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Abstract
This study focused on finding, culturing, and identifying the biological and genetic characteristics of three louping ill virus (LIV) strains in the south of the Russian Far East. The Primorye-155-77 and Primorye-20-79 virus strains were isolated from Ixodes persulcatus ticks, and the Primorye-185-91 strain was isolated from the blood of a person after a tick bite. According to the hemagglutination and neutralization tests, Primorye-155-77, Primorye-20-79 and Primorye-185-91 had weak reactivity with antibodies in an antiserum against tick-borne encephalitis virus. In Primorye-155-77 and Primorye-20-79, the sequences of the 5' ends of the 2456-nucleotide-long viral RNA including the 5' untranslated region (UTR) and genes of the capsid protein, prM protein and envelope E protein were determined. The complete genome sequence of Primorye-185-91 was determined. The E protein gene of the Negishi strain differed from those of three analyzed strains, as there were mutations resulting in the replacement of three amino acids: Ala163Thr, Asp193Asn and Ala313Thr. The homology of Primorye-185-91 to LIV 369/T2 was 97.57 %, and to the Penrith strain, it was 98.36 %. Phylogenetic analysis showed that Primorye-155-77, Primorye-20-79 and Primorye-185-91 are related to LI/A and LI/K strains isolated in England and Scotland and to the Negishi strain; these strains have a common progenitor. Negishi-like strains were represented by one subtype of louping ill virus, i.e. the British subtype (LIV-Brit). The possibility is discussed of a single introduction of the virus to the Far Eastern region (Japan and Primorsky Krai) from a single natural locus more than 50 years ago.
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Jeffries CL, Mansfield KL, Phipps LP, Wakeley PR, Mearns R, Schock A, Bell S, Breed AC, Fooks AR, Johnson N. Louping ill virus: an endemic tick-borne disease of Great Britain. J Gen Virol 2014; 95:1005-1014. [PMID: 24552787 DOI: 10.1099/vir.0.062356-0] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
In Europe and Asia, Ixodid ticks transmit tick-borne encephalitis virus (TBEV), a flavivirus that causes severe encephalitis in humans but appears to show no virulence for livestock and wildlife. In the British Isles, where TBEV is absent, a closely related tick-borne flavivirus, named louping ill virus (LIV), is present. However, unlike TBEV, LIV causes a febrile illness in sheep, cattle, grouse and some other species, that can progress to fatal encephalitis. The disease is detected predominantly in animals from upland areas of the UK and Ireland. This distribution is closely associated with the presence of its arthropod vector, the hard tick Ixodes ricinus. The virus is a positive-strand RNA virus belonging to the genus Flavivirus, exhibiting a high degree of genetic homology to TBEV and other mammalian tick-borne viruses. In addition to causing acute encephalomyelitis in sheep, other mammals and some avian species, the virus is recognized as a zoonotic agent with occasional reports of seropositive individuals, particularly those whose occupation involves contact with sheep. Preventative vaccination in sheep is effective although there is no treatment for disease. Surveillance for LIV in Great Britain is limited despite an increased awareness of emerging arthropod-borne diseases and potential changes in distribution and epidemiology. This review provides an overview of LIV and highlights areas where further effort is needed to control this disease.
