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Olech M. The genetic variability of small-ruminant lentiviruses and its impact on tropism, the development of diagnostic tests and vaccines and the effectiveness of control programmes. J Vet Res 2023; 67:479-502. [PMID: 38130459 PMCID: PMC10730557 DOI: 10.2478/jvetres-2023-0064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 11/13/2023] [Indexed: 12/23/2023] Open
Abstract
Introduction Maedi-visna virus and caprine arthritis encephalitis virus are two closely related lentiviruses which cause multisystemic, progressive and persistent infection in goats and sheep. Because these viruses frequently cross the species barrier, they are considered to be one genetic group called small-ruminant lentiviruses (SRLV). They have in vivo tropism mainly for monocytes and macrophages and organ tropism with unknown mechanisms. Typical clinical signs are pneumonia in sheep, arthritis in goats, and mastitis in both species. Infection with SRLV cannot currently be treated or prevented, and control programmes are the only approaches to avoiding its spread. These programmes rely mainly on annual serological testing and elimination of positive animals. However, the high genetic and antigenic variability of SRLV complicate their early and definitive diagnosis. The objective of this review is to summarise the current knowledge of SRLV genetic variation and its implications for tropism, the development of diagnostic tests and vaccines and the effectiveness of control and eradication programmes. Material and Methods Subject literature was selected from the PubMed and the Google Scholar databases. Results The high genetic diversity of SRLV affects the performance of diagnostic tools and therefore control programmes. For the early and definitive diagnosis of SRLV infection, a combination of serological and molecular tests is suggested. Testing by PCR can also be considered for sub-yearling animals. There are still significant gaps in our knowledge of the epidemiology, immunology and biology of SRLV and their impact on animal production and welfare. Conclusion This information may aid selection of the most effective SRLV spread reduction measures.
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Affiliation(s)
- Monika Olech
- Department of Pathology, National Veterinary Research Institute, 24-100Puławy, Poland
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2
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Jacob-Ferreira J, Coelho AC, Grau Vila A, Lacasta D, Quintas H. Small Ruminant Lentivirus Infection in Sheep and Goats in North Portugal: Seroprevalence and Risk Factors. Pathogens 2023; 12:829. [PMID: 37375519 DOI: 10.3390/pathogens12060829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 06/07/2023] [Accepted: 06/12/2023] [Indexed: 06/29/2023] Open
Abstract
Small ruminant lentiviruses (SRLVs) are transmitted among ovine and caprine species. This disease is a severe problem for small ruminant production, not only for animals' well-being but also for flocks' efficiency. The main aim of this research was to quantify the seroprevalence and associated risk factors for SRLV infection in the northern region of Portugal. Samples were collected from a total of 150 flocks, of which 129 (86.0%; 95% CI: 80.67%-91.33%) had at least one seropositive animal. Out of 2607 individual blood samples, 1074 (41.2%) were positive for SRLVs. Risk factors associated with SRLV infection were species (caprine), age (>2 years old), flock size (>100 animals), production system (intensive), food production system (milk), type of activity (professional), participation in livestock competitions (yes), replacement young ewe bought (yes), and natural feeding management (yes). This knowledge empowers the implementation of effective preventive measures. Overall, biosecurity measures should be promoted and implemented with the main aim of reducing viral transmission and reducing the prevalence of this disease. We recognise that government authorities should promote and audit voluntary control and eradication programs in small ruminant flocks in the region studied.
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Affiliation(s)
- João Jacob-Ferreira
- Animal and Veterinary Research Centre, University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal
- Mountain Research Center (CIMO), Polytechnic Institute of Bragança (IPB), Campus de Santa Apolónia, 5300-253 Bragança, Portugal
| | - Ana Cláudia Coelho
- Animal and Veterinary Research Centre, University of Trás-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal
| | - Ana Grau Vila
- Servicio de Sanidad Animal, Dirección General de Producción Agropecuaria e Infraestructuras Agrarias, Consejería de Agricultura y Ganadería, Junta de Castilla y León, 47014 Valladolid, Spain
| | - Delia Lacasta
- Animal Pathology Department, Instituto Agroalimentario de Aragón-IA2, Universidad de Zaragoza-CITA, Veterinary Faculty of Zaragoza C/Miguel Servet 177, 50013 Zaragoza, Spain
| | - Hélder Quintas
- Mountain Research Center (CIMO), Polytechnic Institute of Bragança (IPB), Campus de Santa Apolónia, 5300-253 Bragança, Portugal
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Longitudinal Study on Seroreactivity of Goats Exposed to Colostrum and Milk of Small Ruminant Lentivirus-infected Dams. J Vet Res 2022; 66:511-521. [PMID: 36846043 PMCID: PMC9945002 DOI: 10.2478/jvetres-2022-0071] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 12/07/2022] [Indexed: 12/27/2022] Open
Abstract
Introduction Small ruminant lentivirus (SRLV) causes caprine arthritis-encephalitis in goats and maedi-visna disease in sheep. Transmission is via ingestion of colostrum and milk from infected dams or long-term direct contact between animals. Lifelong seroconversion can occur several weeks after infection via ingestion. However, sub-yearling lambs that ingest contaminated colostrum may be able to clear the infection and become seronegative. Whether a similar phenomenon occurs in goats remains unknown. Therefore, the serological status of goats was studied longitudinally from the moment of natural exposure to colostrum and milk of SRLV-positive dams through the age of 24 months. Material and Methods Between February 2014 and March 2017 a dairy goat herd was studied which had been infected with SRLV for more than 20 years and carried maedi-visna virus-like genotype A subtype A17. Thirty-one kids born to dams seropositive for SRLV for at least a year beforehand were followed. They ingested colostrum immediately after birth and then remained with their dams for three weeks. The goats were tested serologically every month using two commercial ELISAs. The clinical condition of the goats was also regularly assessed. Results Out of 31 goats, 13 (42%) seroconverted at the age ranging from 3 to 22 months with a median of 5 months. Two goats seroconverted in the second year of life. The other eleven did so before the age of one year; two of these reverted to seronegative status. Only 9 out of 31 goats (29%) seroconverted in the first year of life and remained seropositive. They were early and stable seroreactors to which SRLV was transmitted lactogenically. The age at which they seroconverted ranged from 3 to 10 months with a median of 5 months. In 8 of the 18 persistently seronegative goats, a single isolated positive result occurred. No goats showed any clinical signs of arthritis. The level of maternal antibodies at the age of one week did not differ significantly between the stable seroreactors and the remainder. Conclusion Seroconversion appears to occur in less than 50% of goats exposed to heterologous SRLV genotype A via ingestion of colostrum and milk from infected dams and is delayed by 3-10 months. The natural lactogenic route of transmission of SRLV genotype A in goats appears to be less effective than this route of genotype B transmission reported in earlier studies.
