Seroprevalence of bovine leukemia virus in cattle and buffaloes in the border provinces of the Eastern Anatolia region, Türkiye: insights into the eradication of infection

Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis, an oncogenic deltaretrovirus that has emerged as a potential zoonotic infection. The BLV naturally infects cattle and causes economic losses through a slow persistent infection with various clinical symtoms following preleukosis. The main objective of this study was to determine the seroprevalence of BLV antibodies in cattle and buffaloes in the border provinces of the Eastern Anatolia region, Türkiye, using the agar gel immunodiffusion (AGID) assay and  enzyme-linked immunosorbent assay (ELISA). For this purpose, a total of 1,033 serum samples were collected from 982 cattle and 51 buffaloes from the provinces of Ağrı (n = 178), Iğdır (n = 252), Kars (n = 317), Van (n = 221), and Hakkari (n = 65) during 2021 - 2022. In AGID and ELISA tests, seropositivity for BLV-specific antibodies was not detected in cattle and buffaloes from the mentioned provinces. This study revealed that BLV was not circulating in cattle and buffaloes in the easternmost border provinces of Türkiye during the sampling period and contributed to determine the status of BLV in the mentioned region. Due to the presence of virus in other regions of Türkiye and neighboring countries, Iran and Iraq, it is recommended to control animal movements, continue efforts to combat the transmission of the virus, and maintain control measures.