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Rapid selection against arbovirus-induced apoptosis during infection of a mosquito vector. Proc Natl Acad Sci U S A 2015; 112:E1152-61. [PMID: 25713358 DOI: 10.1073/pnas.1424469112] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Millions of people are infected each year by arboviruses (arthropod-borne viruses) such as chikungunya, dengue, and West Nile viruses, yet for reasons that are largely unknown, only a relatively small number of mosquito species are able to transmit arboviruses. Understanding the complex factors that determine vector competence could facilitate strategies for controlling arbovirus infections. Apoptosis is a potential antiviral defense response that has been shown to be important in other virus-host systems. However, apoptosis is rarely seen in arbovirus-infected mosquito cells, raising questions about its importance as an antiviral defense in mosquitoes. We tested the effect of stimulating apoptosis during arbovirus infection by infecting Aedes aegypti mosquitoes with a Sindbis virus (SINV) clone called MRE/Rpr, in which the MRE-16 strain of SINV was engineered to express the proapoptotic gene reaper from Drosophila. MRE/Rpr exhibited an impaired infection phenotype that included delayed midgut infection, delayed virus replication, and reduced virus accumulation in saliva. Nucleotide sequencing of the reaper insert in virus populations isolated from individual mosquitoes revealed evidence of rapid and strong selection against maintenance of Reaper expression in MRE/Rpr-infected mosquitoes. The impaired phenotype of MRE/Rpr, coupled with the observed negative selection against Reaper expression, indicates that apoptosis is a powerful defense against arbovirus infection in mosquitoes and suggests that arboviruses have evolved mechanisms to avoid stimulating apoptosis in mosquitoes that serve as vectors.
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Sánchez-Matamoros A, Sánchez-Vizcaíno JM, Rodríguez-Prieto V, Iglesias E, Martínez-López B. Identification of Suitable Areas for African Horse Sickness Virus Infections in Spanish Equine Populations. Transbound Emerg Dis 2014; 63:564-73. [PMID: 25476549 DOI: 10.1111/tbed.12302] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Indexed: 11/27/2022]
Abstract
African horse sickness (AHS) is one of the most important vector-borne viral infectious diseases of equines, transmitted mainly by Culicoides spp. The re-emergence of Culicoides-borne diseases in Europe, such as the recent bluetongue (BT) or Schmallenberg outbreaks, has raised concern about the potential re-introduction and further spread of AHS virus (AHSV) in Europe. Spain has one of the largest European equine populations. In addition, its geographical, environmental and entomological conditions favour AHSV infections, as shown by the historical outbreaks in the 1990s. The establishment of risk-based surveillance strategies would allow the early detection and rapid control of any potential AHSV outbreak. This study aimed to identify the areas and time periods that are suitable or at high risk for AHS occurrence in Spain using a GIS-based multicriteria decision framework. Specifically risk maps for AHS occurrence were produced using a weighted linear combination of the main risk factors of disease, namely extrinsic incubation period, equine density and distribution of competent Culicoides populations. Model results revealed that the south-western and north-central areas of Spain and the Balearic Islands are the areas at the highest risk for AHSV infections, particularly in late summer months. Conversely, Galicia, Castile and Leon and La Rioja can be considered as low-risk regions. This result was validated with historical AHS and BT outbreaks in Spain, and with the Culicoides vector distribution area. The model results, together with current Spanish equine production features, should provide the foundations to design risk-based and more cost-effective surveillance strategies for the early detection and rapid control potential of AHS outbreaks in Spain.
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Affiliation(s)
- A Sánchez-Matamoros
- VISAVET Centre and Animal Health Department, Complutense University of Madrid, Madrid, Spain.,CEI Campus Moncloa, UCM-UPM, Madrid, Spain
| | - J M Sánchez-Vizcaíno
- VISAVET Centre and Animal Health Department, Complutense University of Madrid, Madrid, Spain
| | - V Rodríguez-Prieto
- VISAVET Centre and Animal Health Department, Complutense University of Madrid, Madrid, Spain
| | - E Iglesias
- Department of Agricultural Economics, E.T.S Agronomics Engineering, Technical University of Madrid, Madrid, Spain
| | - B Martínez-López
- VISAVET Centre and Animal Health Department, Complutense University of Madrid, Madrid, Spain.,Department of Medicine and Epidemiology, Center for Animal Disease Modeling and Surveillance (CADMS), University of California, Davis, CA, USA
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Mayo CE, Mullens BA, Reisen WK, Osborne CJ, Gibbs EPJ, Gardner IA, MacLachlan NJ. Seasonal and interseasonal dynamics of bluetongue virus infection of dairy cattle and Culicoides sonorensis midges in northern California--implications for virus overwintering in temperate zones. PLoS One 2014; 9:e106975. [PMID: 25215598 PMCID: PMC4162562 DOI: 10.1371/journal.pone.0106975] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 08/05/2014] [Indexed: 11/20/2022] Open
Abstract
Bluetongue virus (BTV) is the cause of an economically important arboviral disease of domestic and wild ruminants. The occurrence of BTV infection of livestock is distinctly seasonal in temperate regions of the world, thus we determined the dynamics of BTV infection (using BTV-specific real time reverse transcriptase polymerase chain reaction) among sentinel cattle and vector Culicoides sonorensis (C. sonorensis) midges on a dairy farm in northern California throughout both the seasonal and interseasonal (overwintering) periods of BTV activity from August 2012 until March 2014. The data confirmed widespread infection of both sentinel cattle and vector midges during the August-November period of seasonal BTV transmission, however BTV infection of parous female midges captured in traps set during daylight hours also was detected in February of both 2013 and 2014, during the interseasonal period. The finding of BTV-infected vector midges during mid-winter suggests that BTV may overwinter in northern California by infection of long-lived female C. sonorensis midges that were infected during the prior seasonal period of virus transmission, and reemerged sporadically during the overwintering period; however the data do not definitively preclude other potential mechanisms of BTV overwintering that are also discussed.
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Affiliation(s)
- Christie E. Mayo
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
| | - Bradley A. Mullens
- Department of Entomology, University of California Riverside, Riverside, California, United States of America
| | - William K. Reisen
- Center for Vectorborne Diseases, University of California Davis, Davis, California, United States of America
| | - Cameron J. Osborne
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
| | - E. Paul J. Gibbs
- College of Veterinary Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Ian A. Gardner
- Department of Health Management, Atlantic Veterinary College, Charlottetown, Prince Edward Island, Canada
| | - N. James MacLachlan
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
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Balenghien T, Pagès N, Goffredo M, Carpenter S, Augot D, Jacquier E, Talavera S, Monaco F, Depaquit J, Grillet C, Pujols J, Satta G, Kasbari M, Setier-Rio ML, Izzo F, Alkan C, Delécolle JC, Quaglia M, Charrel R, Polci A, Bréard E, Federici V, Cêtre-Sossah C, Garros C. The emergence of Schmallenberg virus across Culicoides communities and ecosystems in Europe. Prev Vet Med 2014; 116:360-9. [PMID: 24698329 DOI: 10.1016/j.prevetmed.2014.03.007] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 01/24/2014] [Accepted: 03/08/2014] [Indexed: 12/27/2022]
Abstract
Schmallenberg virus (SBV), a novel arboviral pathogen, has emerged and spread across Europe since 2011 inflicting congenital deformities in the offspring of infected adult ruminants. Several species of Culicoides biting midges (Diptera: Ceratopogonidae) have been implicated in the transmission of SBV through studies conducted in northern Europe. In this study Culicoides from SBV outbreak areas of mainland France and Italy (Sardinia) were screened for viral RNA. The role of both C. obsoletus and the Obsoletus complex (C. obsoletus and C. scoticus) in transmission of SBV were confirmed in France and SBV was also discovered in a pool of C. nubeculosus for the first time, implicating this species as a potential vector. While collections in Sardinia were dominated by C. imicola, only relatively small quantities of SBV RNA were detected in pools of this species and conclusive evidence of its potential role in transmission is required. In addition to these field-based studies, infection rates in colony-derived individuals of C. nubeculosus and field-collected C. scoticus are also examined in the laboratory. Rates of infection in C. nubeculosus were low, confirming previous studies, while preliminary examination of C. scoticus demonstrated that while this species can replicate SBV to a potentially transmissible level, further work is required to fully define comparative competence between species in the region. Finally, the oral competence for SBV of two abundant and widespread mosquito vector species in the laboratory is assessed. Neither Aedes albopictus nor Culex pipiens were demonstrated to replicate SBV to transmissible levels and appear unlikely to play a major role in transmission. Other vector competence data produced from studies across Europe to date is then comprehensively reviewed and compared with that generated previously for bluetongue virus.
