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Shrestha S, Orsel K, Droscha C, Mijar S, van der Meer F. Removing bovine leukemia virus-infected animals with high proviral load leads to lower within-herd prevalence and new case reduction. J Dairy Sci 2024; 107:6015-6024. [PMID: 38554820 DOI: 10.3168/jds.2023-24484] [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: 11/28/2023] [Accepted: 02/22/2024] [Indexed: 04/02/2024]
Abstract
Bovine leukosis is prevalent in the North American dairy industry, and its effect on animal health and production is widely documented. However, not all bovine leukemia virus (BLV)-infected animals transmit the virus equally. Animals with high proviral loads (HPL) of BLV are associated with higher transmission risks, and therefore, their removal may reduce transmission and eventually within-herd prevalence. We aimed to evaluate the impact of selectively removing HPL cows on the within-herd BLV prevalence and incidence rate of BLV infection in 10 dairy herds. Annual blood or milk samples (or both) were collected from adult cows over 3 yr. Positivity with BLV were determined by ELISA tests, and proviral loads in blood of BLV-positive animals were estimated with BLV SS1 quantitative PCR assays. Herd managers were encouraged to consider the proviral load when making culling decisions and implement BLV control practices. Cows with high proviral load had the highest relative risk of removal, indicating the farmers prioritized HPL cows for culling. The within-herd BLV prevalence decreased significantly in 4 herds, whereas BLV incidence rate decreased in 9 herds. Over the 3 yr, the proviral load demonstrated a relatively stable level, suggesting a single proviral load test in an adult cow may suffice to make culling decisions.
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Affiliation(s)
- Sulav Shrestha
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada T2N 4N1.
| | - Karin Orsel
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada T2N 4N1
| | - Casey Droscha
- CentralStar Cooperative Inc., East Lansing, MI 48910
| | - Sanjaya Mijar
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada T2N 4N1
| | - Frank van der Meer
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada T2N 4N1
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2
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Iwamoto J, Koreeda T, Iino M, Eitoku R, Shibata S. Estimation of the proviral load in Japanese Black cattle infected with bovine leukemia virus by statistical modeling. J Vet Med Sci 2024; 86:135-140. [PMID: 38123328 PMCID: PMC10898988 DOI: 10.1292/jvms.23-0157] [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] [Indexed: 12/23/2023] Open
Abstract
Enzootic bovine leukosis (EBL) is B-cell lymphoma in cattle caused by bovine leukemia virus (BLV) infection. The incidence of EBL has been increasing since 1998 in Japan, resulting in significant economic losses for farms. The BLV genome integrates with the host genome as provirus, leading to sustainably infection. Although most of the BLV-infected cattle are aleukemic, some cattle cause persistent lymphocytosis (PL) and subsequently develop EBL. Recent reports suggest the association between the risk for the transmission of BLV and the developing EBL and the proviral load (PVL) in BLV-infected cattle, which cannot measure readily in the field. This study aims to build a statistical model for predicting PVL of BLV-infected asymptomatic or PL cattle based on data accessible in the field. Five negative binomial regression models with different linear predictors were built and compared for the predictability of PVL. Consequently, the model with two explanatory variables (age in months and logarithm of lymphocyte count) was selected as the best model. The model can be used in the field as a cost-beneficial supporting tool to estimate the risk of transmission of BLV and developing EBL in infected cattle.
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Affiliation(s)
- Jiro Iwamoto
- Kagoshima Prefectural Aira Livestock Hygiene Service Center, Kagoshima, Japan
| | - Terunori Koreeda
- Kagoshima Prefectural Hokusatsu Livestock Hygiene Service Center, Kagoshima, Japan
| | - Mei Iino
- Kagoshima Prefectural Soo Livestock Hygiene Service Center, Kagoshima, Japan
| | - Rikako Eitoku
- Kagoshima Prefectural Kagoshima Central Livestock Hygiene Service Center Oshima Branch Office, Kagoshima, Japan
| | - Shoichi Shibata
- Kagoshima Prefectural Aira Livestock Hygiene Service Center, Kagoshima, Japan
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Lv G, Wang J, Lian S, Wang H, Wu R. The Global Epidemiology of Bovine Leukemia Virus: Current Trends and Future Implications. Animals (Basel) 2024; 14:297. [PMID: 38254466 PMCID: PMC10812804 DOI: 10.3390/ani14020297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 01/02/2024] [Accepted: 01/11/2024] [Indexed: 01/24/2024] Open
Abstract
Bovine leukemia virus (BLV) is a retrovirus that causes enzootic bovine leucosis (EBL), which is the most significant neoplastic disease in cattle. Although EBL has been successfully eradicated in most European countries, infections continue to rise in Argentina, Brazil, Canada, Japan, and the United States. BLV imposes a substantial economic burden on the cattle industry, particularly in dairy farming, as it leads to a decline in animal production performance and increases the risk of disease. Moreover, trade restrictions on diseased animals and products between countries and regions further exacerbate the problem. Recent studies have also identified fragments of BLV nucleic acid in human breast cancer tissues, raising concerns for public health. Due to the absence of an effective vaccine, controlling the disease is challenging. Therefore, it is crucial to accurately detect and diagnose BLV at an early stage to control its spread and minimize economic losses. This review provides a comprehensive examination of BLV, encompassing its genomic structure, epidemiology, modes of transmission, clinical symptoms, detection methods, hazards, and control strategies. The aim is to provide strategic information for future BLV research.
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Affiliation(s)
- Guanxin Lv
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing 163319, China; (G.L.); (J.W.); (S.L.)
- Heilongjiang Provincial Key Laboratory of Prevention and Control of Bovine Diseases, Daqing 163319, China
- China Key Laboratory of Bovine Disease Control in Northeast China, Ministry of Agriculture and Rural Affairs, Daqing 163319, China
| | - Jianfa Wang
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing 163319, China; (G.L.); (J.W.); (S.L.)
- Heilongjiang Provincial Key Laboratory of Prevention and Control of Bovine Diseases, Daqing 163319, China
- China Key Laboratory of Bovine Disease Control in Northeast China, Ministry of Agriculture and Rural Affairs, Daqing 163319, China
| | - Shuai Lian
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing 163319, China; (G.L.); (J.W.); (S.L.)
- Heilongjiang Provincial Key Laboratory of Prevention and Control of Bovine Diseases, Daqing 163319, China
- China Key Laboratory of Bovine Disease Control in Northeast China, Ministry of Agriculture and Rural Affairs, Daqing 163319, China
| | - Hai Wang
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing 163319, China; (G.L.); (J.W.); (S.L.)
- Heilongjiang Provincial Key Laboratory of Prevention and Control of Bovine Diseases, Daqing 163319, China
- China Key Laboratory of Bovine Disease Control in Northeast China, Ministry of Agriculture and Rural Affairs, Daqing 163319, China
| | - Rui Wu
- College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing 163319, China; (G.L.); (J.W.); (S.L.)
- Heilongjiang Provincial Key Laboratory of Prevention and Control of Bovine Diseases, Daqing 163319, China
- China Key Laboratory of Bovine Disease Control in Northeast China, Ministry of Agriculture and Rural Affairs, Daqing 163319, China
- College of Biology and Agriculture, Jiamusi University, Jiamusi 154007, China
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Porta NG, Suarez-Archilla G, Miotti C, Molineri AI, Alvarez I, Trono K, Signorini M, Ruiz V. Seroprevalence and risk factors associated with bovine Leukemia virus infection in argentine beef cattle. Res Vet Sci 2023; 164:104999. [PMID: 37708828 DOI: 10.1016/j.rvsc.2023.104999] [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: 07/27/2023] [Revised: 08/29/2023] [Accepted: 08/30/2023] [Indexed: 09/16/2023]
Abstract
Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis, an endemic disease in dairy cattle of Argentina. However, little is known about the seroprevalence of BLV in beef cattle. In this study, we conducted a cross-sectional study including farms from thirteen provinces of Argentina. A total of 5827 bovine serum samples were collected from 76 farms and analyzed using an in-house developed enzyme-linked immunosorbent assay. Information about herd management was collected through a questionnaire, and univariate and multivariate analyses were performed to detect risk factors associated with BLV infection. Herd-level seroprevalence was 71.05%, while the mean animal-level seroprevalence was 7.23% (median = 2.69%; min = 0, max = 75). Only two provinces had no positive BLV samples. The other eleven provinces showed more than 50% of their farms infected with BLV. The multivariate model revealed that BLV prevalence was significantly associated with the use of animals raised in the same farm for cattle replacement (P = 0.005), breeding cows by natural mating with a bull (P < 0.001), and weaning calves after 6 months of age (P = 0.011). This extensive study revealed that BLV seroprevalence in Argentine beef farms has increased during the last years and allowed identifying some management practices associated with BLV prevalence. These data deserve special attention because BLV infection in beef cattle seems to lead to a dissemination pattern similar to that observed during the last decades in dairy cattle, especially considering that Argentina is the sixth beef producer in the world, with about 5% of global beef production.
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Affiliation(s)
- Natalia Gabriela Porta
- Laboratorio de Virus Adventicios, Instituto de Virología e Innovaciones Tecnológicas (IVIT), INTA-CONICET. Nicolás Repetto y De los Reseros (s/n), Hurlingham (CP1686), Buenos Aires, Argentina.
| | - Guillermo Suarez-Archilla
- Instituto de Investigación de la Cadena Láctea (IDICaL) INTA-CONICET. Estación Experimental Agropecuaria Rafaela, Ruta 34 Km 227, Rafaela, Santa Fe, Argentina.
| | - Camila Miotti
- Instituto de Investigación de la Cadena Láctea (IDICaL) INTA-CONICET. Estación Experimental Agropecuaria Rafaela, Ruta 34 Km 227, Rafaela, Santa Fe, Argentina.
| | - Ana Inés Molineri
- Instituto de Investigación de la Cadena Láctea (IDICaL) INTA-CONICET. Estación Experimental Agropecuaria Rafaela, Ruta 34 Km 227, Rafaela, Santa Fe, Argentina.
| | - Irene Alvarez
- Laboratorio de Virus Adventicios, Instituto de Virología e Innovaciones Tecnológicas (IVIT), INTA-CONICET. Nicolás Repetto y De los Reseros (s/n), Hurlingham (CP1686), Buenos Aires, Argentina
| | - Karina Trono
- Laboratorio de Virus Adventicios, Instituto de Virología e Innovaciones Tecnológicas (IVIT), INTA-CONICET. Nicolás Repetto y De los Reseros (s/n), Hurlingham (CP1686), Buenos Aires, Argentina.
| | - Marcelo Signorini
- Instituto de Investigación de la Cadena Láctea (IDICaL) INTA-CONICET. Estación Experimental Agropecuaria Rafaela, Ruta 34 Km 227, Rafaela, Santa Fe, Argentina.
| | - Vanesa Ruiz
- Laboratorio de Virus Adventicios, Instituto de Virología e Innovaciones Tecnológicas (IVIT), INTA-CONICET. Nicolás Repetto y De los Reseros (s/n), Hurlingham (CP1686), Buenos Aires, Argentina.
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Chacón J, Leiva R, Romero-Zuñiga JJ, Navarro L, Dolz G. Seroprevalence and detection of bovine leukosis virus in semen from breeding bulls in Costa Rica. Trop Anim Health Prod 2023; 55:343. [PMID: 37777681 PMCID: PMC10543126 DOI: 10.1007/s11250-023-03763-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 09/19/2023] [Indexed: 10/02/2023]
Abstract
Bovine leukemia virus (BLV) causes enzootic bovine leukosis, a persistent infection and the most important neoplastic disease in cattle. It is spread primarily by transferring infected lymphocytes through blood from carriers to healthy animals. The present study is aimed at determining the seropositivity of BLV in breeding bulls from Costa Rica and at detecting for the first time in the country BLV DNA in bull semen. Between May 2011 and August 2018, 379 blood and 133 semen samples were collected from bulls distributed in 118 farms. The serum was analyzed by an enzymatic immunoassay and the semen by polymerase chain reaction and sequencing. BLV seropositivity was 43.5% (165/379), while 64.4% (76/118) of the farms had positive reactors. Holstein (75.7%) and Jersey (73.0%) breeds showed the highest seropositivity. In addition, Bos taurus bulls (68.1%), older than seven years (50.0%), and those belonging to dairy farms (75.5%) had higher seropositivity compared to Bos indicus (17.7%), younger than seven years (42.2%), and those from beef farms (15.5%), respectively. Moreover, Bos taurus bulls had a higher risk of being seropositive than Bos indicus (OR = 3.4; 95% CI: 1.7-6.8). BLV DNA was found in one semen sample (2.5%; 1/40) from a seropositive bull. The importance of serum and molecular BLV screening in semen samples and the potential role of some risk factors associated with the disease, such as the bull's age, genotype, and type of livestock productive system, is argued in the present report.
