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Pitchers KG, Boakye OD, Campeotto I, Daly JM. The Potential of Plant-Produced Virus-like Particle Vaccines for African Horse Sickness and Other Equine Orbiviruses. Pathogens 2024; 13:458. [PMID: 38921755 PMCID: PMC11206403 DOI: 10.3390/pathogens13060458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2024] [Revised: 05/18/2024] [Accepted: 05/24/2024] [Indexed: 06/27/2024] Open
Abstract
African horse sickness is a devastating viral disease of equids. It is transmitted by biting midges of the genus Culicoides with mortalities reaching over 90% in naïve horses. It is endemic to sub-Saharan Africa and is seasonally endemic in many parts of southern Africa. However, outbreaks in Europe and Asia have occurred that caused significant economic issues. There are attenuated vaccines available for control of the virus but concerns regarding the safety and efficacy means that alternatives are sought. One promising alternative is the use of virus-like particles in vaccine preparations, which have the potential to be safer and more efficacious as vaccines against African horse sickness. These particles are best made in a complex, eukaryotic system, but due to technical challenges, this may cause significant economic strain on the developing countries most affected by the disease. Therefore, this review also summarises the success so far, and potential, of recombinant protein expression in plants to reduce the economic strain of production.
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Affiliation(s)
- Kieran G. Pitchers
- One Virology, School of Veterinary Medicine and Science, Sutton Bonington, University of Nottingham, Nottinghamshire LE12 5RD, UK;
| | - Oliver D. Boakye
- School of Biosciences, Sutton Bonington, University of Nottingham, Nottinghamshire LE12 5RD, UK; (O.D.B.); (I.C.)
| | - Ivan Campeotto
- School of Biosciences, Sutton Bonington, University of Nottingham, Nottinghamshire LE12 5RD, UK; (O.D.B.); (I.C.)
| | - Janet M. Daly
- One Virology, School of Veterinary Medicine and Science, Sutton Bonington, University of Nottingham, Nottinghamshire LE12 5RD, UK;
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Choocherd S, Pattanatanang K, Chimnoi W, Kamyingkird K, Tongyoo P, Phasuk J. Preliminary Study on Comparative Efficacy of Four Light Sources for Trapping Culicoides spp. (Diptera: Ceratopogonidae) in Prachuap Khiri Khan Province, Thailand. JOURNAL OF ECONOMIC ENTOMOLOGY 2022; 115:1719-1723. [PMID: 35899797 DOI: 10.1093/jee/toac117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Indexed: 06/15/2023]
Abstract
The light trap is an important tool to determine the presence and abundance of vectors in the field. However, no one has studied the efficiency of light traps for collecting Culicoides in Thailand. In the present study, the efficacy of four light sources was evaluated in Prachuap Khiri Khan province, Thailand. Incandescent (INCND) light, white fluorescent (WHT-FLR) light, ultraviolet fluorescent (UV-FLR) light, and UV light-emitting diode (UV-LED) light were tested using commercial traps. In total, 30,866 individuals of Culicoides species were collected from November 2020 to June 2021, of which 21,016 were trapped on site 1 and 6,731 were trapped on site 2. The two most abundant Culicoides species were C. imicola (54%) and C. oxystoma (31.2%). UV-FLR was highly effective, followed by UV-LED light, WHT-FLR light, and INCND light, respectively, for Culicoides collection. Significantly, more Culicoides species were collected in those traps baited with UV-FLR light, UV-LED light, or WHT-FLR light than for INCND light traps. Traps equipped with UV-FLR lights can be recommended to trap Culcoides biting midges for monitoring purposes.
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Affiliation(s)
- Suchada Choocherd
- Department of Parasitology, Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand
- Center for Advanced Studies for Agriculture and Food, KU Institute for Advanced Studies, Kasetsart University, Bangkok, Thailand
| | - Khampee Pattanatanang
- Department of Parasitology, Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand
| | - Wissanuwat Chimnoi
- Department of Parasitology, Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand
| | - Ketsarin Kamyingkird
- Department of Parasitology, Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand
| | - Pumipat Tongyoo
- Center for Agricultural Biotechnology, Kasetsart University, Kamphaeng Saen Campus, Nakhon Pathom, Thailand
- Center of Excellence on Agricultural Biotechnology: (AG-BIO/MHESI), Bangkok, Thailand
| | - Jumnongjit Phasuk
- Department of Parasitology, Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand
- Center for Advanced Studies for Agriculture and Food, KU Institute for Advanced Studies, Kasetsart University, Bangkok, Thailand
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Gao H, Wang L, Ma J, Gao X, Xiao J, Wang H. Modeling the current distribution suitability and future dynamics of Culicoides imicola under climate change scenarios. PeerJ 2021; 9:e12308. [PMID: 34760364 PMCID: PMC8559603 DOI: 10.7717/peerj.12308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 09/22/2021] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND African horse sickness, a transboundary and non-contagious arboviral infectious disease of equids, has spread without any warning from sub-Saharan Africa towards the Southeast Asian countries in 2020. It is imperative to predict the global distribution of Culicoides imicola (C. imicola), which was the main vector of African horse sickness virus. METHODS The occurrence records of C. imicola were mainly obtained from the published literature and the Global Biodiversity Information Facility database. The maximum entropy algorithm was used to model the current distribution suitability and future dynamics of C. imicola under climate change scenarios. RESULTS The modeling results showed that the currently suitable habitats for C. imicola were distributed in most of the southern part areas of America, southwestern Europe, most of Africa, the coastal areas of the Middle East, almost all regions of South Asia, southern China, a few countries in Southeast Asia, and the whole Australia. Our model also revealed the important environmental variables on the distribution of C. imicola were temperature seasonality, precipitation of coldest quarter, and mean temperature of wettest quarter. Representative Concentration Pathways (RCPs) is an assumption of possible greenhouse gases emissions in the future. Under future climate change scenarios, the area of habitat suitability increased and decreased with time, and RCP 8.5 in the 2070s gave the worst prediction. Moreover, the habitat suitability of C. imicola will likely expand to higher latitudes. The prediction of this study is of strategic significance for vector surveillance and the prevention of vector-borne diseases.