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Affiliation(s)
- Thomas Balenghien
- Cirad, UMR15 CMAEE, F-34398 Montpellier, France; INRA, UMR1309 CMAEE, F-34398 Montpellier, France.
| | - Nonito Pagès
- Centre de Recerca en Sanitat Animal (CReSA), UAB-IRTA, Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra (Cerdanyola del Vallès), Spain
| | - Maria Goffredo
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise, Campo Boario, 64100 Teramo, Italy
| | - Simon Carpenter
- The Pirbright Institute, Ash Road, Woking, Surrey GU24 0NF, United Kingdom
| | - Denis Augot
- Université de Reims Champagne-Ardenne, ANSES, SFR Cap Santé, EA4688 - USC « VECPAR », Reims, France
| | - Elisabeth Jacquier
- Cirad, UMR15 CMAEE, F-34398 Montpellier, France; INRA, UMR1309 CMAEE, F-34398 Montpellier, France
| | - Sandra Talavera
- Centre de Recerca en Sanitat Animal (CReSA), UAB-IRTA, Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra (Cerdanyola del Vallès), Spain
| | - Federica Monaco
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise, Campo Boario, 64100 Teramo, Italy
| | - Jérôme Depaquit
- Université de Reims Champagne-Ardenne, ANSES, SFR Cap Santé, EA4688 - USC « VECPAR », Reims, France
| | - Colette Grillet
- Cirad, UMR15 CMAEE, F-34398 Montpellier, France; INRA, UMR1309 CMAEE, F-34398 Montpellier, France
| | - Joan Pujols
- Centre de Recerca en Sanitat Animal (CReSA), UAB-IRTA, Campus de la Universitat Autònoma de Barcelona, 08193 Bellaterra (Cerdanyola del Vallès), Spain
| | - Giuseppe Satta
- Istituto Zooprofilattico della Sardegna, Via Duca degli Abruzzi 8, Sardinia, Italy
| | - Mohamed Kasbari
- Université de Reims Champagne-Ardenne, ANSES, SFR Cap Santé, EA4688 - USC « VECPAR », Reims, France
| | | | - Francesca Izzo
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise, Campo Boario, 64100 Teramo, Italy
| | - Cigdem Alkan
- UMR_D 190 "Emergence des Pathologies Virales", Aix Marseille Univ, IRD French Institute of Research for Development, EHESP French School of Public Health, 13005 Marseille, France; IHU Mediterranee Infection, APHM Public Hospitals of Marseille, 13005 Marseille, France
| | | | - Michela Quaglia
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise, Campo Boario, 64100 Teramo, Italy
| | - Rémi Charrel
- UMR_D 190 "Emergence des Pathologies Virales", Aix Marseille Univ, IRD French Institute of Research for Development, EHESP French School of Public Health, 13005 Marseille, France; IHU Mediterranee Infection, APHM Public Hospitals of Marseille, 13005 Marseille, France
| | - Andrea Polci
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise, Campo Boario, 64100 Teramo, Italy
| | | | - Valentina Federici
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise, Campo Boario, 64100 Teramo, Italy
| | - Catherine Cêtre-Sossah
- Cirad, UMR15 CMAEE, F-34398 Montpellier, France; INRA, UMR1309 CMAEE, F-34398 Montpellier, France
| | - Claire Garros
- Cirad, UMR15 CMAEE, F-34398 Montpellier, France; INRA, UMR1309 CMAEE, F-34398 Montpellier, France
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De Regge N, Madder M, Deblauwe I, Losson B, Fassotte C, Demeulemeester J, Smeets F, Tomme M, Cay AB. Schmallenberg virus circulation in culicoides in Belgium in 2012: field validation of a real time RT-PCR approach to assess virus replication and dissemination in midges. PLoS One 2014; 9:e87005. [PMID: 24466312 PMCID: PMC3900700 DOI: 10.1371/journal.pone.0087005] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 12/15/2013] [Indexed: 01/10/2023] Open
Abstract
Indigenous Culicoides biting midges are suggested to be putative vectors for the recently emerged Schmallenberg virus (SBV) based on SBV RNA detection in field-caught midges. Furthermore, SBV replication and dissemination has been evidenced in C. sonorensis under laboratory conditions. After SBV had been detected in Culicoides biting midges from Belgium in August 2011, it spread all over the country by the end of 2011, as evidenced by very high between-herd seroprevalence rates in sheep and cattle. This study investigated if a renewed SBV circulation in midges occurred in 2012 in the context of high seroprevalence in the animal host population and evaluated if a recently proposed realtime RT-PCR approach that is meant to allow assessing the vector competence of Culicoides for SBV and bluetongue virus under laboratory conditions was applicable to field-caught midges. Therefore midges caught with 12 OVI traps in four different regions in Belgium between May and November 2012, were morphologically identified, age graded, pooled and tested for the presence of SBV RNA by realtime RT-PCR. The results demonstrate that although no SBV could be detected in nulliparous midges caught in May 2012, a renewed but short lived circulation of SBV in parous midges belonging to the subgenus Avaritia occured in August 2012 at all four regions. The infection prevalence reached up to 2.86% in the south of Belgium, the region where a lower seroprevalence was found at the end of 2011 than in the rest of the country. Furthermore, a frequency analysis of the Ct values obtained for 31 SBV-S segment positive pools of Avaritia midges showed a clear bimodal distribution with peaks of Ct values between 21–24 and 33–36. This closely resembles the laboratory results obtained for SBV infection of C. sonorensis and implicates indigenous midges belonging to the subgenus Avaritia as competent vectors for SBV.
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Affiliation(s)
- Nick De Regge
- Operational Direction Viral Diseases, CODA-CERVA, Brussel, Belgium
- * E-mail:
| | - Maxime Madder
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
- Department of Veterinary Tropical Diseases, University of Pretoria, Pretoria, South Africa
| | - Isra Deblauwe
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Bertrand Losson
- Department of Infectious and Parasitic Diseases, University of Liège, Liège, Belgium
| | - Christiane Fassotte
- Life Science Department, Walloon Agricultural Research Center (CRA-W), Gembloux, Belgium
| | - Julie Demeulemeester
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - François Smeets
- Department of Infectious and Parasitic Diseases, University of Liège, Liège, Belgium
| | - Marie Tomme
- Life Science Department, Walloon Agricultural Research Center (CRA-W), Gembloux, Belgium
| | - Ann Brigitte Cay
- Operational Direction Viral Diseases, CODA-CERVA, Brussel, Belgium
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Nayduch D, Cohnstaedt LW, Saski C, Lawson D, Kersey P, Fife M, Carpenter S. Studying Culicoides vectors of BTV in the post-genomic era: resources, bottlenecks to progress and future directions. Virus Res 2013; 182:43-9. [PMID: 24355835 PMCID: PMC3979112 DOI: 10.1016/j.virusres.2013.12.009] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 12/08/2013] [Accepted: 12/09/2013] [Indexed: 12/05/2022]
Abstract
Culicoides sonorensis is the only colonized species of bluetongue virus vector. The development of a fully annotated genome for this species is in progress. Transcriptomic analyses are being employed to investigate functional elements of the genome, particularly genes involved in hematophagy, reproduction, development and vector competence.
Culicoides biting midges (Diptera: Ceratopogonidae) are a major vector group responsible for the biological transmission of a wide variety of globally significant arboviruses, including bluetongue virus (BTV). In this review we examine current biological resources for the study of this genus, with an emphasis on detailing the history of extant colonies and cell lines derived from C. sonorensis, the major vector of BTV in the USA. We then discuss the rapidly developing area of genomic and transcriptomic analyses of biological processes in vectors and introduce the newly formed Culicoides Genomics and Transcriptomics Alliance. Preliminary results from these fields are detailed and finally likely areas of future research are discussed from an entomological perspective describing limitations in our understanding of Culicoides biology that may impede progress in these areas.
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Affiliation(s)
- Dana Nayduch
- USDA-ARS, Center for Grain and Animal Health Research, Arthropod Borne Animal Diseases Research Unit, 1515 College Avenue, Manhattan, KS 66502, USA.
| | - Lee W Cohnstaedt
- USDA-ARS, Center for Grain and Animal Health Research, Arthropod Borne Animal Diseases Research Unit, 1515 College Avenue, Manhattan, KS 66502, USA
| | - Christopher Saski
- Clemson University Genomics Institute, Department of Genetics and Biochemistry, BRC #310, 105 Collins Street, Clemson, SC 29634, USA
| | - Daniel Lawson
- EMBL-European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SD, UK
| | - Paul Kersey
- EMBL-European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SD, UK
| | - Mark Fife
- Vector-borne Viral Disease Programme, The Pirbright Institute, Ash Road, Woking, Surrey GU24 0NF, UK
| | - Simon Carpenter
- Vector-borne Viral Disease Programme, The Pirbright Institute, Ash Road, Woking, Surrey GU24 0NF, UK
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Differential emergence of Culicoides (Diptera: Ceratopogonidae) from on-farm breeding substrates in Northern Ireland. Parasitology 2013; 140:699-708. [PMID: 23363545 DOI: 10.1017/s0031182012002016] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) are vectors of a number of viral diseases worldwide. Following the unforeseen outbreak of bluetongue in northern Europe (2006–2009) there was a need to clarify on-farm breeding substrates utilized by temperate Culicoides spp. Six substrates (cow dung, cow slurry, horse dung, sheep dung, maize silage and soil) were investigated for Culicoides spp. emergence over a 31-week period. Overall, most Obsoletus group Culicoides emerged from the cow dung and the most Pulicaris group Culicoides emerged from the sheep dung. Furthermore, Culicoides of the Obsoletus group were found to be abundant in cow slurry and sheep dung. Temperature played a significant role in the emergence times of adult Culicoides. The Obsoletus group appear to have undergone 3 generations during the experimental period. The sex ratio of emergent Obsoletus group Culicoides was affected by substrate type, with a greater proportion of males emerging from cow dung and slurry compared with the other substrates.
