Abstract
Simple SummaryBovine leukemia virus (BLV) is distributed worldwide and affects dairy cattle causing significant economic losses. This study’s objective was to assess the risk factors associated with BLV infection and identify the Egyptian BLV strain’s genetic diversity. The overall seroprevalence of BLV infection in Egyptian dairy cattle was 18.2%, and the grazing cattle in the losing house system had a higher probability of getting BLV infection. The sequencing and phylogenetic analysis for one Egyptian BLV strain was performed, and the obtained results confirmed the clustering of Egyptian BLV strain into genotype-1.Bovine leukemia virus (BLV) is distributed worldwide and affects dairy cattle causing severe economic losses. The BLV has been serologically reported in Egypt, but few studies have evaluated its associated risk factors and genetic classification. Therefore, this study assessed risk factors associated with BLV infection and identified the genetic diversity of the Egyptian strain. The study was conducted on 500 dairy cattle distributed in four Governorates located in Northern Egypt. Overall, the seroprevalence of BLV infection among Egyptian dairy cattle was 18.2%. The grazing cattle in the losing house system had higher odds for BLV seropositivity, and bad practice such as the use of a single needle or one plastic glove for more than one animal was considered a significant risk factor for BLV infection. Besides, the sequencing and phylogenetic analysis for one Egyptian BLV strain was performed, and the obtained results confirmed the clustering of Egyptian BLV strain into genotype-1. The assessment of associated risk factors for BLV infection and determination of its genetic classification are essential to implement an effective control program.
Highlights
Bovine leukemia virus (BLV) is an etiological agent of enzootic bovine leukosis (EBL), belonging to the genus of Deltaretrovirus of the family Retroviridae [1,2].EBL is spread worldwide and is highly prevalent in North and South America, Asia, Eastern Europe, and some Middle Eastern countries [3,4,5,6]
EBL in cattle has three stages: first, the silent stage, characterized by the aleukemic form in which the animal is serologically positive without lymphocytosis; second, persistent lymphocytosis (PL)
The results revealed that the number of seropositive cattle increased significantly among gazing animals (26.3%, 95% CI: 17.8–36.8), raised under loose housing conditions (31.5%, 95% CI: 24.1–39.9)
Summary
Bovine leukemia virus (BLV) is an etiological agent of enzootic bovine leukosis (EBL), belonging to the genus of Deltaretrovirus of the family Retroviridae [1,2].EBL is spread worldwide and is highly prevalent in North and South America, Asia, Eastern Europe, and some Middle Eastern countries [3,4,5,6]. BLV could be shed in the various secretions of infected animals such as blood, milk, semen, saliva, and nasal secretion and transmitted mainly through vertical and horizontal routes via biting insects [7,8]. Horizontal transmission can occur by direct contact of mucosa or the abraded skin of susceptible animals with infected secretions. Occurring in 30% of infected animals, characterized by polyclonal expansion of B cells and the majority of which harbor the BLV provirus; third, leukemia 1–10% of infected animals could develop malignant lymphosarcoma with a long period of latency of about 1–8 years [3,9]. The distribution of EBL among dairy cattle causes severe economic losses due to prematurely culling, poor reproductive performance, decreased milk production, and the longevity of infected cattle [10,11,12]. The investigation and elimination of cattle with high viral loads are crucial in controlling the disease and sustaining animal production [13]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
