Feline leukemia causes a great variety of disease, which include: immunosuppression, neoplasia (cancers), anemia, immune-mediated diseases, and gastroenteritis,
1. Immunosuppression: There is an increased susceptibility to bacterial, fungal, protozoal, and other viral infections.
2. Neoplasia: Most commonly the mediastinal, multicentric, or spinal forms of lymphoma. However it is also found less commonly in renal and other cancers.
3. Anemia is usually a non-regenerative anemia, and can be associated with the disease haemobartonella (cat scratch fever).
4. Immune-mediated diseases: excess antigen against Feleuk can cause systemic vasculitis (the body attacks its own blood vessels) , glomerulonephritis (the body attacks it's own kidneys), polyarthritis (the body attacks it's own joints), and a variety of other immune disorders.
5. Gastroenteritis: anorexia, depression, vomiting, and diarrhea.
Since Feleuk can cause problems anywhere in the body, the symptoms would depend upon where the disease is located. For example in the gastroenteritis form, anywhere from the mouth to the anus can be effected. There could be mouth problems such as stomatitis, chronic periodontal disease, in addition to vomiting and diarrhea.
In the polyarthritis, immunosuppressive form, a cat could have lameness, joint swelling and pain.
Due to the immunosuppression, a cat could have frequent upper respiratory infections, for example, and be infected with other diseases which should be treated, such as haemobartonella.
Thank you for the information. Based on what I read in your response, Buddy seems to have the immunosuppression form. He has the runny eyes, loud breathing, some coughing, snoring. He is also missing several teeth but my guess it was from his previous environment. Even with teeth missing, he prefers crunchy food to wet. Does not present with diarreha or vomiting.