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Rasmussen LD, Savini G, Lorusso A, Bellacicco A, Palmarini M, Caporale M, Rasmussen TB, Belsham GJ, Bøtner A. Transplacental transmission of field and rescued strains of BTV-2 and BTV-8 in experimentally infected sheep. Vet Res 2013; 44:75. [PMID: 24007601 PMCID: PMC3848766 DOI: 10.1186/1297-9716-44-75] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 08/27/2013] [Indexed: 11/10/2022] Open
Abstract
Transplacental transmission of bluetongue virus has been shown previously for the North European strain of serotype 8 (BTV-8) and for tissue culture or chicken egg-adapted vaccine strains but not for field strains of other serotypes. In this study, pregnant ewes (6 per group) were inoculated with either field or rescued strains of BTV-2 and BTV-8 in order to determine the ability of these viruses to cross the placental barrier. The field BTV-2 and BTV-8 strains was passaged once in Culicoides KC cells and once in mammalian cells. All virus inoculated sheep became infected and seroconverted against the different BTV strains used in this study. BTV RNA was detectable in the blood of all but two ewes for over 28 days but infectious virus could only be detected in the blood for a much shorter period. Interestingly, transplacental transmission of BTV-2 (both field and rescued strains) was demonstrated at high efficiency (6 out of 13 lambs born to BTV-2 infected ewes) while only 1 lamb of 12 born to BTV-8 infected ewes showed evidence of in utero infection. In addition, evidence for horizontal transmission of BTV-2 between ewes was observed. As expected, the parental BTV-2 and BTV-8 viruses and the viruses rescued by reverse genetics showed very similar properties to each other. This study showed, for the first time, that transplacental transmission of BTV-2, which had been minimally passaged in cell culture, can occur; hence such transmission might be more frequent than previously thought.
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Affiliation(s)
- Lasse Dam Rasmussen
- National Veterinary Institute, Technical University of Denmark, 4771 Kalvehave, Lindholm, Denmark.
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Carpenter S, Groschup MH, Garros C, Felippe-Bauer ML, Purse BV. Culicoides biting midges, arboviruses and public health in Europe. Antiviral Res 2013; 100:102-13. [PMID: 23933421 DOI: 10.1016/j.antiviral.2013.07.020] [Citation(s) in RCA: 142] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 07/22/2013] [Accepted: 07/30/2013] [Indexed: 11/25/2022]
Abstract
The emergence of multiple strains of bluetongue virus (BTV) and the recent discovery of Schmallenberg virus (SBV) in Europe have highlighted the fact that exotic Culicoides-borne arboviruses from remote geographic areas can enter and spread rapidly in this region. This review considers the potential for this phenomenon to impact on human health in Europe, by examining evidence of the role of Culicoides biting midges in the zoonotic transmission and person-to-person spread of arboviruses worldwide. To date, the only arbovirus identified as being primarily transmitted by Culicoides to and between humans is Oropouche virus (OROV). This member of the genus Orthobunyavirus causes major epidemics of febrile illness in human populations of South and Central America and the Caribbean. We examine factors promoting sustained outbreaks of OROV in Brazil from an entomological perspective and assess aspects of the epidemiology of this arbovirus that are currently poorly understood, but may influence the risk of incursion into Europe. We then review the secondary and rarely reported role of Culicoides in the transmission of high-profile zoonotic infections, while critically reviewing evidence of this phenomenon in endemic transmission and place this in context with the presence of other potential vector groups in Europe. Scenarios for the incursions of Culicoides-borne human-to-human transmitted and zoonotic arboviruses are then discussed, along with control measures that could be employed to reduce their impact. These measures are placed in the context of legislative measures used during current and ongoing outbreaks of Culicoides-borne arboviruses in Europe, involving both veterinary and public health sectors.
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Affiliation(s)
- Simon Carpenter
- The Pirbright Institute, Ash Road, Pirbright, Surrey GU24 0NF, UK.
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Veronesi E, Antony F, Gubbins S, Golding N, Blackwell A, Mertens PPC, Brownlie J, Darpel KE, Mellor PS, Carpenter S. Measurement of the infection and dissemination of bluetongue virus in culicoides biting midges using a semi-quantitative rt-PCR assay and isolation of infectious virus. PLoS One 2013; 8:e70800. [PMID: 23940643 PMCID: PMC3733650 DOI: 10.1371/journal.pone.0070800] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 06/24/2013] [Indexed: 11/20/2022] Open
Abstract
Background Culicoides biting midges (Diptera: Ceratopogonidae) are the biological vectors of globally significant arboviruses of livestock including bluetongue virus (BTV), African horse sickness virus (AHSV) and the recently emerging Schmallenberg virus (SBV). From 2006–2009 outbreaks of BTV in northern Europe inflicted major disruption and economic losses to farmers and several attempts were made to implicate Palaearctic Culicoides species as vectors. Results from these studies were difficult to interpret as they used semi-quantitative RT-PCR (sqPCR) assays as the major diagnostic tool, a technique that had not been validated for use in this role. In this study we validate the use of these assays by carrying out time-series detection of BTV RNA in two colony species of Culicoides and compare the results with the more traditional isolation of infectious BTV on cell culture. Methodology/Principal Findings A BTV serotype 1 strain mixed with horse blood was fed to several hundred individuals of Culicoides sonorensis (Wirth & Jones) and C. nubeculosus (Mg.) using a membrane-based assay and replete individuals were then incubated at 25°C. At daily intervals 25 Culicoides of each species were removed from incubation, homogenised and BTV quantified in each individual using sqPCR (Cq values) and virus isolation on a KC-C. sonorensis embryonic cell line, followed by antigen enzyme-linked immunosorbent assay (ELISA). In addition, comparisons were also drawn between the results obtained with whole C. sonorensis and with individually dissected individuals to determine the level of BTV dissemination. Conclusions/Significance Cq values generated from time-series infection experiments in both C. sonorensis and C. nubeculosus confirmed previous studies that relied upon the isolation and detection of infectious BTV. Implications on the testing of field-collected Culicoides as potential virus vectors by PCR assays and the use of such assays as front-line tools for use in diagnostic laboratories in this role are discussed.
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Affiliation(s)
- Eva Veronesi
- Vector-borne Viral Diseases Programme, The Pirbright Institute, Pirbright, Surrey, United Kingdom
| | - Frank Antony
- Vector-borne Viral Diseases Programme, The Pirbright Institute, Pirbright, Surrey, United Kingdom
| | - Simon Gubbins
- Vector-borne Viral Diseases Programme, The Pirbright Institute, Pirbright, Surrey, United Kingdom
| | - Nick Golding
- Vector-borne Viral Diseases Programme, The Pirbright Institute, Pirbright, Surrey, United Kingdom
| | | | - Peter PC. Mertens
- Vector-borne Viral Diseases Programme, The Pirbright Institute, Pirbright, Surrey, United Kingdom
| | - Joe Brownlie
- Royal Veterinary College, Hatfield, Herts, United Kingdom
| | - Karin E. Darpel
- Vector-borne Viral Diseases Programme, The Pirbright Institute, Pirbright, Surrey, United Kingdom
- University of Surrey, Guildford, Surrey, United Kingdom
| | - Philip S. Mellor
- Vector-borne Viral Diseases Programme, The Pirbright Institute, Pirbright, Surrey, United Kingdom
| | - Simon Carpenter
- Vector-borne Viral Diseases Programme, The Pirbright Institute, Pirbright, Surrey, United Kingdom
- * E-mail:
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Veronesi E, Henstock M, Gubbins S, Batten C, Manley R, Barber J, Hoffmann B, Beer M, Attoui H, Mertens PPC, Carpenter S. Implicating Culicoides biting midges as vectors of Schmallenberg virus using semi-quantitative RT-PCR. PLoS One 2013; 8:e57747. [PMID: 23520481 PMCID: PMC3592918 DOI: 10.1371/journal.pone.0057747] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 01/24/2013] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND The recent unprecedented emergence of arboviruses transmitted by Culicoides biting midges in northern Europe has necessitated the development of techniques to differentiate competent vector species. At present these techniques are entirely reliant upon interpretation of semi-quantitative RT-PCR (sqPCR) data in the form of Cq values used to infer the presence of viral RNA in samples. METHODOLOGY/PRINCIPAL FINDINGS This study investigates the advantages and limitations of sqPCR in this role by comparing infection and dissemination rates of Schmallenberg virus (SBV) in two colony lines of Culicoides. Through the use of these behaviorally malleable lines we provide tools for demarcating arbovirus infection and dissemination rates in Culicoides which to date have prevented clear implication of primary vector species in northern Europe. The study demonstrates biological transmission of SBV in an arthropod vector, supporting the conclusions from field-caught Culicoides and provides a general framework for future assessment of vector competence of Culicoides for arboviruses using sqPCR. CONCLUSIONS/SIGNIFICANCE When adopting novel diagnostic technologies, correctly implicating vectors of arboviral pathogens requires a coherent laboratory framework to fully understand the implications of results produced in the field. This study illustrates these difficulties and provides a full examination of sqPCR in this role for the Culicoides-arbovirus system.