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Affiliation(s)
- Hongyan Gao
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, People’s Republic of China
- Key Laboratory of the Provincial Education Department of Heilongjiang for Common Animal Disease Prevention and Treatment, College of Veterinary Medicine, Northeast Agricultural University, Harbin, People’s Republic of China
| | - Long Wang
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, People’s Republic of China
- Key Laboratory of the Provincial Education Department of Heilongjiang for Common Animal Disease Prevention and Treatment, College of Veterinary Medicine, Northeast Agricultural University, Harbin, People’s Republic of China
| | - Jun Ma
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, People’s Republic of China
- Key Laboratory of the Provincial Education Department of Heilongjiang for Common Animal Disease Prevention and Treatment, College of Veterinary Medicine, Northeast Agricultural University, Harbin, People’s Republic of China
| | - Xiang Gao
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, People’s Republic of China
- Key Laboratory of the Provincial Education Department of Heilongjiang for Common Animal Disease Prevention and Treatment, College of Veterinary Medicine, Northeast Agricultural University, Harbin, People’s Republic of China
| | - Jianhua Xiao
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, People’s Republic of China
- Key Laboratory of the Provincial Education Department of Heilongjiang for Common Animal Disease Prevention and Treatment, College of Veterinary Medicine, Northeast Agricultural University, Harbin, People’s Republic of China
| | - Hongbin Wang
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, People’s Republic of China
- Key Laboratory of the Provincial Education Department of Heilongjiang for Common Animal Disease Prevention and Treatment, College of Veterinary Medicine, Northeast Agricultural University, Harbin, People’s Republic of China
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Duan YL, Yang ZX, Bellis G, Li L. Isolation of Tibet Orbivirus from Culicoides jacobsoni (Diptera, Ceratopogonidae) in China. Parasit Vectors 2021; 14:432. [PMID: 34454575 PMCID: PMC8401062 DOI: 10.1186/s13071-021-04899-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 07/27/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Tibet Orbivirus (TIBOV) is a recently discovered Orbivirus known to infect cattle, Asian buffalo and goats in south-western China. It was first isolated from mosquitoes and subsequently from biting midges (Culicoides spp.) in Yunnan, China, indicating that it is an arbovirus. Little is known of its potential to cause disease, but the economic importance of related viruses promoted an investigation of potential Culicoides spp. vectors of TIBOV. METHODS Biting midges were collected approximately once per week between May and December 2020, at a cattle farm in Wulong village, Shizong County, Yunnan Province, China. Approximately 3000 specimens of nine species were subsequently used in attempts to isolate virus, and a further 2000 specimens of six species were tested for the presence of bluetongue virus (BTV) and TIBOV using a RT-qPCR test. RESULTS Virus isolation attempts resulted in the isolation of three viruses. One isolate from a pool of Culicoides jacobsoni was identified as TIBOV, while the other two viruses from C. orientalis and C. tainanus remain unidentified but are not BTV or TIBOV. RT-qPCR analysis did not detect BTV in any specimens, but a single pool containing five specimens of C. jacobsoni and another containing five specimens of C. tainanus produced PCR quantification cycle (Cq) values of around 28 that may indicate infection with TIBOV. CONCLUSIONS The isolation of TIBOV from C. jacobsoni satisfies one criterion required to prove its status as a vector of this virus. This isolation is supported by a low Cq value produced from a different pool of this species in the RT-qPCR test. The low Cq value obtained from a pool of C. tainanus suggests that this species may also be able to satisfy this criterion. Both of these species are widespread throughout Asia, with C. jacobsoni extending into the Pacific region, which raises the possibility that TIBOV may be more widespread than is currently known.
