HEMATOLOGICAL FINDINGS IN CATS NATURALLY INFECTED WITH FELINE IMMUNODEFICIENCY VIRUS

The types and prevalence of haematological abnormalities occurring in FIV infected cats were determined. In addition, the role of FIV infect ion per se in influencing haematological values was examined by analys ing results between infected and non-infected cats which had been allo cated to similar clinical disease groups. FIV-positive cats were group ed as asymptomatic carriers (AC), cats with AIDS-related complex (ARC) or AIDS. FIV-negative cats were placed into matched groups using the same criteria and designated as healthy, 'ARC' or 'AIDS'. Healthy FIV- negative cats also formed the reference ranges for peripheral blood an d bone marrow. Anaemia was no more frequent in sick ('ARC' and 'AIDS') FIV-positive cats than sick ('ARC' and 'AIDS') FIV-negative cats. How ever, it was observed more frequently in FIV-positive cats than FIV-ne gative cats in the absence of concurrent disease, suggesting a direct effect of FIV infection. Bone marrow was affected by FIV infection, as evidenced by anaemic FIV-positive cats having proportionally less Typ e I reticulocytes than anaemic FIV-negative cats. In addition, FIV-pos itive cats demonstrated proportionally fewer mature erythroid cells in their marrow. This implied that FIV may cause a decreased life span o r maturation arrest of the erythroid cell line. Lymphopenia and eosino penia were seen more frequently in AC FIV-positive cats than healthy F IV-negative cats, suggesting the direct involvement of FIV. Thus, alth ough FIV infection affected some haematological findings in AC cats, i t appeared that haematological abnormalities in sick FIV-positive cats may be due as much to the disease state as to the virus specifically. Apart from the subjective assessment that bone marrow of FIV-positive cats appeared hypercellular, there were no pathognomonic features for FIV infection.