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Affiliation(s)
- Eva Veronesi
- VVD Program, The Pirbright Institute, Pirbright, Surrey, United Kingdom
| | - Mark Henstock
- VVD Program, The Pirbright Institute, Pirbright, Surrey, United Kingdom
| | - Simon Gubbins
- VVD Program, The Pirbright Institute, Pirbright, Surrey, United Kingdom
| | - Carrie Batten
- VVD Program, The Pirbright Institute, Pirbright, Surrey, United Kingdom
| | - Robyn Manley
- VVD Program, The Pirbright Institute, Pirbright, Surrey, United Kingdom
| | - James Barber
- VVD Program, The Pirbright Institute, Pirbright, Surrey, United Kingdom
| | - Bernd Hoffmann
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Houssam Attoui
- VVD Program, The Pirbright Institute, Pirbright, Surrey, United Kingdom
| | | | - Simon Carpenter
- VVD Program, The Pirbright Institute, Pirbright, Surrey, United Kingdom
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62
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Arias-Goeta C, Mousson L, Rougeon F, Failloux AB. Dissemination and transmission of the E1-226V variant of chikungunya virus in Aedes albopictus are controlled at the midgut barrier level. PLoS One 2013; 8:e57548. [PMID: 23437397 PMCID: PMC3578806 DOI: 10.1371/journal.pone.0057548] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Accepted: 01/26/2013] [Indexed: 01/22/2023] Open
Abstract
Emergence of arboviruses could result from their ability to exploit new environments, for example a new host. This ability is facilitated by the high mutation rate occurring during viral genome replication. The last emergence of chikungunya in the Indian Ocean region corroborates this statement since a single viral mutation at the position 226 on the E1 glycoprotein (E1-A226V) was associated with enhanced transmission by the mosquito Aedes albopictus in regions where the major mosquito vector, Aedes aegypti, is absent. We used direct competition assays in vivo to dissect out the mechanisms underlying the selection of E1-226V by Ae. albopictus. When the original variant E1-226A and the newly emerged E1-226V were provided in the same blood-meal at equal titers to both species of mosquitoes, we found that the proportion of both variants was drastically different in the two mosquito species. Following ingestion of the infectious blood-meal, the E1-226V variant was preferentially selected in Ae. albopictus, whereas the E1-226A variant was sometimes favored in Ae. aegypti. Interestingly, when the two variants were introduced into the mosquitoes by intrathoracic inoculations, E1-226V was no longer favored for dissemination and transmission in Ae. albopictus, showing that the midgut barrier plays a key role in E1-226V selection. This study sheds light on the role of the midgut barrier in the selection of novel arbovirus emerging variants. We also bring new insight into how the pre-existing variant E1-226V was selected among other viral variants including E1-226A. Indeed the E1-226V variant present at low levels in natural viral populations could rapidly emerge after being selected in Ae. albopictus at the midgut barrier level.
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Affiliation(s)
- Camilo Arias-Goeta
- Department of Virology, Arboviruses and Insect Vectors, Institut Pasteur, Paris, France
- Cellule Pasteur, Université Pierre et Marie Curie, Paris, France
| | - Laurence Mousson
- Department of Virology, Arboviruses and Insect Vectors, Institut Pasteur, Paris, France
| | | | - Anna-Bella Failloux
- Department of Virology, Arboviruses and Insect Vectors, Institut Pasteur, Paris, France
- * E-mail:
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63
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Tabachnick WJ. Nature, nurture and evolution of intra-species variation in mosquito arbovirus transmission competence. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2013; 10:249-77. [PMID: 23343982 PMCID: PMC3564141 DOI: 10.3390/ijerph10010249] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 12/29/2012] [Accepted: 01/09/2013] [Indexed: 01/14/2023]
Abstract
Mosquitoes vary in their competence or ability to transmit arthropod-borne viruses (arboviruses). Many arboviruses cause disease in humans and animals. Identifying the environmental and genetic causes of variation in mosquito competence for arboviruses is one of the great challenges in public health. Progress identifying genetic (nature) and environmental (nurture) factors influencing mosquito competence for arboviruses is reviewed. There is great complexity in the various traits that comprise mosquito competence. The complex interactions between environmental and genetic factors controlling these traits and the factors shaping variation in Nature are largely unknown. The norms of reaction of specific genes influencing competence, their distributions in natural populations and the effects of genetic polymorphism on phenotypic variation need to be determined. Mechanisms influencing competence are not likely due to natural selection because of the direct effects of the arbovirus on mosquito fitness. More likely the traits for mosquito competence for arboviruses are the effects of adaptations for other functions of these competence mechanisms. Determining these other functions is essential to understand the evolution and distributions of competence for arboviruses. This information is needed to assess risk from mosquito-borne disease, predict new mosquito-arbovirus systems, and provide novel strategies to mitigate mosquito-borne arbovirus transmission.
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Affiliation(s)
- Walter J Tabachnick
- Florida Medical Entomology Laboratory, University of Florida, IFAS, 200 9th St. SE, Vero Beach, FL 32962, USA.
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64
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Thompson GM, Jess S, Murchie AK. A review of African horse sickness and its implications for Ireland. Ir Vet J 2012; 65:9. [PMID: 22553991 PMCID: PMC3390273 DOI: 10.1186/2046-0481-65-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 05/03/2012] [Indexed: 11/12/2022] Open
Abstract
African horse sickness is an economically highly important non-contagious but infectious Orbivirus disease that is transmitted by various species of Culicoides midges. The equids most severely affected by the virus are horses, ponies, and European donkeys; mules are somewhat less susceptible, and African donkeys and zebra are refractory to the devastating consequences of infection. In recent years, Bluetongue virus, an Orbivirus similar to African horse sickness, which also utilises Culicoides spp. as its vector, has drastically increased its range into previously unaffected regions in northern Europe, utilising indigenous vector species, and causing widespread economic damage to the agricultural sector. Considering these events, the current review outlines the history of African horse sickness, including information concerning virus structure, transmission, viraemia, overwintering ability, and the potential implications that an outbreak would have for Ireland. While the current risk for the introduction of African horse sickness to Ireland is considered at worst ‘very low’, it is important to note that prior to the 2006 outbreak of Bluetongue in northern Europe, both diseases were considered to be of equal risk to the United Kingdom (‘medium-risk’). It is therefore likely that any outbreak of this disease would have serious socio-economic consequences for Ireland due to the high density of vulnerable equids and the prevalence of Culicoides species, potentially capable of vectoring the virus.
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Affiliation(s)
- Geoffrey M Thompson
- School of Biological Sciences, Queen's University of Belfast, Belfast, BT7 1NN, Northern Ireland.
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65
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Crabtree MB, Kent Crockett RJ, Bird BH, Nichol ST, Erickson BR, Biggerstaff BJ, Horiuchi K, Miller BR. Infection and transmission of Rift Valley fever viruses lacking the NSs and/or NSm genes in mosquitoes: potential role for NSm in mosquito infection. PLoS Negl Trop Dis 2012; 6:e1639. [PMID: 22563517 PMCID: PMC3341344 DOI: 10.1371/journal.pntd.0001639] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Accepted: 03/27/2012] [Indexed: 01/08/2023] Open
Abstract
Background Rift Valley fever virus is an arthropod-borne human and animal pathogen responsible for large outbreaks of acute and febrile illness throughout Africa and the Arabian Peninsula. Reverse genetics technology has been used to develop deletion mutants of the virus that lack the NSs and/or NSm virulence genes and have been shown to be stable, immunogenic and protective against Rift Valley fever virus infection in animals. We assessed the potential for these deletion mutant viruses to infect and be transmitted by Aedes mosquitoes, which are the principal vectors for maintenance of the virus in nature and emergence of virus initiating disease outbreaks, and by Culex mosquitoes which are important amplification vectors. Methodology and Principal Findings Aedes aegypti and Culex quinquefasciatus mosquitoes were fed bloodmeals containing the deletion mutant viruses. Two weeks post-exposure mosquitoes were assayed for infection, dissemination, and transmission. In Ae. aegypti, infection and transmission rates of the NSs deletion virus were similar to wild type virus while dissemination rates were significantly reduced. Infection and dissemination rates for the NSm deletion virus were lower compared to wild type. Virus lacking both NSs and NSm failed to infect Ae. aegypti. In Cx. quinquefasciatus, infection rates for viruses lacking NSm or both NSs and NSm were lower than for wild type virus. Conclusions/Significance In both species, deletion of NSm or both NSs and NSm reduced the infection and transmission potential of the virus. Deletion of both NSs and NSm resulted in the highest level of attenuation of virus replication. Deletion of NSm alone was sufficient to nearly abolish infection in Aedes aegypti mosquitoes, indicating an important role for this protein. The double deleted viruses represent an ideal vaccine profile in terms of environmental containment due to lack of ability to efficiently infect and be transmitted by mosquitoes. Rift Valley fever virus is transmitted mainly by mosquitoes and causes disease in humans and animals throughout Africa and the Arabian Peninsula. The impact of disease is large in terms of human illness and mortality, and economic impact on the livestock industry. For these reasons, and because there is a risk of this virus spreading to Europe and North America, it is important to develop a vaccine that is stable, safe and effective in preventing infection. Potential vaccine viruses have been developed through deletion of two genes (NSs and NSm) affecting virus virulence. Because this virus is normally transmitted by mosquitoes we must determine the effects of the deletions in these vaccine viruses on their ability to infect and be transmitted by mosquitoes. An optimal vaccine virus would not infect or be transmitted. The viruses were tested in two mosquito species: Aedes aegypti and Culex quinquefasciatus. Deletion of the NSm gene reduced infection of Ae. aegypti mosquitoes indicating a role for the NSm protein in mosquito infection. The virus with deletion of both NSs and NSm genes was the best vaccine candidate since it did not infect Ae. aegypti and showed reduced infection and transmission rates in Cx. quinquefasciatus.
