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Pluta A, Jaworski JP, Droscha C, VanderWeele S, Taxis TM, Valas S, Brnić D, Jungić A, Ruano MJ, Sánchez A, Murakami K, Nakamura K, Puentes R, De Brun ML, Ruiz V, Gómez MEL, Lendez P, Dolcini G, Camargos MF, Fonseca A, Barua S, Wang C, Giza A, Kuźmak J. Inter-laboratory comparison of eleven quantitative or digital PCR assays for detection of proviral bovine leukemia virus in blood samples. BMC Vet Res 2024; 20:381. [PMID: 39187880 DOI: 10.1186/s12917-024-04228-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Accepted: 08/09/2024] [Indexed: 08/28/2024] Open
Abstract
Bovine leukemia virus (BLV) is the etiological agent of enzootic bovine leukosis and causes a persistent infection that can leave cattle with no symptoms. Many countries have been able to successfully eradicate BLV through improved detection and management methods. However, with the increasing novel molecular detection methods there have been few efforts to standardize these results at global scale. This study aimed to determine the interlaboratory accuracy and agreement of 11 molecular tests in detecting BLV. Each qPCR/ddPCR method varied by target gene, primer design, DNA input and chemistries. DNA samples were extracted from blood of BLV-seropositive cattle and lyophilized to grant a better preservation during shipping to all participants around the globe. Twenty nine out of 44 samples were correctly identified by the 11 labs and all methods exhibited a diagnostic sensitivity between 74 and 100%. Agreement amongst different assays was linked to BLV copy numbers present in samples and the characteristics of each assay (i.e., BLV target sequence). Finally, the mean correlation value for all assays was within the range of strong correlation. This study highlights the importance of continuous need for standardization and harmonization amongst assays and the different participants. The results underscore the need of an international calibrator to estimate the efficiency (standard curve) of the different assays and improve quantitation accuracy. Additionally, this will inform future participants about the variability associated with emerging chemistries, methods, and technologies used to study BLV. Altogether, by improving tests performance worldwide it will positively aid in the eradication efforts.
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Affiliation(s)
- Aneta Pluta
- Department of Biochemistry, National Veterinary Research Institute, Puławy, 24-100, Poland.
- Department of Omics Analyses, National Veterinary Research Institute, 24-100, Puławy, Poland.
| | - Juan Pablo Jaworski
- Instituto de Virología E Innovaciones Tecnológicas (IVIT), Centro de Investigaciones en Ciencias Veterinarias y Agronómicas (CICVyA), Instituto Nacional de Tecnología Agropecuaria (INTA) - CONICET, Buenos Aires, Argentina
| | - Casey Droscha
- CentralStar Cooperative, 4200 Forest Rd, Lansing, MI, 48910, USA
| | | | - Tasia M Taxis
- Department of Animal Science, College of Agriculture and Natural Resources, Michigan State University, East Lansing, Michigan, 48824, USA
| | - Stephen Valas
- Niort Laboratory, Unit Pathology and Welfare of Ruminants, French Agency for Food, Environmental and Occupational Health and Safety (Anses), Ploufragan-Plouzané, Niort, France
| | - Dragan Brnić
- Croatian Veterinary Institute, Savska Cesta 143, Zagreb, 10000, Croatia
| | - Andreja Jungić
- Croatian Veterinary Institute, Savska Cesta 143, Zagreb, 10000, Croatia
| | - María José Ruano
- Laboratorio Central de Veterinaria (LCV), Ministry of Agriculture, Fisheries and Food, Carretera M-106 (Km 1,4), Madrid, Algete, 28110, Spain
| | - Azucena Sánchez
- Laboratorio Central de Veterinaria (LCV), Ministry of Agriculture, Fisheries and Food, Carretera M-106 (Km 1,4), Madrid, Algete, 28110, Spain
| | - Kenji Murakami
- Department of Veterinary Sciences, Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, 020-8550, Japan
| | - Kurumi Nakamura
- Department of Veterinary Sciences, Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, 020-8550, Japan
| | - Rodrigo Puentes
- Departamento de Patobiología, Facultad de Veterinaria, Unidad de Microbiología, Universidad de La República, Ruta 8, Km 18, Montevideo, 13000, Uruguay
| | - MLaureana De Brun
- Departamento de Patobiología, Facultad de Veterinaria, Unidad de Microbiología, Universidad de La República, Ruta 8, Km 18, Montevideo, 13000, Uruguay
| | - Vanesa Ruiz
- Instituto de Virología E Innovaciones Tecnológicas (IVIT), Centro de Investigaciones en Ciencias Veterinarias y Agronómicas (CICVyA), Instituto Nacional de Tecnología Agropecuaria (INTA) - CONICET, Buenos Aires, Argentina
| | - Marla Eliana Ladera Gómez
- Laboratorio de Virología, Departamento SAMP, Centro de Investigación Veterinaria de Tandil-CIVETAN (CONICET/UNCPBA/CICPBA), Buenos Aires, Argentina
| | - Pamela Lendez
- Laboratorio de Virología, Departamento SAMP, Centro de Investigación Veterinaria de Tandil-CIVETAN (CONICET/UNCPBA/CICPBA), Buenos Aires, Argentina
| | - Guillermina Dolcini
- Laboratorio de Virología, Departamento SAMP, Centro de Investigación Veterinaria de Tandil-CIVETAN (CONICET/UNCPBA/CICPBA), Buenos Aires, Argentina
| | | | - Antônio Fonseca
- Laboratório Federal de Defesa Agropecuária de Minas Gerais, Pedro Leopoldo, Brazil
| | - Subarna Barua
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL, 36849-5519, USA
| | - Chengming Wang
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL, 36849-5519, USA
| | - Aleksandra Giza
- Department of Omics Analyses, National Veterinary Research Institute, 24-100, Puławy, Poland
| | - Jacek Kuźmak
- Department of Biochemistry, National Veterinary Research Institute, Puławy, 24-100, Poland
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De Brun ML, Cosme B, Petersen M, Alvarez I, Folgueras-Flatschart A, Flatschart R, Panei CJ, Puentes R. Development of a droplet digital PCR assay for quantification of the proviral load of bovine leukemia virus. J Vet Diagn Invest 2022; 34:439-447. [PMID: 35369822 PMCID: PMC9254064 DOI: 10.1177/10406387221085581] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Droplet digital PCR (ddPCR) is a highly sensitive tool developed for the detection and quantification of short-sequence variants—a tool that offers unparalleled precision enabling measurement of smaller-fold changes. We describe here the use of ddPCR for the detection of Bovine leukemia virus (BLV) DNA provirus. Serum samples and whole blood from experimentally infected sheep and naturally infected cattle were analyzed through ddPCR to detect the BLV gp51 gene, and then compared with serologic and molecular tests. The ddPCR assay was significantly more accurate and sensitive than AGID, ELISA, nested PCR, and quantitative PCR. The limit of detection of ddPCR was 3.3 copies/µL, detecting positive experimentally infected sheep beginning at 6 d post-infection. The ddPCR methodology offers a promising tool for evaluating the BLV proviral load, particularly for the detection of low viral loads.