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Braz GF, Heinemann MB, Reis JKP, Teixeira BM, Cruz JCM, Rajão DS, Oliveira FG, Alves F, Castro RS, Leite RC, Valas S. Genetic and antigenic characterization of Brazilian SRLV strains: Natural small ruminant interspecies transmission from mixed herds. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2022; 103:105322. [PMID: 35753623 DOI: 10.1016/j.meegid.2022.105322] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 03/27/2022] [Accepted: 06/20/2022] [Indexed: 06/15/2023]
Abstract
Cross-species transmission events and mixed infection of small ruminant lentiviruses (SRLVs) were studied in seven goats and two sheep from three small ruminant mixed flocks from Northeast and Southeast Brazil. Genetic and antigenic analyses with gag/env genes and ELISA multiepitope SU1/SU5 recombinant antigens were carried out, respectively. The genetic analysis of gag and env sequences showed high viral diversity in both species, MVV-like (subtype A1) and CAEV-like B1 in goats, and CAEV-like (subtype B1) in sheep, revealing SRLV interspecies transmission from sheep to goats and vice versa in Brazilian farms. Two Brazilian caprine lentiviruses were segregated in two new genetic clades based on gag analyses, which suggests a new classification into heterogenic genotype A. Furthermore, goat isolates were grouped into subtype A1 and B1 clusters. Cross-reactive antibodies were detected in goats using ELISA with a recombinant antigen carrying SU1 and SU5 immunodominant epitopes; the results showed anti-CAEV and MVV antibodies in goats and anti-CAEV antibodies in sheep. This result can be associated with the high divergence in the V4 region due to SRLV variability. All results confirm cross-species infection of SRLV in Brazilian mixed herds.
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Affiliation(s)
- G F Braz
- Curso de Medicina Veterinária, Centro Universitário INTA-UNINTA, Brazil.
| | - M B Heinemann
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, USP, Brazil.
| | - J K P Reis
- Laboratório de Retroviroses, Departamento de Medicina Veterinária Preventiva, Escola de Veterinária, UFMG, Brazil.
| | - B M Teixeira
- Curso de Medicina Veterinária, Centro Universitário INTA-UNINTA, Brazil
| | - J C M Cruz
- Curso de Medicina Veterinária, Centro Universitário INTA-UNINTA, Brazil
| | - D S Rajão
- Virus and Prion Research Unit, National Animal Disease Center, USDA-ARS, United States.
| | | | - F Alves
- Departamento de Fisiologia e Biofísica - ICB, UFMG, Brazil.
| | - R S Castro
- Departamento de Medicina Veterinária, UFRPE, Brazil.
| | - R C Leite
- Laboratório de Retroviroses, Departamento de Medicina Veterinária Preventiva, Escola de Veterinária, UFMG, Brazil
| | - S Valas
- Agence Française de Sécurité Sanitaire des Aliments - ANSES, Niort Laboratory, France
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Bazzucchi M, Pierini I, Gobbi P, Pirani S, Torresi C, Iscaro C, Feliziani F, Giammarioli M. Genomic Epidemiology and Heterogeneity of SRLV in Italy from 1998 to 2019. Viruses 2021; 13:v13122338. [PMID: 34960606 PMCID: PMC8706641 DOI: 10.3390/v13122338] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 11/12/2021] [Accepted: 11/19/2021] [Indexed: 01/28/2023] Open
Abstract
Small ruminant lentiviruses (SRLV) are viruses that retro-transcribe RNA to DNA and show high rates of genetic variability. SRLV affect animals with strains specific for each host species (sheep or goats), resulting in a series of clinical manifestations depending on the virulence of the strain, the host’s genetic background and farm production system. The aim of this work was to present an up-to-date overview of the genomic epidemiology and genetic diversity of SRLV in Italy over time (1998–2019). In this study, we investigated 219 SRLV samples collected from 17 different Italian regions in 178 geographically distinct herds by CEREL. Our genetic study was based on partial sequencing of the gag-pol gene (800 bp) and phylogenetic analysis. We identified new subtypes with high heterogeneity, new clusters and recombinant forms. The genetic diversity of Italian SRLV strains may have diagnostic and immunological implications that affect the performance of diagnostic tools. Therefore, it is extremely important to increase the control of genomic variants to improve the control measures.
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Affiliation(s)
- Moira Bazzucchi
- Istituto Zooprofilattico Sperimentale Umbrita-Marche “Togo Rosati”, 06126 Perugia, Italy; (M.B.); (I.P.); (P.G.); (S.P.); (C.T.); (C.I.); (F.F.)
- Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna “Bruno Ubertini”, 27100 Pavia, Italy
| | - Ilaria Pierini
- Istituto Zooprofilattico Sperimentale Umbrita-Marche “Togo Rosati”, 06126 Perugia, Italy; (M.B.); (I.P.); (P.G.); (S.P.); (C.T.); (C.I.); (F.F.)
| | - Paola Gobbi
- Istituto Zooprofilattico Sperimentale Umbrita-Marche “Togo Rosati”, 06126 Perugia, Italy; (M.B.); (I.P.); (P.G.); (S.P.); (C.T.); (C.I.); (F.F.)
| | - Silvia Pirani
- Istituto Zooprofilattico Sperimentale Umbrita-Marche “Togo Rosati”, 06126 Perugia, Italy; (M.B.); (I.P.); (P.G.); (S.P.); (C.T.); (C.I.); (F.F.)
| | - Claudia Torresi
- Istituto Zooprofilattico Sperimentale Umbrita-Marche “Togo Rosati”, 06126 Perugia, Italy; (M.B.); (I.P.); (P.G.); (S.P.); (C.T.); (C.I.); (F.F.)
| | - Carmen Iscaro
- Istituto Zooprofilattico Sperimentale Umbrita-Marche “Togo Rosati”, 06126 Perugia, Italy; (M.B.); (I.P.); (P.G.); (S.P.); (C.T.); (C.I.); (F.F.)
| | - Francesco Feliziani
- Istituto Zooprofilattico Sperimentale Umbrita-Marche “Togo Rosati”, 06126 Perugia, Italy; (M.B.); (I.P.); (P.G.); (S.P.); (C.T.); (C.I.); (F.F.)
| | - Monica Giammarioli
- Istituto Zooprofilattico Sperimentale Umbrita-Marche “Togo Rosati”, 06126 Perugia, Italy; (M.B.); (I.P.); (P.G.); (S.P.); (C.T.); (C.I.); (F.F.)
