou University, Lanzhou 730000, China
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Ochwoto M, Offerdahl DK, Leung JM, Schwartz CL, Long D, Rosenke R, Stewart PE, Saturday GA, Bloom ME. Cytoarchitecture of ex vivo midgut cultures of unfed Ixodes scapularis infected with a tick-borne flavivirus. Ticks Tick Borne Dis 2024; 15:102301. [PMID: 38134511 PMCID: PMC10923016 DOI: 10.1016/j.ttbdis.2023.102301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 12/06/2023] [Accepted: 12/07/2023] [Indexed: 12/24/2023]
Abstract
A bite from an infected tick is the primary means of transmission for tick-borne flaviviruses (TBFV). Ticks ingest the virus while feeding on infected blood. The traditional view is that the virus first replicates in and transits the tick midgut prior to dissemination to other organs, including salivary glands. Thus, understanding TBFV infection in the tick midgut is a key first step in identifying potential countermeasures against infection. Ex vivo midgut cultures prepared from unfed adult female Ixodes scapularis ticks were viable and remained morphologically intact for more than 8 days. The midgut consisted of two clearly defined cell layers separated by a basement membrane: an exterior network of smooth muscle cells and an internal epithelium composed of digestive generative cells. The smooth muscle cells were arranged in a stellate circumferential pattern spaced at regular intervals along the long axis of midgut diverticula. When the cultures were infected with the TBFV Langat virus (LGTV), virus production increased by two logs with a peak at 96 hours post-infection. Infected cells were readily identified by immunofluorescence staining for the viral envelope protein, nonstructural protein 3 (NS3) and dsRNA. Microscopy of the stained cultures suggested that generative cells were the primary target for virus infection in the midgut. Infected cells exhibited an expansion of membranes derived from the endoplasmic reticulum; a finding consistent with TBFV infected cell cultures. Electron microscopy of infected cultures revealed virus particles in the basolateral region between epithelial cells. These results demonstrated LGTV replication in midgut generative cells of artificially infected, ex vivo cultures of unfed adult female I. scapularis ticks.
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Affiliation(s)
- Missiani Ochwoto
- Biology of Vector Borne Viruses Section, Laboratory of Virology, Rocky Mountain Laboratories, NIAID, NIH, USA.
| | - Danielle K Offerdahl
- Biology of Vector Borne Viruses Section, Laboratory of Virology, Rocky Mountain Laboratories, NIAID, NIH, USA
| | - Jacqueline M Leung
- Research Technologies Branch, Rocky Mountain Laboratories, NIAID, NIH, USA
| | - Cindi L Schwartz
- Research Technologies Branch, Rocky Mountain Laboratories, NIAID, NIH, USA
| | - Dan Long
- Rocky Mountain Veterinary Branch, Rocky Mountain Laboratories, NIAID, NIH, USA
| | - Rebecca Rosenke
- Rocky Mountain Veterinary Branch, Rocky Mountain Laboratories, NIAID, NIH, USA
| | - Philip E Stewart
- Biology of Vector Borne Viruses Section, Laboratory of Virology, Rocky Mountain Laboratories, NIAID, NIH, USA
| | - Greg A Saturday
- Rocky Mountain Veterinary Branch, Rocky Mountain Laboratories, NIAID, NIH, USA
| | - Marshall E Bloom
- Biology of Vector Borne Viruses Section, Laboratory of Virology, Rocky Mountain Laboratories, NIAID, NIH, USA.
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Bezymennyi M, Tarasov O, Kyivska GV, Mezhenska NA, Mandyhra S, Kovalenko G, Sushko M, Hudz N, Skorokhod SV, Datsenko R, Muzykina L, Milton E, Sapachova MA, Nychyk S, Halka I, Frant M, Huettmann F, Drown DM, Gerilovych A, Mezhenskyi AA, Bortz E, Lange CE. Epidemiological Characterization of African Swine Fever Dynamics in Ukraine, 2012-2023. Vaccines (Basel) 2023; 11:1145. [PMID: 37514961 PMCID: PMC10384127 DOI: 10.3390/vaccines11071145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 06/09/2023] [Accepted: 06/11/2023] [Indexed: 07/30/2023] Open
Abstract
African swine fever (ASF) is a viral disease, endemic to Africa, that causes high mortality when introduced into domestic pig populations. Since the emergence of p72-genotype II African swine fever virus (ASFV) in Georgia in 2007, an ASF epidemic has been spreading across Europe and many countries in Asia. The epidemic first reached Ukraine in 2012. To better understand the dynamics of spread of ASF in Ukraine, we analyzed spatial and temporal outbreak data reported in Ukraine between 2012 and mid-2023. The highest numbers of outbreaks were reported in 2017 (N = 163) and 2018 (N = 145), with overall peak numbers of ASF outbreaks reported in August (domestic pigs) and January (wild boars). While cases were reported from most of Ukraine, we found a directional spread from the eastern and northern borders towards the western and southern regions of Ukraine. Many of the early outbreaks (before 2016) were adjacent to the border, which is again true for more recent outbreaks in wild boar, but not for recent outbreaks in domestic pigs. Outbreaks prior to 2016 also occurred predominantly in areas with a below average domestic pig density. This new analysis suggests that wild boars may have played an important role in the introduction and early spread of ASF in Ukraine. However, in later years, the dynamic suggests human activity as the predominant driver of spread and a separation of ASF epizootics between domestic pigs and in wild boars. The decline in outbreaks since 2019 suggests that the implemented mitigation strategies are effective, even though long-term control or eradication remain challenging and will require continued intensive surveillance of ASF outbreak patterns.
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Affiliation(s)
- Maksym Bezymennyi
- Institute of Veterinary Medicine (IVM), National Academy of Agrarian Sciences of Ukraine, 03151 Kyiv, Ukraine
| | - Oleksandr Tarasov
- Institute of Veterinary Medicine (IVM), National Academy of Agrarian Sciences of Ukraine, 03151 Kyiv, Ukraine
| | - Ganna V Kyivska
- State Scientific Research Institute of Laboratory Diagnostics and Veterinary and Sanitary Expertise (SSRILDVSE), 03151 Kyiv, Ukraine
| | - Nataliia A Mezhenska
- State Scientific Research Institute of Laboratory Diagnostics and Veterinary and Sanitary Expertise (SSRILDVSE), 03151 Kyiv, Ukraine
| | - Svitlana Mandyhra
- Institute of Veterinary Medicine (IVM), National Academy of Agrarian Sciences of Ukraine, 03151 Kyiv, Ukraine
- State Scientific Research Institute of Laboratory Diagnostics and Veterinary and Sanitary Expertise (SSRILDVSE), 03151 Kyiv, Ukraine
| | - Ganna Kovalenko
- Institute of Veterinary Medicine (IVM), National Academy of Agrarian Sciences of Ukraine, 03151 Kyiv, Ukraine
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK 99508, USA
| | - Mykola Sushko
- State Scientific Research Institute of Laboratory Diagnostics and Veterinary and Sanitary Expertise (SSRILDVSE), 03151 Kyiv, Ukraine
| | - Nataliia Hudz
- Institute of Veterinary Medicine (IVM), National Academy of Agrarian Sciences of Ukraine, 03151 Kyiv, Ukraine
| | - Serhii V Skorokhod
- State Scientific Research Institute of Laboratory Diagnostics and Veterinary and Sanitary Expertise (SSRILDVSE), 03151 Kyiv, Ukraine
| | - Roman Datsenko
- State Scientific Research Institute of Laboratory Diagnostics and Veterinary and Sanitary Expertise (SSRILDVSE), 03151 Kyiv, Ukraine
| | - Larysa Muzykina
- Institute of Veterinary Medicine (IVM), National Academy of Agrarian Sciences of Ukraine, 03151 Kyiv, Ukraine
| | - Elaina Milton
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK 99508, USA
| | - Maryna A Sapachova
- State Scientific Research Institute of Laboratory Diagnostics and Veterinary and Sanitary Expertise (SSRILDVSE), 03151 Kyiv, Ukraine
| | - Serhii Nychyk
- Institute of Veterinary Medicine (IVM), National Academy of Agrarian Sciences of Ukraine, 03151 Kyiv, Ukraine
| | - Ihor Halka
- Institute of Veterinary Medicine (IVM), National Academy of Agrarian Sciences of Ukraine, 03151 Kyiv, Ukraine
| | - Maciej Frant
- Department of Swine Diseases, National Veterinary Research Institute (NVRI), 24-100 Pulawy, Poland
| | - Falk Huettmann
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
- Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
| | - Devin M Drown
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
- Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
| | - Anton Gerilovych
- State Scientific Research Institute of Laboratory Diagnostics and Veterinary and Sanitary Expertise (SSRILDVSE), 03151 Kyiv, Ukraine
| | - Andrii A Mezhenskyi
- State Scientific Research Institute of Laboratory Diagnostics and Veterinary and Sanitary Expertise (SSRILDVSE), 03151 Kyiv, Ukraine
| | - Eric Bortz
- Institute of Veterinary Medicine (IVM), National Academy of Agrarian Sciences of Ukraine, 03151 Kyiv, Ukraine
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK 99508, USA
| | - Christian E Lange
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK 99508, USA
- Metabiota Inc., San Francisco, CA 94104, USA
- Labyrinth Global Health, Saint Petersburg, FL 33704, USA
- Department of Biology, Kwantlen Polytechnic University, Surrey, BC V3W 2MB, Canada
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Ren J, Li D, Zhu G, Yang W, Ru Y, Feng T, Qin X, Hao R, Duan X, Liu X, Zheng H. Deletion of MGF-110-9L gene from African swine fever virus weakens autophagic degradation of TBK1 as a mechanism for enhancing type I interferon production. FASEB J 2023; 37:e22934. [PMID: 37144880 DOI: 10.1096/fj.202201856r] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 03/19/2023] [Accepted: 04/11/2023] [Indexed: 05/06/2023]
Abstract
African swine fever (ASF) caused by African swine fever virus (ASFV) is a devastating disease for the global pig industry and economic benefit. The limited knowledge on the pathogenesis and infection mechanisms of ASF restricts progress toward vaccine development and ASF control. Previously, we illustrated that deletion of the MGF-110-9L gene from highly virulent ASFV CN/GS/2018 strains (ASFV∆9L) results in attenuated virulence in swine, but the underlying mechanism remains unclear. In this study, we found that the difference in virulence between wild-type ASFV (wt-ASFV) and ASFV∆9L strains was mainly caused by the difference in TANK Binding Kinase 1 (TBK1) reduction. TBK1 reduction was further identified to be mediated by the autophagy pathway and this degradative process requires the up-regulation of a positive autophagy regulation molecule- Phosphatidylinositol-4-Phosphate 3-Kinase Catalytic Subunit Type 2 Beta (PIK3C2B). Moreover, TBK1 over-expression was confirmed to inhibit ASFV replication in vitro. In summary, these results indicate that wt-ASFV counteracts type I interferon (IFN) production by degrading TBK1, while ASFVΔ9L enhanced type I IFN production by weakening TBK1 reduction, clarifying the mechanism that ASFVΔ9L present the attenuated virulence in vitro.
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Affiliation(s)
- Jingjing Ren
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Dan Li
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Guoqiang Zhu
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Wenping Yang
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Yi Ru
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Tao Feng
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Xiaodong Qin
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Rongzeng Hao
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Xianghan Duan
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Xiangtao Liu
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Haixue Zheng
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
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An Updated Review of Ornithodoros Ticks as Reservoirs of African Swine Fever in Sub-Saharan Africa and Madagascar. Pathogens 2023; 12:pathogens12030469. [PMID: 36986391 PMCID: PMC10059854 DOI: 10.3390/pathogens12030469] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/13/2023] [Accepted: 03/14/2023] [Indexed: 03/19/2023] Open
Abstract
This updated review provides an overview of the available information on Ornithodoros ticks as reservoirs and biological vectors of the ASF virus in Africa and Indian Ocean islands in order to update the current knowledge in this field, inclusive of an overview of available methods to investigate the presence of ticks in the natural environment and in domestic pig premises. In addition, it highlights the major areas of research that require attention in order to guide future investigations and fill knowledge gaps. The available information suggests that current knowledge is clearly insufficient to develop risk-based control and prevention strategies, which should be based on a sound understanding of genotype distribution and the potential for spillover from the source population. Studies on tick biology in the natural and domestic cycle, including genetics and systematics, represent another important knowledge gap. Considering the rapidly changing dynamics affecting the African continent (demographic growth, agricultural expansion, habitat transformation), anthropogenic factors influencing tick population distribution and ASF virus (ASFV) evolution in Africa are anticipated and have been recorded in southern Africa. This dynamic context, together with the current global trends of ASFV dissemination, highlights the need to prioritize further investigation on the acarological aspects linked with ASF ecology and evolution.