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Affiliation(s)
- María L. De Brun
- Instituto de Patobiología, Unidad de Microbiología, Facultad de Veterinaria–Universidad de la República, Montevideo, Uruguay
| | - Bruno Cosme
- Instituto Nacional de Metrología, Calidad y Tecnología (Inmetro), Rio de Janeiro, Brazil
| | - Marcos Petersen
- Instituto Nacional de Tecnología Agropecuaria (INTA), Instituto de Virología e Innovaciones Tecnológicas (IVIT), Buenos Aires, Argentina
| | - Irene Alvarez
- Instituto Nacional de Tecnología Agropecuaria (INTA), Instituto de Virología e Innovaciones Tecnológicas (IVIT), Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | | | - Roberto Flatschart
- Instituto Nacional de Metrología, Calidad y Tecnología (Inmetro), Rio de Janeiro, Brazil
| | - Carlos Javier Panei
- Laboratorio de Virología, Facultad de Ciencias Veterinarias, Universidad Nacional de la Plata (FCV-UNLP), La Plata, Argentina
| | - Rodrigo Puentes
- Instituto de Patobiología, Unidad de Microbiología, Facultad de Veterinaria–Universidad de la República, Montevideo, Uruguay
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3
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Saushkin NY, Samsonova JV, Osipov AP, Kondakov SE. Strip-dried blood sampling: applicability for bovine leukemia virus detection with ELISA and real-time PCR. J Virol Methods 2018; 263:101-104. [PMID: 30412721 DOI: 10.1016/j.jviromet.2018.11.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 10/23/2018] [Accepted: 11/05/2018] [Indexed: 11/18/2022]
Abstract
We recently proposed a new so-called strip-dried format aimed for convenient use of dried biomaterial in diagnostic purposes. In this work, 334 blood samples obtained in strip-dried form were used for bovine leucosis analysis with ELISA and real-time PCR methods. High percentage of seropositive animals (18.3%) let us estimate both indirect (serological) and direct methods applicability for the analysis of strip-dried blood samples and also to compare them (PCR results concurred with ELISA in 93.4% cases). Parallel analysis of native and corresponding strip-dried samples approved the proposed format as a reliable analytical way of sampling being in 100% concordance with conventional serum/whole blood ELISA and PCR analysis. Even distribution of antibodies against bovine leukemia virus along the membrane carrier was demonstrated by square-to-square analyzing of the sample strip (CV not exceeded 7%). Also, strip-dried blood samples showed enhanced stability at elevated temperatures comparing to liquid serum. The proposed strip-blood format is a promising way of sampling, storage and transportation and can find application in veterinary practice for infectious disease monitoring.
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Affiliation(s)
- Nikolay Yu Saushkin
- Faculty of Chemistry, M.V. Lomonosov Moscow State University, 119991, Moscow, Russia.
| | - Jeanne V Samsonova
- Faculty of Chemistry, M.V. Lomonosov Moscow State University, 119991, Moscow, Russia; National University of Science and Technology "MISiS", 119049, Moscow, Russia
| | - Alexander P Osipov
- Faculty of Chemistry, M.V. Lomonosov Moscow State University, 119991, Moscow, Russia; National University of Science and Technology "MISiS", 119049, Moscow, Russia
| | - Sergey E Kondakov
- Faculty of Chemistry, M.V. Lomonosov Moscow State University, 119991, Moscow, Russia; National University of Science and Technology "MISiS", 119049, Moscow, Russia
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Petersen M, Alvarez I, Trono K, Jaworski J. Quantification of bovine leukemia virus proviral DNA using a low-cost real-time polymerase chain reaction. J Dairy Sci 2018; 101:6366-6374. [DOI: 10.3168/jds.2017-14253] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 03/01/2018] [Indexed: 11/19/2022]
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Interlaboratory Comparison of Six Real-Time PCR Assays for Detection of Bovine Leukemia Virus Proviral DNA. J Clin Microbiol 2018; 56:JCM.00304-18. [PMID: 29669790 DOI: 10.1128/jcm.00304-18] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 04/13/2018] [Indexed: 01/09/2023] Open
Abstract
Quantitative real-time PCR (qPCR) is increasingly being used for the detection of bovine leukemia virus (BLV) proviral DNA. Nevertheless, quality control for the validation and standardization of such tests is currently lacking. Therefore, the present study was initiated by three Office International des Epizooties (OIE) reference laboratories and three collaborating laboratories to measure the interlaboratory variability of six already developed and available BLV qPCR assays. For that purpose, an international panel of 58 DNA samples reflecting the dynamic range of the majority of the assays was distributed to six testing centers. Based on qualitative results, the overall agreement among all six laboratories was moderate. However, significant variability in the measurement of the BLV proviral DNA copy number was observed among different laboratories. Quantitative PCR assays, even when performed by experienced staff, can yield large variability in BLV proviral DNA copy numbers without harmonization. Further standardization of different factors (i.e., utilization of unified protocols and unique calibrators) should increase interlaboratory agreement.