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Affiliation(s)
- Mary B Crabtree
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, United States of America.
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66
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Richards SL, Anderson SL, Lord CC, Smartt CT, Tabachnick WJ. Relationships between infection, dissemination, and transmission of West Nile virus RNA in Culex pipiens quinquefasciatus (Diptera: Culicidae). JOURNAL OF MEDICAL ENTOMOLOGY 2012; 49:132-142. [PMID: 22308781 PMCID: PMC3320798 DOI: 10.1603/me10280] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Culex pipiens quinquefasciatus Say fed blood containing 6.8 +/- 0.3 logs (mean +/- SE) plaque-forming units of West Nile virus (WNV)/ml were maintained at 28 degrees C for incubation periods (IP) of 7, 14, or 21 d. Several attributes of vector competence were determined at each IP using quantitative real-time reverse transcriptase polymerase chain reaction to estimate plaque forming unit equivalents including: infection rate (WNV-positive abdomens), dissemination rate (WNV-positive legs or thoraces), combined dissemination rate (WNV-positive legs and thoraces), transmission rate (WNV-positive saliva), and WNV titers in abdomens, legs, thoraces, and saliva. Each rate increased or was equivalent with increasing IP. Mosquitoes transmitting WNV in saliva also had significantly higher IP-dependent WNV titers in abdomens, legs, and thoraces. Titers of WNV in abdomens were significantly correlated with titers in legs and thoraces, but the degree of association changed with IP. However, titers of abdomens, legs, and thoraces were not correlated with WNV presence or titer in the saliva. The results show that WNV presence or titer in the saliva of infected Cx. p. quinquefasciatus was not directly influenced by processes involved in WNV replication in other tissues. The processes controlling midgut infection and escape are, in part, independent from the infection processes in other tissues. The relationship between infection, dissemination, and transmission varied over time. The infection and replication of WNV in different tissues is likely influenced by different barriers encountered during the extrinsic incubation period. The significance of these observations for understanding vector competence is discussed.
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Affiliation(s)
- Stephanie L Richards
- Florida Medical Entomology Laboratory, Department of Entomology and Nematology, University of Florida-IFAS, 200 9th Street Southeast, Vero Beach, FL 32962, USA.
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67
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Dadawala AI, Biswas SK, Rehman W, Chand K, De A, Mathapati BS, Kumar P, Chauhan HC, Chandel BS, Mondal B. Isolation of Bluetongue Virus Serotype 1 from Culicoides vector Captured in Livestock Farms and Sequence Analysis of the Viral Genome Segment-2. Transbound Emerg Dis 2011; 59:361-8. [DOI: 10.1111/j.1865-1682.2011.01279.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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68
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Carpenter S, Wilson A, Barber J, Veronesi E, Mellor P, Venter G, Gubbins S. Temperature dependence of the extrinsic incubation period of orbiviruses in Culicoides biting midges. PLoS One 2011; 6:e27987. [PMID: 22125649 PMCID: PMC3220716 DOI: 10.1371/journal.pone.0027987] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 10/30/2011] [Indexed: 11/18/2022] Open
Abstract
Background The rate at which viruses replicate and disseminate in competent arthropod vectors is limited by the temperature of their environment, and this can be an important determinant of geographical and seasonal limits to their transmission by arthropods in temperate regions. Methodology/Principal Findings Here, we present a novel statistical methodology for estimating the relationship between temperature and the extrinsic incubation period (EIP) and apply it to both published and novel data on virus replication for three internationally important orbiviruses (African horse sickness virus (AHSV), bluetongue virus (BTV) and epizootic haemorrhagic disease virus (EHDV)) in their Culicoides vectors. Our analyses show that there can be differences in vector competence for different orbiviruses in the same vector species and for the same orbivirus in different vector species. Both the rate of virus replication (approximately 0.017-0.021 per degree-day) and the minimum temperature required for replication (11-13°C), however, were generally consistent for different orbiviruses and across different Culicoides vector species. The estimates obtained in the present study suggest that previous publications have underestimated the replication rate and threshold temperature because the statistical methods they used included an implicit assumption that all negative vectors were infected. Conclusions/Significance Robust estimates of the temperature dependence of arbovirus replication are essential for building accurate models of transmission and for informing policy decisions about seasonal relaxations to movement restrictions. The methodology developed in this study provides the required robustness and is superior to methods used previously. Importantly, the methods are generic and can readily be applied to other arbovirus-vector systems, as long as the assumptions described in the text are valid.
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Affiliation(s)
- Simon Carpenter
- Vector-borne Disease Programme, Institute for Animal Health, Woking, Surrey, United Kingdom.
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69
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Serologic investigation for bluetongue virus type 4, 9 and 16 in Anatolian water buffaloes. ACTA VET BRNO 2011. [DOI: 10.2754/avb201180010041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Bluetongue has emerged as a threat for ruminant species especially in European countries; three serotypes of Bluetongue virus have been described in Turkey. In this study, a total of 380 sera were obtained from healthy adult buffaloes in 8 different provinces in Central and Northern Anatolia. Sera were tested using a Virus Neutralisation test for types 4, 9 and 16. Seropositivity rates of 16.5% (63/380), 7.1% (27/380), and 8.4% (32/380) were detected for types 4, 9, and 16, respectively. No positives were found in Northest province (41°17’). This is the first report of Bluetongue virus in buffaloes in Turkey.
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70
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Vilar MJ, Guis H, Krzywinski J, Sanderson S, Baylis M. Culicoides
vectors of bluetongue virus in Chester Zoo. Vet Rec 2011; 168:242. [DOI: 10.1136/vr.c6684] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- M. J. Vilar
- Liverpool University Climate and Infectious Diseases of Animals (LUCINDA) Group; University of Liverpool, Leahurst; Chester High Road Neston Cheshire CH64 7TE
| | - H. Guis
- Liverpool University Climate and Infectious Diseases of Animals (LUCINDA) Group; University of Liverpool, Leahurst; Chester High Road Neston Cheshire CH64 7TE
| | - J. Krzywinski
- Vector Group; Liverpool School of Tropical Medicine; Liverpool L3 5QA
| | | | - M. Baylis
- Liverpool University Climate and Infectious Diseases of Animals (LUCINDA) Group; University of Liverpool, Leahurst; Chester High Road Neston Cheshire CH64 7TE
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71
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Richards SL, Anderson SL, Smartt CT. Vector competence of Florida mosquitoes for chikungunya virus. JOURNAL OF VECTOR ECOLOGY : JOURNAL OF THE SOCIETY FOR VECTOR ECOLOGY 2010; 35:439-443. [PMID: 21175954 PMCID: PMC3076135 DOI: 10.1111/j.1948-7134.2010.00105.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Affiliation(s)
- Stephanie L Richards
- University of Florida/IFAS, Florida Medical Entomology Laboratory 2009th St. SE, Vero Beach, FL 32962, USA
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72
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Kampen H, Werner D. Three years of bluetongue disease in central Europe with special reference to Germany: what lessons can be learned? Wien Klin Wochenschr 2010; 122 Suppl 3:31-9. [DOI: 10.1007/s00508-010-1435-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Richards SL, Lord CC, Pesko KN, Tabachnick WJ. Environmental and biological factors influencing Culex pipiens quinquefasciatus (Diptera: Culicidae) vector competence for West Nile Virus. Am J Trop Med Hyg 2010; 83:126-34. [PMID: 20595491 DOI: 10.4269/ajtmh.2010.09-0776] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Interactions between environmental and biological factors affect the vector competence of Culex pipiens quinquefasciatus for West Nile virus. Three age cohorts from two Cx. p. quinquefasciatus colonies were fed blood containing a low- or high-virus dose, and each group was held at two different extrinsic incubation temperatures (EIT) for 13 days. The colonies differed in the way that they responded to the effects of the environment on vector competence. The effects of mosquito age on aspects of vector competence were dependent on the EIT and dose, and they changed depending on the colony. Complex interactions must be considered in laboratory studies of vector competence, because the extent of the genetic and environmental variation controlling vector competence in nature is largely unknown. Differences in the environmental (EIT and dose) and biological (mosquito age and colony) effects from previous studies of Cx. p. quinquefasciatus vector competence for St. Louis encephalitis virus are discussed.
