scholarly journals Quantitative Risk Assessment for the Introduction of Bovine Leukemia Virus-Infected Cattle Using a Cattle Movement Network Analysis

Pathogens ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 903
Author(s):  
Kosuke Notsu ◽  
Anuwat Wiratsudakul ◽  
Shuya Mitoma ◽  
Hala El Daous ◽  
Chiho Kaneko ◽  
...  
Keyword(s):  
Bovine Leukemia Virus ◽  
Linear Mixed Model ◽  
Leukemia Virus ◽  
Clinical Signs ◽  
Quantitative Risk Assessment ◽  
Economic Losses ◽  
Degree Centrality ◽  
Infected Cattle ◽  
Worst Case ◽  
Cattle Movement

The cattle industry is suffering economic losses caused by bovine leukemia virus (BLV) and enzootic bovine leukosis (EBL), the clinical condition associated with BLV infection. This pathogen spreads easily without detection by farmers and veterinarians due to the lack of obvious clinical signs. Cattle movement strongly contributes to the inter-farm transmission of BLV. This study quantified the farm-level risk of BLV introduction using a cattle movement analysis. A generalized linear mixed model predicting the proportion of BLV-infected cattle was constructed based on weighted in-degree centrality. Our results suggest a positive association between weighted in-degree centrality and the estimated number of introduced BLV-infected cattle. Remarkably, the introduction of approximately six cattle allowed at least one BLV-infected animal to be added to the farm in the worst-case scenario. These data suggest a high risk of BLV infection on farms with a high number of cattle being introduced. Our findings indicate the need to strengthen BLV control strategies, especially along the chain of cattle movement.

scholarly journals Pathogenetic aspects of rabbits’ experimental infection caused by bovine leukemia virus

2020 ◽  
Vol 22 (100) ◽  
pp. 16-22
Author(s):  
T. A. Romanishina ◽  
D. V. Feschenko ◽  
G. O. Rinyak ◽  
V. V. Honcharenko ◽  
A. A. Macibora ◽  
...  
Keyword(s):  
Blood Serum ◽  
Bovine Leukemia Virus ◽  
Viral Infections ◽  
Early Stage ◽  
Leukemia Virus ◽  
Clinical Signs ◽  
Development Stage ◽  
The Body ◽  
Interspecies Transmission ◽  
Economic Losses

Bovine leukemia virus (BLV) is an infectious disease of cattle, causing high economic losses worldwide, especially in the field of dairy farming. There is no common vision on the problem of interspecies transmission of BLV. Therefore, a detailed study of the etiologic relationship between leukemia in cattle and other animal species is relevant. Various laboratory animal models provide insight into the pathogenesis of viral infections. The article presents the research results of two series rabbits’ intravenous infection with bovine leukemia virus (BLV) using the culture antigen FLK-BLV and the blood of rabbits with clinical, hematological and immunological signs of viral tumor growth. Blood from all animals was taken from the ear vein after 14, 21, 30 days, and then monthly for six months: to study the morphological parameters of blood and to determine the titer of antibodies to BLV. Blood serum for the presence of antibodies to BLV was examined using a diagnostic kit for the indication of animals infected with the leukemia virus in an immunodiffusion reaction produced by LLC “SRE Veterinary Medicine”, Kharkiv. It was found that the stage of the BLV provirus in the blood leukogram of infected animals was characterized by pronounced lymphocytosis on the 21st day of the experiment. The highest concentration of antibodies to BLV in the blood serum was found on the 90th day after the administration of the virus-containing material, which disappeared from the blood on the 150–180th day after infection. In experimental rabbits, after five months for thirty days, in the absence of antibodies to leukemia in the blood serum, multiple tumors of a dense consistency began to develop throughout the body. Such clinical signs and changes in the of rabbits’ blood of the experimental group are characteristic of serologically positive cows on the hematological development stage of leukemic process and correlate with the results of domestic and foreign authors. The presence of a large number of lymphoblasts, as well as leukolysis cells, in the histological preparation of lymph nodes, lungs, heart and the accumulation of lymphocytes’ immature forms around the interlobular vessels of the liver, which were found in pathohistological studies of the experimental rabbits’ organs, may indicate the development of the leukemia process on early stage in them. The results obtained indicate the ability of BLV to overcome successfully the interspecies barrier upon parenteral ingestion of heterologous individuals from infected lymphocytes and in the form of a culture antigen.

scholarly journals MASKED GENOTYPE 6 OF BOVINE LEUKEMIA VIRUS IS FOUND IN COLOMBIAN CATTLE

2019 ◽  
Author(s):  
Adriana Patricia Corredor-Figueroa ◽  
Nury Nathalia Olaya-Galán ◽  
Sandra Patricia Salas ◽  
Juan Sebastián Quintero ◽  
Álvaro Fajardo ◽  
...  
Keyword(s):  
Genetic Variability ◽  
Bovine Leukemia Virus ◽  
Phylogenetic Analyses ◽  
Leukemia Virus ◽  
Gene Analysis ◽  
Economic Losses ◽  
Envelope Gene ◽  
Genotype 1 ◽  
Global Epidemiology ◽  
Bovine Leukosis

Abstract Background Viral diseases such as bovine leukosis are a major cause of health problems associated with economic losses in the livestock industry worldwide. The prevalence of bovine leukosis ranges between 4% and 90%, and this disease is considered endemic. The etiological agent is bovine leukemia virus (BLV). Ten BLV genotypes have been reported based on analysis of complete or partial envelope gene sequences, of which genotype 1 is the most prevalent. However, the genetic variability of BLV variants circulating in Colombia remains unexplored. Therefore, in the present study, we analyzed blood samples collected from 289 cows distributed in 75 farms across the country. PCR amplification of env, gag and tax gene segments was performed. The obtained amplicons were sequenced and then subjected to phylogenetic analyses. Results A total of 62% of the cows present at 92% of the farms were BLV-positive. Genotype 1 was exclusively detected by env and gag gene segments when analyzed using previously reported primers. However, tax gene analysis revealed circulation of genotype 6 variants, which were also detected based on env gene analysis with newly designed primers. These results indicate that current genotyping approaches based on partial env sequencing may bias BLV genetic variability approaches and underestimate the diversity of the detected BLV genotypes. Conclusions This report is the first molecular and epidemiological study of BLV conducted in Colombia and contributes to the global epidemiology of the virus; it also reinforces the great impact of BLV on the country’s livestock and thus is a useful resource for farmers and government entities.

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