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Affiliation(s)
- C L Jeffries
- Animal Health and Veterinary Laboratories Agency - Weybridge, Woodham Lane, Addlestone, Surrey KT15 3NB, UK
| | - K L Mansfield
- Animal Health and Veterinary Laboratories Agency - Weybridge, Woodham Lane, Addlestone, Surrey KT15 3NB, UK
| | - L P Phipps
- Animal Health and Veterinary Laboratories Agency - Weybridge, Woodham Lane, Addlestone, Surrey KT15 3NB, UK
| | - P R Wakeley
- Animal Health and Veterinary Laboratories Agency - Weybridge, Woodham Lane, Addlestone, Surrey KT15 3NB, UK
| | - R Mearns
- Animal Health and Veterinary Laboratories Agency - Penrith, Merrythought, Calthwaite, Penrith CA11 9RR, UK
| | - A Schock
- Animal Health and Veterinary Laboratories Agency - Lasswade, Pentlands Science Park, Penicuik, Midlothian EH26 0PZ, UK
| | - S Bell
- Animal Health and Veterinary Laboratories Agency -Shrewsbury Investigation Centre & Laboratory, Kendal Road, Harlscott, Shrewsbury, Shropshire SY1 4HD, UK
| | - A C Breed
- Animal Health and Veterinary Laboratories Agency - Weybridge, Woodham Lane, Addlestone, Surrey KT15 3NB, UK
| | - A R Fooks
- University of Liverpool, Department of Clinical Infection, Microbiology and Immunology, Liverpool, Merseyside L69 7BE, UK.,Animal Health and Veterinary Laboratories Agency - Weybridge, Woodham Lane, Addlestone, Surrey KT15 3NB, UK
| | - N Johnson
- Animal Health and Veterinary Laboratories Agency - Weybridge, Woodham Lane, Addlestone, Surrey KT15 3NB, UK
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Rapid molecular detection methods for arboviruses of livestock of importance to northern Europe. J Biomed Biotechnol 2011; 2012:719402. [PMID: 22219660 PMCID: PMC3246798 DOI: 10.1155/2012/719402] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 10/14/2011] [Accepted: 10/25/2011] [Indexed: 11/18/2022] Open
Abstract
Arthropod-borne viruses (arboviruses) have been responsible for some of the most explosive epidemics of emerging infectious diseases over the past decade. Their impact on both human and livestock populations has been dramatic. The early detection either through surveillance or diagnosis of virus will be a critical feature in responding and resolving the emergence of such epidemics in the future. Although some of the most important emerging arboviruses are human pathogens, this paper aims to highlight those diseases that primarily affect livestock, although many are zoonotic and some occasionally cause human mortality. This paper also highlights the molecular detection methods specific to each virus and identifies those emerging diseases for which a rapid detection methods are not yet developed.
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The effect of host movement on viral transmission dynamics in a vector-borne disease system. Parasitology 2009; 136:1221-34. [DOI: 10.1017/s0031182009990424] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
SUMMARYMany vector-borne pathogens whose primary vectors are generalists, such as Ixodid ticks, can infect a wide range of host species and are often zoonotic. Understanding their transmission dynamics is important for the development of disease management programmes. Models exist to describe the transmission dynamics of such diseases, but are necessarily simplistic and generally limited by knowledge of vector population dynamics. They are typically deterministic SIR-type models, which predict disease dynamics in a single, non-spatial, closed patch. Here we explore the limitations of such a model of louping-ill virus dynamics by challenging it with novel field data. The model was only partially successful in predicting Ixodes ricinus density and louping-ill virus prevalence at 6 Scottish sites. We extend the existing multi-host model by forming a two-patch model, incorporating the impact of roaming hosts. This demonstrates that host movement may account for some of the discrepancies between the original model and empirical data. We conclude that insights into the dynamics of multi-host vector-borne pathogens can be gained by using a simple two-patch model. Potential improvements to the model, incorporating aspects of spatial and temporal heterogeneity, are outlined.
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Preliminary evaluation of exotic tick species and exotic pathogens imported on migratory birds into the British Isles. Vet Parasitol 2008; 155:328-32. [DOI: 10.1016/j.vetpar.2008.05.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2008] [Revised: 04/21/2008] [Accepted: 05/06/2008] [Indexed: 11/15/2022]
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Marriott L, Willoughby K, Chianini F, Dagleish MP, Scholes S, Robinson AC, Gould EA, Nettleton PF. Detection of Louping ill virus in clinical specimens from mammals and birds using TaqMan RT-PCR. J Virol Methods 2006; 137:21-8. [PMID: 16814876 DOI: 10.1016/j.jviromet.2006.05.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2006] [Revised: 05/18/2006] [Accepted: 05/25/2006] [Indexed: 11/19/2022]
Abstract
The identification of Louping ill virus (LIV) in clinical specimens has been routinely achieved by virus isolation using susceptible pig kidney cells and subsequent serological analysis. While this method is sensitive and detects infectious virus, it is relatively labour intensive and time-consuming. In view of the veterinary and potential medical importance of LIV, a rapid and precise detection method for routine use that employs the TaqMan reverse transcription polymerase chain reaction (RT-PCR) has been developed to detect LIV RNA extracted from field samples. The TaqMan assay was evaluated against virus isolation using 22 cell culture grown LIV isolates, which had previously been partially characterised by sequencing, and material from 63 suspect field cases. Histopathological and/or serological reports were available for 39 of the suspect cases, providing additional diagnostic information to evaluate the results obtained from the TaqMan RT-PCR assay. The TaqMan assay was as sensitive as the cell culture infectious virus assay currently used and had the advantage that it was able to detect LIV in clinical specimens from which infectious virus could not be isolated possibly due to the presence of high levels of LIV antibody.