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Affiliation(s)
- Stephanie L Richards
- Florida Medical Entomology Laboratory, Department of Entomology and Nematology, University of Florida-IFAS, Vero Beach, FL, USA.
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74
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Maclachlan NJ. Global implications of the recent emergence of bluetongue virus in Europe. Vet Clin North Am Food Anim Pract 2010; 26:163-71, table of contents. [PMID: 20117549 DOI: 10.1016/j.cvfa.2009.10.012] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
The recent emergence of bluetongue virus (BTV) infection has attracted much interest because of the potential role of climate change and increased ambient temperature in causing the drastic recent alteration in the global distribution of this virus. Although there have been repeated assertions that climate change will alter the distribution of arboviruses and their vectors, specific examples are lacking in which the role of global warming alone has been unambiguously defined in the spread of such infections. This article summarizes recent events in Europe and the current status of BTV in the Americas and elsewhere in the context of potential global emergence of the BTV infection and disease of ruminants.
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Affiliation(s)
- N James Maclachlan
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
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75
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Khoo CCH, Piper J, Sanchez-Vargas I, Olson KE, Franz AWE. The RNA interference pathway affects midgut infection- and escape barriers for Sindbis virus in Aedes aegypti. BMC Microbiol 2010; 10:130. [PMID: 20426860 PMCID: PMC2877022 DOI: 10.1186/1471-2180-10-130] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Accepted: 04/28/2010] [Indexed: 11/23/2022] Open
Abstract
Background The RNA interference (RNAi) pathway acts as an innate antiviral immune response in Aedes aegypti, modulating arbovirus infection of mosquitoes. Sindbis virus (SINV; family: Togaviridae, genus: Alphavirus) is an arbovirus that infects Ae. aegypti in the laboratory. SINV strain TR339 encounters a midgut escape barrier (MEB) during infection of Ae. aegypti. The nature of this barrier is not well understood. To investigate the role of the midgut as the central organ determining vector competence for arboviruses, we generated transgenic mosquitoes in which the RNAi pathway was impaired in midgut tissue of bloodfed females. We used these mosquitoes to reveal effects of RNAi impairment in the midgut on SINV replication, midgut infection and dissemination efficiencies, and mosquito longevity. Results As a novel tool for studying arbovirus-mosquito interactions, we engineered a transgenic mosquito line with an impaired RNAi pathway in the midgut of bloodfed females by silencing expression of the Aa-dcr2 gene. In midgut tissue of the transgenic Carb/dcr16 line, Aa-dcr2 expression was reduced ~50% between 1-7 days post-bloodmeal (pbm) when compared to the recipient mosquito strain. After infection with SINV-TR339EGFP, Aa-dcr2 expression levels were enhanced in both mosquito strains. In the RNAi pathway impaired mosquito strain SINV titers and midgut infection rates were significantly higher at 7 days pbm. There was also a strong tendency for increased virus dissemination rates among the transgenic mosquitoes. Between 7-14 days pbm, SINV was diminished in midgut tissue of the transgenic mosquitoes. Transgenic impairment of the RNAi pathway and/or SINV infection did not affect longevity of the mosquitoes. Conclusions We showed that RNAi impaired transgenic mosquitoes are a useful tool for studying arbovirus-mosquito interactions at the molecular level. Following ingestion by Ae. aegypti, the recombinant SINV-TR339EGFP was confronted with both MEB and a midgut infection barrier (MIB). Impairment of the RNAi pathway in the midgut strongly reduced both midgut barriers for the virus. This confirms that the endogenous RNAi pathway of Ae. aegypti modulates vector competence for SINV in the midgut. The RNAi pathway acts as a gatekeeper to the incoming virus by affecting infection rate of the midgut, intensity of infection, and dissemination from the midgut to secondary tissues.
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Affiliation(s)
- Cynthia C H Khoo
- Arthropod-Borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
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76
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Wilson AJ, Mellor PS. Bluetongue in Europe: past, present and future. Philos Trans R Soc Lond B Biol Sci 2009; 364:2669-81. [PMID: 19687037 DOI: 10.1098/rstb.2009.0091] [Citation(s) in RCA: 263] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The recent arrival in Northern and Western (NW) Europe of bluetongue virus (BTV), which causes the ruminant disease 'bluetongue', has raised the profile of this vector-borne ruminant disease and sparked discussions on the reasons for its sudden emergence so far north. This expansion has not happened in isolation and the disease has been expanding into Southern and Eastern Europe for the last decade. This shifting disease distribution is being facilitated by a number of different introduction mechanisms including the movement of infected livestock, the passive movement of infected Culicoides on the wind and, in NW Europe, an unknown route of introduction. The expansion of BTV in Europe has forced a re-evaluation of the importance of Palaearctic Culicoides species in transmission, as well as the importance of secondary transmission routes, such as transplacental transmission, in facilitating the persistence of the virus. The current European outbreak of BTV-8 is believed to have caused greater economic damage than any previous single-serotype outbreak. Although attempts are being made to improve the capacity of European countries to cope with future BTV incursions, the options available are limited by a lack of basic entomological data and limited virological surveillance.
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Affiliation(s)
- Anthony J Wilson
- Institute for Animal Health Pirbright Laboratory, Pirbright, Woking, Surrey GU24 0NF, UK.
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77
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Pesko K, Mores CN. Effect of sequential exposure on infection and dissemination rates for West Nile and St. Louis encephalitis viruses in Culex quinquefasciatus. Vector Borne Zoonotic Dis 2009; 9:281-6. [PMID: 19492941 DOI: 10.1089/vbz.2007.0281] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
West Nile virus has spread rapidly throughout the United States since its introduction in 1999, into some areas that are also endemic for St. Louis encephalitis virus (SLEV). These viruses are in the same antigenic complex within the genus Flavivirus, family Flaviviridae. Further, both viruses are transmitted primarily by Culex spp. mosquitoes and use birds as amplifying hosts. These viruses could contemporaneously coinfect individual vectors wherein changes in mosquito immune responses might occur. To explore this possibility, we evaluated the effect of sequential infection with both West Nile virus and SLEV on the infection and dissemination rates of these viruses in the vector mosquito, Culex quinquefasciatus. Prior exposure to either virus lowered susceptibility to infection with the second virus, and lower dissemination rates of the second virus, compared to controls. Exposure to one virus followed by a second virus resulted in similar infection rates for the first virus to those of controls, but higher SLEV dissemination rates when exposed first to SLEV than in singly SLEV infected controls. While some mosquitoes became infected with both viruses, only one of those viruses disseminated from the midgut into the legs, indicating a midgut infection barrier to secondary infection. Lower infection rates in mosquitoes exposed to both viruses could change transmission patterns when these viruses are present at epizootic levels.
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Affiliation(s)
- Kendra Pesko
- Florida Medical Entomology Laboratory, University of Florida, Vero Beach, Florida, USA
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78
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Lobo FP, Mota BEF, Pena SDJ, Azevedo V, Macedo AM, Tauch A, Machado CR, Franco GR. Virus-host coevolution: common patterns of nucleotide motif usage in Flaviviridae and their hosts. PLoS One 2009; 4:e6282. [PMID: 19617912 PMCID: PMC2707012 DOI: 10.1371/journal.pone.0006282] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2009] [Accepted: 06/17/2009] [Indexed: 12/18/2022] Open
Abstract
Virus-host biological interaction is a continuous coevolutionary process involving both host immune system and viral escape mechanisms. Flaviviridae family is composed of fast evolving RNA viruses that infects vertebrate (mammals and birds) and/or invertebrate (ticks and mosquitoes) organisms. These host groups are very distinct life forms separated by a long evolutionary time, so lineage-specific anti-viral mechanisms are likely to have evolved. Flaviviridae viruses which infect a single host lineage would be subjected to specific host-induced pressures and, therefore, selected by them. In this work we compare the genomic evolutionary patterns of Flaviviridae viruses and their hosts in an attempt to uncover coevolutionary processes inducing common features in such disparate groups. Especially, we have analyzed dinucleotide and codon usage patterns in the coding regions of vertebrate and invertebrate organisms as well as in Flaviviridae viruses which specifically infect one or both host types. The two host groups posses very distinctive dinucleotide and codon usage patterns. A pronounced CpG under-representation was found in the vertebrate group, possibly induced by the methylation-deamination process, as well as a prominent TpA decrease. The invertebrate group displayed only a TpA frequency reduction bias. Flaviviridae viruses mimicked host nucleotide motif usage in a host-specific manner. Vertebrate-infecting viruses possessed under-representation of CpG and TpA, and insect-only viruses displayed only a TpA under-representation bias. Single-host Flaviviridae members which persistently infect mammals or insect hosts (Hepacivirus and insect-only Flavivirus, respectively) were found to posses a codon usage profile more similar to that of their hosts than to related Flaviviridae. We demonstrated that vertebrates and mosquitoes genomes are under very distinct lineage-specific constraints, and Flaviviridae viruses which specifically infect these lineages appear to be subject to the same evolutionary pressures that shaped their host coding regions, evidencing the lineage-specific coevolutionary processes between the viral and host groups.