- Correspondence:
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Kalogianni AI, Bossis I, Ekateriniadou LV, Gelasakis AI. Etiology, Epizootiology and Control of Maedi-Visna in Dairy Sheep: A Review. Animals (Basel) 2020; 10:E616. [PMID: 32260101 PMCID: PMC7222820 DOI: 10.3390/ani10040616] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 03/27/2020] [Accepted: 03/31/2020] [Indexed: 01/04/2023] Open
Abstract
Maedi-visna (MV) in sheep is caused by maedi-visna virus (MVV), a small ruminant lentivirus (SRLV) that causes chronic infection and inflammatory lesions in infected animals. Pneumonia and mastitis are its predominant clinical manifestations, and the tissues infected by MVV are mainly the lungs, the mammary gland, the nervous system and the joints. MV has a worldwide distribution with distinct MVV transmission patterns depending on circulating strains and regionally applied control/eradication schemes. Nevertheless, the prevalence rate of MV universally increases. Currently, gaps in understanding the epizootiology of MV, the continuous mutation of existing and the emergence of new small ruminant lentiviruses (SRLVs) strains, lack of an effective detection protocol and the inefficiency of currently applied preventive measures render elimination of MV an unrealistic target. Therefore, modifications on the existing MV surveillance and control schemes on an evidentiary basis are necessary. Updated control schemes require the development of diagnostic protocols for the early and definitive diagnosis of MVV infections. The objectives of this review are to summarize the current knowledge in the epizootiology and control of MV in dairy sheep, to describe the research framework and to cover existing gaps in understanding future challenges regarding MV.
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Affiliation(s)
- Aphrodite I Kalogianni
- Laboratory of Anatomy and Physiology of Farm Animals, Department of Animal Science, Agricultural University of Athens (AUA), Iera Odos 75 str., 11855 Athens, Greece
| | - Ioannis Bossis
- Laboratory of Anatomy and Physiology of Farm Animals, Department of Animal Science, Agricultural University of Athens (AUA), Iera Odos 75 str., 11855 Athens, Greece
| | | | - Athanasios I Gelasakis
- Laboratory of Anatomy and Physiology of Farm Animals, Department of Animal Science, Agricultural University of Athens (AUA), Iera Odos 75 str., 11855 Athens, Greece
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Nogarol C, Bertolotti L, Klevar S, Profiti M, Gjerset B, Rosati S. Serological characterization of small ruminant lentiviruses: A complete tool for serotyping lentivirus infection in goat. Small Rumin Res 2019. [DOI: 10.1016/j.smallrumres.2019.05.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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8
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Souza TSD, Pinheiro RR, Lima CCVD, Brito RLLD, Azevedo DAAD, Dias RP, Santos VWSD, Andrioli A, Costa JN. Sheep infection by caprine lentivirus. REVISTA BRASILEIRA DE SAÚDE E PRODUÇÃO ANIMAL 2018. [DOI: 10.1590/s1519-99402018000300004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
SUMMARY The objective of this study was to demonstrate iatrogenic transmission of small ruminant lentivirus (SRLV) from goats to sheep and horizontal transmission between sheep. The study was conducted on a farm with separate goat and sheep rearing, and animals were monitored for lentivirus occurrence by clinical examination and testing by immunoblotting (IB), agar gel immunodiffusion (AGID), and nested polymerase chain reaction (nPCR). Positive results had not been observed in the sheep flock until this study. Conversely, virus positive dairy goats were known. For this reason, the farm performed the caprine arthritis-encephalitis (CAE) control program. The study was designed with a sheep group that presented positive animals for SRLV by nPCR. It was verified that three newborn animals in this group were rejected by their mothers and consequently received milk from the goat herd. These three animals remained with another 20 sheep of the same age, totaling 23 animals. After one year, during monitoring, 11 of the 23 animals in the group presented positive results in the nPCR and three demonstrated seroconversion by IB. Of the animals that had received goat milk, two had positive results in the nPCR and IB. The 11 animals positive in the nPCR were followed and it was verified that five animals did not present further positive results in the nPCR, nor seroconversion; two continued presenting positive results in the nPCR but were negative in the IB and AGID and four were positive in the nPCR, IB, and AGID. Thus, it was possible to demonstrate iatrogenic interspecific infection and the occurrence of horizontal caprine lentivirus transmission among sheep.
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Genetic characterisation of small ruminant lentiviruses in sheep and goats from the Czech Republic. ACTA VET BRNO 2018. [DOI: 10.2754/avb201887010019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The aim of this study was to determine the prevalence of small ruminant lentivirus (SRLV) infections on sheep and goat farms which are exempt from state monitoring and carry molecular characterisation of strains circulating amongst these farms without SRLV eradication. A total number of 3,410 blood samples of sheep and goats from 21 herds were collected for the purpose of the project. The detected serological prevalence of maedi visna in sheep was 19.9% (556/2801) and the seroprevalence of caprine arthritis and encephalitis in goats was 14.1% (86/609). All positive animals were tested by the nested polymerase chain reaction (nPCR) method for the presence of provirus in the buffy-coats from EDTA-blood samples. Phylogenetic analysis of 93 SRLV strains identified the genotype in 77 sequences, where 60 of them were genotype A and 17 belonged to genotype B. Whereas all of the genotype B sequences were classified in subtype B2, the genotype A group of isolates showed higher variability and were related to subgenotypes A2 and A3. This study represents the first report of genetic characterisation of SRLV strains circulating in the territory of the Czech Republic.
