Laboratory and clinical findings and their association with viral and proviral loads in cats naturally infected with feline leukemia virus

•Myelodisplastic disorders are associated with higher bone marrow proviral loads.•Viral and proviral loads in serum or bone marrow classify the infection stage.•Molecular methods to detect feline leukemia virus for endemic areas.•Severity of hematological disease depends of leukemia viral and proviral loads. This study was conducted to correlate clinical, laboratory, and bone marrow (BM) changes in cats naturally infected with feline leukemia virus and their association with viral loads in blood and BM and proviral loads in BM. Cats were classified into five groups based on antigenemia, clinical and/or laboratory findings and viral/proviral loads, according to a prospective study: symptomatic progressive (GI); asymptomatic progressive (GII); regressive (GIII); unclassified (GIV); or healthy (GV). |Correlations between these five groups and viral/proviral loads were evaluated. High viral and proviral loads were detected in GI and GII and viral loads were significantly associated with laboratory signs. Proviral loads detected in BM were significantly lower in GIII and GIV. GI cats were more likely to develop hematopoietic disorders than those from the other groups. Hematological and clinical disorders and disease severity are related to higher viral blood and proviral BM loads.