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CP204L Is a Multifunctional Protein of African Swine Fever Virus That Interacts with the VPS39 Subunit of the Homotypic Fusion and Vacuole Protein Sorting Complex and Promotes Lysosome Clustering. J Virol 2023; 97:e0194322. [PMID: 36722971 PMCID: PMC9972913 DOI: 10.1128/jvi.01943-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Virus replication depends on a complex interplay between viral and host proteins. In the case of African swine fever virus (ASFV), a large DNA virus, only a few virus-host protein-protein interactions have been identified to date. In this study, we demonstrate that the ASFV protein CP204L interacts with the cellular homotypic fusion and protein sorting (HOPS) protein VPS39, blocking its association with the lysosomal HOPS complex, which modulates endolysosomal trafficking and promotes lysosome clustering. Instead, CP204L and VPS39 are targeted to virus factories and localized at the periphery of the virus DNA replication sites. Furthermore, we show that loss of VPS39 reduces the levels of virus proteins synthesized in the early phase of infection and delays ASFV replication but does not completely inhibit it. Collectively, these results identify a novel virus-host protein interaction that modulates host membrane rearrangement during infection and provide evidence that CP204L is a multifunctional protein engaged in distinct steps of the ASFV life cycle. IMPORTANCE African swine fever virus (ASFV) was first identified over a hundred years ago. Since then, much effort has been made to understand the pathogenesis of ASFV. However, the specific roles of many individual ASFV proteins during the infection remain enigmatic. This study provides evidence that CP204L, one of the most abundant ASFV proteins, modulates endosomal trafficking during virus infection. Through protein-protein interaction, CP204L prevents the recruitment of VPS39 to the endosomal and lysosomal membranes, resulting in their accumulation. Consequently, CP204L and VPS39 become sequestered in the ASFV replication and assembly site, known as the virus factory. These results uncover a novel function of viral protein CP204L and extend our understanding of complex interaction between virus and host.
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Lv T, Xie X, Song N, Zhang S, Ding Y, Liu K, Diao L, Chen X, Jiang S, Li T, Zhang W, Cao Y. Expounding the role of tick in Africa swine fever virus transmission and seeking effective prevention measures: A review. Front Immunol 2022; 13:1093599. [PMID: 36591310 PMCID: PMC9800779 DOI: 10.3389/fimmu.2022.1093599] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 11/29/2022] [Indexed: 12/23/2022] Open
Abstract
African swine fever (ASF), a highly contagious, deadly infectious disease, has caused huge economic losses to animal husbandry with a 100% mortality rate of the most acute and acute infection, which is listed as a legally reported animal disease by the World Organization for Animal Health (OIE). African swine fever virus (ASFV) is the causative agent of ASF, which is the only member of the Asfarviridae family. Ornithodoros soft ticks play an important role in ASFV transmission by active biological or mechanical transmission or by passive transport or ingestion, particularly in Africa, Europe, and the United States. First, this review summarized recent reports on (1) tick species capable of transmitting ASFV, (2) the importance of ticks in the transmission and epidemiological cycle of ASFV, and (3) the ASFV strains of tick transmission, to provide a detailed description of tick-borne ASFV. Second, the dynamics of tick infection with ASFV and the tick-induced immune suppression were further elaborated to explain how ticks spread ASFV. Third, the development of the anti-tick vaccine was summarized, and the prospect of the anti-tick vaccine was recapitulated. Then, the marked attenuated vaccine, ASFV-G-ΔI177L, was compared with those of the anti-tick vaccine to represent potential therapeutic or strategies to combat ASF.
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Affiliation(s)
- Tianbao Lv
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Xufeng Xie
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Ning Song
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Shilei Zhang
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Yue Ding
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Kun Liu
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Luteng Diao
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Xi Chen
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Shuang Jiang
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Tiger Li
- Portsmouth Abbey School, Portsmouth, RI, United States
| | - Wenlong Zhang
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, China,Key Laboratory for Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China,*Correspondence: Yongguo Cao, ; Wenlong Zhang,
| | - Yongguo Cao
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, China,Key Laboratory for Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China,*Correspondence: Yongguo Cao, ; Wenlong Zhang,
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Detection of African Swine Fever Virus in Ornithodoros Tick Species Associated with Indigenous and Extralimital Warthog Populations in South Africa. Viruses 2022; 14:v14081617. [PMID: 35893686 PMCID: PMC9331695 DOI: 10.3390/v14081617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/18/2022] [Accepted: 07/21/2022] [Indexed: 11/23/2022] Open
Abstract
We investigated the possibility that sylvatic circulation of African swine fever virus (ASFV) in warthogs and Ornithodoros ticks had extended beyond the historically affected northern part of South Africa that was declared a controlled area in 1935 to prevent the spread of infection to the rest of the country. We recently reported finding antibody to the virus in extralimital warthogs in the south of the country, and now describe the detection of infected ticks outside the controlled area. A total of 5078 ticks was collected at 45 locations in 7/9 provinces during 2019-2021 and assayed as 711 pools for virus content by qPCR, while 221 pools were also analysed for tick phylogenetics. Viral nucleic acid was detected in 50 tick pools representing all four members of the Ornithodoros (Ornithodoros) moubata complex known to occur in South Africa: O. (O.) waterbergensis and O. (O.) phacochoerus species yielded ASFV genotypes XX, XXI, XXII at 4 locations and O. (O.) moubata yielded ASFV genotype I at two locations inside the controlled area. Outside the controlled area, O. (O.) moubata and O. (O.) compactus ticks yielded ASFV genotype I at 7 locations, while genotype III ASFV was identified in O. (O.) compactus ticks at a single location. Two of the three species of the O. (O.) savignyi complex ticks known to be present in the country, O. (O.) kalahariensis and O. (O.) noorsveldensis, were collected at single locations and found negative for virus. The only member of the Pavlovskyella subgenus of Ornithodoros ticks known to occur in South Africa, O. (P.) zumpti, was collected from warthog burrows for the first time, in Addo National Park in the Eastern Cape Province where ASFV had never been recorded, and it tested negative for the viral nucleic acid. While it is confirmed that there is sylvatic circulation of ASFV outside the controlled area in South Africa, there is a need for more extensive surveillance and for vector competence studies with various species of Ornithodoros ticks.
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Zhou G, Shi Z, Luo J, Cao L, Yang B, Wan Y, Wang L, Song R, Ma Y, Tian H, Zheng H. Preparation and epitope mapping of monoclonal antibodies against African swine fever virus P30 protein. Appl Microbiol Biotechnol 2022; 106:1199-1210. [PMID: 35089400 DOI: 10.1007/s00253-022-11784-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 12/10/2021] [Accepted: 01/14/2022] [Indexed: 11/25/2022]
Abstract
African swine fever virus (ASFV) causes acute, febrile, and highly contagious diseases in swine. Early diagnosis is critically important for African swine fever (ASF) prevention and control in the absence of an effective vaccine. P30 is one of the most immunogenic proteins that are produced during the early stage of an ASFV infection. This makes P30 a good serological target for ASF detection and surveillance. In this study, two P30-reactive monoclonal antibodies (mAbs), 2H2 and 5E8, were generated from mice immunized with recombinant P30 protein (rP30). Epitope mapping was performed with overlapping polypeptides, alanine mutants, and synthetic peptides. The mapping results revealed that 2H2 recognized a region located in the N-terminal, 16-48 aa. In contrast, 5E8 recognized a linear epitope in the C-terminal, 122-128 aa. Further analysis indicated that the epitope recognized by 2H2 was highly conserved in genotypes I and II, while the 5E8 epitope was conserved in most genotypes and the Ser to Pro change at position 128 in genotypes IV, V, and VI did not affect recognition. Overall, the results of this study provide valuable information on the antigenic regions of ASFV P30 and lay the foundation for the serological diagnosis of ASF and vaccine research. KEY POINTS: • Two specific and reactive mAbs were prepared and their epitopes were identified. • 2H2 recognized a novel epitope highly conserved in genotypes I and II. • 5E8 recognized a seven-amino acid linear epitope highly conserved in most genotypes.
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Affiliation(s)
- Gaijing Zhou
- State Key Laboratory of Veterinary Etiological Biology, National Foot-and-Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agriculture Science, Lanzhou, 730046, China
| | - Zhengwang Shi
- State Key Laboratory of Veterinary Etiological Biology, National Foot-and-Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agriculture Science, Lanzhou, 730046, China
| | - Juncong Luo
- State Key Laboratory of Veterinary Etiological Biology, National Foot-and-Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agriculture Science, Lanzhou, 730046, China
| | - Liyan Cao
- State Key Laboratory of Veterinary Etiological Biology, National Foot-and-Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agriculture Science, Lanzhou, 730046, China
| | - Bo Yang
- State Key Laboratory of Veterinary Etiological Biology, National Foot-and-Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agriculture Science, Lanzhou, 730046, China
| | - Ying Wan
- State Key Laboratory of Veterinary Etiological Biology, National Foot-and-Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agriculture Science, Lanzhou, 730046, China
| | - Lijuan Wang
- State Key Laboratory of Veterinary Etiological Biology, National Foot-and-Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agriculture Science, Lanzhou, 730046, China
| | - Rui Song
- State Key Laboratory of Veterinary Etiological Biology, National Foot-and-Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agriculture Science, Lanzhou, 730046, China
| | - Yuan Ma
- State Key Laboratory of Veterinary Etiological Biology, National Foot-and-Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agriculture Science, Lanzhou, 730046, China
| | - Hong Tian
- State Key Laboratory of Veterinary Etiological Biology, National Foot-and-Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agriculture Science, Lanzhou, 730046, China.
| | - Haixue Zheng
- State Key Laboratory of Veterinary Etiological Biology, National Foot-and-Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agriculture Science, Lanzhou, 730046, China.
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10
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Thoughts on African Swine Fever Vaccines. Viruses 2021; 13:v13050943. [PMID: 34065425 PMCID: PMC8161283 DOI: 10.3390/v13050943] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 05/11/2021] [Accepted: 05/11/2021] [Indexed: 12/22/2022] Open
Abstract
African swine fever (ASF) is an acute viral hemorrhagic disease of domestic swine with mortality rates approaching 100%. Devastating ASF outbreaks and continuing epidemics starting in the Caucasus region and now in the Russian Federation, Europe, China, and other parts of Southeast Asia (2007 to date) highlight its significance. ASF strain Georgia-07 and its derivatives are now endemic in extensive regions of Europe and Asia and are "out of Africa" forever, a situation that poses a grave if not an existential threat to the swine industry worldwide. While our current concern is Georgia-07, other emerging ASFV strains will threaten for the indefinite future. Economic analysis indicates that an ASF outbreak in the U.S. would result in approximately $15 billion USD in losses, assuming the disease is rapidly controlled and the U.S. is able to reenter export markets within two years. ASF's potential to spread and become endemic in new regions, its rapid and efficient transmission among pigs, and the relative stability of the causative agent ASF virus (ASFV) in the environment all provide significant challenges for disease control. Effective and robust methods, including vaccines for ASF response and recovery, are needed immediately.
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11
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Li D, Liu Y, Qi X, Wen Y, Li P, Ma Z, Liu Y, Zheng H, Liu Z. African Swine Fever Virus MGF-110-9L-deficient Mutant Has Attenuated Virulence in Pigs. Virol Sin 2021; 36:187-195. [PMID: 33689140 DOI: 10.1007/s12250-021-00350-6] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Accepted: 12/17/2020] [Indexed: 12/18/2022] Open
Abstract
African swine fever virus (ASFV) is the etiological agent of African swine fever (ASF), an often lethal disease in domestic and wild pigs. ASF represents a major threat to the swine industry worldwide. Currently, no commercial vaccine is available because of the complexity of ASFV or biosecurity concerns. Live attenuated viruses that are naturally isolated or genetically manipulated have demonstrated reliable protection against homologous ASFV strain challenge. In the present study, a mutant ASFV strain with the deletion of ASFV MGF-110-9L (ASFV-Δ9L) was generated from a highly virulent ASFV CN/GS/2018 parental strain, a genotype II ASFV. Relative to the parental ASFV isolate, deletion of the MGF-110-9L gene significantly decreased the ability of ASFV-Δ9L to replicate in vitro in primary swine macrophage cell cultures. The majority of animals inoculated intramuscularly with a low dose of ASFV-Δ9L (10 HAD50) remained clinically normal during the 21-day observational period. Three of five ASFV-Δ9L-infected animals displayed low viremia titers and low virus shedding and developed a strong virus-specific antibody response, indicating partial attenuation of the ASFV-Δ9L strain in pigs. The findings imply the potential usefulness of the ASFV-Δ9L strain for further development of ASF control measures.
