Animals infected with EBL virus will pass slaughter inspection because the infection is not transmissible to humans. Once clinical signs develop or tumours are detected in more than one internal organ, the carcass is likely to be condemned. Diagnosis of the disease is based on the observation of clinical signs and is confirmed by an autopsy or laboratory examination of biopsy tissue. When an animal has been diagnosed as having clinical enzootic bovine leukosis, the animal should be slaughtered or euthanized for humane reasons. Once an animal becomes infected with the EBL virus, it remains infected for life.
Antibodies usually appear in the blood about two weeks after the animal becomes infected.
The AGID test therefore is useful in detecting infected animals before clinical signs develop. Calves under six months of age pay give a false positive test because of antibodies absorbed from colostrum of infected cows. In some countries the prevalence EBL has been drastically reduced using blood tests to detect infected animals which are then culled for slaughter. At the present time, there is no national policy to eradicate EBL from Canada because the cost of such a program far outweighs the costs currently associated with the disease. Individual herd owners may wish to eradicate EBL from their own herds on a voluntary basis.