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7
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Comparison of the copy numbers of bovine leukemia virus in the lymph nodes of cattle with enzootic bovine leukosis and cattle with latent infection. Arch Virol 2014; 159:2693-7. [DOI: 10.1007/s00705-014-2137-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 05/29/2014] [Indexed: 10/25/2022]
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8
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Grünberg W, Eisenberg SWF. Atypical form of sporadic bovine leukosis (SBL) in the Netherlands. Vet Rec 2013; 173:398. [PMID: 24068696 DOI: 10.1136/vr.101885] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- W Grünberg
- Department of Farm Animal Health, Utrecht University, Yalelaan 7, Utrecht 3584CL, The Netherlands
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9
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de Castro CC, Nunes CF, Finger PF, Siedler BS, Dummer L, de Lima M, Leite FPL, Fischer G, Vargas GD, Hübner SDO. Peroxidase-linked assay for detection of antibodies against bovine leukosis virus. J Immunoassay Immunochem 2013; 34:376-83. [PMID: 23859788 DOI: 10.1080/15321819.2012.747442] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
A peroxidase linked assay (PLA) was designed to screen bovine sera for the presence of specific antibodies against bovine leukosis virus (BLV). Out of 201 samples of bovine sera analyzed, 52.2% were considered positive by PLA, 26.4% by AGID, and 38.9% by ELISA. Western blotting analyses excluded 27 samples found to be positive by PLA. PLA showed 100% of sensitivity when compared with AGID and ELISA. Specificity was 64.8% and 78%, respectively (kappa coefficients were 0.70 and 0.83). These findings indicate that PLA can be used as an alternative method for the diagnosis of BLV infection in cattle.
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Affiliation(s)
- Clarissa C de Castro
- Laboratory of Virology and Immunology, Universidade Federal de Pelotas, Pelotas, Brazil
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Swenson CL, Erskine RJ, Bartlett PC. Impact of bovine leukemia virus infection on neutrophil and lymphocyte concentrations in dairy cattle. J Am Vet Med Assoc 2013; 243:131-5. [DOI: 10.2460/javma.243.1.131] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Rola-Łuszczak M, Finnegan C, Olech M, Choudhury B, Kuźmak J. Development of an improved real time PCR for the detection of bovine leukaemia provirus nucleic acid and its use in the clarification of inconclusive serological test results. J Virol Methods 2013; 189:258-64. [PMID: 23499259 DOI: 10.1016/j.jviromet.2013.02.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 02/21/2013] [Accepted: 02/27/2013] [Indexed: 10/27/2022]
Abstract
With the aim to erradicate Enzootic Bovine Leukosis from Poland, a more sensitive real-time polymerase chain reaction was required and developed to detect proviral Bovine leukaemia virus (BLV) DNA, the causative agent of Enzootic Bovine Leukosis (EBL). This new method proved more sensitive for our needs, than the current protocols available in the public domain. DNA was extracted from peripheral blood leukocytes of 51 cattle, which had given rise to doubtful serological test results by ELISA, and from mesenteric lymph nodes of six cattle that were slaughtered as EBL suspect cases. Additionally, fourteen DNA samples were obtained from animals with a strong BLV antibody response by ELISA. All real-time data were compared to results obtained from three different nested PCR methods. All 14 strongly positive ELISA samples were positive in all PCR tests. The real-time assay in comparison to the conventional PCR methods detected 7.8% (4/51) more specimens positive for BLV nucleic acid and showed a detection limit down to one copy. These observations represent the first report in the value of using a real-time method to help elucidate the disease status of animals when inconclusive ELISA results are obtained in the diagnostic laboratory. Thus, this method should be recommended for use in countries which have implemented an EBL-eradication programme, where a low level of BLV infection is evident.
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Affiliation(s)
- Marzena Rola-Łuszczak
- OIE Reference Laboratory for EBL, Department of Biochemistry, National Veterinary Research Institute, Pulawy, Poland.
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Jimba M, Takeshima SN, Murakami H, Kohara J, Kobayashi N, Matsuhashi T, Ohmori T, Nunoya T, Aida Y. BLV-CoCoMo-qPCR: a useful tool for evaluating bovine leukemia virus infection status. BMC Vet Res 2012; 8:167. [PMID: 22995575 PMCID: PMC3489618 DOI: 10.1186/1746-6148-8-167] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Accepted: 09/13/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Bovine leukemia virus (BLV) is associated with enzootic bovine leukosis, which is the most common neoplastic disease of cattle. BLV infects cattle worldwide, imposing a severe economic impact on the dairy cattle industry. Recently, we developed a new quantitative real-time polymerase chain reaction (PCR) method using Coordination of Common Motifs (CoCoMo) primers to measure the proviral load of known and novel BLV variants in BLV-infected animals. Indeed, the assay was highly effective in detecting BLV in cattle from a range of international locations. This assay enabled us to demonstrate that proviral load correlates not only with BLV infection capacity as assessed by syncytium formation, but also with BLV disease progression. In this study, we compared the sensitivity of our BLV-CoCoMo-qPCR method for detecting BLV proviruses with the sensitivities of two real-time PCR systems, and also determined the differences of proviral load with serotests. RESULTS BLV-CoCoMo-qPCR was found to be highly sensitive when compared with the real-time PCR-based TaqMan MGB assay developed by Lew et al. and the commercial TaKaRa cycleave PCR system. The BLV copy number determined by BLV-CoCoMo-qPCR was only partially correlated with the positive rate for anti-BLV antibody as determined by the enzyme-linked immunosorbent assay, passive hemagglutination reaction, or agar gel immunodiffusion. This result indicates that, although serotests are widely used for the diagnosis of BLV infection, it is difficult to detect BLV infection with confidence by using serological tests alone. Two cattle were experimentally infected with BLV. The kinetics of the provirus did not precisely correlate with the change in anti-BLV antibody production. Moreover, both reactions were different in cattle that carried different bovine leukocyte antigen (BoLA)-DRB3 genotypes. CONCLUSIONS Our results suggest that the quantitative measurement of proviral load by BLV-CoCoMo-qPCR is useful tool for evaluating the progression of BLV-induced disease. BLV-CoCoMo-qPCR allows us to monitor the spread of BLV infection in different viewpoint compared with classical serotest.