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Affiliation(s)
- Dan Li
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046, China
| | - Yinguang Liu
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046, China
| | - Xiaolan Qi
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046, China
| | - Yuan Wen
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046, China
| | - Pan Li
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046, China
| | - Zhao Ma
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046, China
| | - Yongjie Liu
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046, China
| | - Haixue Zheng
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046, China.
| | - Zhijie Liu
- State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046, China.
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12
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Wu J, Mukama O, Wu W, Li Z, Habimana JDD, Zhang Y, Zeng R, Nie C, Zeng L. A CRISPR/Cas12a Based Universal Lateral Flow Biosensor for the Sensitive and Specific Detection of African Swine-Fever Viruses in Whole Blood. BIOSENSORS 2020; 10:E203. [PMID: 33321741 PMCID: PMC7763806 DOI: 10.3390/bios10120203] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/03/2020] [Accepted: 12/04/2020] [Indexed: 12/26/2022]
Abstract
Cross-border pathogens such as the African swine fever virus (ASFV) still pose a socio-economic threat. Cheaper, faster, and accurate diagnostics are imperative for healthcare and food safety applications. Currently, the discovery of the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) has paved the way for the diagnostics based on Cas13 and Cas12/14 that exhibit collateral cleavage of target and single-stranded DNA (ssDNA) reporter. The reporter is fluorescently labeled to report the presence of a target. These methods are powerful; however, fluorescence-based approaches require expensive apparatuses, complicate results readout, and exhibit high-fluorescence background. Here, we present a new CRISPR-Cas-based approach that combines polymerase chain reaction (PCR) amplification, Cas12a, and a probe-based lateral flow biosensor (LFB) for the simultaneous detection of seven types of ASFV. In the presence of ASFVs, the LFB responded to reporter trans-cleavage by naked eyes and achieved a sensitivity of 2.5 × 10-15 M within 2 h, and unambiguously identified ASFV from swine blood. This system uses less time for PCR pre-amplification and requires cheaper devices; thus, it can be applied to virus monitoring and food samples detection.
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Affiliation(s)
- Jinghua Wu
- School of Food Science and Engineering, Foshan University, Foshan 528231, China; (J.W.); (Y.Z.); (R.Z.)
| | - Omar Mukama
- Key Laboratory of Regenerative Biology, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China; (O.M.); (Z.L.); (J.D.D.H.)
- Department of Applied Biology, College of Science and Technology, University of Rwanda, Avenue de l’armée, Kigali P.O. Box 3900, Rwanda
- University of Chinese Academy of Sciences, 19 Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Wei Wu
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao 266109, China;
| | - Zhiyuan Li
- Key Laboratory of Regenerative Biology, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China; (O.M.); (Z.L.); (J.D.D.H.)
| | - Jean De Dieu Habimana
- Key Laboratory of Regenerative Biology, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China; (O.M.); (Z.L.); (J.D.D.H.)
| | - Yinghui Zhang
- School of Food Science and Engineering, Foshan University, Foshan 528231, China; (J.W.); (Y.Z.); (R.Z.)
| | - Rong Zeng
- School of Food Science and Engineering, Foshan University, Foshan 528231, China; (J.W.); (Y.Z.); (R.Z.)
| | - Chengrong Nie
- School of Food Science and Engineering, Foshan University, Foshan 528231, China; (J.W.); (Y.Z.); (R.Z.)
| | - Lingwen Zeng
- School of Food Science and Engineering, Foshan University, Foshan 528231, China; (J.W.); (Y.Z.); (R.Z.)
- Langyuan Biotechnology LLC, Foshan 528313, China
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13
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Pereira De Oliveira R, Hutet E, Lancelot R, Paboeuf F, Duhayon M, Boinas F, Pérez de León AA, Filatov S, Le Potier MF, Vial L. Differential vector competence of Ornithodoros soft ticks for African swine fever virus: What if it involves more than just crossing organic barriers in ticks? Parasit Vectors 2020; 13:618. [PMID: 33298119 PMCID: PMC7725119 DOI: 10.1186/s13071-020-04497-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 11/23/2020] [Indexed: 11/26/2022] Open
Abstract
Background Several species of soft ticks in genus Ornithodoros are known vectors and reservoirs of African swine fever virus (ASFV). However, the underlying mechanisms of vector competence for ASFV across Ornithodoros species remain to be fully understood. To that end, this study compared ASFV replication and dissemination as well as virus vertical transmission to descendants between Ornithodorosmoubata, O. erraticus, and O. verrucosus in relation to what is known about the ability of these soft tick species to transmit ASFV to pigs. To mimic the natural situation, a more realistic model was used where soft ticks were exposed to ASFV by allowing them to engorge on viremic pigs. Methods Ornithodoros moubata ticks were infected with the ASFV strains Liv13/33 (genotype I) or Georgia2007/1 (genotype II), O. erraticus with OurT88/1 (genotype I) or Georgia2007/1 (genotype II), and O. verrucosus with Ukr12/Zapo (genotype II), resulting in five different tick–virus pairs. Quantitative PCR (qPCR) assays targeting the VP72 ASFV gene was carried out over several months on crushed ticks to study viral replication kinetics. Viral titration assays were also carried out on crushed ticks 2 months post infection to confirm virus survival in soft ticks. Ticks were dissected. and DNA was individually extracted from the following organs to study ASFV dissemination: intestine, salivary glands, and reproductive organs. DNA extracts from each organ were tested by qPCR. Lastly, larval or first nymph-stage progeny emerging from hatching eggs were tested by qPCR to assess ASFV vertical transmission. Results Comparative analyses revealed higher rates of ASFV replication and dissemination in O. moubata infected with Liv13/33, while the opposite was observed for O. erraticus infected with Georgia2007/1 and for O. verrucosus with Ukr12/Zapo. Intermediate profiles were found for O. moubata infected with Georgia2007/1 and for O. erraticus with OurT88/1. Vertical transmission occurred efficiently in O. moubata infected with Liv13/33, and at very low rates in O. erraticus infected with OurT88/1. Conclusions This study provides molecular data indicating that viral replication and dissemination in Ornithodoros ticks are major mechanisms underlying ASFV horizontal and vertical transmission. However, our results indicate that other determinants beyond viral replication also influence ASFV vector competence. Further research is required to fully understand this process in soft ticks.
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Affiliation(s)
- Rémi Pereira De Oliveira
- UMR Animals, Health, Territories, Risks and Ecosystems (ASTRE), French Agricultural Research Center for International Development (CIRAD), Montpellier, France.,UMR ASTRE, CIRAD, National Research Institute for Agriculture, Food and the Environment (INRAE), University of Montpellier, Montpellier, France.,Swine Virology and Immunology Unit, Ploufragan-Plouzané-Niort Laboratory, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Ploufragan, France
| | - Evelyne Hutet
- Swine Virology and Immunology Unit, Ploufragan-Plouzané-Niort Laboratory, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Ploufragan, France
| | - Renaud Lancelot
- UMR Animals, Health, Territories, Risks and Ecosystems (ASTRE), French Agricultural Research Center for International Development (CIRAD), Montpellier, France.,UMR ASTRE, CIRAD, National Research Institute for Agriculture, Food and the Environment (INRAE), University of Montpellier, Montpellier, France
| | - Frédéric Paboeuf
- Swine Virology and Immunology Unit, Ploufragan-Plouzané-Niort Laboratory, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Ploufragan, France
| | - Maxime Duhayon
- UMR Animals, Health, Territories, Risks and Ecosystems (ASTRE), French Agricultural Research Center for International Development (CIRAD), Montpellier, France.,UMR ASTRE, CIRAD, National Research Institute for Agriculture, Food and the Environment (INRAE), University of Montpellier, Montpellier, France
| | - Fernando Boinas
- Center for Interdisciplinary Research in Animal Health (CIISA), Faculty of Veterinary Medicine, University of Lisbon, Avenida da Universidade Técnica, Lisbon, 1300-477, Portugal
| | - Adalberto A Pérez de León
- Knipling-Bushland U.S. Livestock Insects Research Laboratory and Veterinary Pest Genomics Center, US Department of Agriculture-Agriculture Research Service (USDA-ARS), Kerrville, TX, USA
| | - Serhii Filatov
- National Scientific Center Institute of Experimental and Clinical Veterinary Medicine (NSC IECVM), Kharkiv, Ukraine
| | - Marie-Frédérique Le Potier
- Swine Virology and Immunology Unit, Ploufragan-Plouzané-Niort Laboratory, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Ploufragan, France
| | - Laurence Vial
- UMR Animals, Health, Territories, Risks and Ecosystems (ASTRE), French Agricultural Research Center for International Development (CIRAD), Montpellier, France. .,UMR ASTRE, CIRAD, National Research Institute for Agriculture, Food and the Environment (INRAE), University of Montpellier, Montpellier, France.
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14
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Feng Z, Chen J, Liang W, Chen W, Li Z, Chen Q, Cai S. The recombinant pseudorabies virus expressing African swine fever virus CD2v protein is safe and effective in mice. Virol J 2020; 17:180. [PMID: 33198749 PMCID: PMC7668019 DOI: 10.1186/s12985-020-01450-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 11/05/2020] [Indexed: 12/14/2022] Open
Abstract
Background African swine fever (ASF) leads to high mortality in domestic pigs and wild boar and is caused by the African swine fever virus (ASFV). Currently, no vaccine is commercially available for prevention, and the epidemic is still spreading. Here, we constructed a recombinant pseudorabies virus (PRV) (PRV-ΔgE/ΔgI/ΔTK-(CD2v)) that expresses the CD2v protein of ASFV and evaluated its effectiveness and safety as a vaccine candidate in mice. Methods A homologous recombination fragment containing ASFV CD2v was synthesized and co-transfected into HEK 293 T cells, a knockout vector targeting the PRV TK gene. The transfected cells were infected with PRV-ΔgE/ΔgI, and the recombinant strain (PRV-ΔgE/ΔgI/ΔTK-(CD2v)) was obtained by plaque purification in Vero cells. The expression of ASFV CD2v in the recombinant virus was confirmed by sequencing, Western blotting, and immunofluorescence analysis, and the genetic stability was tested in Vero cells over 20 passages. The virulence, immunogenicity and protective ability of the recombinant virus were further tested in a mouse model. Results The PRV-ΔgE/ΔgI/ΔTK-(CD2v) recombinant strain is stable in Vero cells, and the processing of CD2v does not depend on ASFV infection. The vaccination of PRV-ΔgE/ΔgI/ΔTK-(CD2v) causes neither pruritus, not a systemic infection and inflammation (with the high expression of interleukin-6 (IL6)). Besides, the virus vaccination can produce anti-CD2v specific antibody and activate a specific cellular immune response, and 100% protect mice from the challenge of the virulent strain (PRV-Fa). The detoxification occurs much earlier upon the recombinant virus vaccination and the amount of detoxification is much lower as well. Conclusions The PRV-ΔgE/ΔgI/ΔTK-(CD2v) recombinant strain has strong immunogenicity, is safe and effective, and maybe a potential vaccine candidate for the prevention of ASF and Pseudorabies.
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Affiliation(s)
- Zhihua Feng
- Fujian Key Laboratory of Innate Immune Biology, Biomedical Research Center of South China, Fujian Province, Fujian Normal University Qishan Campus, College Town, Fuzhou, 350117, People's Republic of China
| | - Jianghua Chen
- Fujian Key Laboratory of Innate Immune Biology, Biomedical Research Center of South China, Fujian Province, Fujian Normal University Qishan Campus, College Town, Fuzhou, 350117, People's Republic of China
| | - Wangwang Liang
- Fujian Key Laboratory of Innate Immune Biology, Biomedical Research Center of South China, Fujian Province, Fujian Normal University Qishan Campus, College Town, Fuzhou, 350117, People's Republic of China
| | - Wenzhi Chen
- Fujian Key Laboratory of Innate Immune Biology, Biomedical Research Center of South China, Fujian Province, Fujian Normal University Qishan Campus, College Town, Fuzhou, 350117, People's Republic of China
| | - Zhaolong Li
- Fujian Key Laboratory of Innate Immune Biology, Biomedical Research Center of South China, Fujian Province, Fujian Normal University Qishan Campus, College Town, Fuzhou, 350117, People's Republic of China. .,Institute of Animal Husbandry and Veterinary Medicine, Fujian Province, Fujian Academy of Agricultural Sciences, Pudang, Jin-an District, Fuzhou, 350117, People's Republic of China.
| | - Qi Chen
- Fujian Key Laboratory of Innate Immune Biology, Biomedical Research Center of South China, Fujian Province, Fujian Normal University Qishan Campus, College Town, Fuzhou, 350117, People's Republic of China.
| | - Shaoli Cai
- Fujian Key Laboratory of Innate Immune Biology, Biomedical Research Center of South China, Fujian Province, Fujian Normal University Qishan Campus, College Town, Fuzhou, 350117, People's Republic of China.