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Azevedo DAAD, Santos VWSD, Sousa ALMD, Peixoto RM, Pinheiro RR, Andrioli A, Teixeira MFDS. Small ruminant lentiviruses: economic and productive losses, consequences of the disease. ARQUIVOS DO INSTITUTO BIOLÓGICO 2018. [DOI: 10.1590/1808-1657000552016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
ABSTRACT: Small ruminant lentiviruses, caprine arthritis encephalitis virus, and Maedi-Visna virus cause diseases that result in significant productive losses, mostly in dairy animals. These viruses belong to the Retroviridae family, Lentivirus genus, and constitute a heterogeneous group, which may generate implications for the diagnosis and control of small ruminant lentiviruses. Losses caused by them are associated with reproductive failure, short productive life, and decreased milk production by the infected animals. In addition, these viruses may reduce milk quality, affecting the production of dairy products such as cheese. Small ruminant lentiviruses lead to indirect losses, decreasing herd value and forcing the development of epidemiological trade barriers for animal germplasm. Control of small ruminant lentiviruses is important to promote optimal milk production and to reduce costs with medicine and technical assistance. This control may vary in caprine and ovine populations of each country, according to seroprevalence, variety of breeds, and peculiarities of the practiced management.
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Development of a recombinase polymerase amplification lateral flow dipstick (RPA-LFD) for the field diagnosis of caprine arthritis-encephalitis virus (CAEV) infection. J Virol Methods 2017; 243:98-104. [PMID: 28159666 DOI: 10.1016/j.jviromet.2017.01.023] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 12/23/2016] [Accepted: 01/29/2017] [Indexed: 12/20/2022]
Abstract
Caprine arthritis-encephalitis (CAE) in goats is a complex disease syndrome caused by a lentivirus. This persistent viral infection results in arthritis in adult goats and encephalitis in lambs. The prognosis for the encephalitic form is normally poor, and this form of the disease has caused substantial economic losses for goat farmers. Hence, a more efficient detection platform based on recombinase polymerase amplification (RPA) and a lateral flow dipstick (LFD) was developed in the present study for detecting the proviral DNA of caprine arthritis-encephalitis virus (CAEV). Under the optimal incubation conditions, specifically, 30min at 37°C for RPA followed by 5min at room temperature for LFD, the assay was found to be sensitive to a lower limit of 80pg of total DNA and 10 copies of plasmid DNA. Furthermore, there was no cross-reaction with other tested viruses, including goat pox virus and bovine leukemia virus. Given its simplicity and portability, this RPA-LFD protocol can serve as an alternative tool to ELISA for the primary screening of CAEV, one that is suitable for both laboratory and field application. When the RPA-LFD was applied in parallel with serological ELISA for the detection of CAEV in field samples, the RPA-LFD assay exhibited a higher sensitivity than the traditional method, and 82% of the 200 samples collected in Taiwan were found to be positive. To our knowledge, this is the first report providing evidence to support the use of an RPA-LFD assay as a specific and sensitive platform for detecting CAEV proviral DNA in goats in a faster manner, one that is also applicable for on-site utilization at farms and that should be useful in both eradication programs and epidemiological studies.
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12
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Diseases of the Nervous System. Vet Med (Auckl) 2017. [PMCID: PMC7322266 DOI: 10.1016/b978-0-7020-5246-0.00014-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Minguijón E, Reina R, Pérez M, Polledo L, Villoria M, Ramírez H, Leginagoikoa I, Badiola JJ, García-Marín JF, de Andrés D, Luján L, Amorena B, Juste RA. Small ruminant lentivirus infections and diseases. Vet Microbiol 2015; 181:75-89. [PMID: 26371852 DOI: 10.1016/j.vetmic.2015.08.007] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Small ruminant lentiviruses include viruses with diverse genotypes that frequently cross the species barrier between sheep and goats and that display a great genetic variability. These characteristics stress the need to consider the whole host range and to perform local surveillance of the viruses to opt for optimum diagnostic tests, in order to establish control programmes. In the absence of effective vaccines, a comprehensive knowledge of the epidemiology of these infections is of major importance to limit their spread. This article intends to cover these aspects and to summarise information related to characteristics of the viruses, pathogenesis of the infection and description of the various syndromes produced, as well as the diagnostic tools available, the mechanisms involved in transmission of the pathogens and, finally, the control strategies that have been designed until now, with remarks on the drawbacks and the advantages of each one. We conclude that there are many variables influencing the expected cost and benefits of control programs that must be evaluated, in order to put into practice measures that might lead to control of these infections.
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Affiliation(s)
- E Minguijón
- Department of Animal Health, NEIKER-Tecnalia, Berreaga 1, 48160 Derio, Vizcaya, Spain
| | - R Reina
- Institute of Agrobiotechnology (CSIC-UPNA-Government of Navarra), Avenida de Pamplona 123, 31192 Mutilva, Spain
| | - M Pérez
- Department of Anatomy, Embryology and Genetics. University of Zaragoza, Miguel Servet 177, 50013 Zaragoza, Spain
| | - L Polledo
- Pathological Anatomy Section, Animal Health Department, Veterinary School, University of León, 24007 León, Spain
| | - M Villoria
- Department of Animal Health, NEIKER-Tecnalia, Berreaga 1, 48160 Derio, Vizcaya, Spain
| | - H Ramírez
- Facultad de Estudios Superiores Cuautitlán. UNAM. Laboratorio de Virología, Genética y Biología Molecular, Campo 4. Veterinaria.Carretera Cuautitlán-Teoloyucan, Km 2.5. San Sebastián Xhala, Cuautitlán Izcalli, CP.54714 Mexico
| | - I Leginagoikoa
- Department of Animal Health, NEIKER-Tecnalia, Berreaga 1, 48160 Derio, Vizcaya, Spain
| | - J J Badiola
- Department of Animal Pathology, University of Zaragoza, Miguel Servet 177, 50013 Zaragoza, Spain
| | - J F García-Marín
- Pathological Anatomy Section, Animal Health Department, Veterinary School, University of León, 24007 León, Spain
| | - D de Andrés
- Institute of Agrobiotechnology (CSIC-UPNA-Government of Navarra), Avenida de Pamplona 123, 31192 Mutilva, Spain
| | - L Luján
- Department of Animal Pathology, University of Zaragoza, Miguel Servet 177, 50013 Zaragoza, Spain
| | - B Amorena
- Institute of Agrobiotechnology (CSIC-UPNA-Government of Navarra), Avenida de Pamplona 123, 31192 Mutilva, Spain
| | - R A Juste
- Department of Animal Health, NEIKER-Tecnalia, Berreaga 1, 48160 Derio, Vizcaya, Spain.