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Affiliation(s)
- Mayuko Jimba
- Viral Infectious Diseases Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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Mohammadabadi M, Soflaei M, Mostafavi H, Honarmand M. Using PCR for early diagnosis of bovine leukemia virus infection in some native cattle. GENETICS AND MOLECULAR RESEARCH 2011; 10:2658-63. [DOI: 10.4238/2011.october.27.2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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14
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Juliarena MA, Gutierrez SE, Ceriani C. Determination of proviral load in bovine leukemia virus–infected cattle with and without lymphocytosis. Am J Vet Res 2007; 68:1220-5. [DOI: 10.2460/ajvr.68.11.1220] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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15
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Acaite J, Tamosiunas V, Lukauskas K, Milius J, Pieskus J. The eradication experience of enzootic bovine leukosis from Lithuania. Prev Vet Med 2007; 82:83-9. [PMID: 17640751 DOI: 10.1016/j.prevetmed.2007.05.010] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2004] [Revised: 05/11/2007] [Accepted: 05/15/2007] [Indexed: 11/26/2022]
Abstract
Before 1985 the situation regarding enzootic bovine leukosis (EBL) in Lithuanian cattle was described only haphazardly. In 1986 serological investigations were initiated together with an eradication programme. The EBL bovine leukosis virus (BLV) situation was monitored by the Institute of Immunology Vilnius University, national and regional veterinary laboratories. Starting in 1986 all EBL-positive cattle were separated from negative cattle into BLV-infected and BLV-free herds. To create the latter, calves were fed pasteurized milk. The seroprevalence in 1990 was 7.29%, but it steadily declined to 0.32% in 2006.
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Affiliation(s)
- J Acaite
- Institute of Immunology Vilnius University, Moletu pl 29, LT-08409 Vilnius-21, Lithuania
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Monti GE, Frankena K, Engel B, Buist W, Tarabla HD, de Jong MCM. Evaluation of a new antibody-based enzyme-linked immunosorbent assay for the detection of bovine leukemia virus infection in dairy cattle. J Vet Diagn Invest 2006; 17:451-7. [PMID: 16312236 DOI: 10.1177/104063870501700507] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The objective of this study was to validate a new blocking enzyme-linked immunosorbent assay (ELISA) (designated M108 for milk and S108 for serum samples) for detecting bovine leukemia virus (BLV) infection in dairy cattle. Milk, serum, and ethylenediaminetetraacetic acid-blood samples were collected from 524 adult Holstein cows originating from 6 dairy herds in Central Argentina. The M108 and S108 were compared with agar gel immunodiffusion (AGID), polymerase chain reaction and a commercial ELISA. Because there is currently no reference test capable of serving as a gold standard, the test sensitivity (SE) and specificity (SP) were evaluated by the use of a latent class model. Statistical inference was performed by classical maximum likelihood and by Bayesian techniques. The maximum-likelihood analysis was performed assuming conditional independence of tests, whereas the Bayesian approach allowed for conditional dependence. No clear conclusion could be drawn about conditional dependence of tests. Results with maximum likelihood (under conditional independence) and posterior Bayes (under conditional dependence) were practically the same. Conservative estimates of SE and SP (with 95% confidence intervals) for M108 were 98.6 (96.7; 99.6) and 96.7 (92.9; 98.8) and for S108 99.5 (98.2; 99.9) and 95.4 (90.9; 98.1), respectively. The ELISA 108 using either milk or serum to detect BLV-infected animals had comparable SE and SP with the official AGID and a commercial ELISA test, which are currently the most widely accepted tests for the serological diagnosis of BLV infection. Therefore, ELISA 108 can be used as an alternative test in monitoring and control programs.
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Affiliation(s)
- Gustavo E Monti
- Universidad Austral de Chile, Instituto de Medicina Preventiva, Facultad de Ciencias Veterinarias, Valdiva, Chile
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17
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Affiliation(s)
- N. F. Starodub
- Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine
| | - V. M. Starodub
- Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine
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Kuckleburg CJ, Chase CC, Nelson EA, Marras SAE, Dammen MA, Christopher-Hennings J. Detection of bovine leukemia virus in blood and milk by nested and real-time polymerase chain reactions. J Vet Diagn Invest 2003; 15:72-6. [PMID: 12580302 DOI: 10.1177/104063870301500117] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Concerns about retroviruses in livestock and products derived from them have necessitated the development of tests to detect the bovine leukemia virus (BLV) in blood and milk from cattle. Dairy cattle (n = 101) from 5 different geographical areas were used for this study. A nested polymerase chain reaction (PCR) identified 98% of BLV seropositive cattle (n = 80) from blood and 65% from milk, whereas real-time PCR detected 94% of BLV seropositive cattle from blood and 59% from milk. Bovine leukemia virus was also detected by PCR in approximately 10% of seronegative cattle (n = 21), most likely because of early detection before seroconversion.