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15
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Forth JH, Forth LF, Lycett S, Bell-Sakyi L, Keil GM, Blome S, Calvignac-Spencer S, Wissgott A, Krause J, Höper D, Kampen H, Beer M. Identification of African swine fever virus-like elements in the soft tick genome provides insights into the virus' evolution. BMC Biol 2020; 18:136. [PMID: 33032594 PMCID: PMC7542975 DOI: 10.1186/s12915-020-00865-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 09/04/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND African swine fever virus (ASFV) is a most devastating pathogen affecting swine. In 2007, ASFV was introduced into Eastern Europe where it continuously circulates and recently reached Western Europe and Asia, leading to a socio-economic crisis of global proportion. In Africa, where ASFV was first described in 1921, it is transmitted between warthogs and soft ticks of the genus Ornithodoros in a so-called sylvatic cycle. However, analyses into this virus' evolution are aggravated by the absence of any closely related viruses. Even ancient endogenous viral elements, viral sequences integrated into a host's genome many thousand years ago that have proven extremely valuable to analyse virus evolution, remain to be identified. Therefore, the evolution of ASFV, the only known DNA virus transmitted by arthropods, remains a mystery. RESULTS For the identification of ASFV-like sequences, we sequenced DNA from different recent Ornithodoros tick species, e.g. O. moubata and O. porcinus, O. moubata tick cells and also 100-year-old O. moubata and O. porcinus ticks using high-throughput sequencing. We used BLAST analyses for the identification of ASFV-like sequences and further analysed the data through phylogenetic reconstruction and molecular clock analyses. In addition, we performed tick infection experiments as well as additional small RNA sequencing of O. moubata and O. porcinus soft ticks. CONCLUSION Here, we show that soft ticks of the Ornithodoros moubata group, the natural arthropod vector of ASFV, harbour African swine fever virus-like integrated (ASFLI) elements corresponding to up to 10% (over 20 kb) of the ASFV genome. Through orthologous dating and molecular clock analyses, we provide data suggesting that integration could have occurred over 1.47 million years ago. Furthermore, we provide data showing ASFLI-element specific siRNA and piRNA in ticks and tick cells allowing for speculations on a possible role of ASFLI-elements in RNA interference-based protection against ASFV in ticks. We suggest that these elements, shaped through many years of co-evolution, could be part of an evolutionary virus-vector 'arms race', a finding that has not only high impact on our understanding of the co-evolution of viruses with their hosts but also provides a glimpse into the evolution of ASFV.
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Affiliation(s)
- Jan H Forth
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Leonie F Forth
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Samantha Lycett
- The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK
| | - Lesley Bell-Sakyi
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, 146 Brownlow Hill, Liverpool, L3 5RF, UK
| | - Günther M Keil
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Sandra Blome
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | | | - Antje Wissgott
- Max Planck Institute for the Science of Human History, Kahlaische Str. 10, 07745, Jena, Germany
| | - Johannes Krause
- Max Planck Institute for the Science of Human History, Kahlaische Str. 10, 07745, Jena, Germany
| | - Dirk Höper
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Helge Kampen
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Martin Beer
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald-Insel Riems, Germany.
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16
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Putative Role of Arthropod Vectors in African Swine Fever Virus Transmission in Relation to Their Bio-Ecological Properties. Viruses 2020; 12:v12070778. [PMID: 32698448 PMCID: PMC7412232 DOI: 10.3390/v12070778] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/17/2020] [Accepted: 07/18/2020] [Indexed: 12/18/2022] Open
Abstract
African swine fever (ASF) is one of the most important diseases in Suidae due to its significant health and socioeconomic consequences and represents a major threat to the European pig industry, especially in the absence of any available treatment or vaccine. In fact, with its high mortality rate and the subsequent trade restrictions imposed on affected countries, ASF can dramatically disrupt the pig industry in afflicted countries. In September 2018, ASF was unexpectedly identified in wild boars from southern Belgium in the province of Luxembourg, not far from the Franco-Belgian border. The French authorities rapidly commissioned an expert opinion on the risk of ASF introduction and dissemination into metropolitan France. In Europe, the main transmission routes of the virus comprise direct contact between infected and susceptible animals and indirect transmission through contaminated material or feed. However, the seasonality of the disease in some pig farms in Baltic countries, including outbreaks in farms with high biosecurity levels, have led to questions on the possible involvement of arthropods in the transmission of the virus. This review explores the current body of knowledge on the most common arthropod families present in metropolitan France. We examine their potential role in spreading ASF-by active biological or mechanical transmission or by passive transport or ingestion-in relation to their bio-ecological properties. It also highlights the existence of significant gaps in our knowledge on vector ecology in domestic and wild boar environments and in vector competence for ASFV transmission. Filling these gaps is essential to further understanding ASF transmission in order to thus implement appropriate management measures.
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Gaudreault NN, Madden DW, Wilson WC, Trujillo JD, Richt JA. African Swine Fever Virus: An Emerging DNA Arbovirus. Front Vet Sci 2020; 7:215. [PMID: 32478103 PMCID: PMC7237725 DOI: 10.3389/fvets.2020.00215] [Citation(s) in RCA: 191] [Impact Index Per Article: 47.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 03/31/2020] [Indexed: 12/13/2022] Open
Abstract
African swine fever virus (ASFV) is the sole member of the family Asfarviridae, and the only known DNA arbovirus. Since its identification in Kenya in 1921, ASFV has remained endemic in Africa, maintained in a sylvatic cycle between Ornithodoros soft ticks and warthogs (Phacochoerus africanus) which do not develop clinical disease with ASFV infection. However, ASFV causes a devastating and economically significant disease of domestic (Sus scrofa domesticus) and feral (Sus scrofa ferus) swine. There is no ASFV vaccine available, and current control measures consist of strict animal quarantine and culling procedures. The virus is highly stable and easily spreads by infected swine, contaminated pork products and fomites, or via transmission by the Ornithodoros vector. Competent Ornithodoros argasid soft tick vectors are known to exist not only in Africa, but also in parts of Europe and the Americas. Once ASFV is established in the argasid soft tick vector, eradication can be difficult due to the long lifespan of Ornithodoros ticks and their proclivity to inhabit the burrows of warthogs or pens and shelters of domestic pigs. Establishment of endemic ASFV infections in wild boar populations further complicates the control of ASF. Between the late 1950s and early 1980s, ASFV emerged in Europe, Russia and South America, but was mostly eradicated by the mid-1990s. In 2007, a highly virulent genotype II ASFV strain emerged in the Caucasus region and subsequently spread into the Russian Federation and Europe, where it has continued to circulate and spread. Most recently, ASFV emerged in China and has now spread to several neighboring countries in Southeast Asia. The high morbidity and mortality associated with ASFV, the lack of an efficacious vaccine, and the complex makeup of the ASFV virion and genome as well as its lifecycle, make this pathogen a serious threat to the global swine industry and national economies. Topics covered by this review include factors important for ASFV infection, replication, maintenance, and transmission, with attention to the role of the argasid tick vector and the sylvatic transmission cycle, current and future control strategies for ASF, and knowledge gaps regarding the virus itself, its vector and host species.
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Affiliation(s)
- Natasha N. Gaudreault
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States
| | - Daniel W. Madden
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States
| | - William C. Wilson
- Arthropod Borne Animal Diseases Research Unit, Agricultural Research Service, United States Department of Agriculture, Manhattan, KS, United States
| | - Jessie D. Trujillo
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States
| | - Juergen A. Richt
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States
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Pereira de Oliveira R, Hutet E, Paboeuf F, Duhayon M, Boinas F, Perez de Leon A, Filatov S, Vial L, Le Potier MF. Comparative vector competence of the Afrotropical soft tick Ornithodoros moubata and Palearctic species, O. erraticus and O. verrucosus, for African swine fever virus strains circulating in Eurasia. PLoS One 2019; 14:e0225657. [PMID: 31774871 PMCID: PMC6881060 DOI: 10.1371/journal.pone.0225657] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 11/08/2019] [Indexed: 11/26/2022] Open
Abstract
African swine fever (ASF) is a lethal hemorrhagic disease in domestic pigs and wild suids caused by African swine fever virus (ASFV), which threatens the swine industry globally. In its native African enzootic foci, ASFV is naturally circulating between soft ticks of the genus Ornithodoros, especially in the O. moubata group, and wild reservoir suids, such as warthogs (Phacochoerus spp.) that are bitten by infected soft ticks inhabiting their burrows. While the ability of some Afrotropical soft ticks to transmit and maintain ASFV is well established, the vector status of Palearctic soft tick species for ASFV strains currently circulating in Eurasia remains largely unknown. For example, the Iberian soft tick O. erraticus is a known vector and reservoir of ASFV, but its ability to transmit different ASFV strains has not been assessed since ASF re-emerged in Europe in 2007. Little is known about vector competence for ASFV in other species, such as O. verrucosus, which occurs in southern parts of Eastern Europe, including Ukraine and parts of Russia, and in the Caucasus. Therefore, we conducted transmission trials with two Palearctic soft tick species, O. erraticus and O. verrucosus, and the Afrotropical species O. moubata. We tested the ability of ticks to transmit virulent ASFV strains, including one of direct African origin (Liv13/33), and three from Eurasia that had been involved in previous (OurT88/1), and the current epizooties (Georgia2007/1 and Ukr12/Zapo). Our experimental results showed that O. moubata was able to transmit the African and Eurasian ASFV strains, whereas O. erraticus and O. verrucosus failed to transmit the Eurasian ASFV strains. However, naïve pigs showed clinical signs of ASF when inoculated with homogenates of crushed O. erraticus and O. verrucosus ticks that fed on viraemic pigs, which proved the infectiousness of ASFV contained in the ticks. These results documented that O. erraticus and O. verrucosus are unlikely to be capable vectors of ASFV strains currently circulating in Eurasia. Additionally, the persistence of infection in soft ticks for several months reaffirms that the infectious status of a given tick species is only part of the data required to assess its vector competence for ASFV.