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Affiliation(s)
- Jorge Chacón
- Programa de Investigación en Andrología Animal Aplicada, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica.
| | - Roberto Leiva
- Programa de Investigación en Medicina Poblacional, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
| | - Juan José Romero-Zuñiga
- Programa de Investigación en Medicina Poblacional, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
| | - Leonel Navarro
- Programa de Investigación en Andrología Animal Aplicada, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
| | - Gaby Dolz
- Programa de Investigación en Medicina Poblacional, Escuela de Medicina Veterinaria, Universidad Nacional, Heredia, Costa Rica
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6
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Nobrega DB, French JE, Kelton DF. A scoping review of the testing of bulk tank milk to detect nonbacterial pathogens or herd exposure to nonbacterial pathogens in dairy cattle. J Dairy Sci 2023; 106:5636-5658. [PMID: 37291033 DOI: 10.3168/jds.2022-22586] [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: 07/27/2022] [Accepted: 02/06/2023] [Indexed: 06/10/2023]
Abstract
In this scoping review, we characterized the literature reporting on the testing of bulk milk samples to detect microorganisms other than bacteria that can cause diseases in dairy cattle, including viruses, helminths, algae, and protozoa. A search strategy was completed by screening databases, conference proceedings, animal health agency websites, disease surveillance program websites, and handbooks of cattle-related diagnostic tests for potentially relevant articles. Two reviewers independently screened articles in English, Portuguese, or Spanish; original studies reporting on the testing of farm-level, unprocessed bulk milk samples for presence of pathogens or specific antibodies against agents other than bacteria that can cause diseases in cows were retained. From all studies, we used spreadsheets to extract relevant information, including pathogen screened, test used, and country of origin of bulk milk samples. Additionally, for studies reporting sufficient data to estimate test characteristics, we extracted detailed information about herd eligibility, testing protocol, and herd-level infection definition. A total of 8,829 records were identified, from which 1,592 were retained and assessed for eligibility, and 306 were included. Bovine viral diarrhea virus, Fasciola hepatica, Ostertagia ostertagi, and bovine herpesvirus 1 were the most frequently screened agents, reported from 107, 45, 45, and 33 studies, respectively. Sensitivity of bulk milk ELISA to detect herds with animals infected by bovine herpesvirus 1 ranged from 2 to 100%, and was affected mostly by antigen selection, cut-off adopted, herd vaccination status, and seroprevalence of lactating cows. Bulk milk ELISA had very high specificity to detect herds free of bovine leukemia virus, and varying sensitivity to detect herds with infected animals, which depended on the within-herd seroprevalence of lactating cattle. As for bovine viral diarrhea virus, in general, the sensitivity of bulk milk ELISA was moderate to high (>80%) when infection status was defined based on presence of persistently infected cattle or a high proportion of seropositive lactating cattle. Nevertheless, bulk milk ELISA was not able to distinguish infected and noninfected herds based on presence of seropositive unvaccinated weanlings. The PCR or quantitative PCR protocols employed had very low sensitivities (<40%) and very high specificities (>95%) to classify bovine viral diarrhea virus infection status of dairy herds. Sensitivity and specificity of bulk milk ELISA to classify herds with regards to presence of F. hepatica- or O. ostertagi-parasitized cattle were generally high and driven mostly by the definition of herd infection status. Conversely, bulk milk ELISA demonstrated varying characteristics to detect herds with or without Dictyocaulus viviparus-parasitized cattle, depending primarily on the antigen selected and presence of cattle with clinical signs of lungworm infection.
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Affiliation(s)
- Diego B Nobrega
- Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, ON, N1G 2W1, Canada.
| | - Julie E French
- Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - David F Kelton
- Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, ON, N1G 2W1, Canada
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Abstract
In the transmission control of chronic and untreatable livestock diseases such as bovine leukemia virus (BLV) infection, the removal of viral superspreaders is a fundamental approach. On the other hand, selective breeding of cattle with BLV-resistant capacity is also critical for reducing the viral damage to productivity by keeping infected cattle. To provide a way of measuring BLV proviral load (PVL) and identifying susceptible/resistant cattle simply and rapidly, we developed a fourplex droplet digital PCR method targeting the BLV pol gene, BLV-susceptible bovine major histocompatibility complex (BoLA)-DRB3*016:01 allele, resistant DRB3*009:02 allele, and housekeeping RPP30 gene (IPATS-BLV). IPATS-BLV successfully measured the percentage of BLV-infected cells and determined allele types precisely. Furthermore, it discriminated homozygous from heterozygous carriers. Using this method to determine the impact of carrying these alleles on the BLV PVL, we found DRB3*009:02-carrying cattle could suppress the PVL to a low or undetectable level, even with the presence of a susceptible heterozygous allele. Although the population of DRB3*016:01-carrying cattle showed significantly higher PVLs compared with cattle carrying other alleles, their individual PVLs were highly variable. Because of the simplicity and speed of this single-well assay, our method has the potential of being a suitable platform for the combined diagnosis of pathogen level and host biomarkers in other infectious diseases satisfying the two following characteristics of disease outcomes: (i) pathogen level acts as a critical maker of disease progression; and (ii) impactful disease-related host genetic biomarkers are already identified. IMPORTANCE While pathogen-level quantification is an important diagnostic of disease severity and transmissibility, disease-related host biomarkers are also useful in predicting outcomes in infectious diseases. In this study, we demonstrate that combined proviral load (PVL) and host biomarker diagnostics can be used to detect bovine leukemia virus (BLV) infection, which has a negative economic impact on the cattle industry. We developed a fourplex droplet digital PCR assay for PVL of BLV and susceptible and resistant host genes named IPATS-BLV. IPATS-BLV has inherent merits in measuring PVL and identifying susceptible and resistant cattle with superior simplicity and speed because of a single-well assay. Our new laboratory technique contributes to strengthening risk-based herd management used to control within-herd BLV transmission. Furthermore, this assay design potentially improves the diagnostics of other infectious diseases by combining the pathogen level and disease-related host genetic biomarker to predict disease outcomes.
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Kanno T, Ishihara R, Mori H, Tomiyasu T, Okazaki K. Impact of amino acid 233 in Tax on bovine leukemia virus infection in Japanese Black cattle. Res Vet Sci 2023; 154:102-107. [PMID: 36571887 DOI: 10.1016/j.rvsc.2022.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 12/08/2022] [Accepted: 12/08/2022] [Indexed: 12/23/2022]
Abstract
Bovine leukemia virus (BLV) is an economically important pathogen that both causes fatal enzootic bovine leukosis (EBL) and reduces lifetime milk production, reproductive efficiency, carcass weight, and longevity in dairy cows. The virus can be divided into two categories based on the amino acid at position 233 in Tax protein, which activates viral transcription and probably plays crucial roles in leukemogenesis. We recently reported that early-onset EBL in Japanese Black (JB) cattle was frequently caused by L233-Tax-carrying virus. This study examined the impact of BLV infection, the proviral load (PVL), and amino acid 233 in Tax on the outcomes of JB cattle. We measured PVL in cattle enrolled between February 2016 and December 2018, determined the Tax type of the isolates, and performed follow-up until March 2022. The results demonstrated that BLV infection increased the risk of involuntary culling and mortality in JB cattle in a PVL-dependent manner. Infection with L233-Tax-carrying virus increased the likelihood of mortality by 1.6-fold compared with the effects of P233-Tax-carrying virus infection. Intrauterine and perinatal infections were frequently caused by L233-Tax-carrying virus, and these infections were likely to influence the early onset of EBL in JB cattle. Conversely, breeding cows infected with P233-Tax-carrying virus were often eliminated by involuntary culling. These findings indicate that amino acid 233 in Tax has importance in terms of preventing economic loss attributable to EBL in JB cattle.
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Affiliation(s)
- T Kanno
- Division of Pathology and Pathophysiology, National Institute of Animal Health, 4 Hitsujigaoka, Toyohira, Sapporo, Hokkaido, Japan
| | - R Ishihara
- Division of Pathology and Pathophysiology, National Institute of Animal Health, 4 Hitsujigaoka, Toyohira, Sapporo, Hokkaido, Japan; Department of Animal Disease Control and Prevention, National Institute of Animal Health, 3-1-5 Kannondai, Tsukuba, Ibaraki, Japan
| | - H Mori
- Laboratory of Microbiology and Immunology, Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido, Japan
| | - T Tomiyasu
- Laboratory of Microbiology and Immunology, Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido, Japan
| | - K Okazaki
- Laboratory of Microbiology and Immunology, Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido, Japan.
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Tsukada F, Takashima S, Wakihara Y, Kamatari YO, Shimizu K, Okada A, Inoshima Y. Characterization of miRNAs in Milk Small Extracellular Vesicles from Enzootic Bovine Leukosis Cattle. Int J Mol Sci 2022; 23:ijms231810782. [PMID: 36142686 PMCID: PMC9503721 DOI: 10.3390/ijms231810782] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 09/09/2022] [Accepted: 09/12/2022] [Indexed: 11/17/2022] Open
Abstract
Enzootic bovine leukosis (EBL) is a B-cell lymphosarcoma caused by the bovine leukemia virus (BLV). Most BLV-infected cattle show no clinical signs and only some develop EBL. The pathogenesis of EBL remains unclear and there are no methods for predicting EBL before its onset. Previously, it was reported that miRNA profiles in milk small extracellular vesicles (sEVs) were affected in cattle in the late stage of BLV infection. It raised a possibility that miRNA profile in milk sEVs from EBL cattle could be also affected. To characterize the difference in milk of EBL cattle and healthy cattle, we examined the miRNA profiles in milk sEVs from four EBL and BLV-uninfected cattle each using microarray analysis. Among the detected miRNAs, three miRNAs—bta-miR-1246, hsa-miR-1290, and hsa-miR-424-5p—which were detectable using quantitative real-time PCR (qPCR) and are associated with cancers in humans—were selected as biomarker candidates for EBL. To evaluate the utility of these miRNAs as biomarkers for EBL, their levels were measured using milk that was freshly collected from 13 EBL and seven BLV-uninfected cattle. bta-miR-1246 and hsa-miR-424-5p, but not hsa-miR-1290, were detected using qPCR and their levels in milk sEVs from EBL cattle were significantly higher than those in BLV-uninfected cattle. bta-miR-1246 and hsa-miR-424-5p in sEVs may promote metastasis by targeting tumor suppressor genes, resulting in increased amounts in milk sEVs in EBL cattle. These results suggest that bta-miR-1246 and hsa-miR-424-5p levels in milk sEVs could serve as biomarkers for EBL.
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Affiliation(s)
- Fumi Tsukada
- Laboratory of Food and Environmental Hygiene, Cooperative Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193, Japan
| | - Shigeo Takashima
- Division of Genomics Research, Life Science Research Center, Gifu University, Gifu 501-1193, Japan
- Institute of Glyco-Core Research (iGCORE), Gifu University, Gifu 501-1193, Japan
- The United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Gifu 501-1193, Japan
| | - Yoshiko Wakihara
- Division of Genomics Research, Life Science Research Center, Gifu University, Gifu 501-1193, Japan
| | - Yuji O. Kamatari
- Institute of Glyco-Core Research (iGCORE), Gifu University, Gifu 501-1193, Japan
- The United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Gifu 501-1193, Japan
- Division of Instrumental Analysis, Life Science Research Center, Gifu University, Gifu 501-1193, Japan
| | - Kaori Shimizu
- Laboratory of Food and Environmental Hygiene, Cooperative Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193, Japan
| | - Ayaka Okada
- Laboratory of Food and Environmental Hygiene, Cooperative Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193, Japan
- Education and Research Center for Food Animal Health, Gifu University (GeFAH), Gifu 501-1193, Japan
| | - Yasuo Inoshima
- Laboratory of Food and Environmental Hygiene, Cooperative Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193, Japan
- Education and Research Center for Food Animal Health, Gifu University (GeFAH), Gifu 501-1193, Japan
- The United Graduate School of Veterinary Sciences, Gifu University, Gifu 501-1193, Japan
- Joint Graduate School of Veterinary Sciences, Gifu University, Gifu 501-1193, Japan
- Correspondence:
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10
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Fló M, Carrión F, Olivero-Deibe N, Bianchi S, Portela M, Rammauro F, Alvarez B, Pritsch O. Kinetics of Bovine leukemia virus aspartic protease reveals its dimerization and conformational change. PLoS One 2022; 17:e0271671. [PMID: 35867649 PMCID: PMC9307154 DOI: 10.1371/journal.pone.0271671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 07/05/2022] [Indexed: 11/28/2022] Open
Abstract
The retropepsin (PR) of the Bovine leukemia virus (BLV) plays, as in other retroviruses, a crucial role in the transition from the non-infective viral particle to the infective virion by processing the polyprotein Gag. PR is expressed as an immature precursor associated with Gag, after an occasional −1 ribosomal frameshifting event. Self-hydrolysis of PR at specific N- and C-terminal sites releases the monomer that dimerizes giving rise to the active protease. We designed a strategy to express BLV PR in E. coli as a fusion protein with maltose binding protein, with a six-histidine tag at its N-terminal end, and bearing a tobacco etch virus protease hydrolysis site. This allowed us to obtain soluble and mature recombinant PR in relatively good yields, with exactly the same amino acid composition as the native protein. As PR presents relative promiscuity for the hydrolysis sites we designed four fluorogenic peptide substrates based on Förster resonance energy transfer (FRET) in order to characterize the activity of the recombinant enzyme. These substrates opened the way to perform kinetic studies, allowing us to characterize the dimer-monomer equilibrium. Furthermore, we obtained kinetic evidence for the existence of a conformational change that enables the interaction with the substrate. These results constitute a starting point for the elucidation of the kinetic properties of BLV-PR, and may be relevant not only to improve the chemical warfare against this virus but also to better understand other viral PRs.