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Licursi M, Inoshima Y, Wu D, Yokoyama T, González ET, Sentsui H. Genetic heterogeneity among bovine leukemia virus genotypes and its relation to humoral responses in hosts. Virus Res 2002; 86:101-10. [PMID: 12076834 DOI: 10.1016/s0168-1702(02)00059-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The existence of bovine leukemia virus (BLV) genotypes was investigated by restriction fragment length polymorphism (RFLP) analysis using bovine peripheral blood leukocytes collected from different geographical areas of Japan. For this purpose a nested polymerase chain reaction (PCR) for a 444 bp fragment of the envelope (env) gene was used because it was previously reported that this region might be responsible for the serological status in the host. The PCR products from 60 samples of BLV-infected cells were digested with endonucleases BamH I, Bgl I, Bcl I, Hae III and Pvu II. RFLP analysis demonstrated that there were six different genotypes of BLV present among cattle in Japan. In some herds PCR-positive animals were infected with only one genotype, but in other herds a few genotypes were found. One genotype was dominant throughout infected cattle and it was also detected in neoplastic cells from three of four animals with lymphosarcoma and three cell lines persistently infected with BLV. Production of antibodies to BLV in each cattle was surveyed by agar gel immunodiffusion and indirect hemagglutination tests, and the results were compared with those obtained from PCR. No genotype related to decreased immunoreactivity was detected. The difference in anti-viral immune responses of each animal appears to be related to the infection stage and other host factors, not to genetic heterogeneity of the envelope gene.
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Affiliation(s)
- Maria Licursi
- National Institute of Animal Health, 3-1-5 Kannondai, Tsukuba, Ibaraki, Japan
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Zaghawa A, Beier D, Abd El-Rahim IHA, Karim I, El-ballal S, Conraths FJ, Marquardt O. An outbreak of enzootic bovine leukosis in upper Egypt: clinical, laboratory and molecular-epidemiological studies. JOURNAL OF VETERINARY MEDICINE. B, INFECTIOUS DISEASES AND VETERINARY PUBLIC HEALTH 2002; 49:123-9. [PMID: 12019942 DOI: 10.1046/j.1439-0450.2002.00517.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In 1989, 220 Holstein Friesian cattle (212 heifers and eight bulls) were imported from Minnesota, USA, to form a closed dairy herd in Arab El-Aoumar, Assiut, Upper Egypt. In November 1996, some abnormal signs such as loss of weight, decreased milk yield, external lymphadenopathy and decreased appetite were observed on this farm. Serological screening by enzyme-linked immunosorbent assay revealed a seroprevalence of antibodies directed against bovine leukaemia virus (BLV) of 37.7% in cattle under 2 years old and of 72.8% in animals more than 2 years old. Diagnosis was confirmed by the detection of BLV proviral DNA using polymerase chain reaction with primers amplifying a fragment of the env gene. Out of 21 tested leucocyte fractions from individual animals, 15 were positive showing a BLV-specific amplicon of 444 base pairs. Analysis of the amplicons for restriction fragment length polymorphisms and DNA sequencing results allowed the isolates to be typed. Since this was the first recorded case of enzootic bovine leukosis in Upper Egypt, strict quarantine measures were adopted and all serologically positive animals in the herd were culled.
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Affiliation(s)
- A Zaghawa
- Department of Animal Medicine and Infections and Fish Disease, Faculty of Veterinary Medicine, Menoufia University, Sadat City, Egypt
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21
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Abstract
A sensitive non-radioactive microplate hybridization assay for the detection of proviral DNA of bovine leukemia virus (BLV)-specific polymerase chain reaction (PCR) product is described. The PCR products are labeled by adding digoxigenin-dUTP to the nested PCR reaction and are captured by a microtitre plate coated with oligonucleotide probe, which is complementary to the inner region of the amplification product. Captured products are reacted with an anti-DIG Fab fragment conjugated to peroxidase, and detected using a colorimetric reaction. The PCR-enzyme linked immunosorbent assay (ELISA), detecting as low as 10(-4) ng of proviral DNA in a background of 1 microg of BLV-negative DNA, was up to 100-fold more sensitive than ethidium bromide staining, and showed equal sensitivity to Southern blot hybridization. Using this method it was possible to monitor the presence of proviral DNA in four sheep infected experimentally with BLV, over a 10 months postinfection period, as well as in 29 cattle infected naturally. The test is rapid and highly sensitive and is a useful additional tool for the detection of BLV-infected animals.
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Affiliation(s)
- M Rola
- National Veterinary Research Institute, Al.Partyzantow 57, 24-100, Pulawy, Poland
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22
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Trono KG, Pérez-Filgueira DM, Duffy S, Borca MV, Carrillo C. Seroprevalence of bovine leukemia virus in dairy cattle in Argentina: comparison of sensitivity and specificity of different detection methods. Vet Microbiol 2001; 83:235-48. [PMID: 11574172 DOI: 10.1016/s0378-1135(01)00420-5] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Bovine leukemia virus (BLV) is a retrovirus that induces a chronic infection in cattle, which develop in three possible pathological forms: asymptomatic course, persistent lymphocytosis (PL) and lymphosarcoma. Once infected, cattle remain virus carriers for life and start to show a serological reaction within a few weeks after infection. Eradication and control of the disease is based on early diagnostic and segregation of the carriers. The agar gel immunodiffusion (AGID) test has been the serological test of choice for routine diagnosis of serum samples. Nevertheless, in more recent years, the enzyme-linked immunosorbent assay (ELISA) has replaced the AGID for large scale testing. Although Argentina has over 60 million cattle population, no nationwide studies have been conducted yet to determine the prevalence of the infection. To estimate the rate of BLV infection in dairy cattle in Argentina, a survey for specific antibodies in >10,000 serum samples from animals over 18 months old, belonging to 363 different herds from the largest dairy production areas of the country, was carried out in our laboratory, along 1999. For this purpose, we developed an ELISA to detect serum antibodies against the BLV virus. The cut-off of the ELISA was established over 339 serum samples, using polymerase chain reaction and southern blot (PCR-SB) as confirmatory test. The sensitivity and specificity of the ELISA was of 97.2 and 97.5%, respectively, while the local official AGID test showed a sensitivity of 79.7% and specificity of 99.0%. To know the seroprevalence of BLV on dairy herds, and also the incidence of the infection within the herd, the serological survey was based on individual serum samples. The results show that the prevalence of infected individuals is of 32.85%, while the percentage of infected herds, harboring one or more infected animals, is of 84%. These results indicate a medium level of seropositive animals when taken individually, but a high prevalence of infected farms, which has been notoriously increased in the last 15 years as shown when compared with previous data from particular geographic areas, indicating that BLV constitutes a serious sanitary problem for dairy producers in Argentina. They also indicate the poor sensitivity of the official AGID test used in the country.