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Affiliation(s)
- Rémi Pereira de Oliveira
- Swine Virology and Immunology Unit, Laboratoire de Ploufragan-Plouzané-Niort, Agence Nationale de Sécurité Sanitaire (ANSES), Ploufragan, France
- UMR ASTRE Animal Santé, Territoires, Risques et Ecosystèmes, Centre de coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), Montpellier, France
- University of Montpellier, Montpellier, France
| | - Evelyne Hutet
- Swine Virology and Immunology Unit, Laboratoire de Ploufragan-Plouzané-Niort, Agence Nationale de Sécurité Sanitaire (ANSES), Ploufragan, France
| | - Frédéric Paboeuf
- Swine Virology and Immunology Unit, Laboratoire de Ploufragan-Plouzané-Niort, Agence Nationale de Sécurité Sanitaire (ANSES), Ploufragan, France
| | - Maxime Duhayon
- UMR ASTRE Animal Santé, Territoires, Risques et Ecosystèmes, Centre de coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), Montpellier, France
| | - Fernando Boinas
- CIISA—Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisboa, Portugal
| | - Adalberto Perez de Leon
- Knipling-Bushland U.S. Livestock Insects Research Laboratory and Veterinary Pest Genomics Center, USDA-ARS, Kerrville, Texas, United States of America
| | - Serhii Filatov
- National Scientific Center Institute of Experimental and Clinical Veterinary Medicine, NSC IECVM), Kharkiv, Ukraine
| | - Laurence Vial
- UMR ASTRE Animal Santé, Territoires, Risques et Ecosystèmes, Centre de coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), Montpellier, France
- University of Montpellier, Montpellier, France
| | - Marie-Frédérique Le Potier
- Swine Virology and Immunology Unit, Laboratoire de Ploufragan-Plouzané-Niort, Agence Nationale de Sécurité Sanitaire (ANSES), Ploufragan, France
- * E-mail:
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Pautienius A, Grigas J, Pileviciene S, Zagrabskaite R, Buitkuviene J, Pridotkas G, Stankevicius R, Streimikyte Z, Salomskas A, Zienius D, Stankevicius A. Prevalence and spatiotemporal distribution of African swine fever in Lithuania, 2014-2017. Virol J 2018; 15:177. [PMID: 30454055 PMCID: PMC6245807 DOI: 10.1186/s12985-018-1090-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 11/08/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The emergence in 2014 and persistence of African Swine Fever (ASF) in Lithuania has been linked to infected wild boar movement and close contact with the carcasses of other infected wild boars. Over time the number of reported cases of ASF in wild boars gradually increased, but no detailed epidemiological data has been available. Therefore, the objective of the present study was to determine ASF virus prevalence in wild boars and domestic pigs during the 2014-2017 period and further explore the current geographical distribution of the virus. RESULTS Our study results show that ASF virus prevalence in hunted wild boars using PCR analysis increased from 0.83% (95% CI 0.69-0.98) to 2.27% (95% CI 2.05-2.48) from 2014 to 2016 respectively. However, there was a dramatic jump in the number of ASF positive wild boars cases in 2017 resulting in prevalence of 12.39% (95% CI 11.91-12.86) (p < 0.05). The average prevalence of ASF-specific antibodies in wild boar population during years 2014-2017 was 0.45% (95% CI 0.39-0.51) based on ELISA test results. Prevalence of ASF virus in domestic pigs ranged from 0.24% (95% CI 0.17% - 0.32) in 2015 to 2.74% (95% CI 2.33% - 3.15) in 2017. The average seasonal prevalence of ASF virus in pigs was statistically significant (p < 0.05) and ranged from 0% in spring to 3.68% (95% CI 3.32-4.05) in summer. Correlation between the pig density and number of recorded pig ASF cases in affected regions was only found in 2017 (R = 0.78, p < 0.05). No correlation was detected between the wild boar density and number of recorded pig or wild boar ASF - positive cases. CONCLUSIONS This study provides the first results of ASF virus prevalence changes in Lithuania during the 2014-2017. The overall results confirm the relatively high prevalence of ASF virus in wild boar that was gradually increasing from 2014 to 2017. In the last year of study, the number of ASF positive cases in both domestic pigs and wild boars had unexpectedly increased several times. A better understanding of current status of the disease will enable better control and prevent further spread of ASF virus in Western Europe.
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Affiliation(s)
- Arnoldas Pautienius
- Faculty of Veterinary Medicine, Department of Anatomy and Physiology, Lithuanian University of Health Sciences, Tilzes str. 18, Kaunas, Lithuania.
| | - Juozas Grigas
- Faculty of Veterinary Medicine, Department of Anatomy and Physiology, Lithuanian University of Health Sciences, Tilzes str. 18, Kaunas, Lithuania.,Faculty of Veterinary Medicine, Institute of Microbiology and Virology, Lithuanian University of Health Sciences, Tilzes str. 18, Kaunas, Lithuania
| | - Simona Pileviciene
- National Food and Veterinary Risk Assessment Institute, J. Kairiukscio str. 10, Vilnius, Lithuania
| | - Ruta Zagrabskaite
- National Food and Veterinary Risk Assessment Institute, J. Kairiukscio str. 10, Vilnius, Lithuania
| | - Jurate Buitkuviene
- National Food and Veterinary Risk Assessment Institute, J. Kairiukscio str. 10, Vilnius, Lithuania
| | - Gediminas Pridotkas
- National Food and Veterinary Risk Assessment Institute, J. Kairiukscio str. 10, Vilnius, Lithuania
| | - Rolandas Stankevicius
- Faculty of Animal Husbandry Technology, Department of Animal Breeding and Nutrition, Lithuanian University of Health Sciences, Tilzes str. 18, Kaunas, Lithuania
| | - Zaneta Streimikyte
- Faculty of Veterinary Medicine, Institute of Microbiology and Virology, Lithuanian University of Health Sciences, Tilzes str. 18, Kaunas, Lithuania
| | - Algirdas Salomskas
- Faculty of Veterinary Medicine, Department of Pathobiology, Lithuanian University of Health Sciences, Tilzes str. 18, Kaunas, Lithuania
| | - Dainius Zienius
- Faculty of Veterinary Medicine, Institute of Microbiology and Virology, Lithuanian University of Health Sciences, Tilzes str. 18, Kaunas, Lithuania
| | - Arunas Stankevicius
- Faculty of Veterinary Medicine, Department of Anatomy and Physiology, Lithuanian University of Health Sciences, Tilzes str. 18, Kaunas, Lithuania
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20
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Grabowski JM, Offerdahl DK, Bloom ME. The Use of Ex Vivo Organ Cultures in Tick-Borne Virus Research. ACS Infect Dis 2018; 4:247-256. [PMID: 29473735 DOI: 10.1021/acsinfecdis.7b00274] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Each year there are more than 15 000 cases of human disease caused by infections with tick-borne viruses (TBVs). These illnesses occur worldwide and can range from very mild illness to severe encephalitis and hemorrhagic fever. Although TBVs are currently identified as neglected vector-borne pathogens and receive less attention than mosquito-borne viruses, TBVs are expanding into new regions, and infection rates are increasing. Furthermore, effective vaccines, diagnostic tools, and other countermeasures are limited. The application of contemporary technologies to TBV infections presents an excellent opportunity to develop improved, effective countermeasures. Experimental tick and mammal models of infection can be used to characterize determinants of infection, transmission, and virulence and to test candidate countermeasures. The use of ex vivo tick cultures in TBV research provides a unique way to look at infection in specific tick organs. Mammal ex vivo organ slice and, more recently, organoid cultures are additional models that can be used to elucidate direct tissue-specific responses to infection. These ex vivo model systems are convenient for testing methods involving transcript knockdown and small molecules under tightly controlled conditions. They can also be combined with in vitro and in vivo studies to tease out possible host factors and potential vaccine or therapeutic candidates. In this brief perspective, we describe how ex vivo cultures can be combined with modern technologies to advance research on TBV infections.
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Affiliation(s)
- Jeffrey M. Grabowski
- Biology of Vector-Borne Viruses Section, Laboratory of Virology, Rocky Mountain Laboratories, NIAID/NIH, 903 South Fourth Street, Hamilton, Montana 59840, United States
| | - Danielle K. Offerdahl
- Biology of Vector-Borne Viruses Section, Laboratory of Virology, Rocky Mountain Laboratories, NIAID/NIH, 903 South Fourth Street, Hamilton, Montana 59840, United States
| | - Marshall E. Bloom
- Biology of Vector-Borne Viruses Section, Laboratory of Virology, Rocky Mountain Laboratories, NIAID/NIH, 903 South Fourth Street, Hamilton, Montana 59840, United States
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21
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Abstract
Ticks are important vectors for the transmission of pathogens including viruses. The viruses carried by ticks also known as tick-borne viruses (TBVs), contain a large group of viruses with diverse genetic properties and are concluded in two orders, nine families, and at least 12 genera. Some members of the TBVs are notorious agents causing severe diseases with high mortality rates in humans and livestock, while some others may pose risks to public health that are still unclear to us. Herein, we review the current knowledge of TBVs with emphases on the history of virus isolation and identification, tick vectors, and potential pathogenicity to humans and animals, including assigned species as well as the recently discovered and unassigned species. All these will promote our understanding of the diversity of TBVs, and will facilitate the further investigation of TBVs in association with both ticks and vertebrate hosts.
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Affiliation(s)
- Junming Shi
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Zhihong Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Fei Deng
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China.
| | - Shu Shen
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China.
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22
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Hübner A, Petersen B, Keil GM, Niemann H, Mettenleiter TC, Fuchs W. Efficient inhibition of African swine fever virus replication by CRISPR/Cas9 targeting of the viral p30 gene (CP204L). Sci Rep 2018; 8:1449. [PMID: 29362418 PMCID: PMC5780455 DOI: 10.1038/s41598-018-19626-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 01/05/2018] [Indexed: 12/30/2022] Open
Abstract
African swine fever is a devastating viral disease of domestic and wild pigs against which no vaccine or therapy is available. Therefore, we applied the CRISPR (clustered regularly interspaced short palindromic repeats) – Cas9 nuclease system to target the double-stranded DNA genome of African swine fever virus (ASFV). To this end, a permissive wild boar lung (WSL) cell line was modified by stable transfection with a plasmid encoding Cas9 and a guide RNA targeting codons 71 to 78 of the phosphoprotein p30 gene (CP204L) of ASFV. Due to targeted Cas9 cleavage of the virus genome, plaque formation of ASFV was completely abrogated and virus yields were reduced by four orders of magnitude. The specificity of these effects could be demonstrated by using a natural ASFV isolate and escape mutants possessing nucleotide exchanges within the target sequence, which were not inhibited in the Cas9-expressing cell line. Growth of the cell line was not affected by transgene expression which, as well as virus inhibition, proved to be stable over at least 50 passages. Thus, CRISPR-Cas9 mediated targeting of the ASFV p30 gene is a valid strategy to convey resistance against ASF infection, which may also be applied in its natural animal host.
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Affiliation(s)
- Alexandra Hübner
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, 17493, Greifswald-Insel Riems, Germany
| | - Bjoern Petersen
- Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, 31535, Neustadt, Germany
| | - Günther M Keil
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, 17493, Greifswald-Insel Riems, Germany
| | - Heiner Niemann
- Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, 31535, Neustadt, Germany
| | - Thomas C Mettenleiter
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, 17493, Greifswald-Insel Riems, Germany
| | - Walter Fuchs
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, 17493, Greifswald-Insel Riems, Germany.
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23
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Galindo I, Alonso C. African Swine Fever Virus: A Review. Viruses 2017; 9:v9050103. [PMID: 28489063 PMCID: PMC5454416 DOI: 10.3390/v9050103] [Citation(s) in RCA: 349] [Impact Index Per Article: 49.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 04/27/2017] [Accepted: 05/04/2017] [Indexed: 02/06/2023] Open
Abstract
African swine fever (ASF) is a highly contagious viral disease of swine which causes high mortality, approaching 100%, in domestic pigs. ASF is caused by a large, double stranded DNA virus, ASF virus (ASFV), which replicates predominantly in the cytoplasm of macrophages and is the only member of the Asfarviridae family, genus Asfivirus. The natural hosts of this virus include wild suids and arthropod vectors of the Ornithodoros genus. The infection of ASFV in its reservoir hosts is usually asymptomatic and develops a persistent infection. In contrast, infection of domestic pigs leads to a lethal hemorrhagic fever for which there is no effective vaccine. Identification of ASFV genes involved in virulence and the characterization of mechanisms used by the virus to evade the immune response of the host are recognized as critical steps in the development of a vaccine. Moreover, the interplay of the viral products with host pathways, which are relevant for virus replication, provides the basic information needed for the identification of potential targets for the development of intervention strategies against this disease.
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Affiliation(s)
- Inmaculada Galindo
- Dpto. de Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Ctra. de la Coruña km 7.5, 28040 Madrid, Spain.
| | - Covadonga Alonso
- Dpto. de Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Ctra. de la Coruña km 7.5, 28040 Madrid, Spain.
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24
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de la Fuente J, Antunes S, Bonnet S, Cabezas-Cruz A, Domingos AG, Estrada-Peña A, Johnson N, Kocan KM, Mansfield KL, Nijhof AM, Papa A, Rudenko N, Villar M, Alberdi P, Torina A, Ayllón N, Vancova M, Golovchenko M, Grubhoffer L, Caracappa S, Fooks AR, Gortazar C, Rego ROM. Tick-Pathogen Interactions and Vector Competence: Identification of Molecular Drivers for Tick-Borne Diseases. Front Cell Infect Microbiol 2017; 7:114. [PMID: 28439499 PMCID: PMC5383669 DOI: 10.3389/fcimb.2017.00114] [Citation(s) in RCA: 243] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 03/22/2017] [Indexed: 01/10/2023] Open
Abstract
Ticks and the pathogens they transmit constitute a growing burden for human and animal health worldwide. Vector competence is a component of vectorial capacity and depends on genetic determinants affecting the ability of a vector to transmit a pathogen. These determinants affect traits such as tick-host-pathogen and susceptibility to pathogen infection. Therefore, the elucidation of the mechanisms involved in tick-pathogen interactions that affect vector competence is essential for the identification of molecular drivers for tick-borne diseases. In this review, we provide a comprehensive overview of tick-pathogen molecular interactions for bacteria, viruses, and protozoa affecting human and animal health. Additionally, the impact of tick microbiome on these interactions was considered. Results show that different pathogens evolved similar strategies such as manipulation of the immune response to infect vectors and facilitate multiplication and transmission. Furthermore, some of these strategies may be used by pathogens to infect both tick and mammalian hosts. Identification of interactions that promote tick survival, spread, and pathogen transmission provides the opportunity to disrupt these interactions and lead to a reduction in tick burden and the prevalence of tick-borne diseases. Targeting some of the similar mechanisms used by the pathogens for infection and transmission by ticks may assist in development of preventative strategies against multiple tick-borne diseases.