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Affiliation(s)
- Ying Liang Duan
- Yunnan Tropical and Subtropical Animal Virus Diseases Laboratory, Yunnan Animal Science and Veterinary Institute, Kunming, Yunnan China
| | - Zhen Xing Yang
- Yunnan Tropical and Subtropical Animal Virus Diseases Laboratory, Yunnan Animal Science and Veterinary Institute, Kunming, Yunnan China
| | - Glenn Bellis
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, NT Australia
- Department of Agriculture, Water and the Environment, Darwin, NT Australia
| | - Le Li
- Yunnan Tropical and Subtropical Animal Virus Diseases Laboratory, Yunnan Animal Science and Veterinary Institute, Kunming, Yunnan China
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Epidemiology and Genomic Analysis of Equine Encephalosis Virus Detected in Horses with Clinical Signs in South Africa, 2010-2017. Viruses 2021; 13:v13030398. [PMID: 33801457 PMCID: PMC8001977 DOI: 10.3390/v13030398] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/25/2021] [Accepted: 02/26/2021] [Indexed: 12/23/2022] Open
Abstract
Equine encephalosis virus (EEV) is a neglected virus endemic to South Africa and is considered to generally result in mild disease in equines. Specimens were analyzed from live horses that presented with undefined neurological, febrile, or respiratory signs, or sudden and unexpected death. Between 2010 and 2017, 111 of 1523 (7.3%) horse samples tested positive for EEV using a nested real-time reverse transcriptase polymerase chain reaction (rRT-PCR). Clinical signs were reported in 106 (7.2%) EEV positive and 1360 negative horses and included pyrexia (77/106, 72.6%), icterus (20/106, 18.9%) and dyspnea (12/106, 11.3%). Neurological signs were inversely associated with EEV infection (OR < 1, p < 0.05) relative to EEV negative cases despite a high percentage of animals presenting with neurological abnormalities (51/106, 48.1%). Seventeen of the EEV positive horses also had coinfections with either West Nile (5/106, 4.7%), Middelburg (4/106, 3.8%) or African Horse sickness virus (8/106, 7.6%). To investigate a possible genetic link between EEV strains causing the observed clinical signs in horses, the full genomes of six isolates were compared to the reference strains. Based on the outer capsid protein (VP2), serotype 1 and 4 were identified as the predominant serotypes with widespread reassortment between the seven different serotypes.
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Vermaak E, Maree FF, Theron J. The Culicoides sonorensis inhibitor of apoptosis 1 protein protects mammalian cells from apoptosis induced by infection with African horse sickness virus and bluetongue virus. Virus Res 2017; 232:152-161. [PMID: 28267609 DOI: 10.1016/j.virusres.2017.03.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 02/13/2017] [Accepted: 03/01/2017] [Indexed: 12/14/2022]
Abstract
African horse sickness virus (AHSV) and bluetongue virus (BTV) are arboviruses of the genus Orbivirus that are transmitted to their vertebrate hosts by Culicoides biting midges. These orbiviruses exhibit lytic infection (apoptosis) in mammalian cells, but cause persistent infection with no cytopathic effects in Culicoides sonorensis cells. Although regulation of apoptosis could thus be integral for establishing persistent virus infection in midge cells, nothing is known about the presence and function of apoptosis pathways in Culicoides midges and their derived cell lines. Here, we report the cloning and functional characterization of an inhibitor of apoptosis protein (IAP), designated CsIAP1, from C. sonorensis cells. The CsIAP1 protein contains two baculoviral IAP repeat (BIR) domains and a RING domain. Silencing of the Cs iap1 gene in C. sonorensis cells caused apoptosis, indicating that CsIAP1 plays a role in cell survival. Stable expression of the CsIAP1 protein in BSR mammalian cells suppressed apoptosis induced by AHSV-4 and BTV-10 infection, and biochemical data indicated that CsIAP1 is an inhibitor of mammalian caspase-9, an initiator caspase in the intrinsic apoptotic pathway. Mutagenesis studies indicated that the BIR2 and RING domains are required for the anti-apoptotic activity of CsIAP1. The results suggest that the mechanism by which CsIAP1 suppresses apoptosis in insect cells may involve inhibition of a Culicoides caspase-9 homologue through a mechanism that requires both the BIR2 and RING domains. This study provides the first evidence that the CsIAP1 protein is a key negative regulator of apoptosis in C. sonorensis cells.
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Affiliation(s)
- Elaine Vermaak
- Department of Microbiology and Plant Pathology, University of Pretoria, Pretoria 0002, South Africa
| | - Francois F Maree
- Department of Microbiology and Plant Pathology, University of Pretoria, Pretoria 0002, South Africa; Transboundary Animal Diseases, Onderstepoort Veterinary Institute, Agricultural Research Council, Pretoria 0110, South Africa
| | - Jacques Theron
- Department of Microbiology and Plant Pathology, University of Pretoria, Pretoria 0002, South Africa.
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Carpenter S, Mellor PS, Fall AG, Garros C, Venter GJ. African Horse Sickness Virus: History, Transmission, and Current Status. ANNUAL REVIEW OF ENTOMOLOGY 2017; 62:343-358. [PMID: 28141961 DOI: 10.1146/annurev-ento-031616-035010] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
African horse sickness virus (AHSV) is a lethal arbovirus of equids that is transmitted between hosts primarily by biting midges of the genus Culicoides (Diptera: Ceratopogonidae). AHSV affects draft, thoroughbred, and companion horses and donkeys in Africa, Asia, and Europe. In this review, we examine the impact of AHSV critically and discuss entomological studies that have been conducted to improve understanding of its epidemiology and control. The transmission of AHSV remains a major research focus and we critically review studies that have implicated both Culicoides and other blood-feeding arthropods in this process. We explore AHSV both as an epidemic pathogen and within its endemic range as a barrier to development, an area of interest that has been underrepresented in studies of the virus to date. By discussing AHSV transmission in the African republics of South Africa and Senegal, we provide a more balanced view of the virus as a threat to equids in a diverse range of settings, thus leading to a discussion of key areas in which our knowledge of transmission could be improved. The use of entomological data to detect, predict and control AHSV is also examined, including reference to existing studies carried out during unprecedented outbreaks of bluetongue virus in Europe, an arbovirus of wild and domestic ruminants also transmitted by Culicoides.