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Affiliation(s)
- Martín Fló
- Laboratorio de Inmunovirología, Institut Pasteur de Montevideo, Montevideo, Uruguay
- Departamento de Inmunobiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
- * E-mail: (OP); (MF)
| | - Federico Carrión
- Laboratorio de Inmunovirología, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | | | - Sergio Bianchi
- Laboratorio de Inmunovirología, Institut Pasteur de Montevideo, Montevideo, Uruguay
- Laboratorio de Biomarcadores Moleculares, Departamento de Fisiopatología, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Madelón Portela
- Unidad de Bioquímica y Proteómica Analíticas, Institut Pasteur de Montevideo, Facultad de Ciencias, Montevideo, Uruguay
| | - Florencia Rammauro
- Laboratorio de Inmunovirología, Institut Pasteur de Montevideo, Montevideo, Uruguay
- Departamento de Inmunobiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Beatriz Alvarez
- Laboratorio de Enzimología, Instituto de Química Biológica, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Otto Pritsch
- Laboratorio de Inmunovirología, Institut Pasteur de Montevideo, Montevideo, Uruguay
- Departamento de Inmunobiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
- * E-mail: (OP); (MF)
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Tomiyasu T, Mori H, Okazaki K. Epidemiological evidence for early-onset of enzootic bovine leukosis by L233-Tax-carrying bovine leukemia virus in Japanese Black cattle. J Vet Med Sci 2022; 84:1216-1220. [PMID: 35831122 PMCID: PMC9523299 DOI: 10.1292/jvms.22-0169] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis (EBL), of which annual number has rapidly increased in Japan, and it can be divided into two categories based
on the amino acid at position 233 in the Tax protein. Here, we conducted a nationwide surveillance of Japanese Black cattle between 2008 and 2021 in Japan. Among 237 tumor samples, 131
(55.3%) and 101 (42.6%) were harbored L233- and P233-Tax, respectively. Onset of EBL under the age of 3 years by L233-Tax-carrying BLV was frequently observed, especially in the animals born
via embryo transfer. We also found that L233-Tax-carrying BLV was more prevalent in dairy areas than non-dairy areas. These findings give insight into prevention of EBL.
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Affiliation(s)
- Takafumi Tomiyasu
- Laboratory of Microbiology and Immunology, Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido
| | - Hiroshi Mori
- Laboratory of Microbiology and Immunology, Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido
| | - Katsunori Okazaki
- Laboratory of Microbiology and Immunology, Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido
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12
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Muurinen J, Cairns J, Ekakoro JE, Wickware CL, Ruple A, Johnson TA. Biological units of antimicrobial resistance and strategies for their containment in animal production. FEMS Microbiol Ecol 2022; 98:6589402. [PMID: 35587376 DOI: 10.1093/femsec/fiac060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 05/27/2022] [Indexed: 11/14/2022] Open
Abstract
The increasing prevalence of antimicrobial resistant bacterial infections has ushered in a major global public health crisis. Judicious or restricted antimicrobial use in animal agriculture, aiming to confine the use for the treatment of infections, is the most commonly proposed solution to reduce selection pressure for resistant bacterial strains and resistance genes. However, a multifaceted solution will likely be required to make acceptable progress in reducing antimicrobial resistance, due to other common environmental conditions maintaining antimicrobial resistance and limited executionary potential as human healthcare and agriculture will continue to rely heavily on antimicrobials in the foreseeable future. Drawing parallels from systematic approaches to the management of infectious disease agents and biodiversity loss, we provide examples that a more comprehensive approach is required, targeting antimicrobial resistance in agroecosystems on multiple fronts simultaneously. We present one such framework, based on nested biological units of antimicrobial resistance, and describe established or innovative strategies targeting units. Some of the proposed strategies are already in use or ready to be implemented, while some require further research and discussion among scientists and policymakers. We envision that antimicrobial resistance mitigation strategies for animal agriculture combining multiple tools would constitute powerful ecosystem-level interventions necessary to mitigate antimicrobial resistance.
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Affiliation(s)
- Johanna Muurinen
- Department of Animal Sciences, Purdue University, West Lafayette, IN, USA.,Department of Microbiology, Viikinkaari 9, 00014 University of Helsinki, Helsinki, Finland
| | - Johannes Cairns
- Organismal and Evolutionary Biology Research Programme (OEB), Department of Computer Science, 00014 University of Helsinki, Helsinki, Finland
| | - John Eddie Ekakoro
- Department of Public and Ecosystem Health, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Carmen L Wickware
- Department of Animal Sciences, Purdue University, West Lafayette, IN, USA
| | - Audrey Ruple
- Department of Population Health Sciences, Virginia Tech, Blacksburg, VA, USA
| | - Timothy A Johnson
- Department of Animal Sciences, Purdue University, West Lafayette, IN, USA
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Righi C, Iscaro C, Petrini S, Lomolino R, Feliziani F. Enzootic Bovine Leukosis in Italy: Epidemiological Issues after Free Status Recognition and Measures Applied to Tackle the Last Persistent Clusters. Pathogens 2021; 10:pathogens10111475. [PMID: 34832629 PMCID: PMC8621218 DOI: 10.3390/pathogens10111475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/03/2021] [Accepted: 11/08/2021] [Indexed: 11/19/2022] Open
Abstract
Enzootic Bovine Leukosis (EBL), caused by the bovine leukemia virus (BLV), has been eradicated in over 20 countries, most of which are in Western Europe. The European Commission, in 2017, declared Italy to be an officially EBL-free country by means of Commission Implementing Decision (EU) 2017/1910, despite the presence of some infection clusters located in four regions of Central-Southern Italy. As a consequence of persisting infection, the Italian Ministry of Health established specific eradication measures in these areas. In collaboration with the National Reference Laboratory for the Study of Ruminant Retroviral Infectious Diseases, the Ministry of Health employed data from the veterinary information system digital platform, combined with a gap analysis exercise, to monitor and verify the progress of control activities within infection clusters during the period 2018–2021. Our aim was to identify any remaining gaps and, consequently, specific measures to eliminate the factors favouring EBL persistence, on the basis of a description and analysis of the current data regarding epidemiological trends in Italian clusters. The final goal is to achieve the implementation of a less expensive surveillance plan in these areas, as well. The results of comprehensive analysis showed that the eradication activities had been effectively implemented by official local veterinary services, resulting in a drastic reduction of EBL outbreaks in most territories during the period 2018–2021.
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Affiliation(s)
- Cecilia Righi
- Istituto Zooprofilattico Sperimentale Umbria-Marche “Togo Rosati”, Via Gaetano Salvemini, 1, 06126 Perugia, Italy; (C.R.); (S.P.); (F.F.)
| | - Carmen Iscaro
- Istituto Zooprofilattico Sperimentale Umbria-Marche “Togo Rosati”, Via Gaetano Salvemini, 1, 06126 Perugia, Italy; (C.R.); (S.P.); (F.F.)
- Correspondence: ; Tel.: +39-075-3433071
| | - Stefano Petrini
- Istituto Zooprofilattico Sperimentale Umbria-Marche “Togo Rosati”, Via Gaetano Salvemini, 1, 06126 Perugia, Italy; (C.R.); (S.P.); (F.F.)
| | - Roberto Lomolino
- Ministero della Salute, Viale Giorgio Ribotta, 5, 00144 Roma, Italy;
| | - Francesco Feliziani
- Istituto Zooprofilattico Sperimentale Umbria-Marche “Togo Rosati”, Via Gaetano Salvemini, 1, 06126 Perugia, Italy; (C.R.); (S.P.); (F.F.)
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Evidence of bovine leukemia virus circulating in sheep and buffaloes in Colombia: insights into multispecies infection. Arch Virol 2021; 167:807-817. [PMID: 34762149 PMCID: PMC8581130 DOI: 10.1007/s00705-021-05285-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 09/15/2021] [Indexed: 12/18/2022]
Abstract
Bovine leukemia virus (BLV) is the causative agent of leukemia/lymphoma in cattle. However, previous evidence has shown its presence in other species of livestock as well as in humans, suggesting that other species can be accidental hosts of the virus. In viral infections, receptors that are common to different animal species are proposed to be involved in cross-species infections. For BLV, AP3D1 has been proposed to be its receptor, and this protein is conserved in most mammalian species. In Colombia, BLV has been reported in cattle with high prevalence rates, but there has been no evidence of BLV infections in other animal species. In this study, we tested for the virus in sheep (n = 44) and buffaloes (n = 61) from different regions of Colombia by nested PCR, using peripheral blood samples collected from the animals. BLV was found in 25.7% of the animals tested (12 buffaloes and 15 sheep), and the results were confirmed by Sanger sequencing. In addition, to gain more information about the capacity of the virus to infect these species, the predicted interactions of AP3D1 of sheep and buffaloes with the BLV-gp51 protein were analyzed in silico. Conserved amino acids in the binding domains of the proteins were identified. The detection of BLV in sheep and buffaloes suggests circulation of the virus in multiple species, which could be involved in dissemination of the virus in mixed livestock production settings. Due to the presence of the virus in multiple species and the high prevalence rates observed, integrated prevention and control strategies in the livestock industry should be considered to decrease the spread of BLV.
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15
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Diagnostic Measures of Disease Progression in Cattle Following Natural Infection with Bovine Leukemia Virus. Pathogens 2021; 10:pathogens10080987. [PMID: 34451451 PMCID: PMC8398158 DOI: 10.3390/pathogens10080987] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/02/2021] [Accepted: 08/03/2021] [Indexed: 11/17/2022] Open
Abstract
This study describes the longitudinal changes in bovine leukemia virus (BLV) ELISA antibodies, proviral load (PVL), and blood lymphocyte counts (LC) observed over a 2.5-year period in naturally infected cattle. The dataset utilized was from a BLV intervention field trial on three Midwestern dairy herds. Our analysis showed ELISA false negatives were more likely to occur in cattle with low PVL and normal LC. On average, negligible changes in LC were observed during six-month intervals. Periods of lymphocytosis, defined as >10,000 lymphocytes per uL of blood, were observed in 31.5% (68/216) of BLV test-positive cattle. In BLV test-positive cows, an average increase of 2900 to 3100 proviral copies per 100,000 cells was observed during each subsequent six-month sampling interval. The difference between the minimum and maximum PVL observed for an ELISA-positive cow with 3 or more observations ranged from 0 to 115,600 copies per 100,000 cells (median: 12,900; mean: 19,200). Therefore, following the identification of ELISA-positive cattle and the assessment of PVL and LC, subsequent semiannual tests to assess disease progression may not be needed. Further work is needed to determine how available diagnostic tests can be optimized to design cost-effective testing schemes for BLV control programs.
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Autio T, Tuunainen E, Nauholz H, Pirkkalainen H, London L, Pelkonen S. Overview of Control Programs for Non-eu-regulated Cattle Diseases in Finland. Front Vet Sci 2021; 8:688936. [PMID: 34395573 PMCID: PMC8361753 DOI: 10.3389/fvets.2021.688936] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 06/16/2021] [Indexed: 11/23/2022] Open
Abstract
Animal disease control has a long tradition in Finland. The country is free of all EU-regulated cattle diseases of categories A and B. Infectious bovine rhinotracheitis, enzootic bovine leucosis, bovine viral diarrhea, bluetongue, bovine genital campylobacteriosis, and trichomoniasis do not currently exist in the country. The prevalence of paratuberculosis, Mycoplasma bovis, salmonella infection, and Q-fever is low. The geographic location, cold climate, low cattle density, and limited animal imports have contributed to the favorable disease situation. Besides screening for selected regulated diseases, the national disease-monitoring program includes periodic active monitoring of non-regulated diseases, which allows assessment of the need for new control measures. The detection of diseases through efficient passive surveillance also plays an important part in disease monitoring. The Finnish cattle population totals 850,000 animals kept on 9,300 cattle farms, with 62,000 suckler cows in 2,100 herds and 260,000 dairy cows in 6,300 herds. Animal Health ETT, an association owned by the dairy and meat industry, keeps a centralized cattle health care register. Animal Health ETT supervises cattle imports and trade within the country and runs voluntary control programs (CP) for selected diseases. Active cooperation between authorities, the cattle industry, Animal Health ETT, and herd health experts enables the efficient planning and implementation of CPs. CPs have been implemented for cattle diseases such as salmonella, Mycoplasma bovis, ringworm, and Streptococcus agalactiae. The CP for salmonellosis is compulsory and includes all Salmonella serotypes and all cattle types. It has achieved the goal of keeping the salmonella prevalence under 1% of cattle herds. CPs for M. bovis, ringworm, and S. agalactiae are on a voluntary basis and privately funded. The CP for Mycoplasma was designed in collaboration with national experts and has been implemented since 2013. The CP includes observation of clinical signs, nasal swab sampling from calves, and bulk tank milk and clinical mastitis samples for M. bovis. M. bovis-negative herds gradually achieve lower status levels for M. bovis infection. The general challenge facing voluntary CPs is getting farms to join the programs.