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Affiliation(s)
- K G Trono
- Instituto de Virología, C.I.C.V.yA. INTA Castelar, Morón 1708, Pvcia., Buenos Aires, Argentina
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23
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Gutiérrez SE, Dolcini GL, Arroyo GH, Rodriguez Dubra C, Ferrer JF, Esteban EN. Development and evaluation of a highly sensitive and specific blocking enzyme-linked immunosorbent assay and polymerase chain reaction assay for diagnosis of bovine leukemia virus infection in cattle. Am J Vet Res 2001; 62:1571-7. [PMID: 11592321 DOI: 10.2460/ajvr.2001.62.1571] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To develop a blocking ELISA for detection of bovine leukemia virus (BLV) antibodies that is comparable to a radioimmunoprecipitation (RIP) assay, to evaluate use of this ELISA for identification of BLV-infected herds, and to develop a polymerase chain reaction (PCR) assay for direct diagnosis of infection with BLV. SAMPLE POPULATION Serum samples and pooled bulk-tank milk samples from cattle. PROCEDURE The blocking ELISA was developed, using BLV gp51 as antigen, captured by a selected bovine polyclonal serum. A nested PCR was conducted with primers specific for a segment of the pol region of the BLV genome. RESULTS Sensitivity and specificity of the ELISA were comparable to those of the RIP assay. Use of the ELISA on pooled milk samples allowed identification of herds in which prevalence of BLV infection among lactating cows was as low as 2.5%. Pooled milk samples from BLV-free herds did not react in the ELISA. All cattle that had positive results for the nested PCR had BLV antibodies, but cattle with consistantly low antibody titers required examination of sequential DNA samples to detect viral sequences. None of the 63 antibody-negative cattle had positive results for the PCR. CONCLUSIONS AND CLINICAL RELEVANCE This ELISA is a highly specific and sensitive assay for the detection of BLV antibodies in serum and milk samples of cattle. Examination of pooled milk samples with the ELISA provides a reliable, practical, and economic procedure for identification of BLV-infected herds. The nested PCR also constitutes a specific procedure for direct diagnosis of infection with BLV.
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Affiliation(s)
- S E Gutiérrez
- Departamento de Sanidad Animal y Medicina Preventiva, Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires, Tandil, Argentina
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24
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Martin D, Arjona A, Soto I, Barquero N, Viana M, Gómez-Lucía E. Comparative study of PCR as a direct assay and ELISA and AGID as indirect assays for the detection of bovine leukaemia virus. JOURNAL OF VETERINARY MEDICINE. B, INFECTIOUS DISEASES AND VETERINARY PUBLIC HEALTH 2001; 48:97-106. [PMID: 11315529 DOI: 10.1046/j.1439-0450.2001.00424.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The choice of a diagnostic method depends on the characteristics of the herd to be analysed. Two herds with different prevalences of enzootic bovine leukaemia were chosen to study the concordance between agar gel immunodiffusion (AGID), enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR) methods. PCR, an increasingly used virological method, was performed with four sets of primers, amplifying different genomic regions (env, pol and tax), from DNA extracted either from peripheral blood monocytes (PBMCs) or milk leucocytes. The highest percentage of positive animals was obtained using PCR performed with DNA extracted from PBMCs using primers which amplified either env or pol, followed by PCR using PBMCs and primers which hybridized with tax, then ELISA using serum and finally AGID. The results of PCR were more consistent with PBMCs than when milk leucocytes were used.
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Affiliation(s)
- D Martin
- Departamento Patología Animal I, Facultad de Veterinaria, Universidad Complutense, 28040 Madrid, Spain
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25
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Reichert M, Stec J. Simultaneous use of two primer pairs increases the efficiency of polymerase chain reaction assay in the diagnosis of bovine leukemia virus infection. J Vet Diagn Invest 1999; 11:543-7. [PMID: 12968741 DOI: 10.1177/104063879901100613] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- M Reichert
- Department of Biochemistry, National Veterinary Research Institute, Al. Partyzantow, 57, 24-100, Pulawy, Poland
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26
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González ET, Norimine J, Valera AR, Travería G, Oliva GA, Etcheverrigaray ME. A rapid and sensitive diagnosis of bovine leukaemia virus infection using the nested shuttle polymerase chain reaction. PESQUISA VETERINARIA BRASILEIRA 1999. [DOI: 10.1590/s0100-736x1999000200002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
Abstract
Bovine leukaemia virus (BLV) is the causative agent of enzootic bovine leukosis (EBL). In Argentina, where a program to eradicate EBL has been introduced, sensitive and reliable diagnosis has attained high priority. Although the importance of the agar gel immunodiffusion test remains unchanged for routine work, an additional diagnostic technique is necessary to confirm cases of sera with equivocal results or of calves carrying maternal antibodies.Utilizing a nested shuttle polymerase chain reaction, the proviral DNA was detected from cows experimentally infected with as little as 5 ml of whole blood from BLV seropositive cows that were nonetheless normal in haematological terms. It proved to be a very sensitive technique, since it rapidly revealed the presence of the provirus, frequently at 2 weeks postinoculation and using a two-round procedure of nested PCR taking only 3 hours. Additionally, the primers used flanked a portion of the viral genome often employed to differentiate BLV type applying BamHI digestion. It is concluded that this method might offer a highly promising diagnostic tool for BLV infection.
