Detection of bovine leukemia virus in pasteurized milk from a number of industrial milk factories in Iran by Nested Polymerase Chain Reaction (PCR)

<p style="text-align: left;">Bovine leukemia virus (BLV) as the causative agent of enzootic bovine leukosis (EBL) is a retrovirus which is closely related to type 1 and 2 leukemia virus of human T cells and it is also considered as a possible cause of breast cancer in women. The virus is transmitted to humans through animal products such as milk and meat. This study aimed to detect DNA of bovine leukemia virus in pasteurized milk. For this purpose, pasteurized milk belonging to 5 industrial factories of Tehran, Mazandaran, Khuzestan and Fars provinces available in Ahvaz stores (10 milk samples from each factory with different production dates) were sampled and stored at -20 degrees centigrade until examination. They were examined by nested PCR to detect bovine leukemia virus DNA. Out of 50 samples of pasteurized milk from different factories, 14(28%) samples were positive. Statistical analysis using Fisher's exact test also showed that there was no significant difference between milk produced by different factories (p=0.423) and also between factories in Tehran and other provinces (p=0.198). The results of this study showed that the virus is present in pasteurized milk, but whether it is active or not requires further investigation.