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Identification and characterization of an emerging small ruminant lentivirus circulating recombinant form (CRF). Virology 2014; 475:159-71. [PMID: 25462356 DOI: 10.1016/j.virol.2014.11.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 10/26/2014] [Accepted: 11/05/2014] [Indexed: 11/21/2022]
Abstract
The molecular epidemiology of small ruminant lentiviruses (SRLVs) is constantly changing due to animal movements, cross species transmission and because of their rapid evolutionary rate. This study reports a comprehensive genetic and phylogenetic analysis based on consensus gag and pol sequences covering 3kb of the SRLV genome from small ruminants in Québec, Canada. A group of strains obtained from goats originating from different flocks, segregated in a unique clade distinct from currently known SRLV groups. Genetic dissection of the gag gene from these strains revealed that it originated as a result of a recombination event between parental strains currently circulating in small ruminants of the country. Following HIV nomenclature, we propose to call this group of strains, circulating recombinant form 1 SRLV, or CRF01_AB SRLV. In addition, the study confirms the existence of genetically distinct and homogeneous populations of SRLVs infecting sheep and goats housed in single species flocks.
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Small ruminant lentiviruses (SRLVs) break the species barrier to acquire new host range. Viruses 2013; 5:1867-84. [PMID: 23881276 PMCID: PMC3738966 DOI: 10.3390/v5071867] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 07/10/2013] [Accepted: 07/16/2013] [Indexed: 12/16/2022] Open
Abstract
Zoonotic events of simian immunodeficiency virus (SIV) from non-human primates to humans have generated the acquired immunodeficiency syndrome (AIDS), one of the most devastating infectious disease of the last century with more than 30 million people dead and about 40.3 million people currently infected worldwide. Human immunodeficiency virus (HIV-1 and HIV-2), the two major viruses that cause AIDS in humans are retroviruses of the lentivirus genus. The genus includes arthritis-encephalitis virus (CAEV) and Maedi-Visna virus (MVV), and a heterogeneous group of viruses known as small ruminant lentiviruses (SRLVs), affecting goat and sheep. Lentivirus genome integrates into the host DNA, causing persistent infection associated with a remarkable diversity during viral replication. Direct evidence of mixed infections with these two closely related SRLVs was found in both sheep and goats. The evidence of a genetic continuum with caprine and ovine field isolates demonstrates the absence of an efficient species barrier preventing cross-species transmission. In dual-infected animals, persistent infections with both CAEV and MVV have been described, and viral chimeras have been detected. This not only complicates animal trade between countries but favors the risk that highly pathogenic variants may emerge as has already been observed in the past in Iceland and, more recently, in outbreaks with virulent strains in Spain. SRLVs affecting wildlife have already been identified, demonstrating the existence of emergent viruses adapted to new hosts. Viruses adapted to wildlife ruminants may acquire novel biopathological properties which may endanger not only the new host species but also domestic ruminants and humans. SRLVs infecting sheep and goats follow a genomic evolution similar to that observed in HIV or in other lentiviruses. Lentivirus genetic diversity and host factors leading to the establishment of naturally occurring virulent versus avirulent infections, in addition to the emergence of new strains, challenge every aspect of SRLV control measures for providing efficient tools to prevent the transmission of diseases between wild ungulates and livestock.
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Fras M, Leboeuf A, Labrie FM, Laurin MA, Singh Sohal J, L'Homme Y. Phylogenetic analysis of small ruminant lentiviruses in mixed flocks: multiple evidence of dual infection and natural transmission of types A2 and B1 between sheep and goats. INFECTION GENETICS AND EVOLUTION 2013; 19:97-104. [PMID: 23811153 DOI: 10.1016/j.meegid.2013.06.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 06/08/2013] [Accepted: 06/17/2013] [Indexed: 10/26/2022]
Abstract
Previous molecular analyses of small ruminant lentivirus (SRLV) populations in single species herds in Quebec, Canada, have revealed a relatively simple structure where goats and sheep appeared exclusively infected with B1 and A2 subtypes respectively. The present work aimed at extending these earlier findings with the analysis of SRLVs in mixed flocks. Molecular analyses revealed a more complex picture of SRLV population structure in mixed herds compared to single species herds. Notably, phylogenetic analyses of long gag sequences strongly support transmission of A2 subtype from sheep to goats as well as transmission of B1 subtype from goats to sheep. Hence, this work uncovered for the first time natural transmission between sheep and goats of North American subtype A2. In addition, multiple evidences of mixed infection of sheep and goats with A2 and B1 subtypes were found. The data reported in this study reinforces the concept of a genetic continuum of SRLVs where strains are exchanged between sheep and goats under favourable conditions and in the absence of specific species barriers. Most interestingly, this study suggests that dual infection, which is a hallmark of the lentivirus paradigm HIV, may not be such rare events in small ruminants but may simply be understudied and underreported. Overall, the present data shows that sheep and goats in Canada can be infected with both SRLV A and B types, sometimes simultaneously, and that mixed flocks may represent a breeding ground for their evolution.