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Affiliation(s)
- Francisco P Lobo
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
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79
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Maclachlan N, Drew C, Darpel K, Worwa G. The Pathology and Pathogenesis of Bluetongue. J Comp Pathol 2009; 141:1-16. [DOI: 10.1016/j.jcpa.2009.04.003] [Citation(s) in RCA: 317] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Revised: 04/09/2009] [Accepted: 04/20/2009] [Indexed: 11/16/2022]
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80
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Li Q, Maddox C, Rasmussen L, Hobrath JV, White LE. Assay development and high-throughput antiviral drug screening against Bluetongue virus. Antiviral Res 2009; 83:267-73. [PMID: 19559054 PMCID: PMC2727572 DOI: 10.1016/j.antiviral.2009.06.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Revised: 06/15/2009] [Accepted: 06/17/2009] [Indexed: 11/02/2022]
Abstract
Bluetongue virus (BTV) infection is one of the most important diseases of domestic livestock. There are no antivirals available against BTV disease. In this paper, we present the development, optimization and validation of an in vitro cell-based high-throughput screening (HTS) assay using the luminescent-based CellTiter-Glo reagent to identify novel antivirals against BTV. Conditions of the cytopathic effect (CPE)-based assay were optimized at cell density of 5000 cells/well in medium containing 1% FBS and a multiplicity of infection at 0.01 in 384-well plate, with Z'-values > or = 0.70, Coefficient of Variations > or = 5.68 and signal-to-background ratio > or = 7.10. This assay was further validated using a 9532 compound library. The fully validated assay was then used to screen the 194,950 compound collection, which identified 693 compounds with >30% CPE inhibition. The 10-concentration dose response assay identified 185 structures with IC(50) < or =100 microM, out of which 42 compounds were grouped into six analog series corresponding to six scaffolds enriched within the active set compared to their distribution in the library. The CPE-based assay development demonstrated its robustness and reliability, and its application in the HTS campaign will make significant contribution to the antiviral drug discovery against BTV disease.
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Affiliation(s)
- Qianjun Li
- Department of Biochemistry and Molecular Biology, Southern Research Institute, Birmingham, AL 35205, United States.
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81
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Abd-Alla AMM, Vlak JM, Bergoin M, Maruniak JE, Parker A, Burand JP, Jehle JA, Boucias DG. Hytrosaviridae: a proposal for classification and nomenclature of a new insect virus family. Arch Virol 2009; 154:909-18. [PMID: 19458899 DOI: 10.1007/s00705-009-0398-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2008] [Accepted: 04/29/2009] [Indexed: 11/30/2022]
Abstract
Salivary gland hypertrophy viruses (SGHVs) have been identified from different dipteran species, such as the tsetse fly Glossina pallidipes (GpSGHV), the housefly Musca domestica (MdSGHV) and the narcissus bulbfly Merodon equestris (MeSGHV). These viruses share the following characteristics: (i) they produce non-occluded, enveloped, rod-shaped virions that measure 500-1,000 nm in length and 50-100 nm in diameter; (ii) they possess a large circular double-stranded DNA (dsDNA) genome ranging in size from 120 to 190 kbp and having G + C ratios ranging from 28 to 44%; (iii) they cause overt salivary gland hypertrophy (SGH) symptoms in dipteran adults and partial to complete sterility. The available information on the complete genome sequence of GpSGHV and MdSGHV indicates significant co-linearity between the two viral genomes, whereas no co-linearity was observed with baculoviruses, ascoviruses, entomopoxviruses, iridoviruses and nudiviruses, other large invertebrate DNA viruses. The DNA polymerases encoded by the SGHVs are of the type B and closely related, but they are phylogenetically distant from DNA polymerases encoded by other large dsDNA viruses. The great majority of SGHV ORFs could not be assigned by sequence comparison. Phylogenetic analysis of conserved genes clustered both SGHVs, but distantly from the nudiviruses and baculoviruses. On the basis of the available morphological, (patho)biological, genomic and phylogenetic data, we propose that the two viruses are members of a new virus family named Hytrosaviridae. This proposed family currently comprises two unassigned species, G. pallidipes salivary gland hypertrophy virus and M. domestica salivary gland hypertrophy virus, and a tentative unassigned species, M. equestris salivary gland hypertrophy virus. Here, we present the characteristics and the justification for establishing this new virus family.
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Affiliation(s)
- Adly M M Abd-Alla
- Entomology Unit, FAO/IAEA Agriculture and Biotechnology Laboratory, IAEA Laboratories Seibersdorf, 2444, Seibersdorf, Austria.
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82
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Carpenter S, McArthur C, Selby R, Ward R, Nolan DV, Luntz AJM, Dallas JF, Tripet F, Mellor PS. Experimental infection studies of UK Culicoides species midges with bluetongue virus serotypes 8 and 9. Vet Rec 2009; 163:589-92. [PMID: 19011244 DOI: 10.1136/vr.163.20.589] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
This paper describes a rapid, standardised method for testing the susceptibility to bluetongue virus (BTV) of northern Palaearctic Culicoides species midges that can be used to assess the competence of both field-caught and laboratory-infected midges. The method has been used to show that Culicoides scoticus can replicate btv serotype 8 and BTV serotype 9 strains to more than 3 log(10) TCID50/midge, the first evidence of the potential of this species to transmit BTV.
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Affiliation(s)
- S Carpenter
- Institute for Animal Health (IAH) Pirbright, Ash Road, Woking, Surrey GU24 0BN, UK
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83
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Wilson A, Mellor PS, Szmaragd C, Mertens PPC. Adaptive strategies of African horse sickness virus to facilitate vector transmission. Vet Res 2008; 40:16. [PMID: 19094921 PMCID: PMC2695022 DOI: 10.1051/vetres:2008054] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Accepted: 12/16/2008] [Indexed: 11/14/2022] Open
Abstract
African horse sickness virus (AHSV) is an orbivirus that is usually transmitted between its equid hosts by adult Culicoides midges. In this article, we review the ways in which AHSV may have adapted to this mode of transmission. The AHSV particle can be modified by the pH or proteolytic enzymes of its immediate environment, altering its ability to infect different cell types. The degree of pathogenesis in the host and vector may also represent adaptations maximising the likelihood of successful vectorial transmission. However, speculation upon several adaptations for vectorial transmission is based upon research on related viruses such as bluetongue virus (BTV), and further direct studies of AHSV are required in order to improve our understanding of this important virus.
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Affiliation(s)
- Anthony Wilson
- Vector-Borne Disease Programme, Institute for Animal Health, Ash Road, Pirbright, Woking, Surrey, GU24 0NF, United Kingdom
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84
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Wilson A, Mellor P. Bluetongue in Europe: vectors, epidemiology and climate change. Parasitol Res 2008; 103 Suppl 1:S69-77. [DOI: 10.1007/s00436-008-1053-x] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2008] [Accepted: 05/26/2008] [Indexed: 11/29/2022]
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85
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Aitken ID. The journal of comparative pathology from 1943 to 2008. J Comp Pathol 2008; 139:160-8. [PMID: 18823903 DOI: 10.1016/j.jcpa.2008.07.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2008] [Accepted: 07/24/2008] [Indexed: 11/17/2022]
Abstract
The account of the Journal's first 53 years (Pattison, 1988), also reproduced in this issue, closed by noting the interruption of publication brought about by wartime exigencies and the death in 1941 of its founder and owner, Sir John McFadyean (Fig. 1). The present article considers the further development of the Journal from that time to the present day, a period of 65 years.
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86
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Abstract
Bluetongue (BT) is a reportable disease of considerable socioeconomic concern and of major importance in the international trade of animals and animal products. Before 1998, BT was considered an exotic disease in Europe. From 1998 through 2005, at least 6 BT virus strains belonging to 5 serotypes (BTV-1, BTV-2, BTV-4, BTV-9, and BTV-16) were continuously present in the Mediterranean Basin. Since August 2006, BTV-8 has caused a severe epizootic of BT in northern Europe. The widespread recrudescence and extension of BTV-8 infections in northern Europe during 2007 suggest that requirements for BTV establishment may now be fulfilled in this area. In addition, the radial extension of BTV-8 across Europe increases the risk for an encounter between this serotype and others, particularly those that occur in the Mediterranean Basin, where vector activity continues for more of the year. This condition increases the risk for reassortment of individual BTV gene segments.
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Affiliation(s)
- Claude Saegerman
- Department of Infectious and Parasitic Diseases, Epidemiology and Risk Analysis Applied to Veterinary, University of Liège, Liège, Belgium.
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87
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Opinion of the Scientific Panel on Animal Health and Welfare on request from the Commission on bluetongue. EFSA J 2008; 6:735. [DOI: 10.2903/j.efsa.2008.735] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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88
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Gloster J, Burgin L, Witham C, Athanassiadou M, Mellor PS. Bluetongue in the United Kingdom and northern Europe in 2007 and key issues for 2008. Vet Rec 2008; 162:298-302. [PMID: 18326840 DOI: 10.1136/vr.162.10.298] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
As predicted, bluetongue arrived in the UK in 2007. Here, John Gloster and colleagues investigate the meteorological parameters that allowed this incursion into the UK and discuss key issues related to the disease's possible re-establishment in 2008.
