Cat leukemia virus can be transmitted by vertical infection (mother-child) or horizontal infection (cat-cat). It is infected by saliva, runny nose, and tears of the infected individual, and a large amount of virus is secreted into the mother's breast milk. It is the first infection from the pharynx and moves to the bone marrow to progress viremia. Symptoms include anemia, lymphoma, immune suppression reactions, immune-mediated diseases, and enteritis.