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Affiliation(s)
- Marion Fras
- Canadian Food Inspection Agency, St-Hyacinthe Laboratory, 3400 Blvd Casavant West, St-Hyacinthe, Quebec J2S 8E3, Canada
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Li Y, Zhou F, Li X, Wang J, Zhao X, Huang J. Development of TaqMan-based qPCR method for detection of caprine arthritis-encephalitis virus (CAEV) infection. Arch Virol 2013; 158:2135-41. [PMID: 23670072 PMCID: PMC3785178 DOI: 10.1007/s00705-013-1728-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Accepted: 04/09/2013] [Indexed: 11/27/2022]
Abstract
A specific and sensitive two-step TaqMan real-time PCR has been developed for rapid diagnosis of caprine arthritis-encephalitis virus (CAEV) infection by using a set of specific primers and a TaqMan probe targeting a highly conserved region within the gene encoding the viral capsid protein (CA). The assay successfully detected CAEV proviral DNA in total DNA extracts originating from cell culture, whole blood samples and isolated PBMCs, with a lower detection limit of 102 copies and a linear dynamic range of 105 to 1010 copies/ml. There was no cross-reaction with other animal viruses (e.g., goat pox virus, bovine leukemia virus, bovine mucosal disease virus, swine influenza virus and Nipah virus). When applied in parallel with serological AGID and conventional PCR for detection of CAEV in field samples, this assay exhibited a higher sensitivity than these traditional methods, and 7.8 % of the 308 specimens collected in the Shanxi and Tianjin regions of China from 1993 to 2011 were found to be positive. Thus, the TaqMan qPCR assay provides a fast, specific and sensitive means for detecting CAEV proviral DNA in goat specimens and should be useful for large-scale detection in eradication programs and epidemiological studies.
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Affiliation(s)
- Yi Li
- School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China. No. 92, Weijin road, Nankai District, Tianjin, 300072, China
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Small ruminant lentiviruses: genetic variability, tropism and diagnosis. Viruses 2013; 5:1175-207. [PMID: 23611847 PMCID: PMC3705272 DOI: 10.3390/v5041175] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 04/09/2013] [Accepted: 04/12/2013] [Indexed: 02/05/2023] Open
Abstract
Small ruminant lentiviruses (SRLV) cause a multisystemic chronic disease affecting animal production and welfare. SRLV infections are spread across the world with the exception of Iceland. Success in controlling SRLV spread depends largely on the use of appropriate diagnostic tools, but the existence of a high genetic/antigenic variability among these viruses, the fluctuant levels of antibody against them and the low viral loads found in infected individuals hamper the diagnostic efficacy. SRLV have a marked in vivo tropism towards the monocyte/macrophage lineage and attempts have been made to identify the genome regions involved in tropism, with two main candidates, the LTR and env gene, since LTR contains primer binding sites for viral replication and the env-encoded protein (SU ENV), which mediates the binding of the virus to the host’s cell and has hypervariable regions to escape the humoral immune response. Once inside the host cell, innate immunity may interfere with SRLV replication, but the virus develops counteraction mechanisms to escape, multiply and survive, creating a quasi-species and undergoing compartmentalization events. So far, the mechanisms of organ tropism involved in the development of different disease forms (neurological, arthritic, pulmonary and mammary) are unknown, but different alternatives are proposed. This is an overview of the current state of knowledge on SRLV genetic variability and its implications in tropism as well as in the development of alternative diagnostic assays.
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Virological and phylogenetic characterization of attenuated small ruminant lentivirus isolates eluding efficient serological detection. Vet Microbiol 2013. [DOI: 10.1016/j.vetmic.2012.11.017] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Rachid A, Croisé B, Russo P, Vignoni M, Lacerenza D, Rosati S, Kuźmak J, Valas S. Diverse host–virus interactions following caprine arthritis-encephalitis virus infection in sheep and goats. J Gen Virol 2013. [DOI: 10.1099/vir.0.044768-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Interspecies transmissions substantially contribute to the epidemiology of small ruminant lentiviruses (SRLVs), including caprine arthritis encephalitis virus (CAEV) and visna-maëdi virus. However, comprehensive studies of host–virus interactions during SRLV adaptation to the new host are lacking. In this study, virological and serological features were analysed over a 6 month period in five sheep and three goats experimentally infected with a CAEV strain. Provirus load at the early stage of infection was significantly higher in sheep than in goats. A broad antibody reactivity against the matrix and capsid proteins was detected in goats, whereas the response to these antigens was mostly type-specific in sheep. The humoral response to the major immunodominant domain of the surface unit glycoprotein was type-specific, regardless of the host species. These species-specific immune responses were then confirmed in naturally infected sheep and goats using sera from mixed flocks in which interspecies transmissions were reported. Taken together, these results provide evidence that SRLV infections evolve in a host-dependent manner, with distinct host–virus interactions in sheep and goats, and highlight the need to consider both SRLV genotypes in diagnosis, particularly in sheep.
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Affiliation(s)
- Antoine Rachid
- Anses, Niort Laboratory, Ruminant Retrovirus Unit, F-79012 Niort, France
| | - Benoit Croisé
- Anses, Niort Laboratory, Ruminant Retrovirus Unit, F-79012 Niort, France
| | - Pierre Russo
- Anses, Sophia-Antipolis Laboratory, Ruminant Pathology Unit, 06902 Sophia-Antipolis, France
| | - Michel Vignoni
- Anses, Sophia-Antipolis Laboratory, Ruminant Pathology Unit, 06902 Sophia-Antipolis, France
| | - Daniela Lacerenza
- Department of Animal Production, Epidemiology and Ecology, University of Turin, Italy
| | - Sergio Rosati
- Department of Animal Production, Epidemiology and Ecology, University of Turin, Italy
| | - Jacek Kuźmak
- Department of Biochemistry, National Veterinary Research Institute, 24-100 Pulawy, Poland
| | - Stephen Valas
- Anses, Niort Laboratory, Ruminant Retrovirus Unit, F-79012 Niort, France
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Kuhar U, Barlič-Maganja D, Grom J. Phylogenetic analysis of small ruminant lentiviruses detected in Slovenia. Vet Microbiol 2012; 162:201-6. [PMID: 23022680 DOI: 10.1016/j.vetmic.2012.08.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 08/23/2012] [Accepted: 08/24/2012] [Indexed: 10/27/2022]
Abstract
Small ruminant lentiviruses (SRLV), which belong to the Retroviridae family, infect goats and sheep worldwide. The aim of this study was to characterize the SRLV strains circulating in Slovenia, by phylogenetic analysis of two genomic regions, 1.8 kb gag-pol fragment and 1.2kb pol fragment. The results of our study revealed that Slovenian SRLV strains are highly heterogeneous, with ovine strains belonging to genotype A and caprine strains to genotypes A and B. The closest relatives of sheep virus sequences from two flocks that clustered together (SLO 35, 36) were found to be in subtype A5. A cluster composed of four sheep virus sequences (SLO 31) was clearly divergent from all other subtypes in group A and could not be assigned to any of them. The virus sequences from one goat flock belonged solely to subtype B1, whereas virus sequences from more than one genotype were found to circulate within the other two goat flocks, belonging to subtype B1 (SLO 1 and SLO 37) and to genotype A (SLO 2 and 78-88 g). Two goat virus sequences (SLO 2) were found to belong to genotype A and could not be assigned to existing subtypes. One goat virus sequence (37-88 g) from flock 37 was clearly different from other sequences of this flock and was more closely related to genotype A sequences. We propose two new subtypes within genotype A, subtype A14 (SLO 2) and A15 (SLO 31).