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Affiliation(s)
- J Gloster
- Met Office, Fitzroy Road, Exeter EX1 3PB, UK
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89
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Gür S. A serologic investigation of blue tongue virus (BTV) in cattle, sheep and gazella subgutturosa subgutturosa in southeastern Turkey. Trop Anim Health Prod 2008; 40:217-21. [PMID: 18484124 DOI: 10.1007/s11250-007-9083-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Bluetongue virus (BTV) is a vector-borne disease of ruminants disseminated in the tropic and sub-tropic zone of the world. It is also an important problem in the Middle East. Three serotypes (4-9-16) of the virus have been isolated so far in Turkey. Gazella subgutturosa subgutturosa (Goitred Gazella) is native species of Anatolia. Due to risk of extinction, captured Gazelles have been taken under protection in a restricted area at Ceylanpinar state farm. In this study, the presence of Bluetongue virus (BTV) was investigated serologically in 82 Goitred Gazella, 684 sheep and 100 cattle. Seropositivity rates in Gazella, sheep and cattle were detected as 40.2%, 295% and 88%, respectively.
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Affiliation(s)
- S Gür
- Department of Virology, Afyonkarahisar Kocatepe University, Faculty of Veterinary Medicine, ANS Campus, 03100 Afyonkarahisar, Turkey.
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90
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91
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Opinion of the Scientific Panel on Animal Health an Welfare (AHAW) on the EFSA Selfmandate on bluetongue origin and occurrence. EFSA J 2007. [DOI: 10.2903/j.efsa.2007.480] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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92
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Opinion of the Scientific Panel on Animal Health and Welfare (AHAW) on request from the Commission on bluetongue vectors and vaccines. EFSA J 2007. [DOI: 10.2903/j.efsa.2007.479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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93
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Li Q, Li H, Blitvich BJ, Zhang J. The Aedes albopictus inhibitor of apoptosis 1 gene protects vertebrate cells from bluetongue virus-induced apoptosis. INSECT MOLECULAR BIOLOGY 2007; 16:93-105. [PMID: 17257212 DOI: 10.1111/j.1365-2583.2007.00705.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
We sequenced and characterized the inhibitor of apoptosis (iap) 1 gene from Aedes albopictus, designated as Aaiap1. The Aaiap1 gene rescued Spodoptera frugiperda (Sf9) cells from apoptosis when cotransfected with the Drosophila pro-apoptotic hid gene. The antiapoptotic function of the Aaiap1 gene was evaluated in the bluetongue virus (BTV)-induced apoptosis system. BTV infection induced apoptosis in vertebrate cells via the intrinsic apoptotic pathway. This was shown by the translocation of cytochrome C and the second mitochondria-derived activator of caspase (Smac, also known as DIABLO) from the mitochondria and the subsequent activation of caspase-9 and -3. Stable expression of the Aaiap1 gene in derivative baby hamster kidney cells delayed BTV-induced apoptosis by 24 h and reduced the BTV progeny yield by 10-fold. This study provides the first evidence that the mosquito AaIAP1 protein possesses antiapoptotic activity.
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Affiliation(s)
- Q Li
- Division of Geographic Medicine, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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94
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Veronesi E, Hamblin C, Mellor PS. Live attenuated bluetongue vaccine viruses in Dorset Poll sheep, before and after passage in vector midges (Diptera: Ceratopogonidae). Vaccine 2005; 23:5509-16. [PMID: 16111787 DOI: 10.1016/j.vaccine.2005.07.039] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2005] [Accepted: 07/12/2005] [Indexed: 11/20/2022]
Abstract
The aim of this study was to address concerns associating with the use of BTV attenuated commercial vaccines in European sheep. These concerns include development of viraemia, possibility of transmission by vectors, reversion to virulence and re-assortment with wild-type viruses. The two vaccine viruses (BTV 2 and 9) replicated in two species of Culicoides subsequent to oral infection reaching titres suggesting transmission would occur. Viraemia in Dorset Poll sheep inoculated with either vaccine or insect passaged vaccine viruses persisted for up to 17 days, recording titres that ranged from 2.5 to 6.25 log(10)TCID(50)/ml, which is easily sufficient to infect vector Culicoides. Moderate to severe clinical signs of BT, albeit short lived, were observed in sheep following vaccination. However, to date there is no evidence of increasing virulence following two sequential passages through the vectors.
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Affiliation(s)
- E Veronesi
- Institute for Animal Health, Department of Arbovirology, Ash Road, Pirbright, Woking, Surrey GU24 ONF, UK.
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95
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Drolet BS, Campbell CL, Stuart MA, Wilson WC. Vector competence of Culicoides sonorensis (Diptera: Ceratopogonidae) for vesicular stomatitis virus. JOURNAL OF MEDICAL ENTOMOLOGY 2005; 42:409-18. [PMID: 15962795 DOI: 10.1603/0022-2585(2005)042[0409:vcocsd]2.0.co;2] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
To determine the vector competence of Culicoides sonorensis Wirth & Jones midges for vesicular stomatitis virus (VSV)-New Jersey, insects were experimentally infected per os and sampled over time. Viral replication, as determined by in situ hybridization, was seen in epithelial, neural, and hemolymph cell types throughout the insect. Spatial and temporal distribution of virus was determined by immunohistochemical examination of sequentially sampled insects. Tissues of the alimentary canal were infected in a temporal pattern that paralleled the route of digestion/absorption: foregut and midgut by day 1, surrounding hemolymph and Malpighian tubules by day 3, and finally the midgut/ hindgut junction, hindgut, and rectal region by day 5. The circulation of virus in the hemolymph by day 3 coincided with infection of the dermis and fat bodies, the salivary glands, eyes, cerebral and subthoracic ganglia, and the ovaries. Oviduct epithelium and ovarial sheaths were infected by day 3, followed by infection of the developing oocytes by day 5. Interestingly, neural infections were seen in the subabdominal ganglia innervating the midgut in 33% of insects by 1 d postfeeding in the absence of positive staining in the hemolymph or surrounding tissues. A retrograde axonal transport infection route for these ganglia is discussed. The disseminated, productive, noncytolytic infection in Culicoides is consistent with that of an efficient biological vector for VSV. Virus readily replicated throughout the insect, passing both midgut and salivary gland infection barriers and reaching transmission-related organs in 3 d. Establishing the competence of this insect vector for VSV provides the foundation for animal transmission studies in the future. The possibility of horizontal, transovarial, and mechanical transmission is discussed.
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Affiliation(s)
- Barbara S Drolet
- Arthropod-Borne Animal Diseases Research Laboratory, USDA-ARS, 1000 E. University Avenue, Department 3354, Laramie, WY 82071, USA
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96
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Glass K. Ecological mechanisms that promote arbovirus survival: a mathematical model of Ross River virus transmission. Trans R Soc Trop Med Hyg 2005; 99:252-60. [PMID: 15708384 DOI: 10.1016/j.trstmh.2004.08.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2004] [Revised: 07/26/2004] [Accepted: 08/05/2004] [Indexed: 10/26/2022] Open
Abstract
Many assessments of host and vector competence for arboviruses focus on level and length of infectivity and ignore ecological mechanisms that contribute to virus survival. In this paper, mathematical models are used to compare local survival mechanisms for a range of scenarios, using Ross River virus as a case study. Ross River virus is an Australian arbovirus with many mosquito vectors and reservoir hosts. The mechanisms for maintaining long-term transmission of the virus vary between salt and freshwater mosquito vectors, and according to the availability of susceptible hosts. The models demonstrate that overwintering of virus in adult freshwater mosquitoes requires a large host population, while overwintering of virus in infected eggs of saltwater mosquitoes is an effective survival strategy when filial infection rates are high. The virus survives longer when both salt and freshwater mosquito species are included in the model than when only one mosquito species is present. When the marsupial host is replaced by a host with higher birth rate and shorter infectious period, the virus survived longer under all models. This suggests that birth rate can be a key factor when assessing the competence of reservoir hosts to maintain virus transmission.
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Affiliation(s)
- K Glass
- National Centre for Epidemiology and Population Health, The Australian National University, Canberra, ACT 0200, Australia.
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97
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Purse BV, Mellor PS, Rogers DJ, Samuel AR, Mertens PPC, Baylis M. Climate change and the recent emergence of bluetongue in Europe. Nat Rev Microbiol 2005; 3:171-81. [PMID: 15685226 DOI: 10.1038/nrmicro1090] [Citation(s) in RCA: 480] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Bluetongue, a devastating disease of ruminants, has historically made only brief, sporadic incursions into the fringes of Europe. However, since 1998, six strains of bluetongue virus have spread across 12 countries and 800 km further north in Europe than has previously been reported. We suggest that this spread has been driven by recent changes in European climate that have allowed increased virus persistence during winter, the northward expansion of Culicoides imicola, the main bluetongue virus vector, and, beyond this vector's range, transmission by indigenous European Culicoides species - thereby expanding the risk of transmission over larger geographical regions. Understanding this sequence of events may help us predict the emergence of other vector-borne pathogens.
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98
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Arboviruses – Viruses Transmissible by Arthropods. Transfus Med Hemother 2005. [DOI: 10.1159/000087621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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99
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100
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