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Affiliation(s)
- Simon Carpenter
- Vector-borne Viral Diseases Program, Pirbright Institute, Woking, Surrey GU24 0NF, United Kingdom;
| | - Philip S Mellor
- Vector-borne Viral Diseases Program, Pirbright Institute, Woking, Surrey GU24 0NF, United Kingdom;
| | | | - Claire Garros
- Cirad UMR15 CMAEE, 34398 Montpellier, Cedex 5, France
| | - Gert J Venter
- Parasites, Vectors, and Vector-Borne Diseases, Agricultural Research Council-Onderstepoort Veterinary Institute, Onderstepoort 0110, South Africa
- Department of Veterinary Tropical Diseases, University of Pretoria, Pretoria 0001, South Africa
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Faverjon C, Leblond A, Lecollinet S, Bødker R, de Koeijer AA, Fischer EAJ. Comparative Risk Analysis of Two Culicoides-Borne Diseases in Horses: Equine Encephalosis More Likely to Enter France than African Horse Sickness. Transbound Emerg Dis 2016; 64:1825-1836. [PMID: 27658808 DOI: 10.1111/tbed.12577] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Indexed: 11/29/2022]
Abstract
African horse sickness (AHS) and equine encephalosis (EE) are Culicoides-borne viral diseases that could have the potential to spread across Europe if introduced, thus being potential threats for the European equine industry. Both share similar epidemiology, transmission patterns and geographical distribution. Using stochastic spatiotemporal models of virus entry, we assessed and compared the probabilities of both viruses entering France via two pathways: importation of live-infected animals or importation of infected vectors. Analyses were performed for three consecutive years (2010-2012). Seasonal and regional differences in virus entry probabilities were the same for both diseases. However, the probability of EE entry was much higher than the probability of AHS entry. Interestingly, the most likely entry route differed between AHS and EE: AHS has a higher probability to enter through an infected vector and EE has a higher probability to enter through an infectious host. Consequently, different effective protective measures were identified by 'what-if' scenarios for the two diseases. The implementation of vector protection on all animals (equine and bovine) coming from low-risk regions before their importation was the most effective in reducing the probability of AHS entry. On the other hand, the most significant reduction in the probability of EE entry was obtained by the implementation of quarantine before import for horses coming from both EU and non-EU countries. The developed models can be useful to implement risk-based surveillance.
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Affiliation(s)
- C Faverjon
- INRA UR0346 Animal Epidemiology, VetagroSup, Marcy l'Etoile, France
| | - A Leblond
- INRA UR0346 Animal Epidemiology and Equine Department, VetAgroSup, Marcy L'Etoile, France
| | - S Lecollinet
- Animal Health Laboratory, UMR1161 Virologie, INRA ANSES ENVA, UPE, ANSES, Maisons-Alfort, France
| | - R Bødker
- National Veterinary Institute, Technical University of Denmark, Frederiksgerg, Denmark
| | - A A de Koeijer
- Central Veterinary Institute, part of Wageningen UR, Lelystad, The Netherlands
| | - E A J Fischer
- Central Veterinary Institute, part of Wageningen UR, Lelystad, The Netherlands.,Department of Farm Animal Health, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
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Development and evaluation of a new lateral flow assay for simultaneous detection of antibodies against African Horse Sickness and Equine Infectious Anemia viruses. J Virol Methods 2016; 237:127-131. [PMID: 27616197 DOI: 10.1016/j.jviromet.2016.09.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 09/07/2016] [Accepted: 09/07/2016] [Indexed: 11/24/2022]
Abstract
African horse sickness (AHS) and equine infectious anemia (EIA) are both notifiable equid specific diseases that may present similar clinical signs. Considering the increased global movement of horses and equine products over the past decades, together with the socio-economic impact of previous AHS and EIA outbreaks, there is a clear demand for an early discrimination and a strict control of their transmission between enzootic and AHS/EIA-free regions. Currently, the individual control and prevention of AHS or EIA relies on a series of measures, including the restriction of animal movements, vector control, and the use of several laboratory techniques for viral identification, amongst others. Despite being widely employed in surveillance programmes and in the control of animal movements, the available serological assays can only detect AHS- or EIA-specific antibodies individually. In this work, a duplex lateral flow assay (LFA) for simultaneous detection and differentiation of specific antibodies against AHS virus (AHSV) and EIA virus (EIAV) was developed and evaluated with experimental and field serum samples. The duplex LFA was based on the AHSV-VP7 outer core protein and the EIAV-P26 major core protein. The results indicated that the duplex LFA presented a good analytical performance, detecting simultaneously and specifically antibodies against AHSV and EIAV. The initial diagnostic evaluation revealed a good agreement with results from the AHS and EIA tests prescribed by the OIE, and it highlighted the usefulness of the new AHSV/EIAV duplex LFA for an on-field and point-of-care first diagnosis.