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27
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Reichel MP, Tham KM, Barnes S, Kittelberger R. Evaluation of alternative methods for the detection of bovine leukaemia virus in cattle. N Z Vet J 1998; 46:140-6. [PMID: 16032038 DOI: 10.1080/00480169.1998.36078] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
AIM To evaluate commercially available enzyme-linked immunosorbent assays (ELISAs) and the polymerase chain reaction (PCR) for their ability to detect antibodies against or nucleic acid of the bovine leukaemia virus (BLV), the causal agent of enzootic bovine leukosis (EBL), and to assess their usefulness in a national eradication programme. METHODS Eighty-two well-defined sera (including 18 from an OIE reference laboratory) and 399 field sera from New Zealand cattle were tested in five ELISAs and the results compared with the agar gel immunodiffusion (AGID) test and electrophoretic immunoblotting (EIB) results. A polymerase chain reaction-based technique, which could detect BLV-RNA and proviral-DNA, was also evaluated on a subsample of the field cases. RESULTS Two commercial ELISAs classified 99% of the defined sera correctly, with the other three ranging in their correct classification between 88% and 95%. The ELISAs agreed in their general classification on the majority of the 399 blood samples (91.7%), and with the AGID for more than 95 % of the sera. In a dilution series of the international reference serum E4, the highest dilution with a positive (or suspicious) result ranged from 1:80 to 1:5120. A dilution series of 202 field positive samples tested in the preferred ELISA detected 98% of positive sera at a 15 and 1: 10 dilution, reducing to 78% at a 1:80 dilution of the sera. Agreement between serological tests and PCR was poor, mainly due to failure of the PCR to detect a number of serologically positive animals. CONCLUSION ELISA tests detected about 10% more reactors than the AGID and the EIB combined. Some ELISA-positive animals were not detected by PCR, raising doubts about the usefulness of PCR-based technology in EBL eradication programmes.
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Affiliation(s)
- M P Reichel
- Central Animal Health Laboratory, MAF Quality Management, Wallaceville, P.O. Box 40063, Upper Hutt, New Zealand.
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28
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Fechner H, Blankenstein P, Looman AC, Elwert J, Geue L, Albrecht C, Kurg A, Beier D, Marquardt O, Ebner D. Provirus variants of the bovine leukemia virus and their relation to the serological status of naturally infected cattle. Virology 1997; 237:261-9. [PMID: 9356338 DOI: 10.1006/viro.1997.8784] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Infection of cattle with the bovine leukemia virus (BLV) results in a strong permanent antibody response to the BLV antigens some weeks after infection. However, cattle may carry provirus and not have detectable antibody titers. To prove the occurrence of different BLV provirus variants in German cattle and to study the influence of special BLV variants on the immunoreaction, a 444-bp fragment of the env gene of 35 naturally BLV infected animals was analyzed. Seven different groups of BLV provirus variants were found on the basis of restriction fragment length polymorphism. Three BLV provirus variant groups and five additionally sequenced BLV isolates showed a high similarity to BLV provirus isolates from other geographical areas. The variation in nucleotide sequence of the five BLV isolates compared with nine previously sequenced BLV isolates ranged up to 5. 3%. While BLV provirus variant groups A, C, D, E, F, and G were clearly related to agar-gel immunodiffusion test (AGID)- and enzyme-linked immunosorbent assay (ELISA)-positive animals, BLV provirus variant group B was solely found in permanent AGID- and ELISA-negative or in transient ELISA-positive animals. Altogether, these results indicate that special BLV provirus variants may be responsible for atypical forms of BLV infection in cattle.
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Affiliation(s)
- H Fechner
- Faculty of Veterinary Medicine, Free University of Berlin, Luisenstrasse 56, Berlin D-10117, Germany
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29
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Evermann JF, Jackson MK. Laboratory diagnostic tests for retroviral infections in dairy and beef cattle. Vet Clin North Am Food Anim Pract 1997; 13:87-106. [PMID: 9071748 DOI: 10.1016/s0749-0720(15)30366-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Detection of bovine retroviruses stretches our diagnostic creativity to its limits. The nucleic acid-based, PCR-amplified assays are finding increased clinical use as the veterinary and livestock industry seek earlier detection of infection for eventual corrective management decisions. We are evolving from a point of disease diagnosis by tumor identification through conventional histopathology, to molecular diagnostics for early identification of retroviral nucleic acid (provirus). The clinical use of antibody-based assays lies in the simplicity of testing large numbers of animals, the relative sensitivity of the assays, and the low cost of testing. Although the pathogenicity of bovine leukemia virus (BLV) for cattle has been well documented, the disease potential for bovine immunodeficiency-like virus (BIV) for cattle is still being determined. Nevertheless, pressure to test for retroviral infections of livestock and, when feasible, removal of these infected animals from the herd will be increased.
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Affiliation(s)
- J F Evermann
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, USA
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30
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Fechner H, Kurg A, Geue L, Blankenstein P, Mewes G, Ebner D, Beier D. Evaluation of polymerase chain reaction (PCR) application in diagnosis of bovine leukaemia virus (BLV) infection in naturally infected cattle. ZENTRALBLATT FUR VETERINARMEDIZIN. REIHE B. JOURNAL OF VETERINARY MEDICINE. SERIES B 1996; 43:621-30. [PMID: 9011158 DOI: 10.1111/j.1439-0450.1996.tb00361.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The practical application of polymerase chain reaction (PCR) for the diagnosis of bovine leukaemia virus (BLV) infections in naturally infected cattle was evaluated. Compared to serological tests the PCR was definitely found to be a more sensitive method, yielding the highest number of positive results (10% more compared to enzyme-linked immunosorbent assay, (ELISA), and 17.7% more compared to agar-gel immunodiffusion, (AGID)). In testing cattle from herds with BLV incidence under 5%, out of 52 provirus positive cattle only 43 were correctly identified by ELISA. When compared to AGID only 37 of the 52 PCR positive animals were correctly identified. Of 18 cattle imported from the Slovak Republic and kept in a quarantine stable, four were found to be BLV provirus positive by PCR, while serological tests indicated one animal positive and three negative. Therefore, it is impossible to prevent the spread of the infection from one country to another by serological testing only. Moreover, it is feasible to identify animals with changing antibody titres correctly by PCR. Using PCR we were also able to distinguish BLV infected from uninfected calves that were serologically positive due to colostral antibodies. Higher sensitivity of BLV provirus detection by PCR was achieved using env gene rather than tax gene specific primers. Negative results by PCR in cases of positive serological reactions are still possible, as shown in case of one adult animal. These findings indicate that PCR is a highly sensitive method and might be successfully used and economically advantageous for different practical applications in detection of BLV infection in naturally infected cattle.
