Enzootic bovine leukosis in a two-month-old calf

Oguma, Koichi; Suzuki, Miho; Sentsui, Hiroshi

doi:10.1016/j.virusres.2017.03.016

Cited by 28 publications

(31 citation statements)

References 19 publications

(17 reference statements)

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“…Quantitation of BLV by real time PCR was performed according to the methods as described previously [ 27 ]. The standard plasmid samples for quantitation containing both BLV pol and beta-actin (ACTB) at an accurately equivalent molecular ratio were shown in the previous study [ 27 ]. The standard plasmids were diluted by 10-fold serial dilution using EASY Dilution (Takara Bio, Kusatsu, Japan).…”

Section: Methodsmentioning

confidence: 99%

Genomic characterization and distribution of bovine foamy virus in Japan

Okamoto

Oguma

Yamashita‐Kawanishi

et al. 2020

The Journal of Veterinary Medical Science

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Bovine foamy virus (BFV) is distributed through worldwide cattle herds. Although the biological features of BFV are not well understood, appearance of clinical manifestation by superinfection with other microorganisms is inferred. In Japan, reports of genomic characterizations and epidemiology of this virus are limited. In this study, we performed whole genomic sequencing of BFV strains Ibaraki and No.43, which were isolated in this country. Additionally, we investigated BFV in geographically distant four daily farms in Japan, to estimate the distribution of BFV and its correlation to bovine leukemia virus (BLV). BFV was distributed throughout Japan; the average positive rate was 12.7%. The nucleotide sequence identities of the isolates were 99.6% when compared with BFV strain isolated in the USA. The phylogenetic tree using env gene sequence showed strains Ibaraki, No.43 and Kagoshima were sorted in the same cluster including the USA and Chinese strains, while Hokkaido strain was in the other cluster including European strains. Although no clear correlation between BFV and BLV could be found, BFV and BLV infections were likely to increase with ages. Our data on epidemiology and characteristics of BFV will provide important information to reveal biological features of BFV.

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Section: Methodsmentioning

confidence: 99%

Genomic characterization and distribution of bovine foamy virus in Japan

Okamoto

Oguma

Yamashita‐Kawanishi

et al. 2020

The Journal of Veterinary Medical Science

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“…Although tumors caused by BLV are typically seen in animals over 3 years of age [2], infected calves have the potential to be affected by EBL at a younger age. Recently, several cases of EBL in cattle younger than 2 years old were reported in Japan [3]. The loss of young successor or fattening cattle can cause major economic damage to farms.…”

Section: Introductionmentioning

confidence: 99%

The effectiveness of colostral antibodies for preventing bovine leukemia virus (BLV) infection in vitro

et al. 2018

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BackgroundBovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis (EBL). The incidence of EBL in Japan is increasing annually; and the cases of EBL in cattle younger than 2 years old has been reported. Therefore, it is vital to find a method to control BLV infection, especially in young calves. In this study, to evaluate the protective ability of colostral antibodies against BLV infection, as well as the potential for BLV infection mediated by colostrum/milk, we investigated temporal fluctuations in the anti-BLV antibody titer and BLV proviral load (PVL) in colostrum/milk and peripheral blood of six infected dams during lactation. The association between PVL and antibody titer in colostrum and peripheral blood was then investigated using samples from a further twenty-seven cattle. Antibody concentrations were measured with a Syncytium-induction Inhibition Assay using colostral/milk whey and serum. PVL in peripheral blood and colostrum was measured by real-time PCR.ResultsColostral antibodies showed high inhibitory activity until day 3 of lactation. The antibody titer and PVL in peripheral blood showed lesser changes than those in colostrum/milk throughout lactation. The colostral antibody titer was significantly higher than the serum antibody titer in all samples, whereas the colostrum PVL was significantly lower than the blood PVL. The blood PVL showed a significant correlation with serum antibody titer, colostrum PVL, and colostral antibody titer. However, there were no major correlations between the serum and colostral antibody titers.ConclusionsThis is the first report investigating the temporal changes in colostral antibody titer in terms of inhibiting BLV infection in vitro. The results of antibody detection by Syncytium-induction Inhibition Assay suggested that the protective activity of the colostral antibodies against BLV infection would be conferred by anti-BLV gp51 antibody. The high antibody titer of colostral whey suggests that colostral whey could be a potential source of antibodies with a low risk of infection in neonatal calves.

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“…Currently, little is known about the occurrence of EBL in young cattle under 1 year of age, and only a few reports investigate about that (Oguma et. al., 2017).…”

Section: Discussionmentioning

confidence: 99%

Enzootic bovine leukosis accompanied by splenomegaly in an 8-month-old calf

Okada¹,

Tagawa²,

Wada³

et al. 2020

J Hellenic Vet Med Soc

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In this report, an 8-month-old calf (crossbred, Holstein × Japanese Black) developed fever and accompanied abomasum displacement. Blood chemical test showed remarkably high values of white blood cell count and heteromorphic lymphocytes. In pathological appraisal, enlarged splenomegaly and swelling of the lymph nodes were observed. Histopathological examination revealed invasion of tumor cells derived from B1 cells into systemic lymph nodes, liver and spleen. The provirus loads of bovine leukemia virus (BLV) was 1,439 copies per 10 ng DNA by using real time PCR. In conclusion, this case was diagnosed as bovine leukemia caused by BLV infection with a huge splenomegaly.

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Enzootic bovine leukosis in a two-month-old calf

Cited by 28 publications

References 19 publications

Genomic characterization and distribution of bovine foamy virus in Japan

Genomic characterization and distribution of bovine foamy virus in Japan

The effectiveness of colostral antibodies for preventing bovine leukemia virus (BLV) infection in vitro

Enzootic bovine leukosis accompanied by splenomegaly in an 8-month-old calf

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