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Affiliation(s)
- Tiina Autio
- Finnish Food Authority, Veterinary Bacteriology and Pathology Unit, Kuopio, Finland
| | | | | | | | - Laura London
- Finnish Food Authority, Virology Unit, Helsinki, Finland
| | - Sinikka Pelkonen
- Finnish Food Authority, Veterinary Bacteriology and Pathology Unit, Kuopio, Finland
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Sakhawat A, Rola-Łuszczak M, Osiński Z, Bibi N, Kuźmak J. Bayesian Estimation of the True Seroprevalence and Risk Factor Analysis of Bovine Leukemia Virus Infection in Pakistan. Animals (Basel) 2021; 11:ani11051404. [PMID: 34069156 PMCID: PMC8156210 DOI: 10.3390/ani11051404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 05/07/2021] [Accepted: 05/07/2021] [Indexed: 12/03/2022] Open
Abstract
Simple Summary The enzootic bovine leucosis is the most common and economically important viral disease of cattle, caused by bovine leukemia virus (BLV). In cattle, infection with BLV leads to decreased milk production and premature culling and also impairs the immune system predisposing animals to other infections and increasing severity of disease. The aim of this study was to estimate the true seropositivity to BLV at the farm and within-farm levels in Pakistan, using a latent class analysis. In addition, some factors influencing BLV seropositivity were analyzed. We tested 1380 dairy cattle from 451 herds and 92 water buffalo. Analysis at the within-herd and herd levels showed 3.8% of cattle and 1.4% of herds were truly seropositive. All 92 serum samples from water buffalo were negative. The study demonstrated strong association between BLV seroprevalence and herd size but not with common housing of cattle representing indigenous breeds with exotic breed or their crossbred and also common housing of cattle and water buffalo. Abstract The objective of this study was to determine the true seroprevalence of bovine leukemia virus (BLV) infection in dairy cattle from Pakistan at the animal and herd-level. We tested 1380 dairy cattle from 451 herds and 92 water buffalo. The sera were tested by ELISA and the results were analyzed using Bayesian inference. The median posterior estimate of the herd level true BLV prevalence was 1.4%, with a 95% credible interval (CI) 0.7–3.1, whereas the median posterior estimate of the within-farm true seroprevalence was 3.8% with a 95% CI 2.8–4.8. All 92 sera collected from water buffalo were negative. Several risk factors potentially associated with seropositivity to BLV infections in Pakistan were analyzed using logistic regression model based on calculation of an odds ratio (OR). The study showed an association between seropositivity and medium herd (≥50) size (OR = 23.57, 95% CI: 3.01–103.48). Common housing of indigenous cattle with exotic-breed cattle (OR = 0.67, 95% CI: 06–2.35) or housing indigenous or their crossbred cattle with exotic-breed cattle (OR = 0.95, 95% CI: 0.14–3.01) had no effect on the BLV seroprevalence. Similarly, common housing of cattle and water buffalo was not risk factor for increased BLV seropositivity (OR = 27.10, 95% CI: 0.63–119.34).
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Affiliation(s)
- Ali Sakhawat
- National Veterinary Laboratories, Islamabad 45500, Pakistan;
- Animal Quarantine Department, Ministry of National Food Security and Research, Peshawar 25000, Pakistan
- Department of Bio Sciences, COMSATS University, Islamabad 45500, Pakistan;
| | - Marzena Rola-Łuszczak
- National Veterinary Research Institute, 24-100 Puławy, Poland; (Z.O.); (J.K.)
- Correspondence:
| | - Zbigniew Osiński
- National Veterinary Research Institute, 24-100 Puławy, Poland; (Z.O.); (J.K.)
| | - Nazia Bibi
- Department of Bio Sciences, COMSATS University, Islamabad 45500, Pakistan;
| | - Jacek Kuźmak
- National Veterinary Research Institute, 24-100 Puławy, Poland; (Z.O.); (J.K.)
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Kuczewski A, Orsel K, Barkema HW, Mason S, Erskine R, van der Meer F. Invited review: Bovine leukemia virus-Transmission, control, and eradication. J Dairy Sci 2021; 104:6358-6375. [PMID: 33741150 DOI: 10.3168/jds.2020-18925] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 11/21/2020] [Indexed: 11/19/2022]
Abstract
Bovine leukemia virus (BLV) infection, endemic in North American dairy herds, has production-limiting effects. A literature review of available papers published since 1995 concerning BLV transmission and its control was conducted. Although confirmed transmission routes were reviewed (blood, natural breeding, in utero, colostrum, and milk), there is still a lack of detailed information on other specific risks for transmission (e.g., contact transmission and hoof-trimming knives). Eradication of BLV has been achieved by combined management, segregation, and culling approaches. In contrast, although sole implementation of best management practices aimed at prevention of BLV transmission has decreased within-herd BLV prevalence, it has not eradicated BLV from a herd. Therefore, control and eradication of BLV by best management practices only should be further investigated. Additionally, the role of proviral load in infected cattle was investigated. Cattle with a high proviral load seem to be more likely to infect others, whereas those with a very low proviral load seem to have low risks of transmitting BLV. Information on proviral load could be taken into account when controlling BLV in high-prevalence herds. In conclusion, there is a need for detailed, large-scale studies investigating roles of specific transmission routes, knowing proviral load of infected individuals.
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Affiliation(s)
- Alessa Kuczewski
- Department of Ecosystem and Public Health, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Karin Orsel
- Department of Production Animal Health, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Herman W Barkema
- Department of Production Animal Health, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Steve Mason
- Agromedia International Inc., Calgary, AB T2L 0T6, Canada
| | - Ron Erskine
- Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing 48824
| | - Frank van der Meer
- Department of Ecosystem and Public Health, University of Calgary, Calgary, AB T2N 4Z6, Canada.
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Korniienko LY, Pyskun AV, Tsarenko TM, Ukhovskyi VV, Kyivska GV, Moroz OA, Kovalenko VL, Aliekseieva GB. Retrospective analysis of the epizootic situation of enzootic bovine leukosis in Ukraine in 1994–2019. REGULATORY MECHANISMS IN BIOSYSTEMS 2020. [DOI: 10.15421/022057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
In Ukraine, prevention and control measures of bovine leukosis were regulated by relevant legislation, regulations and instructions developed in the period 1960–1992. Currently, the instruction on prevention and rehabilitation of this disease in cattle is used (approved in 2007). According to it, the identification of infected animals is carried out from 6 months of age by serological (first scheme in AGID or another in ELISA) and genomic (PCR) methods. The infected animals are removed from the herd or slaughtered. In general, because of the diagnostic and preventive measures carried out during the analyzed period (26 years) 10 519 farms were rehabilitated from leukosis (2 346 affected farms remained from previous years). At the same time, more 4 million infected cattle were slaughtered. The majority of affected farms (more than 1 000) were registered in the period between 1994 (2 346 farms) and 2003 (1 247 farms). Since 2014, the number of affected farms has remained mostly below 10 and the number of infected cattle has decreased to 2 000 animals per year. At the same time, the number of rehabilitated farms also decreased (from 1 307 farms in 1998 to 4 farms in 2014). The same trend was registered with the dynamics of the number of animals that were removed from the herd due to leukosis. Thus, in 1995 and 1997 their numbers were 321 178 and 558 649 animals, respectively, and in 2014 it was 1 124. The obtained indicators of intensity and extensiveness of the epizootic process show that the incidence rate was maximal during 1998–2000 and amounted to 3.7–4.3%. The maximum indicators of the coefficient of affection were recorded in 1997–2000 and equal 11.8–15.3%. The rate of foci remained on the level of 90–270 throughout the all analyzed period. During 2008–2019, specialists of the Ukrainian veterinary laboratories investigated more than 47 million samples of cattle blood sera for enzootic bovine leukosis by AGID and ELISA. However, despite the significant diagnostic work, the important factor in the decrease of the number of affected farms and infected animals is the decrease in the total number of cattle in Ukraine (almost 22 million animals in 1994 against 3 million in 2019). Graphic trends of these indicators are comparable and agree with the decrease in the number of cattle in our country by analyzed period. After 2014, the number of affected farms ranged 10–17 per year (mostly in private households). However, the full recovery of cattle in Ukraine from bovine leukosis has not taken place, although our country is closer than ever to this.
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Saa LR, Guzmán LT, Fierro NC, Castro LM, Reyes-Bueno F, Carbonero A. Seroprevalence and risk factors associated with bovine leukemia virus (BLV) seropositivity in cattle herds from Ecuador. REV COLOMB CIENC PEC 2020. [DOI: 10.17533/udea.rccp.v34n3a01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Background: Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis (EBL). This disease mainly affects cattle, causing severe economic losses to producers. Objective: To establish individual and herd seroprevalence and determine the risk factors associated with BLV seropositivity for dairy and dual-purpose cattle herds in Ecuador. Methods: A total of 2,668 serum samples from 386 herds were collected. A questionnaire, including variables related to cattle health, management and the environment was completed by each herd. A commercial blocking enzyme-linked immunosorbent assay (ELISA) test was used to determine seropositivity. A generalized estimating equation model (GEE) was developed to determine the factors associated with BLV seropositivity. Results: Individual seroprevalence of BLV infection in Ecuador was 17.3% (CI95% = 15.86-18.74%). Herd prevalence was 37.8% (CI95% = 33.0-42.6%), and intra-herd prevalence ranged between 12.5 and 100% (median: 37.5%). The risk factors associated with BLV seropositivity were artificial insemination (OR: 2,215; CI95% = 1.402-3.501), concrete floors (OR: 2.178; CI95% = 1.217-3.889), presence of wild ruminants (OR: 2.998; CI95% = 1.788-5.027), and sampling season (wet; OR: 1.996; CI95% = 1.140-3.497). Conclusions: Results indicate that BLV is widespread in cattle herds in Ecuador. In addition, the study suggests that a control program to fight BLV infection should focus on controlling the risk factors identified.
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Ishikawa H, Rahman MM, Yamauchi M, Takashima S, Wakihara Y, Kamatari YO, Shimizu K, Okada A, Inoshima Y. mRNA Profile in Milk Extracellular Vesicles from Bovine Leukemia Virus-Infected Cattle. Viruses 2020; 12:v12060669. [PMID: 32575783 PMCID: PMC7354454 DOI: 10.3390/v12060669] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/18/2020] [Accepted: 06/19/2020] [Indexed: 02/08/2023] Open
Abstract
Milk extracellular vesicles (EVs) form an excellent source of mRNAs, microRNAs (miRNAs), proteins, and lipids that represent the physiological and pathological status of the host. Recent studies have reported milk EVs as novel biomarkers for many infectious diseases in both humans and animals. For example, miRNAs in milk EVs from cattle were used for early detection of bacterial infection in the mammary gland. Based on these findings, we hypothesized that mRNAs in milk EVs are suitable for gaining a better understanding of the pathogenesis of bovine leukemia virus (BLV) infection and prognosis of the clinical stage in cattle. For that purpose, milk EVs were isolated from BLV-infected and uninfected cattle, and mRNAs were investigated using microarray analysis. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed mainly focusing on the differentially expressed genes (DEGs) in milk EVs from BLV-infected cattle. GO and KEGG analyses suggested the DEGs in milk EVs from BLV-infected cattle had involved in diverse molecular functions, biological processes, and distinct disease-related pathways. The present study suggested that BLV infection causes profound effects on host cellular activity, changing the mRNA expression profile in milk EVs obtained from BLV-infected cattle. Overall, our results suggested that the mRNA profile in milk EVs to be a key factor for monitoring the clinical stage of BLV infection. This is the first report of mRNA profiling of milk EVs obtained from BLV-infected cattle.
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Affiliation(s)
- Hinata Ishikawa
- Laboratory of Food and Environmental Hygiene, Cooperative Department of Veterinary Medicine, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan; (H.I.); (M.M.R.); (M.Y.); (K.S.); (A.O.)
| | - Md. Matiur Rahman
- Laboratory of Food and Environmental Hygiene, Cooperative Department of Veterinary Medicine, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan; (H.I.); (M.M.R.); (M.Y.); (K.S.); (A.O.)
