Performance of 5 commercial ELISA kits for the detection of antibody to bovine leukemia virus

To prevent significant economic losses, some countries have successfully eradicated enzootic bovine leukosis (EBL), which is caused by bovine leukemia virus (BLV) infection. In Serbia, efforts to eliminate EBL commenced in the late 1990s. Recognizing the disparities in test selection among laboratories and variations in quality, we evaluated the diagnostic sensitivity and specificity of commercial ELISAs using field samples in Serbia. Using 5 commercial ELISA kits, we tested 138 cattle serum samples, submitted for confirmatory testing between 2020 and 2023, along with 100 serum samples from BLV-negative herds. We found 100% agreement of the ID Screen BLV Competition (IDvet), Svanovir BLV gp51-Ab (Svanova), and INgezim BLV Compac 2.0 (Ingenasa) ELISAs. We observed 93% agreement comparing these 3 kits to the Bovine Leukemia Virus Antibody test kit (VMRD). Agreements of 92% and 88.4% were determined between Idexx and IDvet, Svanova, and Ingenasa kits, and between Idexx and VMRD kits, respectively.