Detection of feline leukaemia virus in blood and bone marrow of cats with varying suspicion of latent infection

Abstract

The purpose of this study was to determine if polymerase chain reaction (PCR) could be used to detect FeLV proviral DNA in bone marrow samples of cats with varying suspicion of latent infection. Blood and bone marrow samples from 50 cats and bone marrow from one fetus were collected, including 16 cats with diseases suspected to be FeLV-associated. Serum enzyme-linked immunosorbent assay (ELISA), blood and bone marrow immunofluorescent antibody test (IFA), and blood and bone marrow PCR were performed on each cat, and IFA and PCR on bone marrow of the fetus. Forty-one cats were FeLV negative. Five cats and one fetus were persistently infected with FeLV. Four cats had discordant test results. No cats were positive on bone marrow PCR only. It appears persistent or latent FeLV infection is not always present in conditions classically associated with FeLV.

Fig 1.

Results of polymerase chain reaction of feline leukaemia virus on ethidium-bromide stained gel. Expected size 495 bp. Lane 1, 100 bp molecular size marker, arrow indicates 500 bp; 2, PCR product from FL74 (persistently infected FeLV cell culture) used as positive control; 3, PCR product from negative control; 4, PCR product from blood of cat 12; 5, PCR product from bone marrow of cat 12; 6, PCR product from blood of cat 10; 7, PCR product from bone marrow of cat 35.