Feline leukemia virus (FeLV)
infection affects cats worldwide. The course of FeLV
infection can change and vary over time. The complex pathogenesis, the availability of many different testing methods, and the interpretation of test results are often challenging for veterinarians. Cats with progressive
infection (persistently
p27 antigen-positive) shed FeLV mainly through saliva and are therefore considered a source of
infection for uninfected cats. Diagnosing regressive
infection is often challenging, since it usually cannot be detected by commonly used point of care-tests (
p27 antigen test) and thus, it often remains undetected. Nevertheless, cats with regressive
infection are FeLV carriers (provirus-positive) and when the immune system is suppressed, reactivation of the
infection and FeLV-associated clinical signs can occur. Abortively infected cats are never viraemic, do not shed virus, and do not develop clinical signs. Abortive
infection can solely be diagnosed via
antibodies detection in blood. A new point-of-care test for the identification of
antibodies against FeLV p15E
antigen has recently been introduced on the European market and is currently being evaluated.