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Affiliation(s)
- José de la Fuente
- SaBio. Instituto de Investigación en Recursos Cinegéticos CSIC-UCLM-JCCMCiudad Real, Spain.,Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State UniversityStillwater, OK, USA
| | - Sandra Antunes
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de LisboaLisboa, Portugal
| | | | - Alejandro Cabezas-Cruz
- UMR BIPAR INRA-ANSES-ENVAMaisons-Alfort, France.,Biology Centre, Czech Academy of Sciences, Institute of ParasitologyCeske Budejovice, Czechia.,Faculty of Science, University of South BohemiaČeské Budějovice, Czechia
| | - Ana G Domingos
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de LisboaLisboa, Portugal
| | | | - Nicholas Johnson
- Animal and Plant Health AgencySurrey, UK.,Faculty of Health and Medicine, University of SurreyGuildford, UK
| | - Katherine M Kocan
- Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State UniversityStillwater, OK, USA
| | - Karen L Mansfield
- Animal and Plant Health AgencySurrey, UK.,Institute of Infection and Global Health, University of LiverpoolLiverpool, UK
| | - Ard M Nijhof
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität BerlinBerlin, Germany
| | - Anna Papa
- Department of Microbiology, Medical School, Aristotle University of ThessalonikiThessaloniki, Greece
| | - Nataliia Rudenko
- Biology Centre, Czech Academy of Sciences, Institute of ParasitologyCeske Budejovice, Czechia
| | - Margarita Villar
- SaBio. Instituto de Investigación en Recursos Cinegéticos CSIC-UCLM-JCCMCiudad Real, Spain
| | - Pilar Alberdi
- SaBio. Instituto de Investigación en Recursos Cinegéticos CSIC-UCLM-JCCMCiudad Real, Spain
| | - Alessandra Torina
- National Center of Reference for Anaplasma, Babesia, Rickettsia and Theileria, Intituto Zooprofilattico Sperimentale della SiciliaSicily, Italy
| | - Nieves Ayllón
- SaBio. Instituto de Investigación en Recursos Cinegéticos CSIC-UCLM-JCCMCiudad Real, Spain
| | - Marie Vancova
- Biology Centre, Czech Academy of Sciences, Institute of ParasitologyCeske Budejovice, Czechia
| | - Maryna Golovchenko
- Biology Centre, Czech Academy of Sciences, Institute of ParasitologyCeske Budejovice, Czechia
| | - Libor Grubhoffer
- Biology Centre, Czech Academy of Sciences, Institute of ParasitologyCeske Budejovice, Czechia.,Faculty of Science, University of South BohemiaČeské Budějovice, Czechia
| | - Santo Caracappa
- National Center of Reference for Anaplasma, Babesia, Rickettsia and Theileria, Intituto Zooprofilattico Sperimentale della SiciliaSicily, Italy
| | - Anthony R Fooks
- Animal and Plant Health AgencySurrey, UK.,Institute of Infection and Global Health, University of LiverpoolLiverpool, UK
| | - Christian Gortazar
- SaBio. Instituto de Investigación en Recursos Cinegéticos CSIC-UCLM-JCCMCiudad Real, Spain
| | - Ryan O M Rego
- Biology Centre, Czech Academy of Sciences, Institute of ParasitologyCeske Budejovice, Czechia.,Faculty of Science, University of South BohemiaČeské Budějovice, Czechia
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25
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Muñoz-Moreno R, Galindo I, Cuesta-Geijo MÁ, Barrado-Gil L, Alonso C. Host cell targets for African swine fever virus. Virus Res 2015; 209:118-27. [DOI: 10.1016/j.virusres.2015.05.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 05/28/2015] [Accepted: 05/29/2015] [Indexed: 02/08/2023]
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26
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Ribeiro R, Otte J, Madeira S, Hutchings GH, Boinas F. Experimental Infection of Ornithodoros erraticus sensu stricto with Two Portuguese African Swine Fever Virus Strains. Study of Factors Involved in the Dynamics of Infection in Ticks. PLoS One 2015; 10:e0137718. [PMID: 26366570 PMCID: PMC4569400 DOI: 10.1371/journal.pone.0137718] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 08/21/2015] [Indexed: 11/18/2022] Open
Abstract
African swine fever (ASF) is a frequently devastating hemorrhagic disease of domestic pigs and wild boar and Ornithodoros erraticus sensu stricto argasid ticks are the only biological vectors of African swine fever virus (ASFV) known to occur in Europe. Recently this disease emerged in Eastern Europe and Russian Federation, showing a huge potential for a rapid spread between countries. There is some risk of re-emergence of ASF in the countries where these ticks exist, that can contribute for the persistence of infection and compromise control measures. In this study we aimed to identify factors that determine the probability of infection and its dynamics in the tick vector Ornithodoros erraticus sensu stricto, with two Portuguese strains of ASFV. Our results suggest that these ticks have a high likelihood of excreting the two haemadsorbing ASF viruses of different host origins and that, in field surveys, the analysis of adults and 5th nymphal stage can provide the best chance of detecting virus infection. The results also indicate that infection of pigs with highly virulent ASF viruses will promote higher rates of infection and a higher likelihood for virus excretion by ticks. Nevertheless, there is also a risk, although lower, that ticks can become infected on pigs that have overcome the acute phase of infection, which was simulated in our study by membrane feeding ticks with low titres of virus. We believe these results can be valuable in designing and interpreting the results of ASF control programmes, and future work can also be undertaken as our dataset is released under open access, to perform studies in risk assessment for ASFV persistence in a region where O. erraticus sensu stricto ticks are present.
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Affiliation(s)
- Rita Ribeiro
- Centre for Interdisciplinary Research in Animal Health (CIISA), Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
| | - Joachim Otte
- FAO Regional Office for Asia and the Pacific, 39 Phra-Atit Road, 10200 Bangkok, Thailand
| | - Sara Madeira
- Centre for Interdisciplinary Research in Animal Health (CIISA), Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
| | - Geoff H. Hutchings
- The Pirbright Laboratory, Institute for Animal Health, Ash Road, Woking, Surrey, GU24 0NF, United Kingdom
| | - Fernando Boinas
- Centre for Interdisciplinary Research in Animal Health (CIISA), Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
- * E-mail:
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27
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Mori H, Tanaka T, Mochizuki M. The widely distributed hard tick, Haemaphysalis longicornis, can retain canine parvovirus, but not be infected in laboratory condition. J Vet Med Sci 2014; 77:405-11. [PMID: 25650060 PMCID: PMC4427740 DOI: 10.1292/jvms.14-0199] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
ABSTRACT. Ticks are known to transmit various pathogens, radically threatening humans and
animals. Despite the close contact between ticks and viruses, our understanding on their
interaction and biology is still lacking. The aim of this study was to experimentally
assess the interaction between canine parvovirus (CPV) and a widely distributed hard tick,
Haemaphysalis longicornis, in laboratory condition. After inoculation
of CPV into the hemocoel of the ticks, polymerase chain reaction assay revealed that CPV
persisted in inoculated unfed adult female ticks for 28 days. Canine parvovirus was
recovered from the inoculated ticks using a cell culture, indicating that the virus
retained intact in the ticks after inoculation, but significant positive reaction
indicating virus infection was not detected in the tick organs by immunofluorescence
antibody test using a monoclonal antibody. In the case of ticks inoculated with feline
leukemia virus, the virus had shorter persistence in the ticks compared to CPV. These
findings provide significant important information on the characteristic interaction of
tick with non-tick-borne virus.
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Affiliation(s)
- Hiroyuki Mori
- Laboratory of Infectious Diseases, Joint Faculty of Veterinary Medicine, Kagoshima University, 890-0065, Japan
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28
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de Carvalho Ferreira HC, Tudela Zúquete S, Wijnveld M, Weesendorp E, Jongejan F, Stegeman A, Loeffen WLA. No evidence of African swine fever virus replication in hard ticks. Ticks Tick Borne Dis 2014; 5:582-9. [PMID: 24980962 DOI: 10.1016/j.ttbdis.2013.12.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 04/22/2014] [Accepted: 04/22/2014] [Indexed: 11/27/2022]
Abstract
African swine fever (ASF) is caused by African swine fever virus (ASFV), a tick-borne DNA virus. Soft ticks of the genus Ornithodoros are the only biological vectors of ASFV recognized so far. Although other hard ticks have been tested for vector competence, two commonly found tick species in Europe, Ixodes ricinus and Dermacentor reticulatus, have not been assessed for their vector competence for ASFV. In this study, we aimed to determine whether virus replication can occur in any of these two hard tick species (I. ricinus and/or D. reticulatus), in comparison with O. moubata (the confirmed vector), after feeding them blood containing different ASFV isolates using an improved in vitro system. DNA quantities of ASFV in these infected hard ticks were measured systematically, for 6 weeks in I. ricinus, and up to 8 weeks in D. reticulatus, and the results were compared to those obtained from O. moubata. There was evidence of virus replication in the O. moubata ticks. However, there was no evidence of virus replication in I. ricinus or D. reticulatus, even though viral DNA could be detected for up to 8 weeks after feeding in some cases. This study presents the first results on the possible vector competence of European hard (ixodid) ticks for ASFV, in a validated in vitro feeding setup. In conclusion, given the lack of evidence for virus replication under in vitro conditions, D. reticulatus and I. ricinus are unlikely to be relevant biological vectors of ASFV.
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Affiliation(s)
- Helena C de Carvalho Ferreira
- Virology Department, Central Veterinary Institute, Part of Wageningen UR (CVI), P.O. Box 65, 8200 AB Lelystad, The Netherlands; Farm Animal Department, Faculty of Veterinary Medicine, University Utrecht, Yalelaan 7-9, 3584 CL Utrecht, The Netherlands.
| | - Sara Tudela Zúquete
- Utrecht Centre for Tick-borne Diseases (UCTD), Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands
| | - Michiel Wijnveld
- Utrecht Centre for Tick-borne Diseases (UCTD), Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands
| | - Eefke Weesendorp
- Virology Department, Central Veterinary Institute, Part of Wageningen UR (CVI), P.O. Box 65, 8200 AB Lelystad, The Netherlands
| | - Frans Jongejan
- Utrecht Centre for Tick-borne Diseases (UCTD), Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands; Department of Veterinary Tropical Diseases, Faculty of Veterinary Sciences, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| | - Arjan Stegeman
- Farm Animal Department, Faculty of Veterinary Medicine, University Utrecht, Yalelaan 7-9, 3584 CL Utrecht, The Netherlands
| | - Willie L A Loeffen
- Virology Department, Central Veterinary Institute, Part of Wageningen UR (CVI), P.O. Box 65, 8200 AB Lelystad, The Netherlands.
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Cançado PHD, Faccini JLH, Herrera HM, Tavares LER, Mourão GM, Piranda EM, Paes RCS, Ribeiro CCDU, Borghesan TC, Piacenti AK, Kinas MA, Santos CC, Ono TM, Paiva F. Host-Parasite Relationship of Ticks (Acari: Ixodidae and Argasidae) and Feral Pigs (Sus scrofa) in the Nhecolândia Region of the Pantanal Wetlands in Mato Grosso do Sul. ISRN PARASITOLOGY 2013; 2013:610262. [PMID: 27335855 PMCID: PMC4890957 DOI: 10.5402/2013/610262] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 04/11/2013] [Indexed: 11/23/2022]
Abstract
Feral pigs (S. scrofa) were introduced to the Pantanal region around 200 years ago and the population appears to be in expansion. Its eradication is considered to be impossible. The population of feral pigs in the Pantanal wetlands is currently estimated at one million. Two scientific excursions were organized. The first was conducted during the dry season, when 21 feral pigs were captured and the second was during the wet season, when 23 feral pigs were captured. Ticks were collected and the oviposition and hatching process were studied to confirm the biological success of each tick species. Three tick species were found to be feeding on feral pigs: Amblyomma cajennense, A. parvum, and Ornithodoros rostratus. During the dry season, 178 adult A. cajennense were collected, contrasting with 127 A. cajennense specimens in the wet season. This suggests that the seasonality of these ticks in the Brazilian Pantanal wetlands could be different from other regions. The results indicate that A. parvum and A. cajennense are biologically successful parasites in relation to feral pigs. A. cajennense appears to have adapted to this tick-host relationship, as well as the areas where feral pigs are abundant, and could play a role in the amplification of this tick population.