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Affiliation(s)
- L Marriott
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Midlothian EH26 0PZ, UK.
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Gaunt MW, Gould EA. Rapid subgroup identification of the flaviviruses using degenerate primer E-gene RT-PCR and site specific restriction enzyme analysis. J Virol Methods 2005; 128:113-27. [PMID: 15927275 DOI: 10.1016/j.jviromet.2005.04.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2004] [Revised: 04/19/2005] [Accepted: 04/20/2005] [Indexed: 10/25/2022]
Abstract
A simplified and rapid method for the diagnosis of all flaviviruses could provide an important tool for understanding their epidemiology. A protocol based on the use of degenerate nested oligonucleotide primers and RT-PCR was developed for the identification of flaviviruses. The primers were selected to flank the three E-gene markers that identify the viruses, giving DNA products of 971-986 (outer primers) and 859-884 bp (inner primers). Eighty five percent of E genes from flaviviruses representing most of the genus were specifically amplified, representing viruses from each of the 14 virus groups defined by the seventh International Committee for the Taxonomy of Viruses. Categorisation of the flavivirus cDNA products into the corresponding virus groups was undertaken through restriction enzyme analysis by defining conserved restriction sites common to related viruses in appropriate virus groups. Ninety percent of the known vector-borne flaviviruses with published full length E-gene sequences could be identified within 10 h.
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Affiliation(s)
- M W Gaunt
- Pathogen Molecular Biology and Biochemistry Unit, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
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Gavier-Widén D, Bröjer C, Dietz HH, Englund L, Hammer AS, Hedlund KO, Hård af Segerstad C, Nilsson K, Nowotny N, Puurula V, Thorén P, Uhlhorn H, Weissenböck H, Agren E, Klingeborn B. Investigations into shaking mink syndrome: an encephalomyelitis of unknown cause in farmed mink (Mustela vison) kits in Scandinavia. J Vet Diagn Invest 2004; 16:305-12. [PMID: 15305741 DOI: 10.1177/104063870401600408] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
An apparently novel neurological disease clinically characterized by shaking, tremors, seizures, staggering gait, and ataxia was first observed in farmed mink kits in Denmark in 2000 and subsequently in Sweden, Denmark, and Finland in 2001, and again in Denmark in 2002. Lymphoplasmacytic encephalomyelitis was found in the affected kits. The lesions were most severe in the brainstem and cerebellum and consisted of neuronal degeneration and necrosis, neuronophagia, focal and diffuse gliosis, perivascular cuffs formed by lymphocytes, plasma cells and macrophages, and segmental loss of Purkinje cells. Testing was conducted to determine the cause of the disease, including general virological investigations (virus culture, negative-staining electron microscopy, immunoelectron microscopy, polymerase chain reaction for herpesviruses, adenoviruses, pestiviruses, and coronaviruses), tests for specific viral diseases (canine distemper, Borna disease, Louping ill, West Nile virus infection, tick-borne encephalitis, Aleutian disease), tests for protozoa (Toxoplasma gondii, Neospora caninum, Encephalitozoon cuniculi), bacteria (general culture, listeria, Clamydophila psittaci), and intracerebral inoculation of neonatal mice. The results of all these investigations were negative. One group of 3 mink kits inoculated intracerebrally with brain homogenate of affected mink developed clinical signs and histological lesions similar to those observed in naturally infected mink. Based on the histopathological features, it is postulated that the disease is caused by a yet unidentified virus.
