Natural Transmission of Bovine Leukemia Virus among Cattle

Onuma, Misao; Watarai, Shinobu; Ichijo, Shigeru; Ishihara, Katsuya; Ohtani, Tsuyoshi; Sonoda, Mitsuo; Mikami, Takeshi; Izawa, Hisao; Konishi, Tatsuo

doi:10.1111/j.1348-0421.1980.tb02916.x

Cited by 7 publications

(6 citation statements)

References 8 publications

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“…Seasonal variations in the BLV-positive conversion rates were observed, and the rate in the summer was higher than that in the winter ( Table 2 ). The presence of many stable flies from July to October suggested that blood-sucking flies might be responsible for BLV transmission in the summer season, in accordance with previous studies [ 15 , 18 ]. However, the BLV-positive conversion rate was very low in the winter season.…”

supporting

confidence: 91%

“…The proviral load in BLV-infected cattle is an important factor of BLV transmission via insect vectors, and PL cattle, which have a high proviral load, become infectious sources in farms [ 9 , 19 ]. Although previous studies considered that blood-sucking insects were low risk factors for BLV transmission [ 8 , 18 , 24 ], transmission might be dependent on the density of insects around the cattle, the proportion of BLV-infected cattle within farms, and the level of proviral load in BLV-infected cattle [ 1 ].…”

mentioning

confidence: 99%

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Vector control efficacy of fly nets on preventing bovine leukemia virus transmission

Kohara

Miki

Hirano

et al. 2018

The Journal of Veterinary Medical Science

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Bovine leukemia virus (BLV) is horizontally transmitted among cattle through infected blood. This 3-year field study (2013–2016) aimed to confirm the potential of the blood-sucking stable fly as a risk factor of BLV transmission and to determine the efficacy of vector control on preventing the transmission of BLV. The BLV-positive conversion rate during summer was higher than that during winter in a model dairy farm, where many stable flies were observed during the summer. After fly nets were fixed onto the barn to prevent fly invasion, the BLV-positive conversion rate during the summer was significantly decreased compared with that in the absence of fly nets (P<0.01). These findings suggest that vector control using a fly net may inhibit BLV transmission.

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supporting

confidence: 91%

mentioning

confidence: 99%

Vector control efficacy of fly nets on preventing bovine leukemia virus transmission

Kohara

Miki

Hirano

et al. 2018

The Journal of Veterinary Medical Science

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“…Results of this study are consistent with those from a study in which increased rates of seroconversion were observed after cattle grazed together on summer pastures (Onuma et al . , 1980).…”

supporting

confidence: 92%

“…, 1978), In an experimental study, horsefly transmission of BLV infection to sheep was demonstrated (Ohshima et al . , 1981), It has been suggested that high rates of infection observed in animals during summer months support the hypothesis of vector-borne transmission of BLV infection (Bech-Nielsen et al , , 1978;Onuma et al . , 1980).…”

Section: Arthropod Vectorsmentioning

confidence: 87%

Epidemiology of natural transmission of bovine leukemia virus infection / by Mark Cy Thurmond.

Thurmond¹

1982

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A 27-month study examined 473 dairy cattle for associations between bovine leukemia virus (BLV) infection and host and environmental factors. Cattle sera were tested at monthly intervals for BLV antibodies by agar-gel immunodiffusion using the glycoprotein-51 antigen. A model of BLV colostral antibody decay in 130 calves predicted infection in calves less than six months of age and estimated antibody half-life to be 27.1 ±1.2 days. Colostral antibody decay did not differ between BLV-infected and noninfected calves for slope (p = 0.45) or intercept (p = 0.43). By 95 days of age, 50% of the calves had no detectable BLV colostral antibodies. Of 125 calves born to BLV-infected cows and followed for at least four months, eight (6.4%) had precolostral BLV antibodies, as determined by radioimmunoassay using the glycoprotein-51 antigen-In utero infection with BLV was not associated with dam age (p = 0.86), dam parity (p = 0.83), breed (p = 0.66), sex (p = 0.11), or stage of gestation in which the dam was infected (p=0.50). Calves infected in utero did not pose an increased risk of infection to calves penned next to them (p = 0.61). Prevalence rates of infection were 9%, 16%, and 63% at 6, 16, and 27 months of age, respectively. Age-specific rates of infection were not associated with dam age (p = 0.79), dam parity (p=0.75), dam BLV-status (p = 0.46), breed (p = 0.86), or BLV-status of colostrum consumed (p=0.50). An algorithm was described which allocated probabilities of infection to locations occupied by an animal prior to detection of infection. Small calf pastures were associated with less infection than was the calf barn (p< 0.05). No less infection was associated with individual outdoor calf pens compared to contiguous indoor pens (p>0.05). Risk of infection associated with the dry herd was five times that for heifer pastures (p< 0.0001) and accounted 24 infections per 100 heifers per 100 days at risk. Vaccination for infectious diseases was not associated with increased BLV infection (p=0.33). Infection rates were not associated with month of birth (p = 0.24) or with season of potential arthropod vectors (p = 0.20). Heifer infection was likely to occur in late v/inter or spring (p =. 01). Interacting Computing (MUSIC) version 4.1, 197 8.

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“…Infection is lifelong and acquired by horizontal transmission by many natural or iatrogenic vectors (Larson et al, 1970;Onuma et al, 1980;Roberts et al, 1982;Romero et al, 1983;Buxton et al, 1985). BLV is a chronically transforming virus causing tumours in probably less than 5~ of infected cows (Burny et al, 1980).…”

Section: Introductionmentioning

confidence: 99%

Alterations in Humoral Immune Response to Bovine Leukaemia Virus Antigens in Cattle with Lymphoma

Heeney

Valli

Montesanti

1988

Journal of General Virology

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SUMMARYSera collected from cattle with enzootic bovine lymphoma (EBL) were compared to sera from clinically normal bovine leukaemia virus (BLV)-infected cattle for immunoglobulin concentration and for antibodies detecting BLV proteins tested using three different viral isolates. Monoclonal antibodies to bovine immunoglobulin isotypes were used in Western blot analysis to identify isotype reactivity to specific viral antigens. IgG titres to BLV were determined by ELISA. Serum immunoglobulin (G1, G2 and M) concentrations were assessed by radial immunodiffusion. Although EBL was associated with reduced total immunoglobulin production, sera from cattle with EBL had significantly (P< 0-001) higher specific IgG titres and produced antibodies against a greater and more varied number of BLV proteins than did sera from clinically normal BLV-infected cattle. Variations were consistent within groups of cattle and did not depend on the viral isolate used.

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Natural Transmission of Bovine Leukemia Virus among Cattle

Cited by 7 publications

References 8 publications

Vector control efficacy of fly nets on preventing bovine leukemia virus transmission

Vector control efficacy of fly nets on preventing bovine leukemia virus transmission

Epidemiology of natural transmission of bovine leukemia virus infection / by Mark Cy Thurmond.

Alterations in Humoral Immune Response to Bovine Leukaemia Virus Antigens in Cattle with Lymphoma

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