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Affiliation(s)
- H Fechner
- Institute of Virology, Faculty of Veterinary Medicine, Free University Berlin, Germany
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31
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Böse R, Jorgensen WK, Dalgliesh RJ, Friedhoff KT, de Vos AJ. Current state and future trends in the diagnosis of babesiosis. Vet Parasitol 1995; 57:61-74. [PMID: 7597794 DOI: 10.1016/0304-4017(94)03111-9] [Citation(s) in RCA: 184] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
An overview is given of the currently available methods to diagnose babesiosis in livestock. Microscopic techniques are still the only appropriate techniques to diagnose acute disease. Thin or thick blood films stained with Giemsa's stain are sufficient. The sensitivity ranges from 10(-5) to 10(-6), i.e. one parasite per 10(5)-10(6) erythrocytes can be detected. Thick films stained with acridine orange (sensitivity approximately 10(-7)) and the Quantitative Buffy Coat (QBC) analysis tube system (sensitivity approximately 10(-7)-10(-8)) are applicable for diagnosis in the laboratory. DNA probes are very specific tools to identify haemoparasites in organs post mortem and in ticks. For the identification of carrier animals the sensitivity (approximately 10(-5)-10(-6)) is generally not sufficient. For the latter the polymerase chain reaction (PCR) technique is a very powerful tool (sensitivity approximately 10(-9)). Many different serodiagnostic tests have been described; however, the immunofluorescence antibody test is the most widely used, while the enzyme-linked immunosorbent assay (ELISA) is the test system which holds the greatest promise for the future. Thus far, improvements to the ELISA have been limited as the quality of antigen preparations made from infected blood is generally poor with a few exceptions (Babesia bovis, Babesia caballi). Potentially, most of the problems associated with crude antigens can be overcome by the production of recombinant antigens. Several ELISAs based on highly defined recombinant antigens have been described and show promise. None of these tests has been validated to the extent that it could be applied globally. Future research requirements as well as the need for coordination of the research effort and collaboration between institutions involved in the diagnosis of babesiosis are discussed.
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Affiliation(s)
- R Böse
- Institute of Parasitology, School of Veterinary Medicine, Hannover, Germany
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32
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Pfeffer M, Wiedmann M, Batt CA. Applications of DNA amplification techniques in veterinary diagnostics. Vet Res Commun 1995; 19:375-407. [PMID: 8560754 PMCID: PMC7089009 DOI: 10.1007/bf01839319] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/24/1995] [Indexed: 01/31/2023]
Abstract
An overview of the principles of the polymerase chain reaction, ligase chain reaction, self-sustained sequence replication and Q beta replicase is given. The application of these methods for the diagnosis of veterinary infectious and hereditary diseases as well as for other diagnostic purposes is discussed and comprehensive tables of reported assays are provided. Specific areas where these DNA-based amplification methods provide substantial advantages over traditional approaches are also highlighted. With regard to PCR-based assays for the detection of viral pathogens, this article is an update of a previous review by Belák and Ballagi-Pordány (1993).
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Affiliation(s)
- M Pfeffer
- Institute for Medical Microbiology, Infectious and Epidemic Diseases, Ludwig-Maximilians University, Munich, Germany
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33
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Molloy JB, Dimmock CK, Eaves FW, Bruyeres AG, Cowley JA, Ward WH. Control of bovine leukaemia virus transmission by selective culling of infected cattle on the basis of viral antigen expression in lymphocyte cultures. Vet Microbiol 1994; 39:323-33. [PMID: 8042278 DOI: 10.1016/0378-1135(94)90168-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The use of viral antigen expression in lymphocyte cultures to prioritize the culling of bovine leukaemia virus (BLV) infected cattle was evaluated as a means of controlling the spread of infection in heavily infected herds. Selective culling was implemented in five commercial dairy herds containing between 126 and 304 cattle with infection prevalences, based on serological testing using the agar gel immunodiffusion test, of 19.4%, 20.3%, 20.1%, 20.6% and 39%. All seropositive cattle were tested for BLV antigen expression in lymphocyte cultures, and 51% found to express detectable quantities of viral antigens. In the four herds with 19% to 21% infection prevalence, all antigen-positive animals were culled immediately. Antigen-negative animals were retained in the herds for at least 16 months. Only two new infections were recorded in these four herds after antigen-positive animals had been culled, despite the continued presence of the antigen-negative animals. In the herd with 39% infection prevalence, a rapid reduction in the incidence of infection was achieved, even though only those animals with the highest levels of antigen expression were culled initially. Experimental transmissions from seropositive cattle indicated that sheep could be infected from an antigen-positive cow with fewer than 10(3) lymphocytes, whereas more than 10(6) lymphocytes were required to transmit infection from an antigen-negative cow. Estimation of the amount of integrated BLV DNA in serial dilutions of blood from antigen-positive and antigen-negative cattle provided an explanation for the higher infectivity of antigen-positive cattle.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J B Molloy
- Queensland Department of Primary Industries, Animal Research Institute, Australia
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