Estimation of the within-herd transmission parameter of bovine leukemia virus

Tsutsui, Toshiyuki; Kobayashi, Sota; Hayama, Yoko; Nishiguchi, Akiko; Kameyama, Ken-ichiro; Konishi, Misako; Murakami, Kenji

doi:10.1016/j.prevetmed.2010.02.008

Cited by 9 publications

(11 citation statements)

References 14 publications

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“…There is some evidence that horse flies (Tabanus spp.) may have greater potential to transmit BLV within herds in natural conditions (Foil et al, 1989;Manet et al, 1989;Hasselschwert et al, 1993;Kobayashi et al, 2010). Presence of flies in a stable has been reported as a risk factor for higher within-herd prevalence of BLV infection (Kobayashi et al, 2010;Erskine et al, 2012b;Kobayashi et al, 2014).…”

Section: Routes and Speed Of Transmissionmentioning

confidence: 99%

“…Avoiding iatrogenic spread may reduce substantially the speed of within-herd transmission of the infection (DiGiacomo et al, 1987;Sprecher et al, 1991;Suh et al, 2005). Neglecting biosecurity measures aimed to avoid iatrogenic modes of transmission appear to be a risk factor for high within-herd BLV seroprevalence (Kobayashi et al, 2010;Erskine et al, 2012b).…”

Section: Routes and Speed Of Transmissionmentioning

confidence: 99%

“…The rate of direct contact transmission between animals is strongly dependent on within herd prevalence of the herd (Lassauzet et al, 1990;Dimmock et al, 1991). Herd management factors (like housing system, calving management) may impact the spread of the virus within herd (Dimmock et al, 1991;Kobayashi et al, 2010, Kobayashi et al, 2015. It has been estimated that 0.62 (CI95% 0.37-0.89) animals are infected by one infectious animal introduced into a fully susceptible population during a 5-month interval (~1,5/year) in Japan (Tsutsui et al, 2010).…”

Section: Routes and Speed Of Transmissionmentioning

confidence: 99%

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Enzootic bovine leukosis

Sihvonen¹

2015

EFS2

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Enzootic bovine leukosis is a disease of cattle caused by bovine leukemia virus (BLV). The virus causes a persistent, life‐long infection in a subset of B cells. Malignant tumours (lymphomas) ultimately develop in 2–5% of infected animals, predominantly in adult cattle older than 3–5 years. Lymphomas invariably lead to death of the animal within months. Before 1960, BLV was endemic in dairy herds in Northern/Eastern Europe and North America. Since then it has spread to all continents. The disease has been successfully controlled and eliminated from many countries in Europe. There is no evidence to suggest that any significant reservoir of BLV exists among other species, nor for any role of BLV in human disease or cancers. BLV exhibits a slow, progressive spread within a herd and it is likely to persist if control measures are not applied. The main modes of transmission are perinatal from cow to calf, via colostrum and milk, and close contact that allows transfer of infected lymphocytes, such as dehorning and injections using non‐sterile utensils. Transfer between herds is almost entirely by movement of infected animals. Suitable methods have been developed for diagnosis of BLV infection in specimens of blood, milk and lymphomas. EBL has a negative impact on milk yield and leads to increased premature culling. The welfare consequences of lymphomas vary according to the location and magnitude of organ involvement. Criteria for maintaining country freedom from EBL differ substantially between OIE and EU. Surveillance for freedom should be based on a combination of serological testing of adult animals and identification of lymphomas at slaughter.

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Section: Routes and Speed Of Transmissionmentioning

confidence: 99%

Section: Routes and Speed Of Transmissionmentioning

confidence: 99%

Section: Routes and Speed Of Transmissionmentioning

confidence: 99%

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Enzootic bovine leukosis

Sihvonen¹

2015

EFS2

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“…Bovine Leukemia Virus (BLV) is the agent of enzootic bovine leukosis (EBL), a neoplasm of lymphatic tissues in bovine species (1,2,3,4), BLV is classified into the genus Deltaretrovirus in the family Retroviriadae (3). EBL is characterized by three disease stages: asymptomatic or aleukemic (AL), persistent lymphocytosis (PL), and leukemia or lymphoma (5).…”

