Feline leukemia symptoms are very varied and often difficult to spot, even for a pro.
Because cat leukemia causes a general reduction in the cat's ability to fight infections, a cat with the leukemia virus becomes more susceptible to all sorts of infections.
As a result, it's sometimes difficult to tell if these are just "one-offs" or if they're a sign of something more serious.
If your cat gets an infection once in a blue moon which he quickly recovers from (maybe with the help of antibiotics), chances are he's fine.
But if he's getting repeat infections and multiple other problems which aren't clearing up easily, there's a possibility he could be showing signs of feline leukemia or another serious disease (e.g. feline immunodeficiency virus).
This page lists some of the main signs of feline leukemia. But please remember - some may indicate other diseases, and the only way to find out what's going on for sure is by a trip to the vet.
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At the time of infection, the signs of feline leukemia are mild - often just a slight fever and lethargy.
Months, or even years after infection, the cat may start to get frequent, recurring infections. These may show themselves as:
The virus can also cause cancer of the white blood cells; about 20 percent of cats with FeLV die from cancer.
If your cat is showing some of the above feline leukemia symptoms, or if he seems to be repeatedly getting infections, I'd advise you to take him to the vet as soon as you can.
Try not to worry unduly (extremely hard, I know...) In a lot of cases, there may be other, easily treatable causes. But like all cat health problems, the sooner you can get them diagnosed and treated, the better.