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Affiliation(s)
- Urška Kuhar
- University of Ljubljana, Veterinary Faculty, Gerbičeva 60, SI-1115 Ljubljana, Slovenia.
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Lago N, López C, Panadero R, Cienfuegos S, Pato J, Prieto A, Díaz P, Mourazos N, Fernández G. Seroprevalence and risk factors associated with Visna/Maedi virus in semi-intensive lamb-producing flocks in northwestern Spain. Prev Vet Med 2011; 103:163-9. [PMID: 21993274 DOI: 10.1016/j.prevetmed.2011.09.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 09/16/2011] [Accepted: 09/17/2011] [Indexed: 11/26/2022]
Abstract
A cross-sectional study was carried out to determine Visna/Maedi virus (VMV) seroprevalence and risk factors in semi-intensive lamb-producing flocks as a prelude to establishing a monitoring program in northwestern (NW) Spain. A total of 15,155 serum samples were taken from 78 commercial flocks and were submitted to an indirect VMV ELISA. Association between potential risk factors and seroprevalence at the flock level was assessed using a multivariable logistic regression model. A Generalized Estimating Equations (GEE) model and Exhaustive Chi-squared Automatic Interaction Detector (CHAID) were used to determine the seropositivity against VMV at the individual animal level. Individual seropositivity was 24.8% while 52.6% of the flocks examined had a true seroprevalence ≥1%. Flock size and introduction of new animals in the flock were significantly associated with seropositivity at the flock level. Flock size, sheep-goat contact, type of housing of lambs prior to weaning and age were significantly associated with individual VMV seropositivity. Confinement of lambs in preweaning lamb groups and high sheep-goat contact, regardless of the low number of goats per flock, were risk factors associated with individual VMV seropositivity, suggesting that these two factors are crucial for VMV control in semi-intensive lamb-producing flocks. These factors should be considered for developing more efficient strategies that will reduce the rate of VMV transmission.
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Affiliation(s)
- N Lago
- Department of Animal Health, University of Santiago de Compostela, Lugo, Spain.
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Juganaru M, Reina R, Bertolotti L, Stella M, Profiti M, Armentano M, Bollo E, Amorena B, Rosati S. In vitro properties of small ruminant lentivirus genotype E. Virology 2011; 410:88-95. [DOI: 10.1016/j.virol.2010.10.031] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Revised: 07/15/2010] [Accepted: 10/17/2010] [Indexed: 10/18/2022]
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Reina R, Juganaru MM, Profiti M, Cascio P, Cerruti F, Bertolotti L, De Meneghi D, Amorena B, Rosati S. Immunological parameters in goats experimentally infected with SRLV genotype E, strain Roccaverano. Vet Immunol Immunopathol 2010; 139:237-44. [PMID: 21122927 DOI: 10.1016/j.vetimm.2010.11.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Revised: 11/02/2010] [Accepted: 11/04/2010] [Indexed: 10/18/2022]
Abstract
Genotype E of small ruminant lentivirus has been recently described in goats from different breeds in Italy. Genotype E infection may differ from known genotypes since deletions of dUTPase and VPR proteins have been confirmed in different independent areas and goat breed, and play a key role on virus replication and pathogenesis. In particular, genotype E Roccaverano strain has been described as low pathogenic since does not lead to clinical symptoms in goats. In contrast, classical CAEV infected goats of the same area and breed presented arthritis. In this study, we have used intratracheal and intra-bone marrow routes to establish genotype E persistent infections. Humoral and cellular immune responses elicited in the host against genotype E and genotype B derived antigens were evaluated until 200 days post-inoculation. Compared to genotype B antigen, seroconversion against genotype E GAG P16-25 antigen was detected at 2-3 weeks after inoculation, significantly earlier and at higher titres. Interestingly, antibody avidity did not increase in the course of the experiment neither against P16-25 nor against SU5, both derived from genotype E. T cell proliferation against P25-GST fusion protein antigens derived from genotype E was firstly detected at 15 days post-inoculation and was maintained throughout time until week 20 post-infection, while T cell proliferation against the genotype B P25 was not produced by the end of the experiment at 20 weeks post-inoculation. The strength of reaction was also higher when using P25 E as stimulator antigen. In contrast with antibody and T cell proliferation, cytotoxic-T-lymphocyte (CTL) activity in the circulating lymphocytes (effector cells) using blood-derived macrophages (BDM) as target cells, was not strain specific being surprisingly higher against genotype B infected antigen presenting cells (APCs). This is the first study reporting experimentally induced immunological changes in SRLV genotype E infection and indicates that CTL activity may be the adaptive immune response able to induce protection against heterologous infection.