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Affiliation(s)
- P H D Cançado
- Embrapa Beef Cattle, Av. Rádio Maia 830, 79002-970 Campo Grande, MS, Brazil
| | - J L H Faccini
- Departamento de Parasitologia Animal, Universidade Federal Rural do Rio de Janeiro, 23890-000 Seropédica, RJ, Brazil
| | - H M Herrera
- Universidade Católica Dom Bosco, 79117-010 Campo Grande, MS, Brazil
| | - L E R Tavares
- Centro de Ciências Biológicas e da Saúde, Universidade Federal de Mato Grosso do Sul, 79080-190 Campo Grande, MS, Brazil
| | - G M Mourão
- Brazilian Agricultural Research Corporation-CPAP, Wild Life Laboratory, 79320-900 Corumbá, MS, Brazil
| | - E M Piranda
- Centro de Ciências Biológicas e da Saúde, Universidade Federal de Mato Grosso do Sul, 79080-190 Campo Grande, MS, Brazil
| | - R C S Paes
- Agência Estadual de Defesa Sanitária Animal e Vegetal de Mato Grosso do Sul-IAGRO, 79074-902 Campo Grande, MS, Brazil
| | - C C D U Ribeiro
- Departamento de Parasitologia Animal, Universidade Federal Rural do Rio de Janeiro, 23890-000 Seropédica, RJ, Brazil
| | - T C Borghesan
- Programa de Pós-Graduação em Biologia da Relação Patógeno-Hospedeiro-ICB/USP, 05508-000 São Paulo, SP, Brazil
| | - A K Piacenti
- Programa de Pós-Graduação em Ciência Animal-UFMS, 79080-190 Campo Grande, MS, Brazil
| | - M A Kinas
- Programa de Pós-Graduação em Ecologia e Conservação-UFMS, 79080-190 Campo Grande, MS, Brazil
| | - C C Santos
- Associação de Proprietários de RPPN do MS, 79002 004 Campo Grande, MS, Brazil
| | - T M Ono
- Programa de Pós-Graduação em Ciência Animal-UFMS, 79080-190 Campo Grande, MS, Brazil
| | - F Paiva
- Centro de Ciências Biológicas e da Saúde, Universidade Federal de Mato Grosso do Sul, 79080-190 Campo Grande, MS, Brazil
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Netherton CL, Wileman TE. African swine fever virus organelle rearrangements. Virus Res 2013; 173:76-86. [PMID: 23291273 DOI: 10.1016/j.virusres.2012.12.014] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 11/30/2012] [Accepted: 12/03/2012] [Indexed: 11/28/2022]
Abstract
Like most viruses African swine fever virus (ASFV) subsumes the host cell apparatus in order to facilitate its replication. ASFV replication is a highly orchestrated process with a least four stages of transcription, immediate-early, early, intermediate and late. As the infective cycle progresses through these stages most if not all of the organelles that comprise a nucleated cell are modified, adapted or in some cases destroyed. The entry of the virus is receptor-mediated, but the precise mechanism of endocytosis is a matter of keen, current debate. Once ASFV has exited from the endosomal-lysosomal complex the virus life-cycle enters into an intimate relationship with the microtubular network. Genome replication is believed to be initiated within the nucleus and ASFV infection completely reorders the structure of this organelle. The majority of replication and assembly occurs in discrete, perinuclear regions of the cell called virus factories and finally progeny virions are transported to the plasma membrane along microtubules where they bud out or are propelled away along actin projections to infect new cells. The generation of ASFV replication sites induces profound reorganisation of the organelles that comprise the secretory pathway and may contribute to the induction of cellular stress responses that ASFV modulates. The level of organisation and complexity of virus factories are not dissimilar to those seen in cellular organelles. Like their cellular counterparts the formation of virus factories, as well as virus entry and exit, are dependent on the various components of the cytoskeleton. This review will summarise these rearrangements, the viral proteins involved and their functional consequences.
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Affiliation(s)
- Christopher L Netherton
- Vaccinology Group, The Pirbright Institute, Pirbright, Woking, Surrey GU24 0NF, United Kingdom.
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Jori F, Vial L, Penrith ML, Pérez-Sánchez R, Etter E, Albina E, Michaud V, Roger F. Review of the sylvatic cycle of African swine fever in sub-Saharan Africa and the Indian ocean. Virus Res 2012; 173:212-27. [PMID: 23142551 DOI: 10.1016/j.virusres.2012.10.005] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 10/05/2012] [Accepted: 10/06/2012] [Indexed: 11/17/2022]
Abstract
African swine fever (ASF) is a major limiting factor for pig production in most of the countries in Sub-Saharan Africa and the Indian Ocean. In the absence of vaccine, a good understanding of the ecology and epidemiology of the disease is fundamental to implement effective control measures. In selected countries of Southern and East Africa, the association between Ornithodoros moubata ticks and warthogs has been described in detail in the literature. However, for many other countries in the region, information related to the sylvatic cycle is lacking or incomplete. In West African countries, for instance, the role of wild pigs in the epidemiology of ASF has never been demonstrated and the existence and potential impact of a sylvatic cycle involving an association between soft ticks and warthogs is questionable. In other countries, other wild pig species such as the bushpigs (Potamochoerus spp.) can also be asymptomatically infected by the virus but their role in the epidemiology of the disease is unclear and might differ according to geographic regions. In addition, the methods and techniques required to study the role of wild hosts in ASF virus (ASFV) epidemiology and ecology are very specific and differ from the more traditional methods to study domestic pigs or other tick species. The aim of this review is (i) to provide a descriptive list of the methodologies implemented to study the role of wild hosts in African swine fever, (ii) to compile the available knowledge about the sylvatic cycle of ASFV in different regions of Sub-Saharan Africa and the Indian Ocean in addition to the one that has been described for East and Southern Africa, and (iii) to discuss current methodologies and available knowledge in order to identify new orientations for further field and experimental surveys.
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Affiliation(s)
- F Jori
- Cirad, AGIRs Research Unit, Campus International de Baillarguet, 34398 Montpellier, France.
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Cubillos C, Gómez-Sebastian S, Moreno N, Nuñez MC, Mulumba-Mfumu LK, Quembo CJ, Heath L, Etter EMC, Jori F, Escribano JM, Blanco E. African swine fever virus serodiagnosis: a general review with a focus on the analyses of African serum samples. Virus Res 2012; 173:159-67. [PMID: 23131491 DOI: 10.1016/j.virusres.2012.10.021] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 10/18/2012] [Accepted: 10/19/2012] [Indexed: 11/19/2022]
Abstract
African swine fever (ASF) is an infectious disease that causes heavy mortality in domestic pigs. At present there is no vaccine against ASF, and eradication in countries where the disease is endemic is based only on competent diagnosis programs and the sacrifice of infected animals. Due to the presence of natural attenuated strains, certain infection conditions may result in reduced mortality. In these situations, the disease can be diagnosed by detection of specific antibodies. The use of classical and validated diagnosis assays, such as ELISA and Indirect Immunofluorescence or Immunoblotting, allowed the eradication of ASF in the Iberian Peninsula in the 1990s. However, given that conventional tests include the use of antigens obtained from ASF virus (ASFV)-infected cells, they have several disadvantages, such as difficulties to achieve standardization and also the risks associated with the manipulation of live virus. Such drawbacks have led to the development of alternative and more robust systems for the production of ASFV antigens for use in anti-ASFV antibody detection systems. In the present review, we provide an update on current knowledge about antigen targets for ASFV serodiagnosis, the significant progress made in recombinant antigen production, and the refinement of ASF serological diagnostic assays. Moreover, we describe the accuracy of an ELISA developed for the serodiagnosis of ASFV in Africa. This assay is based on a novel p30 recombinant protein (p30r) obtained from an Eastern African viral isolate (Morara strain), which shares 100% amino acid sequence identity with the Georgia virus isolate. That study included the analyses of 587 field sera collected from domestic pigs and warthogs in Senegal (West Africa), the Democratic Republic of Congo (Central Africa), Mozambique (South-East Africa), and South Africa. The results revealed that the novel p30r-based ELISA allows the accurate detection of antibodies against ASFV, independently of the geographical origin of the sera.
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Affiliation(s)
- Carolina Cubillos
- Centro de Investigación en Sanidad Animal, INIA, Valdeolmos 28130 Madrid, Spain
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Burrage TG. African swine fever virus infection in Ornithodoros ticks. Virus Res 2012; 173:131-9. [PMID: 23085123 DOI: 10.1016/j.virusres.2012.10.010] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2012] [Revised: 09/29/2012] [Accepted: 10/07/2012] [Indexed: 01/08/2023]
Abstract
African swine fever virus (ASFV) is an arbovirus which is vectored by soft ticks of the Ornithodoros spp. and in the sylvatic cycle infects wart hogs and bush pigs. ASFV infection of domestic swine causes a high mortality disease. On the other hand, ASFV infection of the tick can result in a high-titered and persistent infection depending upon the ASFV isolate and the tick combination. Recently, morphological, classical virology (titration) and recombinant ASFV have been used to study the cellular, molecular and genetic interactions that occur between ASFV and its host tick.
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Affiliation(s)
- Thomas G Burrage
- Department of Homeland Security, S & T, Targeted Advance Development, Virus, Cellular and Molecular Imaging, PO Box 848, Plum Island Animal Disease Center, Greenport, NY 11944, United States.
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Diaz AV, Netherton CL, Dixon LK, Wilson AJ. African swine fever virus strain Georgia 2007/1 in Ornithodoros erraticus ticks. Emerg Infect Dis 2012; 18:1026-8. [PMID: 22607706 PMCID: PMC3358161 DOI: 10.3201/eid1806.111728] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Scientific Opinion on the Role of Tick Vectors in the Epidemiology of Crimean-Congo Hemorrhagic Fever and African Swine Fever in Eurasia. EFSA J 2010. [DOI: 10.2903/j.efsa.2010.1703] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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African swine fever virus protein p17 is essential for the progression of viral membrane precursors toward icosahedral intermediates. J Virol 2010; 84:7484-99. [PMID: 20504920 DOI: 10.1128/jvi.00600-10] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The first morphological evidence of African swine fever virus (ASFV) assembly is the appearance of precursor viral membranes, thought to derive from the endoplasmic reticulum, within the assembly sites. We have shown previously that protein p54, a viral structural integral membrane protein, is essential for the generation of the viral precursor membranes. In this report, we study the role of protein p17, an abundant transmembrane protein localized at the viral internal envelope, in these processes. Using an inducible virus for this protein, we show that p17 is essential for virus viability and that its repression blocks the proteolytic processing of polyproteins pp220 and pp62. Electron microscopy analyses demonstrate that when the infection occurs under restrictive conditions, viral morphogenesis is blocked at an early stage, immediately posterior to the formation of the viral precursor membranes, indicating that protein p17 is required to allow their progression toward icosahedral particles. Thus, the absence of this protein leads to an accumulation of these precursors and to the delocalization of the major components of the capsid and core shell domains. The study of ultrathin serial sections from cells infected with BA71V or the inducible virus under permissive conditions revealed the presence of large helicoidal structures from which immature particles are produced, suggesting that these helicoidal structures represent a previously undetected viral intermediate.
