The symptoms of this disease vary greatly from fever to forms of cancer. It is difficult to diagnose leukemia on the symptoms alone. Blood tests are valuable as an aid in diagnosing the disease but sometimes the virus can hide in the bone marrow of an infected cat for years with a negative leukemia test. Testing before vaccination is recommended. Cats with leukemia will have lowered immune systems and can remain carriers for life.
Positive cats are susceptible to other infections due to a depressed immune system.
The symptoms vary depending on the cat but the immune system is always lowered. Positive cats never get rid of the virus and are susceptible to other conditions due to a depressed immune system. The virus is spread through the bite of another cat. Fortunately the incidence of FIV is not high for indoor cats. Feline Infectious Peritonitis FIP is a very serious disease that is almost always fatal.