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Abstract
Over the past 10 years, a number of molecular amplification assays have been developed for the detection of flaviviruses. Most of these assays utilize the reverse transcriptase-polymerase chain reaction (RT-PCR) as the amplification format with detection by either agarose gel electrophoresis and ethidium bromide staining or hybridization with molecular probes. Recently, a modification of the standard RT-PCR using fluorescent-labeled oligonucleotide probes for detection (TaqMan) has been described. As a result, several assays for detecting flaviviruses have been developed using this approach. In addition, another amplification format, nucleic acid sequence based amplification (NASBA), has been developed and utilized for the detection of several flaviviruses. The various assay formats will be described and their utility discussed.
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Affiliation(s)
- Robert S Lanciotti
- Diagnostic and Reference Laboratory, Arbovirus Diseases Branch, Division of Vector-Borne Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado 80521, USA
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Gaunt MW, Sall AA, Lamballerie XD, Falconar AKI, Dzhivanian TI, Gould EA. Phylogenetic relationships of flaviviruses correlate with their epidemiology, disease association and biogeography. J Gen Virol 2001; 82:1867-1876. [PMID: 11457992 DOI: 10.1099/0022-1317-82-8-1867] [Citation(s) in RCA: 213] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Phylogenetic analysis of the Flavivirus genus, using either partial sequences of the non-structural 5 gene or the structural envelope gene, revealed an extensive series of clades defined by their epidemiology and disease associations. These phylogenies identified mosquito-borne, tick-borne and no-known-vector (NKV) virus clades, which could be further subdivided into clades defined by their principal vertebrate host. The mosquito-borne flaviviruses revealed two distinct epidemiological groups: (i) the neurotropic viruses, often associated with encephalitic disease in humans or livestock, correlated with the Culex species vector and bird reservoirs and (ii) the non-neurotropic viruses, associated with haemorrhagic disease in humans, correlated with the Aedes species vector and primate hosts. Thus, the tree topology describing the virus-host association may reflect differences in the feeding behaviour between Aedes and Culex mosquitoes. The tick-borne viruses also formed two distinct groups: one group associated with seabirds and the other, the tick-borne encephalitis complex viruses, associated primarily with rodents. The NKV flaviviruses formed three distinct groups: one group, which was closely related to the mosquito-borne viruses, associated with bats; a second group, which was more genetically distant, also associated with bats; and a third group associated with rodents. Each epidemiological group within the phylogenies revealed distinct geographical clusters in either the Old World or the New World, which for mosquito-borne viruses may reflect an Old World origin. The correlation between epidemiology, disease correlation and biogeography begins to define the complex evolutionary relationships between the virus, vector, vertebrate host and ecological niche.
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Affiliation(s)
- Michael W Gaunt
- Centre for Ecology and Hydrology (formerly Institute of Virology and Environmental Microbiology), Mansfield Road, Oxford OX1 3SR, UK5
- Pathogen Molecular Biology and Biochemistry Unit, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK1
| | - Amadou A Sall
- Centre for Ecology and Hydrology (formerly Institute of Virology and Environmental Microbiology), Mansfield Road, Oxford OX1 3SR, UK5
- Institut Pasteur de Dakar, Dakar, Senegal2
| | - Xavier de Lamballerie
- Centre for Ecology and Hydrology (formerly Institute of Virology and Environmental Microbiology), Mansfield Road, Oxford OX1 3SR, UK5
- Unité de Virus Emergents, Faculté de Médecine, Boulevard Jean Moulin, 13005 Marseille, France3
| | - Andrew K I Falconar
- Wellcome Trust Centre for the Epidemiology of Infectious Disease, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3FY, UK4
| | | | - Ernest A Gould
- Centre for Ecology and Hydrology (formerly Institute of Virology and Environmental Microbiology), Mansfield Road, Oxford OX1 3SR, UK5
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