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Affiliation(s)
- Ramses Reina
- Instituto de Agrobiotecnología, CSIC-Universidad Pública de Navarra-Gobierno de Navarra, Mutilva Baja, Navarra, Spain
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Brinkhof J, Moll L, van Maanen C, Houwers D. Use of serology and polymerase chain reaction for the rapid eradication of small ruminant lentivirus infections from a sheep flock: A case report. Res Vet Sci 2010; 88:41-3. [DOI: 10.1016/j.rvsc.2009.05.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Revised: 05/12/2009] [Accepted: 05/14/2009] [Indexed: 11/26/2022]
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Gjerset B, Rimstad E, Teige J, Soetaert K, Jonassen CM. Impact of natural sheep-goat transmission on detection and control of small ruminant lentivirus group C infections. Vet Microbiol 2008; 135:231-8. [PMID: 18986775 DOI: 10.1016/j.vetmic.2008.09.069] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2008] [Revised: 08/28/2008] [Accepted: 09/15/2008] [Indexed: 11/29/2022]
Abstract
Dissemination of small ruminant lentivirus (SRLV) infections in Norway is affected by the different control strategies used for maedi-visna virus (MVV) infections in sheep and caprine arthritis-encephalitis virus (CAEV) infections in goats. Here we investigated SRLV phylogenetic group variants in sheep. CAEV-like isolates, belonging to phylogenetic group C, were found among both seropositive sheep and goats in mixed flocks, in which sheep and goats are kept together. Intra-herd clustering confirmed that mixed flock animals were infected by the same virus variant, suggesting ongoing interspecies transmission. Few sheep flocks were found to be infected with the MVV-like phylogenetic group A. The apparent absence of SRLV group A type in goats is probably due to the MVV control programme and animal management practices. SRLV group C targets lungs and mammary glands in sheep, and induces typical SRLV pathological lesions. SRLV group C isolated from the sheep mammary glands suggested a productive infection and potential for transmission to offspring. SRLV group C was most prevalent among goats. A lower PCR sensitivity in seropositive sheep suggested a lower load of SRLV group C provirus in sheep than in goats. Higher genetic divergence of group C than in other SRLV groups and extensive heterogeneity among group C isolates in the matrix C-terminal region demonstrate the need for identifying conserved target regions when developing PCR protocols for SRLV detection. As sheep and goats may serve as reservoirs for all SRLV genogroup types, successful control programmes require inclusion of both species.
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Affiliation(s)
- Britt Gjerset
- Department of Food Safety & Infection Biology, Norwegian School of Veterinary Science, P.O. Box 8146 Dep, 0033 Oslo, Norway.
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Germain K, Croise B, Valas S. Field evaluation of a gag/env heteroduplex mobility assay for genetic subtyping of small-ruminant lentiviruses. J Gen Virol 2008; 89:2020-2028. [PMID: 18632974 DOI: 10.1099/vir.0.2008/000851-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Small-ruminant lentiviruses (SRLVs) display a high genetic diversity and are currently classified into five genotypes and an increasing number of subtypes. The co-circulation of subtypes in restricted geographical regions, combined with the occurrence of cross-species infection, suggests the need for development of a large-scale screening methodology for rapid monitoring of the prevalence of the various genetic subtypes and their genetic evolution. Here, a heteroduplex mobility assay (HMA) was developed for the rapid identification of group B subtypes. The assay was validated for both the p14 nucleocapsid-coding region of the gag gene and the V1-V2 region of the env gene using a panel of reference standards and was applied to the genetic subtyping of SRLV field isolates from five mixed flocks in France. Subtyping of 75 blood samples using the env HMA revealed a preferential distribution of subtypes B1 and B2 in sheep and goats, despite direct evidence for interspecies transmission of both subtypes. Adding the gag HMA to the env HMA provided evidence for dual infection and putative recombination between subtypes B1 and B2 in five goats, and between groups A and B in one sheep. Phylogenetic analysis revealed that 100 % (23/23) and 96.7 % (30/31) of samples were correctly classified using the gag and env HMAs, respectively. These results indicate that dual infection and recombination may be a significant source of new variation in SRLV and provide a useful tool for the rapid genetic subtyping of SRLV isolates, which could be relevant for the development of more accurate diagnosis of prevalent SRLV strains in different countries.
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Affiliation(s)
- Karine Germain
- Agence Française de Securite Sanitaire des Aliments (AFSSA), Laboratoire d'Etudes et de Recherches Caprines, Niort, France
| | - Benoit Croise
- Agence Française de Securite Sanitaire des Aliments (AFSSA), Laboratoire d'Etudes et de Recherches Caprines, Niort, France
| | - Stephen Valas
- Agence Française de Securite Sanitaire des Aliments (AFSSA), Laboratoire d'Etudes et de Recherches Caprines, Niort, France
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Seroprevalence and spatial distribution of maedi-visna virus and pestiviruses in Catalonia (Spain). Small Rumin Res 2008. [DOI: 10.1016/j.smallrumres.2008.05.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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30
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Haflidadóttir BS, Matthíasdóttir S, Agnarsdóttir G, Torsteinsdóttir S, Pétursson G, Andrésson ÓS, Andrésdóttir V. Mutational analysis of a principal neutralization domain of visna/maedi virus envelope glycoprotein. J Gen Virol 2008; 89:716-721. [PMID: 18272763 DOI: 10.1099/vir.0.83410-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We have shown previously that a type-specific neutralization domain is located within a 39 aa sequence in the fourth variable domain of gp135 in visna/maedi virus. We now show that neutralizing antibodies detected early in infection are directed to this epitope, suggesting an immunodominant nature of this domain. Ten antigenic variants were previously analysed for mutations in this region, and all but one were found to be mutated. To assess the importance of these mutations in replication and neutralization, we reconstructed several of the mutations in an infectious molecular clone and tested the resulting viruses for neutralization phenotype and replication. Mutation of a conserved cysteine was shown to alter the neutralization epitope, whilst the replication kinetics in macrophages were unchanged. Mutations modulating potential glycosylation sites were found in seven of the ten antigenic variants. A frequently occurring mutation, removing a potential glycosylation site, had no effect on its own on the neutralization phenotype of the virus. However, adding an extra potential glycosylation site in the region resulted in antigenic escape. The results indicate that the conserved cysteine plays a role in the structure of the epitope and that glycosylation may shield the principal neutralization site.
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Affiliation(s)
| | | | - Gudrún Agnarsdóttir
- Institute for Experimental Pathology, University of Iceland, Keldur, Reykjavík, Iceland
| | | | - Gudmundur Pétursson
- Institute for Experimental Pathology, University of Iceland, Keldur, Reykjavík, Iceland
| | - Ólafur S Andrésson
- Institute for Experimental Pathology, University of Iceland, Keldur, Reykjavík, Iceland
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