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Sánchez‐Vizcaíno JM, Martínez‐López B, Martínez‐Avilés M, Martins C, Boinas F, Vialc L, Michaud V, Jori F, Etter E, Albina E, Roger F. Scientific review on African Swine Fever. ACTA ACUST UNITED AC 2009. [DOI: 10.2903/sp.efsa.2009.en-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
| | | | | | - Carlos Martins
- Faculdade de Medicina Veterinaria, Universidade Técnica de Lisboa, (FMV‐UTL)
| | - Fernando Boinas
- Faculdade de Medicina Veterinaria, Universidade Técnica de Lisboa, (FMV‐UTL)
| | - Laurence Vialc
- Centre de Cooperation Internationale en Recherche Agronomique pour le Développement (CIRAD)
| | - Vincent Michaud
- Centre de Cooperation Internationale en Recherche Agronomique pour le Développement (CIRAD)
| | - Ferran Jori
- Centre de Cooperation Internationale en Recherche Agronomique pour le Développement (CIRAD)
| | - Eric Etter
- Centre de Cooperation Internationale en Recherche Agronomique pour le Développement (CIRAD)
| | - Emmanuel Albina
- Centre de Cooperation Internationale en Recherche Agronomique pour le Développement (CIRAD)
| | - François Roger
- Centre de Cooperation Internationale en Recherche Agronomique pour le Développement (CIRAD)
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41
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The CD2v protein enhances African swine fever virus replication in the tick vector, Ornithodoros erraticus. Virology 2009; 393:319-28. [PMID: 19729182 DOI: 10.1016/j.virol.2009.07.040] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Revised: 07/28/2009] [Accepted: 07/31/2009] [Indexed: 11/20/2022]
Abstract
The NH/P68 non-haemadsorbing (non-HAD) African swine fever virus (ASFV) isolate contains frameshift mutations in the EP402R and adjacent EP153R genes. These encode, respectively, the protein (CD2v) that is required for the haemadsorption (HAD) of swine erythrocytes to ASFV-infected cells and a C-type lectin protein. Two recombinant HAD viruses were constructed in this parental strain. In one of these the intact EP153R gene sequence was restored. Although restoration of the HAD phenotype did not increase virus virulence in pigs, a significant increase was observed in the number of pigs which developed viraemia. These HAD recombinant viruses replicated to titres approximately 1000-fold higher than the parental non-HAD isolate when membrane fed to Ornithodoros erraticus ticks. Inoculation of the non-HAD isolate across the gut wall increased viral replication to levels comparable to that of the HAD recombinant viruses. These results demonstrate a novel role for the CD2v protein in virus replication in ticks.
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Abstract
African swine fever virus (ASFV) is a large, intracytoplasmically-replicating DNA arbovirus and the sole member of the family Asfarviridae. It is the etiologic agent of a highly lethal hemorrhagic disease of domestic swine and therefore extensively studied to elucidate the structures, genes, and mechanisms affecting viral replication in the host, virus-host interactions, and viral virulence. Increasingly apparent is the complexity with which ASFV replicates and interacts with the host cell during infection. ASFV encodes novel genes involved in host immune response modulation, viral virulence for domestic swine, and in the ability of ASFV to replicate and spread in its tick vector. The unique nature of ASFV has contributed to a broader understanding of DNA virus/host interactions.
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Affiliation(s)
- E R Tulman
- Department of Pathobiology and Veterinary Science, Center of Excellence for Vaccine Research, University of Connecticut, Storrs 06269, USA.
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43
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Kleiboeker SB, Scoles GA. Pathogenesis of African swine fever virus inOrnithodorosticks. Anim Health Res Rev 2007. [DOI: 10.1079/ahrr200133] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
AbstractAfrican swine fever virus (ASFV) is the only known DNA arbovirus and the sole member of the family Asfarviridae. It causes a lethal, hemorrhagic disease in domestic pigs. ASFV is enzootic in sub-Saharan Africa and is maintained in a sylvatic cycle by infecting both wild members of the Suidae (e.g. warthogs) and the argasid tickOrnithodoros porcinus porcinus. The pathogenesis of ASFV inO. porcinus porcinusticks is characterized by a low infectious dose, lifelong infection, efficient transmission to both pigs and ticks, and low mortality until after the first oviposition. ASFV pathogenesis in warthogs is characterized by an inapparent infection with transient, low viremic titers. ThusO. porcinus porcinusticks probably constitute the most important natural vector of ASFV, although both the mammalian and tick hosts are probably required for the maintenance of ASFV in the sylvatic cycle. The mechanism of ASFV transmission from the sylvatic cycle to domestic pigs is probably through infected ticks feeding on pigs. In addition toO. porcinus porcinus, a number of North American, Central American and Caribbean species ofOrnithodoroshave been shown to be potential vectors of ASFV.
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44
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Basto AP, Nix RJ, Boinas F, Mendes S, Silva MJ, Cartaxeiro C, Portugal RS, Leitão A, Dixon LK, Martins C. Kinetics of African swine fever virus infection in Ornithodoros erraticus ticks. J Gen Virol 2006; 87:1863-1871. [PMID: 16760388 DOI: 10.1099/vir.0.81765-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The kinetics of African swine fever virus (ASFV) infection in Ornithodoros erraticus ticks were investigated in specimens collected in the field at different times following an outbreak of the disease in Portugal in 1999 and in ticks infected experimentally with a virus isolated from a tick collected during this outbreak. In ticks collected from the field, initial screening for ASFV was carried out by PCR, followed by attempts to isolate the virus in macrophage cultures. Considering total numbers of ticks tested independently of developmental stages, ASFV DNA was detected in 42.3, 26.4 and 22.4% of specimens collected at weeks 0, 32 and 63 following the outbreak, respectively. Although virus was not isolated from most of these ticks, the proportion of isolations from large nymphs and adults increased between weeks 0 and 32 from 2 to 9 % and from 5 to 11.5%, respectively. These results, together with the higher virus titres at week 32, suggest that virus replication occurred. In contrast, virus isolations from small nymphs decreased over this period, from 5 to 1.3%. At week 63, infection rates decreased for all stages. Experimental infections showed the occurrence of virus replication within 4 weeks post-feeding and maintenance of high titres in almost 100% of ticks until 20 weeks post-infection. At weeks 41 and 61, a drop in virus titres and infection rates was observed. Relevant to the understanding of African swine fever epidemiology, our results show that ASFV replicates and persists in O. erraticus, but a viral clearance occurs at later times in both natural and experimental infections.
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Affiliation(s)
- Afonso P Basto
- Laboratório de Doenças Infecciosas, CIISA, Faculdade de Medicina Veterinária, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Rebecca J Nix
- Institute for Animal Health, Pirbright Laboratory, Ash Road, Pirbright, Surrey GU24 0NF, UK
| | - Fernando Boinas
- Laboratório de Doenças Infecciosas, CIISA, Faculdade de Medicina Veterinária, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Susana Mendes
- Laboratório de Doenças Infecciosas, CIISA, Faculdade de Medicina Veterinária, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Maria J Silva
- Laboratório de Doenças Infecciosas, CIISA, Faculdade de Medicina Veterinária, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Clara Cartaxeiro
- Laboratório de Doenças Infecciosas, CIISA, Faculdade de Medicina Veterinária, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Raquel S Portugal
- Laboratório de Doenças Infecciosas, CIISA, Faculdade de Medicina Veterinária, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Alexandre Leitão
- Instituto de Investigação Científica Tropical, CVZ, CIISA, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Linda K Dixon
- Institute for Animal Health, Pirbright Laboratory, Ash Road, Pirbright, Surrey GU24 0NF, UK
| | - Carlos Martins
- Laboratório de Doenças Infecciosas, CIISA, Faculdade de Medicina Veterinária, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
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Abstract
At least 38 viral species are transmitted by ticks. Virus–tick–vertebrate host relationships are highly specific and less than 10% of all tick species (Argasidae and Ixodidae) are known to play a role as vectors of arboviruses. However, a few tick species transmit several (e.g.Ixodes ricinus,Amblyomma variegatum) or many (I. uriae) tick-borne viruses. Tick-borne viruses are found in six different virus families (Asfarviridae, Reoviridae, Rhabdoviridae, Orthomyxoviridae, Bunyaviridae, Flaviviridae) and at least 9 genera. Some as yet unassigned tick-borne viruses may belong to a seventh family, theArenaviridae. With only one exception (African swine fever virus, family Asfarviridae) all tick-borne viruses (as well as all other arboviruses) are RNA viruses. Tick-borne viruses are found in all the RNA virus families in which insect-borne members are found, with the exception of the family Togaviridae. Some tick-borne viruses pose a significant threat to the health of humans (Tick-borne encephalitis virus,Crimean-Congo haemorrhagic fever virus) or livestock (African swine fever virus,Nairobi sheep disease virus). Key challenges are to determine the molecular adaptations that allow tick-borne viruses to infect and replicate in both tick and vertebrate cells, and to identify the principal ecological determinants of tick-borne virus survival.
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Affiliation(s)
- M Labuda
- Institute of Zoology, Slovak Academy of Sciences, Dubravska cesta 9, 845 06 Bratislava, Slovakia.
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46
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Abstract
Because of the clinical and pathologic similarity to common endemic diseases, introduction of CSFV or ASFV strains of moderate to low virulence represents the greatest risk to North American swine herds. Producers, veterinarians, and diagnosticians should increase their awareness of these devastating diseases and request specific diagnostic testing whenever they are suspected. Production practices that improve biosecurity will reduce the risk of introduction of CSF and ASF and limit the spread if an incursion occurs. Additional resources. The following Web sites contain excellent color photographs that will assist producers and practitioners in identifying clinical signs and gross lesions associated with CSFV and ASFV: http://www.vet.uga.edu/vpp/gray_book/FAD and http://www.pighealth.com. The latter Web site and the OIE Web site (http://www.oie.int) offer updated information on current worldwide epizootics of ASF and CSF and other swine diseases. Details of biosecurity procedures can be found at http://www.agebb.missouri.edu; see publication G2340.
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Affiliation(s)
- Steven B Kleiboeker
- Department of Veterinary Pathobiology, Veterinary Medical Diagnostic Laboratory, College of Veterinary Medicine, University of Missouri, 1600 East Rollins, Columbia, MO 65211, USA.
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47
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Just F, Essbauer S, Ahne W, Blahak S. Occurrence of an invertebrate iridescent-like virus (Iridoviridae) in reptiles. JOURNAL OF VETERINARY MEDICINE. B, INFECTIOUS DISEASES AND VETERINARY PUBLIC HEALTH 2001; 48:685-94. [PMID: 11765804 DOI: 10.1046/j.1439-0450.2001.00495.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Viral isolates were obtained in 1998, 1999 and 2000 from the lung, liver and intestine of two bearded dragons (Pogona vitticeps) and a chameleon (Chamaeleo quadricornis) and from the skin of a frill-necked lizard (Chamydosaurus kingii) by using viper heart cells (VH2) at 28 degrees C. Electron microscopic examination of infected VH2 cells revealed the assembly of icosahedral iridovirus-like particles measuring 139 nm (side to side) and 151 nm (apex to apex). Negatively stained virus particles had dimensions of 149 nm (side to side) and 170 nm (apex to apex). Polymerase chain reaction (PCR) amplification of purified viral DNA with primers corresponding to the partial gene encoding the major capsid protein (MCP) of Frog viris-3 (FV-3), the type species of the genus Ranavirus, was unsuccessful. In contrast, primers corresponding to the partial MCP gene of Chilo iridescent virus (CIV; genus Iridovirus) amplified 500-bp products with 97% identity to the nucleotide sequence of CIV and 100% identity to the nucleotide sequence of Gryllus bimaculatus iridescent virus (GbIV), an invertebrate iridescent virus. Virus protein profiles analysed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and restriction fragment length profiles of purified viral DNA treated with the endonucleases EcoRI, HindIII and HpaII were identical to those of GbIV.
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Affiliation(s)
- F Just
- Institute of Zoology, Fishery Biology and Fish Diseases, Faculty of Veterinary Medicine, Ludwig-Maximilian's University Munich, Gemany
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48
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Tsai MF, Yu HT, Tzeng HF, Leu JH, Chou CM, Huang CJ, Wang CH, Lin JY, Kou GH, Lo CF. Identification and characterization of a shrimp white spot syndrome virus (WSSV) gene that encodes a novel chimeric polypeptide of cellular-type thymidine kinase and thymidylate kinase. Virology 2000; 277:100-10. [PMID: 11062040 DOI: 10.1006/viro.2000.0597] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
From previously constructed genomic libraries of a Taiwan WSSV isolate, a putative WSSV tk-tmk gene was identified. Uniquely, the open reading frame (ORF) of this gene was predicted to encode a novel chimeric protein of 388 amino acids with significant homology to two proteins: thymidine kinase (TK) and thymidylate kinase (TMK). Northern blot analysis with a WSSV tk-tmk-specific riboprobe detected a major transcript of 1.6 kb. When healthy adult Penaeus monodon shrimp were inoculated with WSSV, the tk-tmk gene transcript was first detected by RT-PCR analysis at 4 h postinfection and transcription levels continued to increase over the first 18 h. The gene's major in vitro transcription and translation product, equivalent to the predicted size (43 kDa), is a single chimeric protein that includes both the TK and TMK functional motifs. Evidence for phylogenetic analysis and sequence alignment suggested that the gene may have resulted from the fusion of a cellular-type TK gene and a cellular-type TMK gene. Its unique arrangement may also provide a valuable gene marker for WSSV.
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Affiliation(s)
- M F Tsai
- Department of Zoology, Institute of Biochemistry, Taipei, 106, Taiwan, Republic of China
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