Detection and Identification of Enzootic Bovine Leukosis (EBL) in Calves in Iran

Enzootic bovine leukosis (EBL) is known as bovine lymphosarcoma and normally affects the old cattle. EBL is caused by bovine leukemia virus (BLV), which is generally spread all around the world. This virus is transmitted via bovine blood products within and between cattle herds. Glycoprotein GP51 in the blood is responsible for cattle immune responses to BLV. This virus has been previously detected in cattle and even in the calf. However, to the best of my knowledge, this is the first short communication reporting the detection of EBL in calves in Iran. The samples of the present study were obtained from two calves of different mothers within the same dairy farm of 2000 cattle, located near Tehran, Iran. General clinical signs of the two calves, such as heart rate, respiratory rate, and body temperature were recorded. The clinical observations were confirmed by hematological tests, histopathological examination, enzyme-linked immunosorbent assay, polymerase chain reaction, and phylogenetic analyses. The originality of the detected virus was assessed by blasting against the other strains of BLV available on the NCBI web page. Regarding the clinical symptoms, bulging eyes were noticeable. Moreover, atypical and malignant lymphocytes were detected in the circulatory system and periorbital tissue. It should be noted that the presence and expression of GP51 in both calves and cattle was similar to the previously detected ones in Korea and Japan. The latter result confirms the originality of retrovirus structural subunit GP51.  Similar observations were reported in a six-month follow-up.