Section: Introductionmentioning

confidence: 99%

Sero-prevalence of bovine Leukemia virus in cattle from Caquetá state, Colombia

Delgado

Calderón

Valencia³

et al. 2019

Rev Colombiana Cienc Anim. RECIA

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Bovine Leukemia Virus (BLV) is the agent of enzootic bovine leukosis (EBL), this disease is a neoplasm of lymphatic tissue in bovine species. The aim of this article was determinate the prevalence of bovine leukemia virus in dual-purpose cattle from nine municipalities that produce the 98% of milk in the Caquetá state, Colombia. Blood samples were collected in 100 herds dedicates to dual purpose cattle, obtained blood serum from 1000 animals, of which 893 corresponding to cows. Indirect Elisa test for detection of antibodies anti-GP51 of BLV was performance and the positive cases were considered if the serum-to-positive ratio with percentages of M/N lower than 40%. Categorized data were analyzed by contingency tables and ANOVA at the significant level of p<0.05 by DGC test was performed. The overall sero-prevalence of BLV in Caquetá state was of 25.18% (95%, CI: 21.9-28.46%), in males 26.25% and females 25.37% respectively. At municipal level the sero-prevalence varied of 7.12 to 41.81%. The prevalence of BLV at herd level was of 67% (95%, CI: 57.24-76.76%). In conclusion, the sero-prevalence of BLV in the dual-purpose livestock system over 36 months of age in Caquetá state is moderate, do not exist statistical difference between sero-prevalence of cows and bulls. At level of herds the prevalence of BLV is high. Improving strategies of control and managements in the herds, as well as implement policies of sanitary management are necessary.

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“…Besides an impact on survival, BLV infection also may impair the immune system leading to opportunistic infections (1,2). Disease transmission between cattle is considered to occur via exposure to infected lymphocytes in blood from parturition, contaminated surgical instruments, rectal palpation and bloodsucking insects (2,3,5). Several authors have shown that it is possible to establish BLV-free herds by identifying seropositive animals and eliminating them from the herds (6-8).…”

Section: Introductionmentioning

confidence: 99%

A Serological Study on Bovine Leukemia Virus Infection in Ten Provinces of Iran between 2010 and 2012

et al. 2012

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Background and Aims: Bovine leukaemia virus (BLV) is an oncogenic member of the genus Deltaretrovirus of the family Retroviridae. BLV is the causative agent of enzootic bovine leukaemia and infects cattle worldwide, imposing economic impact on the dairy cattle industry. The purpose of this study was to estimate the seroprevalence of BLV in cattle in some provinces of Iran. Materials and Methods: A total of 280 cows over 2 years old from 10 provinces of Iran in different regions and environments from industrial and less industrial herds were used in the study. Blood samples from all cows were taken both with and without EDTA. Serum separation for the ELISA test and leukocyte count, were performed upon receipt without delay. Cattle without fever that had lymphocyte numbers of more than 9,000/μl were suspected to have persistent lymphocytosis (PL). Sera samples were examined for antibodies against BLV by blocking ELISA. Results: The seroprevalence of BLV among animals was 32.8% and among provinces was 80%. Seropositive cattle had higher total leukocyte and lymphocyte count and lower neutrophil count than seronegative cattle (P<0.001). Among BLV seropositive animals, the rate of PL was 36.9%. None of the seronegative animals showed lymphocytosis. Conclusion: Comparing the data with previous studies on seroprevalence of BLV in different localities in Iran, the prevalence of the infection has been raised. These results suggest that promoting control programs in Iran are very important. Furthermore, it will be essential to conduct nationwide surveillance program and determine the major risk factors.

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Estimation of the within-herd transmission parameter of bovine leukemia virus

Cited by 9 publications

References 14 publications

Enzootic bovine leukosis

Enzootic bovine leukosis

Sero-prevalence of bovine Leukemia virus in cattle from Caquetá state, Colombia

A Serological Study on Bovine Leukemia Virus Infection in Ten Provinces of Iran between 2010 and 2012

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