Related Experiment Video
Updated: Oct 20, 2025
Application of Long-term cultured Interferon-γ Enzyme-linked Immunospot Assay for Assessing Effector and Memory T Cell Responses in Cattle
Published on: July 11, 2015
Isolation of Bovine leukemia virus from cows with persistent lymphocytosis in Iraq
Yahia Ismail Khudhair1, Ahmed Majeed Al-Shammari2, Saleem Amin Hasso3
1Department of internal and preventive Medicine, College of Veterinary Medicine, University of Al-Qadisiyah, Iraq.
Insights
This study isolated bovine leukemia virus (BLV) from Iraqi cattle, identifying its genetic similarity to other global strains. Findings confirm persistently lymphocytotic cattle as a source for BLV isolation and characterization.
Area of Science:
- Veterinary Virology
- Molecular Epidemiology
Background:
- Bovine leukemia virus (BLV) is a significant pathogen affecting cattle globally.
- Persistent lymphocytosis (PL) is a clinical manifestation associated with BLV infection.
- Limited data exists on BLV strains prevalent in the Middle East, specifically Iraq.
Purpose of the Study:
- To report the first isolation and characterization of bovine leukemia virus (BLV) from cattle in Iraq.
- To investigate the cytopathic effects and genetic relatedness of the Iraqi BLV isolates.
- To establish a foundation for future BLV control strategies in Iraq.
Main Methods:
- BLV detection in seropositive cattle using ELISA, followed by isolation from peripheral blood mononuclear cells.
- Cytopathology assessment in primary fetal calf kidney (FCK) cells and cell line cultures.
- Viral confirmation via PCR, immunocytochemistry using anti-gp51 monoclonal antibody, and phylogenetic analysis of the gp51 env gene.
Main Results:
- BLV was successfully isolated from two crossbred cows with persistent lymphocytosis in Iraq.
- Isolates induced characteristic cytopathic effects, including syncytia formation and plaque formation in FCK cells.
- Phylogenetic analysis showed the Iraqi BLV strain is 100% homologous to the Turkey strain and closely related to other global strains.
Conclusions:
- BLV-infected cattle with persistent lymphocytosis are a viable source for viral isolation.
- The cytopathological features of BLV infection vary with cell type.
- This study provides the first report of BLV isolation in Iraq, offering insights into the Iraqi BLV strain for disease control efforts.
Abstract:
This is the first study to report on the isolation of bovine leukemia virus (BLV) from peripheral blood mononuclear cells of two cross bred cows in Iraq. The cattle were seropositive by ELISA when selected while being surveyed for the detection of BLV. Among six cows, two were cases of persistent lymphocytosis (PL). Cytopathology was characterized by the formation of multinucleated giant cells (syncytia) and cytoplasmic vacuoles. Moreover, the viruses produced clear plaques on the monolayer of the primary fetal calf kidney (FCK) cells. Inhibition of plaque formation by BLV-antisera suggested a diagnosis of BLV, which was further confirmed by PCR. Cells infected with the isolates were positive to a monoclonal antibody against the viral gp51 trans-membrane glycoprotein by immunocytochemistry. Both isolates replicated and induced cytopathic effects in bovine and human cell line cultures. Phylogenetic analysis based on partial gp51 env gene sequences revealed that Iraqi strain highly homogenous with Turkey strain (100%) and had 1% distance value with other world strains. In conclusion, this present study found that BLV-infected cattle with PL can be a source for viral isolation, and the cytopathological features of the virus infection are arranged and differ depending on the cell type. This is the first study to report on the isolation of the EBL virus in Iraq, and it provides the basis for further studies about a BLV Iraqi strain that can help control this disease.
