Feline leukemia virus (FeLV) is a common cause of abnormally low numbers of red blood cells (anemia) in cats. As many as 70% of cats with anemia test positive for FeLV.
While FeLV causes more than one kind of anemia, non-regenerative anemia is probably the most serious. In this type of anemia, the virus destroys the parent cells of red blood cells, and new red blood cells are not produced. The life span of a normal feline red blood cell is about 75 days. As these cells die of old age, the absence of new cell production results in a progressive anemia.
Non-regenerative anemia frequently occurs in relatively young (2- to 3-year-old) cats. While occasionally a cat with FeLV-induced non-regenerative anemia recovers, treatment is usually not curative. However, prompt, aggressive therapy can often extend life and improve patient comfort.