- The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
- Department of Medicine, Faculty of Veterinary, Animal and Biomedical Sciences, Sylhet Agricultural University, Sylhet 3100, Bangladesh
| | - Marika Yamauchi
- Laboratory of Food and Environmental Hygiene, Cooperative Department of Veterinary Medicine, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan; (H.I.); (M.M.R.); (M.Y.); (K.S.); (A.O.)
| | - Shigeo Takashima
- Division of Genomics Research, Life Science Research Center, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan; (S.T.); (Y.W.)
| | - Yoshiko Wakihara
- Division of Genomics Research, Life Science Research Center, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan; (S.T.); (Y.W.)
| | - Yuji O. Kamatari
- Division of Instrumental Analysis, Life Science Research Center, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan;
| | - Kaori Shimizu
- Laboratory of Food and Environmental Hygiene, Cooperative Department of Veterinary Medicine, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan; (H.I.); (M.M.R.); (M.Y.); (K.S.); (A.O.)
| | - Ayaka Okada
- Laboratory of Food and Environmental Hygiene, Cooperative Department of Veterinary Medicine, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan; (H.I.); (M.M.R.); (M.Y.); (K.S.); (A.O.)
- Education and Research Center for Food Animal Health, Gifu University (GeFAH), 1-1 Yanagido, Gifu 501-1193, Japan
| | - Yasuo Inoshima
- Laboratory of Food and Environmental Hygiene, Cooperative Department of Veterinary Medicine, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan; (H.I.); (M.M.R.); (M.Y.); (K.S.); (A.O.)
- The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
- Education and Research Center for Food Animal Health, Gifu University (GeFAH), 1-1 Yanagido, Gifu 501-1193, Japan
- Joint Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
- Correspondence:
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22
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LE DT, Yamashita-Kawanishi N, Okamoto M, Nguyen SV, Nguyen NH, Sugiura K, Miura T, Haga T. Detection and genotyping of bovine leukemia virus (BLV) in Vietnamese cattle. J Vet Med Sci 2020; 82:1042-1050. [PMID: 32475959 PMCID: PMC7399327 DOI: 10.1292/jvms.20-0094] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Bovine leukemia virus (BLV) belongs to the genus, Deltaretrovirus of the family, Retroviridae and it is the causative agent of enzootic bovine leukosis. The prevalence of BLV in three provinces in the Red River Delta Region in the North of Vietnam, Hanoi, Vinhphuc and Bacninh was studied from April 2017 to June 2018. A total of 275 blood samples collected from cattle were used for serum isolation and DNA extraction. Of these samples, 266 sera were subjected to ELISA test for detecting antibody against BLV gp51 protein and 152 DNA samples were used to detect the 444 bp fragment corresponding to a part of the gp51 region of the env by nested PCR. The results showed that 16.5% (n=44) and 21.1% (n=32) of samples were positive for BLV gp51 antibody and BLV proviral DNA, respectively. Phylogenetic analysis of the partial (423 bp) and complete (913 bp) BLV env-gp51 gene indicated that Vietnamese strains were clustered into genotypes 1, 6 and 10 (G1, G6 and G10). Of those genotypes, G1 genotype was dominant; G6 strains were designated as G6e and G6f subgenotypes; the existence of genotype 10 was confirmed for the first time in Vietnam. The present study provides important information regarding the prevalence of BLV infection and genetic characteristics of BLV strains identified in Vietnam, contributing to promote the establishment of disease control and eradication strategies in Vietnam.
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Affiliation(s)
- Dung Thi LE
- Division of Infection Control and Disease Prevention, Department of Veterinary Medical Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Nanako Yamashita-Kawanishi
- Division of Infection Control and Disease Prevention, Department of Veterinary Medical Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Mari Okamoto
- Division of Infection Control and Disease Prevention, Department of Veterinary Medical Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Son Vu Nguyen
- Department of Veterinary Pathology, Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi100000, Vietnam
| | - Nam Huu Nguyen
- Department of Veterinary Pathology, Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi100000, Vietnam
| | - Katsuaki Sugiura
- Department of Global Agricultural Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Tomoyuki Miura
- Research Center for Infectious Diseases, Institute for Frontier Life and Medical Science, Kyoto University, 53 Shogoin kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Takeshi Haga
- Division of Infection Control and Disease Prevention, Department of Veterinary Medical Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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Serological evidence of enzootic bovine leukosis in the periurban dairy cattle production system of Al Ain, United Arab Emirates. Trop Anim Health Prod 2020; 52:2327-2332. [PMID: 32157519 DOI: 10.1007/s11250-020-02262-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 03/03/2020] [Indexed: 12/21/2022]
Abstract
The serostatus of enzootic bovine leukosis (EBL) was determined at three dairy farms and the Al Ain Livestock Market (AALM), within the Al Ain region of Abu Dhabi, UAE. Of the 957 bovine sera tested by ELISA, 657 were from Holstein-Friesians from three dairy farms, and 300 from Bos indicus cattle at AALM. The chi-square homogeneity test (CSHT) and the Marascuilo multiple comparison procedure (MMCP) assessed the level of significance between the proportions of EBL-seropositive cattle (ESPC) across the study farms and AALM, and between the age groups at farms 1 and 3. Overall, the proportion of ESPC was 25.7% at dairy farms and AALM, 37.0% for farms and 1.0% for AALM. Furthermore, the proportions of ESPC at farms 1, 2 and 3 were 54.7%, 0.0% and 26.3% respectively, and statistically significant differences were seen across the farm/farm and farm/AALM comparisons, and between two age groups at farms 1 and 3. The 37-72-month-old age group showed the highest proportion of ESPC. This is the first serological evidence of EBL in the UAE. As previously reported, the ESPC are comparatively higher in dairy than Bos indicus cattle. Molecular and more extensive serological studies are needed to further corroborate the present data. Meanwhile, the UAE veterinary authorities will need to formulate national EBL control policies.
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Ruggiero VJ, Norby B, Benitez OJ, Hutchinson H, Sporer KRB, Droscha C, Swenson CL, Bartlett PC. Controlling bovine leukemia virus in dairy herds by identifying and removing cows with the highest proviral load and lymphocyte counts. J Dairy Sci 2019; 102:9165-9175. [PMID: 31378496 DOI: 10.3168/jds.2018-16186] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 06/05/2019] [Indexed: 01/30/2023]
Abstract
The objective of this field trial was to reduce bovine leukemia virus (BLV) transmission and prevalence in commercial dairy herds using proviral load (PVL) and lymphocyte count (LC) measurements as indicators of the most infectious animals for culling or segregation. Bovine leukemia virus causes lymphoma in <5% of infected cattle, and increased lymphocyte counts (lymphocytosis) in about one-third. Recent research has shown that dairy cows infected with BLV have altered immune function associated with decreases in milk production and lifespan. Recent findings show that a minority of infected cattle have PVL concentrations in blood and other body fluids of over 1,000 times that of other infected cattle. In combination with a high LC, these animals are thought to be responsible for most transmission of BLV in a herd. Milk or blood samples from adult cows in our 3 Midwestern dairy farm field trials were tested semiannually with ELISA for BLV antibodies, and ELISA-positive cattle were then retested using a blood LC and a quantitative PCR test for PVL to identify the animals presumed to be most infectious. Herd managers were encouraged to consider PVL and LC status when making cull decisions, and to segregate cows with the highest PVL and LC from their BLV ELISA-negative herd mates where possible. After 2 to 2.5 yr of this intervention, the incidence risk of new infections decreased in all 3 herds combined, from 13.8 to 2.2, and the overall herd prevalence decreased in all 3 herds combined from 62.0 to 20.7%, suggesting that this approach can efficiently reduce BLV transmission as well as prevalence. This is encouraging, because a very low prevalence of BLV infection would make it economically feasible to cull the remaining ELISA-positive cattle, as was achieved in national eradication programs in other countries decades ago.
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Affiliation(s)
- V J Ruggiero
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing 48824.
| | - B Norby
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing 48824
| | - O J Benitez
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing 48824
| | - H Hutchinson
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing 48824
| | - K R B Sporer
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing 48824; NorthStar Cooperative, Lansing, MI 48910
| | - C Droscha
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing 48824; NorthStar Cooperative, Lansing, MI 48910
| | - C L Swenson
- Department of Pathobiology and Diagnostic Investigation and Veterinary Diagnostic Laboratory, Michigan State University, East Lansing 48824
| | - P C Bartlett
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing 48824
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25
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Khalilian M, Hosseini SM, Madadgar O. Bovine leukemia virus detected in the breast tissue and blood of Iranian women. Microb Pathog 2019; 135:103566. [PMID: 31252065 DOI: 10.1016/j.micpath.2019.103566] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 05/30/2019] [Accepted: 05/31/2019] [Indexed: 11/19/2022]
Abstract
BACKGROUND Breast cancer is one of the most common cancers in the world particularly among Iranian women. Bovine leukemia virus (BLV) is an enzootic, exogenous, and oncogenic retrovirus that causes B-cell leukosis in 1-5% of infected cattle. The current study aimed at evaluating the correlation between BLV infection and breast cancer in an Iranian population. MATERIALS AND TECHNIQUES A total of 400 samples including 200 breast cancer-suspected tissue samples and 200 blood samples of women without breast cancer, were collected from July 2017 to October 2018 from women referred to two general hospitals in Qom Province, Iran. The nested PCR technique was performed to determine the presence of tax and gag gene of BLV in the collected samples. RESULTS Out of 200 breast cancer-suspected tissue samples, 172 samples were malignant in terms of pathology. Other samples were reported as non-malignant and non-tumor. Based on nested PCR technique, tax and gag genes of BLV were detected in 30% and 8% of breast cancer-suspected tissue samples, respectively. The frequency of BLV in blood samples collected from women without breast cancer was 16.5% (33/200). CONCLUSION It seems that human breast cancer and BLV infection in cattle could be associated using nested PCR technique.
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Affiliation(s)
- Mohaddeseh Khalilian
- Department of Microbiology and Microbial Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, Iran
| | - Seyed Masoud Hosseini
- Department of Microbiology and Microbial Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, Iran.
| | - Omid Madadgar
- Department of Microbiology, Faculty of Veterinary Medicine, University of Tehran, Iran; Department of Microbiology & Molecular Genetics, Michigan State University, East Lansing, MI, USA
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26
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Blazhko NV, Vyshegurov SK, Donchenko AS, Shatokhin KS, Krytsyna TI, Ryabinina VA. Association of haplotypes for SNPs in the LTR regions of bovine leukemia virus with hematological indices of cattle. Vavilovskii Zhurnal Genet Selektsii 2019. [DOI: 10.18699/vj19.491] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Molecular typing of BLV samples isolated from Holsteinized Russian Black Pied cattle was carried out, and various cytofluorometric and morphological blood indices were examined. We performed the total count of white blood cells (WBC), lymphocyte (lymf), granulocyte (gran), monocyte (mon), red blood cell (RBC), hemoglobin (HGB), hematocrit (HTC), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), red blood cell distribution width (RDW), platelet count (PLT), mean platelet volume (MPV), platelet distribution width (PDW), and platelet crit count (PCT). The LTR-region of BLV was haplotyped. Only viruses of haplotypes I (0.33±0.03) and III (0.67±0.03) of the eight possible were detected. The ratio of hematologically sick, healthy, and suspected carriers of BLV of haplotypes I and II was comparable with the results of other researchers. The numbers of leukocytes, erythrocytes and platelets in the blood of carriers of haplotype III exceeded the corresponding parameters of cattle affected by the virus of haplotype I. It is interesting to note that the difference in the hemolytic status of animals was manifested not only by the concentration of leukocytes as direct immune agents but also by the count of erythrocytes and platelets, which are not directly involved in the immune response. The number of particles of haplotype III of the BLV circulating in the blood of infected individuals exceeded that of the carriers of haplotype I. In this connection, an assumption was made about the evolutionary advantage of the more virulent haplotype III. However, the results of our own research in conjunction with the data of other scientists indicate that the high virulence of individual virus strains is a consequence of the tendency to implement the maximum possible intensity of the synthesis of virus particles but not of the high damaging effect alone. It is shown that high lethality is evolutionarily disadvantageous for viruses, since the extinction of the carrier as a biological species is fraught with the disappearance of the virus itself.
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Affiliation(s)
| | | | - A. S. Donchenko
- Novosibirsk State Agrarian University; Siberian Federal Research Centre for AgroBiotechnology, RAS
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27
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Porta NG, Alvarez I, Suarez Archilla G, Ruiz V, Abdala A, Trono K. Experimental infection of sheep with Bovine leukemia virus (BLV): Minimum dose of BLV-FLK cells and cell-free BLV and neutralization activity of natural antibodies. Rev Argent Microbiol 2019; 51:316-323. [PMID: 31023494 DOI: 10.1016/j.ram.2019.01.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 12/21/2018] [Accepted: 01/08/2019] [Indexed: 10/27/2022] Open
Abstract
Bovine leukemia virus (BLV) is an important cattle pathogen that causes major economic losses worldwide, especially in dairy farms. The use of animal models provides valuable insight into the pathogenesis of viral infections. Experimental infections of sheep have been conducted using blood from BLV-infected cattle, infectious BLV molecular clones or tumor-derived cells. The Fetal Lamb Kidney cell line, persistently infected with BLV (FLK-BLV), is one of the most commonly used long-term culture available for the permanent production of virus. FLK-BLV cells or the viral particles obtained from the cell-free culture supernatant could be used as a source of provirus or virus to experimentally infect sheep. In this report, we aimed to determine the minimum amount of FLK-BLV cells or cell-free supernatant containing BLV needed to produce infection in sheep. We also evaluated the amount of antibodies obtained from a naturally-infected cow required to neutralize this infection. We observed that both sheep experimentally inoculated with 5000 FLK-BLV cells became infected, as well as one of the sheep receiving 500 FLK-BLV cells. None of the animals inoculated with 50 FLK-BLV cells showed evidence of infection. The cell-free FLK-BLV supernatant proved to be infective in sheep up to a 1:1000 dilution. Specific BLV antibodies showed neutralizing activity as none of the sheep became infected. Conversely, the animals receiving a BLV-negative serum showed signs of BLV infection. These results contribute to the optimization of a sheep bioassay which could be useful to further characterize BLV infection.