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Robin M, Page P, Archer D, Baylis M. African horse sickness: The potential for an outbreak in disease-free regions and current disease control and elimination techniques. Equine Vet J 2016; 48:659-69. [PMID: 27292229 DOI: 10.1111/evj.12600] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 06/09/2016] [Indexed: 11/26/2022]
Abstract
African horse sickness (AHS) is an arboviral disease of equids transmitted by Culicoides biting midges. The virus is endemic in parts of sub-Saharan Africa and official AHS disease-free status can be obtained from the World Organization for Animal Health on fulfilment of a number of criteria. AHS is associated with case fatality rates of up to 95%, making an outbreak among naïve horses both a welfare and economic disaster. The worldwide distributions of similar vector-borne diseases (particularly bluetongue disease of ruminants) are changing rapidly, probably due to a combination of globalisation and climate change. There is extensive evidence that the requisite conditions for an AHS epizootic currently exist in disease-free countries. In particular, although the stringent regulations enforced upon competition horses make them extremely unlikely to redistribute the virus, there are great concerns over the effects of illegal equid movement. An outbreak of AHS in a disease free region would have catastrophic effects on equine welfare and industry, particularly for international events such as the Olympic Games. While many regions have contingency plans in place to manage an outbreak of AHS, further research is urgently required if the equine industry is to avoid or effectively contain an AHS epizootic in disease-free regions. This review describes the key aspects of AHS as a global issue and discusses the evidence supporting concerns that an epizootic may occur in AHS free countries, the planned government responses, and the roles and responsibilities of equine veterinarians.
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Affiliation(s)
- M Robin
- Department of Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Leahurst, Neston, Cheshire, UK
| | - P Page
- Department of Companion Animal Clinical Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
| | - D Archer
- Department of Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Leahurst, Neston, Cheshire, UK
| | - M Baylis
- Department of Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Leahurst, Neston, Cheshire, UK.,NIHR Health Protection Research Unit in Emerging and Zoonotic Infections, University of Liverpool, UK
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Baker T, Carpenter S, Gubbins S, Newton R, Lo Iacono G, Wood J, Harrup LE. Can insecticide-treated netting provide protection for Equids from Culicoides biting midges in the United Kingdom? Parasit Vectors 2015; 8:604. [PMID: 26607993 PMCID: PMC4660720 DOI: 10.1186/s13071-015-1182-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 10/28/2015] [Indexed: 11/10/2022] Open
Abstract
Background Biting midges of the genus Culicoides Latreille, 1809 (Diptera: Ceratopogonidae) cause a significant biting nuisance to equines and are responsible for the biological transmission of African horse sickness virus (AHSV). While currently restricted in distribution to sub-Saharan Africa, AHSV has a history of emergence into southern Europe and causes one of the most lethal diseases of horses and other species of Equidae. In the event of an outbreak of AHSV, the use of insecticide treated nets (ITNs) to screen equine accomodation is recommended by competent authorities including the Office International des Épizooties (OIE) in order to reduce vector-host contact. Methods Seven commercially avaliable pyrethroid insecticides and three repellent compounds, all of which are licensed for amateur use, were assessed in modified World Health Organization (WHO) cone bioassay trials in the laboratory using a colony line of Culicoides nubeculosus (Meigen), 1830. Two field trials were subsequently conducted to test the efficiency of treated net screens in preventing entry of Culicoides. Results A formulation of cypermethrin (0.15 % w/w) and pyrethrins (0.2 % w/w) (Tri-Tec 14®, LS Sales (Farnham) Ltd, Bloxham, UK) applied to black polyvinyl-coated polyester insect screen (1.6 mm aperture; 1.6 mm thickness) inflicted 100 % mortality on batches of C. nubeculosus following a three minute exposure in the WHO cone bioassays at 1, 7 and 14 days post-treatment. Tri-Tec 14® outperformed all other treatments tested and was subsequently selected for use in field trials. The first trial demonstrated that treated screens placed around an ultraviolet light-suction trap entirely prevented Culicoides being collected, despite their collection in identical traps with untreated screening or no screening. The second field trial examined entry of Culicoides into stables containing horses and found that while the insecticide treated screens reduced entry substantially, there was still a small risk of exposure to biting. Conclusions Screened stables can be utilised as part of an integrated control program in the event of an AHSV outbreak in order to reduce vector-host contact and may also be applicable to protection of horses from Culicoides during transport.
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Affiliation(s)
- Tiffany Baker
- University of Surrey, Guildford, Surrey, GU2 7XH, UK. .,Vector-borne Viral Diseases Programme, The Pirbright Institute, Ash Road, Pirbright, Surrey, GU24 0NF, UK.
| | - Simon Carpenter
- Vector-borne Viral Diseases Programme, The Pirbright Institute, Ash Road, Pirbright, Surrey, GU24 0NF, UK.
| | - Simon Gubbins
- Vector-borne Viral Diseases Programme, The Pirbright Institute, Ash Road, Pirbright, Surrey, GU24 0NF, UK.
| | - Richard Newton
- Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk, CB8 7UU, UK.
| | - Giovanni Lo Iacono
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge, CB3 0ES, UK.
| | - James Wood
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge, CB3 0ES, UK.
| | - Lara Ellen Harrup
- Vector-borne Viral Diseases Programme, The Pirbright Institute, Ash Road, Pirbright, Surrey, GU24 0NF, UK.
