Feline Leukemia Virus Detection by ELISA and PCR in Peripheral Blood from 68 Cats with High, Moderate, or Low Suspicion of having FeLV-Related Disease

Abstract

Abstract. Clinicopathologic criteria were used to group 68 cats according to high, moderate, or low suspicion of having feline leukemia virus (FeLV)-related disease. Peripheral blood samples were tested for FeLV antigen by enzyme-linked immunosorbent assay (ELISA) and for FeLV DNA by polymerase chain reaction (PCR). There was no significant difference between ELISA and PCR results in the 68 cats. In the high-suspicion group, 46% (11/24) of cytopenic cats were test positive (ELISA and PCR) and 87% (13/15) with hemopoietic neoplasms were test-positive. Also within the high suspicion group, test-positive cats were 2.5 times more likely to die within the 1 year follow-up period than were test-negative (ELISA and PCR) cats. Among cats in the moderatesuspicion group, 15% (2/13) were test-positive, and none (0/16) of the cats in the low suspicion group was test positive. The relative risk of a positive test (ELISA and PCR) in the high suspicion group was 3.7 times that for the moderate-suspicion group and 22.8 times that for the low suspicion group. There was no significant difference in the relative risk of a positive test result between the moderate and low suspicion groups. The results indicate that FeLV detection by PCR can be adapted for diagnostic purposes using peripheral blood samples, however, results do not differ significantly from FeLV ELISA results. Also, a proportion of cats with a high suspicion of having FeLV-related cytopenia and hemopoietic tumors are negative for both circulating FeLV antigen and DNA. These cats may not have FeLV-related disease, or FeLV may exist in a diseaseproducing but nonreplicating form ultimately detectable by PCR in tissues other than peripheral blood.Feline leukemia virus (FeLV) is a horizontally transmitted oncogenic, myelosuppressive, and immunosuppressive retrovirus and represents the most important pathogen of domestic cats. 8,32 Both degenerative and neoplastic conditions of the hemopoietic system can be directly related to naturally occurring FeLV infection. 6,7,9,32,33 A proportion of cats have clinicopathologic findings consistent with FeLV infection but are FeLV negative using antigen detection tests that rely on viral replication. Circulating FeLV antigen is present in about 70% of cats with nonregenerative anemia, 88% with myeloproliferative disease (excluding lymphosarcoma), 70% with lymphosarcoma, and 80% with myelodegenerative disease. 2,7 However, there is evidence that incorporation of FeLV within the DNA of host cells without accompanying viral replication causes disease in some cats. 11,15,25,34,41 Also, high levels of unintegrated FeLV DNA have been associated with disease progression of the acquired immunodeficiency strain of FeLV. 28 Traditionally, FeLV infection has been diagnosed using the immunofluorescent antibody From the Departments of Veterinary Miciobiology (Jackson, Haines, Misra) and Veterinary Internal Medicine (Taylor), Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada.Received for publication F...

Trap-Neuter-Return Activities in Urban Stray Cat Colonies in Australia

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Development and application of a quantitative real-time PCR assay to detect feline leukemia virus RNA

“…With the advent of molecular diagnostics, conventional PCR to detect FeLV DNA was employed in attempt to better understand these discrepant results (Jackson et al, 1996;Miyazawa and Jarrett, 1997;Herring et al, 2001), but the assay did not appear to have increased sensitivity.…”

Detection of Antibodies to the Feline Leukemia Virus (FeLV) Transmembrane Protein p15E: an Alternative Approach for Serological FeLV Detection Based on Antibodies to p15E

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