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Affiliation(s)
- Natalia Gabriela Porta
- Instituto Nacional de Tecnología Agropecuaria (INTA) - Instituto de Virología, Centro de Investigaciones en Ciencias Veterinarias y Agronómicas, Nicolas Repetto y de los Reseros s/n (1686), Hurlingham, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET, Godoy Cruz 2290 (C1425FQB), CABA, Argentina
| | - Irene Alvarez
- Instituto Nacional de Tecnología Agropecuaria (INTA) - Instituto de Virología, Centro de Investigaciones en Ciencias Veterinarias y Agronómicas, Nicolas Repetto y de los Reseros s/n (1686), Hurlingham, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET, Godoy Cruz 2290 (C1425FQB), CABA, Argentina.
| | - Guillermo Suarez Archilla
- Instituto Nacional de Tecnología Agropecuaria (INTA) - Laboratorio de Sanidad Animal, Estación Experimental Agropecuaria Rafaela, Ruta 34 Km 227 (2300) Rafaela, Santa Fe, Argentina
| | - Vanesa Ruiz
- Instituto Nacional de Tecnología Agropecuaria (INTA) - Instituto de Virología, Centro de Investigaciones en Ciencias Veterinarias y Agronómicas, Nicolas Repetto y de los Reseros s/n (1686), Hurlingham, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET, Godoy Cruz 2290 (C1425FQB), CABA, Argentina
| | - Alejandro Abdala
- Instituto Nacional de Tecnología Agropecuaria (INTA) - Laboratorio de Sanidad Animal, Estación Experimental Agropecuaria Rafaela, Ruta 34 Km 227 (2300) Rafaela, Santa Fe, Argentina
| | - Karina Trono
- Instituto Nacional de Tecnología Agropecuaria (INTA) - Instituto de Virología, Centro de Investigaciones en Ciencias Veterinarias y Agronómicas, Nicolas Repetto y de los Reseros s/n (1686), Hurlingham, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET, Godoy Cruz 2290 (C1425FQB), CABA, Argentina
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28
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Nagao K, Makino R, Apego FV, Mekata H, Yamazaki W. Development of a fluorescent loop-mediated isothermal amplification assay for rapid and simple diagnosis of bovine leukemia virus infection. J Vet Med Sci 2019; 81:787-792. [PMID: 30918136 PMCID: PMC6541838 DOI: 10.1292/jvms.19-0009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Bovine leukemia virus (BLV) causes enzootic bovine leukosis (EBL), a condition that threatens the sustainability of the livestock industry. A fluorescent loop-mediated isothermal
amplification (fLAMP) assay targeting BLV env sequences was developed and used to evaluate 100 bovine blood samples. Compared with a conventional real-time PCR (rPCR) assay,
the fLAMP assay achieved 87.3% (62/71) sensitivity and 100% (29/29) specificity. The rPCR assay took 65 min, while the fLAMP assay took 8 min to 30 min from the beginning of DNA
amplification to final judgement with a comparable limit of detection. The fLAMP is a potential tool for the rapid and simple diagnosis of BLV infection to supplement ELISA testing and can
be used by local laboratories and slaughterhouses without special equipment.
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Affiliation(s)
- Konomu Nagao
- Department of Veterinary Science, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuen Kibanadai-nishi, Miyazaki, Miyazaki 889-2192, Japan
| | - Ryohei Makino
- Department of Veterinary Science, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuen Kibanadai-nishi, Miyazaki, Miyazaki 889-2192, Japan
| | - Francis Victor Apego
- Department of Veterinary Science, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuen Kibanadai-nishi, Miyazaki, Miyazaki 889-2192, Japan
| | - Hirohisa Mekata
- Center for Animal Disease Control, University of Miyazaki, 1-1 Gakuen Kibanadai-nishi, Miyazaki, Miyazaki 889-2192, Japan.,Organization for Promotion of Tenure Track, University of Miyazaki, 1-1 Gakuen Kibanadai-nishi, Miyazaki, Miyazaki 889-2192, Japan
| | - Wataru Yamazaki
- Department of Veterinary Science, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuen Kibanadai-nishi, Miyazaki, Miyazaki 889-2192, Japan.,Center for Animal Disease Control, University of Miyazaki, 1-1 Gakuen Kibanadai-nishi, Miyazaki, Miyazaki 889-2192, Japan
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29
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Nakada S, Kohara J, Makita K. Estimation of circulating bovine leukemia virus levels using conventional blood cell counts. J Dairy Sci 2018; 101:11229-11236. [DOI: 10.3168/jds.2018-14609] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Accepted: 08/16/2018] [Indexed: 11/19/2022]
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30
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Ruiz V, Porta NG, Lomónaco M, Trono K, Alvarez I. Bovine Leukemia Virus Infection in Neonatal Calves. Risk Factors and Control Measures. Front Vet Sci 2018; 5:267. [PMID: 30410920 PMCID: PMC6209627 DOI: 10.3389/fvets.2018.00267] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 10/05/2018] [Indexed: 11/13/2022] Open
Abstract
Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis (EBL). Although efficient eradication programs have been successfully implemented in most European countries and Oceania, BLV infection rates are still high worldwide. BLV naturally infects cattle, inducing a persistent infection with diverse clinical outcomes. The virus infects lymphocytes and integrates a DNA intermediate as a provirus into the genome of the cells. Therefore, exposure to biological fluids contaminated with infected lymphocytes potentially spreads the virus. Vertical transmission may occur in utero or during delivery, and about 10% of calves born to BLV-infected dams are already infected at birth. Most frequently, transmission from dams to their offspring occurs through the ingestion of infected colostrum or milk. Therefore, although EBL is not a disease specific to the neonatal period, during this period the calves are at special risk of becoming infected, especially in dairy farms, where they ingest colostrum and/or raw milk either naturally or artificially. Calves infected during the first week of life could play an active role in early propagation of BLV to susceptible animals. This review discusses the main factors that contribute to neonatal BLV infection in dairy herds, as well as different approaches and management practices that could be implemented to reduce the risk of BLV transmission during this period, aiming to decrease BLV infection in dairy herds.
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Affiliation(s)
- Vanesa Ruiz
- Instituto Nacional de Tecnología Agropecuaria-Instituto de Virología, Centro de Investigaciones en Ciencias Veterinarias y Agronómicas, Buenos Aires, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Natalia Gabriela Porta
- Instituto Nacional de Tecnología Agropecuaria-Instituto de Virología, Centro de Investigaciones en Ciencias Veterinarias y Agronómicas, Buenos Aires, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Marina Lomónaco
- Instituto Nacional de Tecnología Agropecuaria-Instituto de Virología, Centro de Investigaciones en Ciencias Veterinarias y Agronómicas, Buenos Aires, Argentina
| | - Karina Trono
- Instituto Nacional de Tecnología Agropecuaria-Instituto de Virología, Centro de Investigaciones en Ciencias Veterinarias y Agronómicas, Buenos Aires, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Irene Alvarez
- Instituto Nacional de Tecnología Agropecuaria-Instituto de Virología, Centro de Investigaciones en Ciencias Veterinarias y Agronómicas, Buenos Aires, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
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31
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Polat M, Takeshima SN, Aida Y. Epidemiology and genetic diversity of bovine leukemia virus. Virol J 2017; 14:209. [PMID: 29096657 PMCID: PMC5669023 DOI: 10.1186/s12985-017-0876-4] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 10/24/2017] [Indexed: 11/10/2022] Open
Abstract
Bovine leukemia virus (BLV), an oncogenic member of the Deltaretrovirus genus, is closely related to human T-cell leukemia virus (HTLV-I and II). BLV infects cattle worldwide and causes important economic losses. In this review, we provide a summary of available information about commonly used diagnostic approaches for the detection of BLV infection, including both serological and viral genome-based methods. We also outline genotyping methods used for the phylogenetic analysis of BLV, including PCR restriction length polymorphism and modern DNA sequencing-based methods. In addition, detailed epidemiological information on the prevalence of BLV in cattle worldwide is presented. Finally, we summarize the various BLV genotypes identified by the phylogenetic analyses of the whole genome and env gp51 sequences of BLV strains in different countries and discuss the distribution of BLV genotypes worldwide.
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Affiliation(s)
- Meripet Polat
- Viral Infectious Diseases Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 Japan
- Nano Medical Engineering Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 Japan
| | - Shin-nosuke Takeshima
- Viral Infectious Diseases Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 Japan
- Nano Medical Engineering Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 Japan
- Bovine Leukemia Virus Vaccine Laboratory RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 Japan
| | - Yoko Aida
- Viral Infectious Diseases Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 Japan
- Nano Medical Engineering Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 Japan
- Bovine Leukemia Virus Vaccine Laboratory RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 Japan
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Abstract
Bovine leukaemia virus (BLV) is the causative agent of enzootic bovine leucosis, which has been reported worldwide. BLV has been found recently in human tissue and it could have a significant impact on human health. A possible hypothesis regarding viral entry to humans is through the consumption of infected foodstuffs. This study was aimed at detecting the presence of BLV DNA in raw beef and fresh milk for human consumption. Nested PCR directed at the BLV gag gene (272 bp) was used as a diagnostic test. PCR products were confirmed by Sanger sequencing. Forty-nine per cent of the samples proved positive for the presence of proviral DNA. This is the first study highlighting the presence of the BLV gag gene in meat products for human consumption and confirms the presence of the viral DNA in raw milk, as in previous reports. The presence of viral DNA in food products could suggest that viral particles may also be found. Further studies are needed to confirm the presence of infected viral particles, even though the present findings could represent a first approach to BLV transmission to humans through foodstuff consumption.
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Identification of an Atypical Enzootic Bovine Leukosis in Japan by Using a Novel Classification of Bovine Leukemia Based on Immunophenotypic Analysis. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2017; 24:CVI.00067-17. [PMID: 28659325 DOI: 10.1128/cvi.00067-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 06/19/2017] [Indexed: 11/20/2022]
Abstract
Bovine leukemia is classified into two types: enzootic bovine leukosis (EBL) and sporadic bovine leukosis (SBL). EBL is caused by infection with bovine leukemia virus (BLV), which induces persistent lymphocytosis and B-cell lymphoma in cattle after a long latent period. Although it has been demonstrated that BLV-associated lymphoma occurs predominantly in adult cattle of >3 to 5 years, suspicious cases of EBL onset in juvenile cattle were recently reported in Japan. To investigate the current status of bovine leukemia in Japan, we performed immunophenotypic analysis of samples from 50 cattle that were clinically diagnosed as having bovine leukemia. We classified the samples into five groups on the basis of the analysis and found two different types of EBL: classic EBL (cEBL), which has the familiar phenotype commonly known as EBL, and polyclonal EBL (pEBL), which exhibited neoplastic proliferation of polyclonal B cells. Moreover, there were several atypical EBL cases even in cEBL, including an early onset of EBL in juvenile cattle. A comparison of the cell marker expressions among cEBL, pEBL, and B-cell-type SBL (B-SBL) revealed characteristic patterns in B-cell leukemia, and these patterns could be clearly differentiated from those of healthy phenotypes, whereas it was difficult to discriminate between cEBL, pEBL, and B-SBL only by the expression patterns of cell markers. This study identified novel characteristics of bovine leukemia that should contribute to a better understanding of the mechanism underlying tumor development in BLV infection.
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Kim EJ, Cheong KM, Joung HK, Kim BH, Song JY, Cho IS, Lee KK, Shin YK. Development and evaluation of an immunochromatographic assay using a gp51 monoclonal antibody for the detection of antibodies against the bovine leukemia virus. J Vet Sci 2017; 17:479-487. [PMID: 27030192 PMCID: PMC5204025 DOI: 10.4142/jvs.2016.17.4.479] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 01/06/2016] [Accepted: 02/22/2016] [Indexed: 11/30/2022] Open
Abstract
Infection of cattle with bovine leukemia virus (BLV) has been observed and reported worldwide, including in Korea. The onsite identification of infected cattle would help decreasing and eradicating BLV infections on farms. Here, we present a new immunochromatographic assay that employs monoclonal antibodies (MAbs) for the detection of antibodies against BLV in the field. BLV envelope glycoprotein (gp)51 was expressed in E. coli, and MAbs against recombinant BLV gp51 were generated for the development of an immunochromatographic assay to detect BLV antibodies in cattle. The sensitivity and specificity of the assay were determined by comparing these results with those obtained from a standard enzyme linked immunosorbent assay (ELISA). A total of 160 bovine sera were used to evaluate the new immunochromatographic assay. Using ELISA as a reference standard, the relative specificity and sensitivity of this assay were determined to be 94.7% and 98%, respectively. Because of its high sensitivity and specificity, this BLV antibody detection assay would be suitable for the onsite identification of BLV infection in the field.
