Bovine leukemia virus becomes established in dairy herds before the first lactation

Merlini, Ramiro; Gutiérrez, Gerónimo; Álvarez, Irene; Jaworski, Juan Pablo; Carignano, Hugo Adrián; Poli, M. A.; Willems, Luc; Trono, K.

doi:10.1007/s00705-016-2973-x

Cited by 10 publications

(9 citation statements)

References 12 publications

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“…Since high levels of BLV infection are associated with higher probability of transmission ( 69 ), the presence of animals with high PVL is epidemiologically dangerous. This could be a reason for the high incidence observed in Argentinean dairy herds before first parturition, when approximately half of pregnant heifers are already infected, and between 20 and 44% of them have high PVL ( 60 , 70 ). Culling the animals with high PVL might be a strategy for reducing overall incidence in the herds, but this would be economically feasible only in herds with low prevalence of high PVL cows.…”

Section: Importance Of Blv Infection During the Neonatal Periodmentioning

confidence: 99%

“…However, it has also been reported that BLV infection can occur during the first 2 years of life, when young animals are still not in contact with adult cows. At this stage, the only potential sources of virus are their own mothers, bulk tank milk, and calves that were born infected (8–11% in dairy herds of Argentina) ( 60 , 70 ).…”

Section: Importance Of Blv Infection During the Neonatal Periodmentioning

confidence: 99%

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Bovine Leukemia Virus Infection in Neonatal Calves. Risk Factors and Control Measures

et al. 2018

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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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Section: Importance Of Blv Infection During the Neonatal Periodmentioning

confidence: 99%

Section: Importance Of Blv Infection During the Neonatal Periodmentioning

confidence: 99%

Bovine Leukemia Virus Infection in Neonatal Calves. Risk Factors and Control Measures

et al. 2018

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“…Disease progression to B cell lymphoma is related to low expression of Tumor Necrosis Factor alpha (TNF-α), due to polymorphism in the promoter region 12 , and the animal’s Bola genotype 13 . The infection is considered eradicated in several parts of the world 14 but is widely spread in North 15,16 and most South American countries 17 including Brazil. As most retroviruses, transmission requires transferring of cells from infected to non-infected individuals 18 and, as such, blood and milk from infected animals are the main sources of the virus 19 .…”

Section: Introductionmentioning

confidence: 99%

Bovine leukemia virus DNA associated with breast cancer in women from South Brazil

Schwingel

Andreolla

Erpen

et al. 2019

Sci Rep

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Breast cancer is a neoplastic condition with a high morbidity and mortality amongst women worldwide. Recent data linking bovine leukemia virus (BLV) with breast cancer has been contested already. Our study investigated the presence of BLV genome in healthy (n = 72) and cancerous (n = 72) paraffin-embedded samples of breast tissues from women in south Brazil. BLV DNA was found most frequently (30.5%) in breast cancer tissue than in healthy breast (13.9%) (Odds ratio = 2.73; confidence interval = 1.18–6.29; p = 0.027). In contrast, antibodies to BLV were found in a very small percentage of healthy blood donors. There was no association between BLV DNA and other tumor prognostic biological markers such as hormonal receptors, HER2 oncoprotein, proliferation index, metastasis in sentinels lymph nodes, and tumor grade and size. Our findings suggest that BLV should be considered a potential predisposing factor to breast cancer in women.

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“…A large percentile of animal infected by the BLV might be asymptomatic or aleukemic (AL), at least at the initial stages of infection, while up to 30% develop a persistent lymphocytosis (PL) 2 that in some cases, depending on the animal's Bola genotype, 3 progresses to B cell lymphoma 4, 5. The infection is considered eradicated in several parts of the world 6 but is widely spread in North7, 8, 9 and most South American countries 10 in which dairy farming is considered an important economic activity. There is no official data on the rate of infection in Brazilian dairy farm and most limited and biased epidemiological studies indicate that the range of seropositive animal varies from 12.5% to 100% 11, 12.…”

Section: Introductionmentioning

confidence: 99%

Development of an indirect ELISA based on recombinant capsid protein to detect antibodies to bovine leukemia virus

Andreolla

Erpen

Frandoloso

et al. 2018

Brazilian Journal of Microbiology

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Serological testing and culling infected animals are key management practices aiming eradication of bovine leukemia virus infection. Here, we report the development of an indirect ELISA based on BLV recombinant capsid protein (BLVp24r) to detect anti-BLV antibodies in cattle serum. The BLVp24r was expressed in Escherichia coli and purified by affinity chromatography, and then used to set up the ELISA parameters. The Polysorp plate coated with 50ng of antigen/well and bovine serum diluted 1:100 gave the best results during standardization. Using sera from infected and non-infected cattle we set up the cutoff point at 0.320 (OD) with a sensitivity of 98.5% and specificity of 100.0%. Then, we tested 1.187 serum samples from dairy (736 samples) and beef cattle (451 samples) with unknown status to BLV. We found that 31.1% (229/736) and 9.5% (43/451) of samples amongst dairy and beef cattle, respectively, had IgGs to BLV. The rate of agreement with a commercial competitive ELISA was 84.3% with a κ value of 0.68. Thus, our BLVp24r iELISA is suitable to detect BLV infected animals and should be a useful tool to control BLV infection in cattle.

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Bovine leukemia virus becomes established in dairy herds before the first lactation

Cited by 10 publications

References 12 publications

Bovine Leukemia Virus Infection in Neonatal Calves. Risk Factors and Control Measures

Bovine Leukemia Virus Infection in Neonatal Calves. Risk Factors and Control Measures

Bovine leukemia virus DNA associated with breast cancer in women from South Brazil

Development of an indirect ELISA based on recombinant capsid protein to detect antibodies to bovine leukemia virus

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