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Faverjon C, Leblond A, Hendrikx P, Balenghien T, de Vos CJ, Fischer EAJ, de Koeijer AA. A spatiotemporal model to assess the introduction risk of African horse sickness by import of animals and vectors in France. BMC Vet Res 2015; 11:127. [PMID: 26040321 PMCID: PMC4455332 DOI: 10.1186/s12917-015-0435-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 05/12/2015] [Indexed: 11/30/2022] Open
Abstract
Background African horse sickness (AHS) is a major, Culicoides-borne viral disease in equines whose introduction into Europe could have dramatic consequences. The disease is considered to be endemic in sub-Saharan Africa. Recent introductions of other Culicoides-borne viruses (bluetongue and Schmallenberg) into northern Europe have highlighted the risk that AHS may arrive in Europe as well. The aim of our study was to provide a spatiotemporal quantitative risk model of AHS introduction into France. The study focused on two pathways of introduction: the arrival of an infectious host (PW-host) and the arrival of an infectious Culicoides midge via the livestock trade (PW-vector). The risk of introduction was calculated by determining the probability of an infectious animal or vector entering the country and the probability of the virus then becoming established: i.e., the virus’s arrival in France resulting in at least one local equine host being infected by one local vector. This risk was assessed using data from three consecutive years (2010 to 2012) for 22 regions in France. Results The results of the model indicate that the annual risk of AHS being introduced to France is very low but that major spatiotemporal differences exist. For both introduction pathways, risk is higher from July to October and peaks in July. In general, regions with warmer climates are more at risk, as are colder regions with larger equine populations; however, regional variation in animal importation patterns (number and species) also play a major role in determining risk. Despite the low probability that AHSV is present in the EU, intra-EU trade of equines contributes most to the risk of AHSV introduction to France because it involves a large number of horse movements. Conclusion It is important to address spatiotemporal differences when assessing the risk of ASH introduction and thus also when implementing efficient surveillance efforts. The methods and results of this study may help develop surveillance techniques and other risk reduction measures that will prevent the introduction of AHS or minimize AHS’ potential impact once introduced, both in France and the rest of Europe. Electronic supplementary material The online version of this article (doi:10.1186/s12917-015-0435-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- C Faverjon
- INRA UR346 Animal Epidemiology, Vetagrosup, F-69280, Marcy l'Etoile, France.
| | - A Leblond
- INRA UR346 Animal Epidemiology et Département Hippique, VetAgroSup, F-69280, Marcy L'Etoile, France.
| | - P Hendrikx
- ANSES, Direction scientifique des laboratoires - unité Survepi, 94700, Maisons-Alfort, France.
| | - T Balenghien
- CIRAD, UMR CMAEE, F-34398 Montpellier, France ; INRA, UMR1309 CMAEE, F-34398, Montpellier, France.
| | - C J de Vos
- Central Veterinary Institute, part of Wageningen UR, PO Box 65, 8200 AB, Lelystad, The Netherlands.
| | - E A J Fischer
- Central Veterinary Institute, part of Wageningen UR, PO Box 65, 8200 AB, Lelystad, The Netherlands.
| | - A A de Koeijer
- Central Veterinary Institute, part of Wageningen UR, PO Box 65, 8200 AB, Lelystad, The Netherlands.
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Study of the virulence of serotypes 4 and 9 of African horse sickness virus in IFNAR(-/-), Balb/C and 129 Sv/Ev mice. Vet Microbiol 2014; 174:322-332. [PMID: 25458420 DOI: 10.1016/j.vetmic.2014.10.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 10/10/2014] [Accepted: 10/14/2014] [Indexed: 11/23/2022]
Abstract
African horse sickness virus (AHSV) is a double-stranded RNA virus which belongs to the family Reoviridae, genus Orbivirus. Recent studies have focused on the interferon-α/β receptor knock-out mice (IFNAR(-/-)) as a small animal laboratory for the development of AHSV vaccines. The aim of this work was to study in vivo the virulence of two strains of AHSV and to compare the outcome of the infection of three mouse strains. To address this, AHSV serotypes 4 (AHSV-4) and 9 (AHSV-9) were inoculated subcutaneously (SC) and intranasally (IN) in two immunocompetent mouse strains (Balb/C and 129 Sv/Ev (129 WT)) as well as IFNAR(-/-) mice (on 129 Sv/Ev genetic background). In IFNAR(-/-) mice, fatality up to 50% was measured and significantly more clinical signs were observed in comparison with SC inoculated immunocompetent mice. The observed clinical signs were significantly more severe after AHSV-4 infection, in particular in immunocompetent mice inoculated by IN route. Considering RNAemia, significantly higher viral loads were measured following AHSV-4 infection. In the organs of 129 WT inoculated by IN route, significantly higher viral loads were detected after AHSV-4 infection. Together the results support a higher virulence for AHSV-4 compared to AHSV-9 and a higher clinical impact following infections in IN inoculated mice, at least in the investigated strains. The study also brought indirect evidences for type I IFN involvement in the control of AHSV infection.