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Affiliation(s)
- Eun-Ju Kim
- Division of Viral Disease, Animal and Plant Quarantine Agency, Anyang 14086, Korea
| | - Kwang-Myun Cheong
- Research Institution, MEDIAN Diagnostics Inc., Chuncheon 24399, Korea
| | - Ha-Kyung Joung
- Division of Viral Disease, Animal and Plant Quarantine Agency, Anyang 14086, Korea
| | - Bo-Hye Kim
- Division of Viral Disease, Animal and Plant Quarantine Agency, Anyang 14086, Korea
| | - Jae-Young Song
- Division of Veterinary Drugs and Biologics, Animal and Plant Quarantine Agency, Anyang 14086, Korea
| | - In-Soo Cho
- Division of Viral Disease, Animal and Plant Quarantine Agency, Anyang 14086, Korea
| | - Kyoung-Ki Lee
- Division of Animal Disease Diagnostic, Animal and Plant Quarantine Agency, Anyang 14086, Korea
| | - Yeun-Kyung Shin
- Division of Viral Disease, Animal and Plant Quarantine Agency, Anyang 14086, Korea
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Pandey GS, Simulundu E, Mwiinga D, Samui KL, Mweene AS, Kajihara M, Mangani A, Mwenda R, Ndebe J, Konnai S, Takada A. Clinical and subclinical bovine leukemia virus infection in a dairy cattle herd in Zambia. Arch Virol 2016; 162:1051-1056. [PMID: 28025710 DOI: 10.1007/s00705-016-3205-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 12/11/2016] [Indexed: 10/20/2022]
Abstract
Bovine leukemia virus (BLV) causes enzootic bovine leucosis (EBL) and is responsible for substantial economic losses in cattle globally. However, information in Africa on the disease is limited. Here, based on clinical, hematological, pathological and molecular analyses, two clinical cases of EBL were confirmed in a dairy cattle herd in Zambia. In contrast, proviral DNA was detected by PCR in five apparently healthy cows from the same herd, suggesting subclinical BLV infection. Phylogenetic analysis of the env gene showed that the identified BLV clustered with Eurasian genotype 4 strains. This is the first report of confirmed EBL in Zambia.
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Affiliation(s)
- Girja S Pandey
- Department of Disease Control, School of Veterinary Medicine, University of Zambia, PO Box 32379, Lusaka, Zambia.
| | - Edgar Simulundu
- Department of Disease Control, School of Veterinary Medicine, University of Zambia, PO Box 32379, Lusaka, Zambia
| | - Danstan Mwiinga
- Department of Disease Control, School of Veterinary Medicine, University of Zambia, PO Box 32379, Lusaka, Zambia
| | - Kenny L Samui
- Department of Disease Control, School of Veterinary Medicine, University of Zambia, PO Box 32379, Lusaka, Zambia
| | - Aaron S Mweene
- Department of Disease Control, School of Veterinary Medicine, University of Zambia, PO Box 32379, Lusaka, Zambia
| | - Masahiro Kajihara
- Division of Global Epidemiology, Hokkaido University Research Center for Zoonosis Control, Sapporo, Japan
| | - Alfred Mangani
- Department of Paraclinical Studies, School of Veterinary Medicine, University of Zambia, PO Box 32379, Lusaka, Zambia
| | - Racheal Mwenda
- Department of Paraclinical Studies, School of Veterinary Medicine, University of Zambia, PO Box 32379, Lusaka, Zambia
| | - Joseph Ndebe
- Department of Disease Control, School of Veterinary Medicine, University of Zambia, PO Box 32379, Lusaka, Zambia
| | - Satoru Konnai
- Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Ayato Takada
- Department of Disease Control, School of Veterinary Medicine, University of Zambia, PO Box 32379, Lusaka, Zambia.,Division of Global Epidemiology, Hokkaido University Research Center for Zoonosis Control, Sapporo, Japan.,Global Institution for Collaborative Research and Education, Hokkaido University, Sapporo, Japan
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Lützelschwab CM, Forletti A, Cepeda R, Esteban EN, Confalonieri O, Gutiérrez SE. Co-infection with Mycobacterium bovis does not alter the response to bovine leukemia virus in BoLA DRB3*0902, genetically resistant cattle. Res Vet Sci 2016; 109:10-16. [PMID: 27892856 DOI: 10.1016/j.rvsc.2016.09.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 08/24/2016] [Accepted: 09/06/2016] [Indexed: 11/17/2022]
Abstract
High proviral load (HPL) profile in bovine leukemia virus infected animals poses increased risk of transmission, and development of HPL or low proviral load (LPL) profile may be attributed to host genetics. Genetic resistance and susceptibility has been mapped to the Major Histocompatibility Complex class II DRB3 gene (BoLA DRB3). The aim of this work was to determine the effect of Mycobacterium bovis infection on certain virological and host immunological parameters of BLV experimental infection. Twenty-six Argentinian Holstein calves carrying the resistance-associated marker allele BoLA DRB3*0902, susceptibility-associated marker allele BoLA DRB3*1501, or neutral BoLA DRB3 alleles, exposed to M. bovis were used. Twenty calves were inoculated with BLV, three were naturally infected and other three were BLV-negative. Seven from twenty six (27%) of the animals resulted positive to the PPD test. The proviral load, absolute leukocyte and lymphocyte counts, time to seroconversion, antibody titer against BLV, and viral antigen expression in vitro at various times post inoculation were determined and compared between PPD+ and PPD- animals. From a total of 23 BLV positive animals (naturally and experimentally infected), 13 (56.5%) developed HPL, and 10 (43.5%) developed LPL. None of the investigated parameters were affected by infection with M. bovis. We concluded that the ability of cattle carrying resistance-associated marker to control BLV and to progress towards a LPL phenotype was not altered by M. bovis co-infection.
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Affiliation(s)
- Claudia M Lützelschwab
- Laboratorio de Virología, Facultad de Ciencias Veterinarias, Centro de Investigación Veterinaria de Tandil (CIVETAN-CONICET-CIC), Universidad Nacional del Centro de la Provincia de Buenos Aires (U.N.C.P.B.A.), Pinto 399, Tandil 7000, Buenos Aires, Argentina.
| | - Agustina Forletti
- Laboratorio de Virología, Facultad de Ciencias Veterinarias, Centro de Investigación Veterinaria de Tandil (CIVETAN-CONICET-CIC), Universidad Nacional del Centro de la Provincia de Buenos Aires (U.N.C.P.B.A.), Pinto 399, Tandil 7000, Buenos Aires, Argentina.
| | - Rosana Cepeda
- Area de Bioestadística, Facultad de Ciencias Veterinarias, Instituto Multidisciplinario de Ecosistemas y Desarrollo Sustentable, Universidad Nacional del Centro de la Provincia de Buenos Aires (U.N.C.P.B.A.), Pinto 399, Tandil 7000, Buenos Aires, Argentina.
| | - Eduardo N Esteban
- Laboratorio de Virología, Facultad de Ciencias Veterinarias, Centro de Investigación Veterinaria de Tandil (CIVETAN-CONICET-CIC), Universidad Nacional del Centro de la Provincia de Buenos Aires (U.N.C.P.B.A.), Pinto 399, Tandil 7000, Buenos Aires, Argentina.
| | - Omar Confalonieri
- Departamento de Clínica, Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires (U.N.C.P.B.A.), Pinto 399, Tandil 7000, Buenos Aires, Argentina.
| | - Silvina E Gutiérrez
- Laboratorio de Virología, Facultad de Ciencias Veterinarias, Centro de Investigación Veterinaria de Tandil (CIVETAN-CONICET-CIC), Universidad Nacional del Centro de la Provincia de Buenos Aires (U.N.C.P.B.A.), Pinto 399, Tandil 7000, Buenos Aires, Argentina.
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Lee E, Kim EJ, Ratthanophart J, Vitoonpong R, Kim BH, Cho IS, Song JY, Lee KK, Shin YK. Molecular epidemiological and serological studies of bovine leukemia virus (BLV) infection in Thailand cattle. INFECTION GENETICS AND EVOLUTION 2016; 41:245-254. [DOI: 10.1016/j.meegid.2016.04.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 04/06/2016] [Accepted: 04/08/2016] [Indexed: 10/21/2022]
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Yang Y, Fan W, Mao Y, Yang Z, Lu G, Zhang R, Zhang H, Szeto C, Wang C. Bovine leukemia virus infection in cattle of China: Association with reduced milk production and increased somatic cell score. J Dairy Sci 2016; 99:3688-3697. [PMID: 26923050 DOI: 10.3168/jds.2015-10580] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 01/09/2016] [Indexed: 01/06/2023]
Abstract
The main objective of this study was to investigate the individual cow effect of bovine leukemia virus (BLV) infection on milk production and somatic cell score (SCS). The fluorescence resonance energy transfer (FRET) quantitative PCR established in this study and a commercial ELISA kit revealed that 49.1% of dairy cattle (964/1,963) from 6 provinces of China and 1.6% of beef cattle (22/1,390) from 15 provinces were BLV positive. In a detailed study of 105 cows, BLV was found most commonly in buffy coat samples that also had highest copy numbers (10(4.75±1.56) per mL); all cows negative for BLV in buffy coat samples were also negative in vaginal swab, milk, and fecal samples. Copy numbers of BLV were 10(2.90±0.42)/gram of feces, 10(0.83±0.62)/mL of milk, and 10(2.18±0.81) per vaginal swab. The BLV-positive cows had significantly lower milk production in the early (26.8 vs. 30.9kg) and middle stages of lactation (22.2 vs. 26.1kg) in animals with ≥4 parities than the BLV-negative cows; they also had significantly higher SCS in early and middle lactation stages (early=5.2 vs. 4.3; middle=4.9 vs. 3.9) in animals with ≥4 parities. Milk production and SCS did not significantly differ between the BLV-infected and -uninfected cows when they were in the late lactation stage or in animals with ≤3 parities. Taken together, our results indicate that BLV infections are widespread in the dairy farms of China. Vaginal secretions and feces may be involved in BLV transmission. A BLV infection may result in reduced milk yield and increased SCS in a parity and lactation stage-restricted manner.
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Affiliation(s)
- Y Yang
- Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University College of Veterinary Medicine, Yangzhou, Jiangsu 225009, China
| | - W Fan
- Laboratory of Zoonosis, China Animal Health and Epidemiology Center, Qingdao, Shandong, China
| | - Y Mao
- Yangzhou University College of Animal Science and Technology, Yangzhou, Jiangsu 266032, China
| | - Z Yang
- Yangzhou University College of Animal Science and Technology, Yangzhou, Jiangsu 266032, China
| | - G Lu
- Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University College of Veterinary Medicine, Yangzhou, Jiangsu 225009, China
| | - R Zhang
- Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University College of Veterinary Medicine, Yangzhou, Jiangsu 225009, China
| | - H Zhang
- Laboratory of Zoonosis, China Animal Health and Epidemiology Center, Qingdao, Shandong, China
| | - C Szeto
- Faculty of Science, The University of British Columbia, Vancouver V6T, Canada
| | - C Wang
- Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University College of Veterinary Medicine, Yangzhou, Jiangsu 225009, China.
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Detection of bovine leukemia virus and identification of its genotype in Mongolian cattle. Arch Virol 2015; 161:985-91. [DOI: 10.1007/s00705-015-2676-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 11/04/2015] [Indexed: 11/25/2022]
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Mycobacterium avium Subspecies paratuberculosis and Bovine Leukemia Virus Seroprevalence and Associated Risk Factors in Commercial Dairy and Beef Cattle in Northern and Northeastern China. BIOMED RESEARCH INTERNATIONAL 2015; 2015:315173. [PMID: 26504798 PMCID: PMC4609356 DOI: 10.1155/2015/315173] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 09/08/2015] [Accepted: 09/20/2015] [Indexed: 11/18/2022]
Abstract
Mycobacterium avium subspecies paratuberculosis (MAP) and bovine leukemia virus (BLV) are important pathogens, commonly responsible for economical loss to cattle farms all over the world, yet their epidemiology in commercial dairy and beef cattle in China is still unknown. Thus, from September 2013 to December 2014, a large-scale seroprevalence study was conducted to determine the seroprevalence and identify herd-level risk factors associated with MAP and BLV infection. The source sample was 3674 cattle from 113 herds in northern and northeastern China. Antibodies against MAP and BLV were detected using ELISA tests. At animal-level, the seroprevalence of antibodies against MAP and BLV was 11.79% (433/3674) and 18.29% (672/3674), respectively. At herd-level, the seroprevalence of antibodies against MAP and BLV was 20.35% and 21.24% (24/113), respectively. Herd size was identified to be associated with MAP infection while herd size and presence of cattle introduced from other farms were significantly associated with BLV infection. Further research is needed to confirm these findings and improve the knowledge of the epidemiology of these two pathogens in these regions and elsewhere in China.
