North American Veterinary Licensing Examination (NAVLE) Practice Test

The most probable long-term outcome for a cat that tests positive for FeLV (Feline Leukemia Virus) infection is a strong chance of lifelong FeLV infection. Feline Leukemia Virus is known to cause a persistent and chronic infection in cats, particularly after the initial stages of infection. Once a cat is infected with FeLV, the virus typically integrates into the cat's genome, leading to a situation where the cat remains a lifelong carrier and has a higher risk of developing associated diseases such as immunosuppression, lymphosarcoma, and other health complications.

Transient infections can occur, particularly in young cats or in situations where the cat's immune system successfully combats the virus. However, a positive test result in an adult cat usually indicates a more established infection rather than a transient one. The vaccination status and the health of the cat can influence outcomes, but those with a confirmed positive FeLV test are generally expected to have a lifelong infection.

Regarding the other possible outcomes, while additional testing like an ELISA test or a Western blot may be used to confirm the initial diagnosis or gauge infection status, the identification of a positive FeLV result typically points to a chronic infection without the implication of needing to verify the diagnosis further for long-term prognosis.