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14
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Diouf ND, Etter E, Lo MM, Lo M, Akakpo AJ. Outbreaks of African horse sickness in Senegal, and methods of control of the 2007 epidemic. Vet Rec 2013; 172:152. [DOI: 10.1136/vr.101083] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- N. D. Diouf
- Direction de l'Elevage/CIMEL de Makhana; BP: 201 St-Louis Senegal
| | - E. Etter
- Department Environment and Societies; CIRAD - UR AGIRs, P.O. Box 1378 Harare Zimbabwe
| | - M. M. Lo
- Department of Microbiologie; LNERV; BP: 2057 Dakar-Hann Senegal
| | - M. Lo
- Direction des Services Vétérinaires; Cité Keur Gorgui, BP: 45677 Dakar Senegal
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15
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Aklilu N, Batten C, Gelaye E, Jenberie S, Ayelet G, Wilson A, Belay A, Asfaw Y, Oura C, Maan S, Bachanek-Bankowska K, Mertens PPC. African horse sickness outbreaks caused by multiple virus types in Ethiopia. Transbound Emerg Dis 2012; 61:185-92. [PMID: 23083078 DOI: 10.1111/tbed.12024] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Indexed: 12/01/2022]
Abstract
African horse sickness (AHS) is associated with high morbidity and mortality in equids, especially horses. A retrospective analysis was carried out concerning 737 AHS outbreaks that occurred during 2007-2010 in Ethiopia. A total of ten outbreaks were investigated in the study period. All four forms of the disease (pulmonary, cardiac, horse sickness fever and the combined form) were observed, with the cardiac form being the most prevalent. Multiple African horse sickness virus serotypes (AHSV-2, AHSV-4, AHSV-6, AHSV-8 and AHSV-9) were detected by molecular methods (type-specific real-time RT-PCR assays), and fourteen isolates were derived from blood and tissue samples collected during 2009-2010. This is the first report of AHSV-4, AHSV-6 or AHSV-8 in Ethiopia.
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Affiliation(s)
- N Aklilu
- Society for the Protection of Animals Abroad (SPANA) Ethiopia Project, College of Veterinary Medicine and Agriculture, Addis Ababa University, Debre Zeit, Ethiopia
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16
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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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17
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Abstract
African horsesickness (AHS) is a devastating disease of horses. The disease is caused by the double-stranded RNA-containing African horsesickness virus (AHSV). Using electron cryomicroscopy and three-dimensional image reconstruction, we determined the architecture of an AHSV serotype 4 (AHSV-4) reference strain. The structure revealed triple-layered AHS virions enclosing the segmented genome and transcriptase complex. The innermost protein layer contains 120 copies of VP3, with the viral polymerase, capping enzyme, and helicase attached to the inner surface of the VP3 layer on the 5-fold axis, surrounded by double-stranded RNA. VP7 trimers form a second, T=13 layer on top of VP3. Comparative analyses of the structures of bluetongue virus and AHSV-4 confirmed that VP5 trimers form globular domains and VP2 trimers form triskelions, on the virion surface. We also identified an AHSV-7 strain with a truncated VP2 protein (AHSV-7 tVP2) which outgrows AHSV-4 in culture. Comparison of AHSV-7 tVP2 to bluetongue virus and AHSV-4 allowed mapping of two domains in AHSV-4 VP2, and one in bluetongue virus VP2, that are important in infection. We also revealed a protein plugging the 5-fold vertices in AHSV-4. These results shed light on virus-host interactions in an economically important orbivirus to help the informed design of new vaccines.
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18
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de Vos CJ, Hoek CA, Nodelijk G. Risk of introducing African horse sickness virus into the Netherlands by international equine movements. Prev Vet Med 2012; 106:108-22. [PMID: 22341773 DOI: 10.1016/j.prevetmed.2012.01.019] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
African horse sickness (AHS) is a vector-borne viral disease of equines that is transmitted by Culicoides spp. and can have severe consequences for the horse industry in affected territories. A study was performed to assess the risk of introducing AHS virus (AHSV) into the Netherlands (P_AHS) by international equine movements. The goal of this study was to provide more insight into (a) the regions and equine species that contribute most to this risk, (b) the seasonal variation in this risk, and (c) the effectiveness of measures to prevent introduction of AHSV. Countries worldwide were grouped into three risk regions: (1) high risk, i.e., those countries in which the virus is presumed to circulate, (2) low risk, i.e., those countries that have experienced outbreaks of AHS in the past and/or where the main vector of AHS, Culicoides imicola, is present, and (3) very low risk, i.e., all other countries. A risk model was constructed estimating P_AHS taking into account the probability of release of AHSV in the Netherlands and the probability that local vectors will subsequently transmit the virus to local hosts. Model calculations indicated that P_AHS is very low with a median value of 5.1×10(-4)/year. The risk is highest in July and August, while equine movements in the period October till March pose a negligible risk. High and low risk regions contribute most to P_AHS with 31% and 53%, respectively. Importations of donkeys and zebras constitute the highest risk of AHSV release from high risk regions, while international movements of competition horses constitute the highest risk of AHSV release from low and very low risk regions. Preventive measures currently applied reduce P_AHS by 46% if compared to a situation in which no preventive measures are applied. A prolonged and more effective quarantine period in high risk regions and more stringent import regulations for low risk regions could further reduce P_AHS. Large uncertainty was involved in estimating model input parameters. Sensitivity analysis indicated that uncertainty about the probability of non-notified presence of AHS in low and very low risk regions, the protective effect of quarantine and the vector-host ratio had most impact on the estimated risk. Furthermore, temperature values at the time of release of AHSV largely influenced the probability of onward spread of the virus by local vectors to local hosts.
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Affiliation(s)
- C J de Vos
- Central Veterinary Institute of Wageningen UR, PO Box 65, 8200 AB Lelystad, The Netherlands.