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Ohno A, Takeshima SN, Matsumoto Y, Aida Y. Risk factors associated with increased bovine leukemia virus proviral load in infected cattle in Japan from 2012 to 2014. Virus Res 2015; 210:283-90. [PMID: 26321160 DOI: 10.1016/j.virusres.2015.08.020] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 08/22/2015] [Accepted: 08/24/2015] [Indexed: 11/17/2022]
Abstract
Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis, a malignant B cell lymphoma. BLV has spread worldwide and causes serious problems. After infection, the BLV genome is integrated into the host DNA and can be amplified during periods of latency. We previously designed degenerate primers using the Coordination of Common Motifs (CoCoMo) algorithm to establish a new quantitative real-time PCR method (BLV-CoCoMo-qPCR-2) of measuring the proviral load of both known and novel BLV variants. Here, we aimed to examine the correlation between proviral load and risk factors for BLV infection, such as breeding systems, parousity, and colostrum feeding. Blood and serum samples were collected from 83 BLV-positive farms in 22 prefectures of Japan, and the BLV proviral load and anti-BLV antibody levels were measured. BLV was detected in 73.3% (1039/1,417) of cattle by BLV-CoCoMo-qPCR-2 and the provirus was detected in 93 of 1039 antibody-negative samples. The results showed that the proviral load increased with progression of lymphocytosis. Next, the risk factors associated with increasing BLV infection rate were examined along with any association with proviral load. The proviral load was higher in cattle with lymphocytosis than in healthy cattle, and higher in multiparous cows than in nulliparous cows. Finally, proviral loads were higher in contact breeding systems than in non-contact breeding systems. Taken together, these findings may help to formulate a plan for eliminating BLV from contaminated farms. This is the first nationwide study to estimate BLV proviral load in Japanese cattle.
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Affiliation(s)
- Ayumu Ohno
- Viral Infectious Diseases Unit, RIKEN, 2-1Hirosawa, Wako, Saitama 351-0198, Japan
| | | | - Yuki Matsumoto
- Viral Infectious Diseases Unit, RIKEN, 2-1Hirosawa, Wako, Saitama 351-0198, Japan
| | - Yoko Aida
- Viral Infectious Diseases Unit, RIKEN, 2-1Hirosawa, Wako, Saitama 351-0198, Japan.
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Association of TNF-α gene promoter region polymorphisms in bovine leukemia virus (BLV)-infected cattle with different proviral loads. Arch Virol 2015; 160:2001-7. [PMID: 26051703 DOI: 10.1007/s00705-015-2448-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 05/05/2015] [Indexed: 01/10/2023]
Abstract
Tumor necrosis factor alpha (TNF-α) is a pleiotropic cytokine involved in the immune response against viral and other infections. Its expression levels are affected by a polymorphism in the promoter region of the gene. Bovine leukemia virus is a retrovirus that infects cattle and develops two different infection profiles in the host. One profile is characterized by a high number of proviral copies integrated into the host genome and a strong immune response against the virus, while the most relevant property of the other profile is that the number of copies integrated into the host genome is almost undetectable and the immune response is very weak. We selected a population of cattle sufficiently large for statistical analysis and classified them according to whether they had a high or low proviral load (HPL or LPL). Polymorphisms in the promoter region were identified by PCR-RFLP. The results indicated that, in the HPL group, the three possible genotypes were normally distributed and that, in the LPL group, there was a significant association between the proviral load and a low frequency of the G/G genotype at position -824.
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Watanabe T, Inoue E, Mori H, Osawa Y, Okazaki K. Delayed-onset enzootic bovine leukosis possibly caused by superinfection with bovine leukemia virus mutated in the pol gene. Arch Virol 2015; 160:2087-91. [PMID: 26025155 DOI: 10.1007/s00705-015-2457-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 05/15/2015] [Indexed: 01/08/2023]
Abstract
Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leucosis (EBL), to which animals are most susceptible at 4-8 years of age. In this study, we examined tumor cells associated with EBL in an 18-year-old cow to reveal that the cells carried at least two different copies of the virus, one of which was predicted to encode a reverse transcriptase (RT) lacking ribonuclease H activity and no integrase. Such a deficient enzyme may exhibit a dominant negative effect on the wild-type RT and cause insufficient viral replication, resulting in delayed tumor development in this cow.
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Affiliation(s)
- Tadaaki Watanabe
- Laboratory of Microbiology and Immunology, Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido, 061-0293, Japan
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Mekata H, Sekiguchi S, Konnai S, Kirino Y, Horii Y, Norimine J. Horizontal transmission and phylogenetic analysis of bovine leukemia virus in two districts of Miyazaki, Japan. J Vet Med Sci 2015; 77:1115-20. [PMID: 25892699 PMCID: PMC4591153 DOI: 10.1292/jvms.14-0624] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Horizontal transmission is recognized as a major infection route for bovine leukemia
virus (BLV), and cattle with high viral loads are considered to be a major infectious
source in a herd. However, a correlation between viral loads and the risk of infection has
been insufficient to use as a foundation for BLV control strategies. In this report, we
examined the epidemiology of BLV infection and the infectious source in a local area. In
2013–2014, BLV infection was investigated in 1,823 cattle from 117 farms in two adjacent
districts, Miyazaki, Japan. Seropositive samples for BLV were detected with 88 cattle and
in 14 farms. Phylogenetic analysis revealed that 94% of the isolates clustered into
genotype I and the remaining isolate into genotype III. Among genotype I, genetically
distinct strains were spread at each farm, and cattle infected with less than 3 copies/100
cells did not transmit BLV to other cattle for more than thirty months. This is the first
report of concrete data of viral load in relation to viral horizontal transmission under
the field condition. The data facilitate farmers and veterinarians understanding the
status of BLV infected cattle. This research contributes to BLV infection control and the
development of effective BLV eradication programs.
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Affiliation(s)
- Hirohisa Mekata
- Project for Zoonoses Education and Research, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan
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Lee E, Kim EJ, Joung HK, Kim BH, Song JY, Cho IS, Lee KK, Shin YK. Sequencing and phylogenetic analysis of the gp51 gene from Korean bovine leukemia virus isolates. Virol J 2015; 12:64. [PMID: 25879943 PMCID: PMC4405874 DOI: 10.1186/s12985-015-0286-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 03/23/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Bovine Leukemia virus (BLV) infection of cattle has been reported in Korea for more than three decades. However, to date, there have been few studies regarding Korean BLV since 1980s. Thus, the purpose of this study is to perform a diagnosis and molecular characterization of BLV strains circulating in Korea and to estimate genetic diversity of different genotypes of BLV. METHOD To investigate the distribution of BLV variants in the world and assess the evolutionary history of Korean BLV isolates, a comprehensive molecular analysis of the BLV env gp51 gene was conducted using recent worldwide BLV isolates. The isolates included 50 samples obtained from two cattle farms in southeastern Korea in 2014. RESULTS Sequence and phylogenetic analyses of partial 444-nt fragment sequences and complete gp51 sequences of BLV revealed eight distinct genotypes of BLV showing geographic distribution of the world. Most Korean BLV isolates were found to belong to genotype 1 which is a major genotype prevailed throughout the world, and only four isolates from one farm were classified as genotype 3 related to the US and Japan isolates. Analysis of amino acids of Korean BLV isolates showed several sequence substitutions in the leader peptide, conformational epitope, and neutralizing domain regions. The observations suggest the possibility of affecting on viral infectivity and formation. CONCLUSION Korean BLV isolates showed the close relationship to genotype 1 and 3. Further study to identify the diversity of BLV circulating in Korea is necessary with samples collected nationwide because this study is the first report of BLV genotype 3 being in circulation in Korea.
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Affiliation(s)
- EunJung Lee
- Viral Disease Division, Animal and Plant Quarantine Agency, 175 Anyangro, Anyang, Gyeonggido, 430-757, Republic of Korea.
| | - Eun-Ju Kim
- Viral Disease Division, Animal and Plant Quarantine Agency, 175 Anyangro, Anyang, Gyeonggido, 430-757, Republic of Korea.
| | - Ha-Kyung Joung
- Viral Disease Division, Animal and Plant Quarantine Agency, 175 Anyangro, Anyang, Gyeonggido, 430-757, Republic of Korea.
| | - Bo-Hye Kim
- Viral Disease Division, Animal and Plant Quarantine Agency, 175 Anyangro, Anyang, Gyeonggido, 430-757, Republic of Korea.
| | - Jae-Young Song
- Veterinary Drugs and Biologics Division, Anyang, 430-757, Gyeonggido, Republic of Korea.
| | - In-Soo Cho
- Viral Disease Division, Animal and Plant Quarantine Agency, 175 Anyangro, Anyang, Gyeonggido, 430-757, Republic of Korea.
| | - Kyoung-Ki Lee
- Animal Disease Diagnostic Division, Animal and Plant Quarantine Agency, Anyang, 430-757, Gyeonggido, Republic of Korea.
| | - Yeun-Kyung Shin
- Viral Disease Division, Animal and Plant Quarantine Agency, 175 Anyangro, Anyang, Gyeonggido, 430-757, Republic of Korea.
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Şevik M, Avcı O, İnce ÖB. An 8-year longitudinal sero-epidemiological study of bovine leukaemia virus (BLV) infection in dairy cattle in Turkey and analysis of risk factors associated with BLV seropositivity. Trop Anim Health Prod 2015; 47:715-20. [DOI: 10.1007/s11250-015-0783-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Accepted: 02/11/2015] [Indexed: 12/01/2022]
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Mekata H, Sekiguchi S, Konnai S, Kirino Y, Honkawa K, Nonaka N, Horii Y, Norimine J. Evaluation of the natural perinatal transmission of bovine leukaemia virus. Vet Rec 2014; 176:254. [PMID: 25510867 DOI: 10.1136/vr.102464] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The perinatal transmission of bovine leukaemia virus (BLV) plays a critical role in the spread and persistence of BLV infection in cattle herds. The purpose of this study was to examine the frequency of perinatal infections in an area in Japan and investigate some risk factors associated with infection. Altogether, 129 calves born to BLV-infected cows in a herd in Japan were tested for infection immediately after birth and again at one month of age using nested PCR. Twenty-four calves (18.6 per cent) were infected with BLV, of which 14 (10.8 per cent) and 10 (7.7 per cent) calves were infected via the transplacental and the birth canal routes, respectively. Maternal viral loads, breed, the presence or absence of assistance during parturition and the number of births per dam were evaluated to investigate risk factors associated with infection. Maternal viral load was significantly correlated with the frequency of perinatal infection, and more than 40 per cent of newborn calves born to dams with high viral loads were infected with BLV. The results of this study could contribute towards developing effective eradication programmes by providing necessary data for replacement of breeding cow in the field.
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Affiliation(s)
- Hirohisa Mekata
- Project for Zoonoses Education and Research, Department of Veterinary Medicine, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan
| | - Satoshi Sekiguchi
- Laboratory of Animal Infectious Disease and Prevention, Department of Veterinary Medicine, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan Center for Animal Disease Control, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan
| | - Satoru Konnai
- Laboratory of Infectious Diseases, Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Kita 18 Nishi 9, Sapporo 060-0818, Japan
| | - Yumi Kirino
- Project for Zoonoses Education and Research, Department of Veterinary Medicine, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan Laboratory of Veterinary Parasitic Diseases, Interdisciplinary Graduate School of Medicine and Veterinary Medicine, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan
| | - Kazuyuki Honkawa
- Laboratory of Veterinary Parasitic Diseases, Interdisciplinary Graduate School of Medicine and Veterinary Medicine, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan
| | - Nariaki Nonaka
- Center for Animal Disease Control, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan Laboratory of Veterinary Parasitic Diseases, Interdisciplinary Graduate School of Medicine and Veterinary Medicine, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan
| | - Yoichiro Horii
- Center for Animal Disease Control, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan Laboratory of Veterinary Parasitic Diseases, Interdisciplinary Graduate School of Medicine and Veterinary Medicine, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan
| | - Junzo Norimine
- Laboratory of Animal Infectious Disease and Prevention, Department of Veterinary Medicine, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan Center for Animal Disease Control, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan
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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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Bartlett PC, Sordillo LM, Byrem TM, Norby B, Grooms DL, Swenson CL, Zalucha J, Erskine RJ. Options for the control of bovine leukemia virus in dairy cattle. J Am Vet Med Assoc 2014; 244:914-22. [DOI: 10.2460/javma.244.8.914] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Kobayashi S, Hidano A, Tsutsui T, Yamamoto T, Hayama Y, Nishida T, Muroga N, Konishi M, Kameyama K, Murakami K. Analysis of risk factors associated with bovine leukemia virus seropositivity within dairy and beef breeding farms in Japan: A nationwide survey. Res Vet Sci 2014; 96:47-53. [DOI: 10.1016/j.rvsc.2013.11.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 11/15/2013] [Accepted: 11/26/2013] [Indexed: 10/25/2022]
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