Unfortunately, FeLV cannot be cured. The secondary bacterial inflammations should be fought with antibiotics. Experimental use is made of Interferon from Virbac. This is an expensive treatment, but to be successful. However, it is still unclear whether this will become THE therapy for cats with FeLV.
Cats that are sick will, unfortunately, die. (50% will have died within one year, 90% within three years) How long the cat can live with his disease depends on the symptoms and his resistance. The cat should, in any case, be kept separate from other cats in connection with infecting other cats. This means that the cat should not go outside either, because it can then infect other cats.
The most commonly used test method is the Snap Combo-test (ELISA) of Idexx. With this test, the virus is detected in the blood. With some blood taken from the cat, a result can be determined within a few minutes. You can wait for the results. The test is very reliable. A negative effect also means no FeLV. In the case of a positive outcome, the blood will also have to be sent to a specialized laboratory for confirmation. This is necessary because false-positive results can occur.