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19
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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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20
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Serotype specific primers and gel-based RT-PCR assays for 'typing' African horse sickness virus: identification of strains from Africa. PLoS One 2011; 6:e25686. [PMID: 22028787 PMCID: PMC3197586 DOI: 10.1371/journal.pone.0025686] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 09/08/2011] [Indexed: 11/19/2022] Open
Abstract
African horse sickness is a devastating, transboundary animal disease, that is ‘listed’ by the Office International des Epizooties (OIE). Although attenuated, inactivated and subunit vaccines have been developed for African horse sickness virus (AHSV), these are serotype-specific and their effective deployment therefore relies on rapid and reliable identification of virus type. AHSV serotype is controlled by the specificity of interactions between neutralising antibodies, and components of the outer-capsid, particularly protein VP2 (encoded by AHSV genome segment 2 (Seg-2)). We report the development and evaluation of novel gel based reverse transcription-PCR (RT–PCR) assays targeting AHSV Seg-2, which can be used to very significantly increase the speed and reliability of detection and identification (compared to virus neutralisation tests) of the nine serotypes of AHSV. Primer sets were designed targeting regions of Seg-2 that are conserved between strains within each of the AHSV serotype (types 1 to 9). These assays were evaluated using multiple AHSV strains from the orbivirus reference collection at IAH (www.reoviridae.org/dsRNA_virus_proteins/ReoID/AHSV-isolates.htm). In each case the Seg-2 primers showed a high level of specificity and failed to cross-amplify the most closely related heterologous AHSV types, or other related orbiviruses (such as bluetongue virus (BTV), or equine encephalosis virus (EEV)). The assays are rapid and sensitive, and can be used to detect and type viral RNA in blood, tissue samples, or cultivated viral suspensions within 24 h. They were used to identify AHSV strains from recent outbreaks in sub-Saharan African countries. These methods also generate cDNAs suitable for sequencing and phylogenetic analyses of Seg-2, identifying distinct virus lineages within each virus-type and helping to identify strain movements/origins. The RT-PCR methods described here provide a robust and versatile tool for rapid and specific detection and identification of AHSV serotypes 1 to 9.
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Stassen L, Huismans H, Theron J. African horse sickness virus induces apoptosis in cultured mammalian cells. Virus Res 2011; 163:385-9. [PMID: 21983259 DOI: 10.1016/j.virusres.2011.09.033] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 09/22/2011] [Accepted: 09/23/2011] [Indexed: 11/15/2022]
Abstract
Infection of mammalian cell cultures with African horse sickness virus (AHSV) is known to result in dramatic cytopathic effects (CPE), but no CPE is observed in infected insect cell cultures despite productive virus replication. The basis for this phenomenon has not yet been investigated, but is suggestive of apoptosis being induced following virus infection of the mammalian cells. To investigate whether AHSV can induce apoptosis in infected mammalian cells, Culicoides variipennis (KC) insect cells and BHK-21 mammalian cells were infected with AHSV-9 and analyzed for morphological and biochemical hallmarks of apoptosis. In contrast to KC cells, infection of BHK-21 cells with AHSV-9 resulted in ultrastructural changes and nuclear DNA fragmentation, both of which are associated with the induction of apoptosis. Results also indicated that AHSV-9 infection of BHK-21 cells resulted in activation of caspase-3, a key agent in apoptosis, and in mitochondrial membrane depolarization. Cumulatively, the data indicate that the intrinsic pathway is activated in AHSV-induced apoptosis.
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Affiliation(s)
- Liesel Stassen
- Department of Microbiology and Plant Pathology, University of Pretoria, Pretoria 0002, South Africa
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Scientific Opinion on Geographic Distribution of Tick-borne Infections and their Vectors in Europe and the other Regions of the Mediterranean Basin. EFSA J 2010. [DOI: 10.2903/j.efsa.2010.1723] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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23
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Matsuo E, Celma CCP, Roy P. A reverse genetics system of African horse sickness virus reveals existence of primary replication. FEBS Lett 2010; 584:3386-91. [PMID: 20600010 DOI: 10.1016/j.febslet.2010.06.030] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Revised: 06/14/2010] [Accepted: 06/18/2010] [Indexed: 10/19/2022]
Abstract
African horse sickness virus (AHSV), a member of the orbivirus genus of the family Reoviridae, is an insect-vectored pathogen of horses of concern to the equine industry. Studies on AHSV replication and pathogenesis have been hampered by the lack of reverse genetics allowing targeted mutation of viral genomes. We demonstrate that AHSV single-stranded RNA synthesized in vitro (core transcripts) is infectious and that there are distinct primary and secondary stages of the replication cycle. Transfection with a mixture of core transcripts from two different serotypes or a mixture of core transcripts and a T7 derived transcript resulted in the recovery of reassortant viruses. Recovery of infectious ASHV from nucleic acid will benefit investigation of the virus and the generation of attenuated vaccines.
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Affiliation(s)
- Eiko Matsuo
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
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Papadopoulos E, Rowlinson M, Bartram D, Carpenter S, Mellor P, Wall R. Treatment of horses with cypermethrin against the biting flies Culicoides nubeculosus, Aedes aegypti and Culex quinquefasciatus. Vet Parasitol 2010; 169:165-71. [DOI: 10.1016/j.vetpar.2009.12.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Revised: 12/01/2009] [Accepted: 12/16/2009] [Indexed: 11/29/2022]
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