Molecular Detection of Feline Leukemia Virus in Oral, Conjunctival, and Rectal Mucosae Provides Results Comparable to Detection in Blood.

Feline leukemia virus (FeLV) infection causes immunosuppression, degeneration of the hematopoietic system, and fatal neoplasms. FeLV transmission occurs mainly by close social contact of infected and susceptible cats. Developing procedures for the diagnosis of feline retroviruses is crucial to reduce negative impacts on cat health and increase the number of animals tested. Blood collection requires physical or chemical restraint and is usually a stressful procedure for cats. Our objective was to evaluate the use of samples obtained from oral, conjunctival, and rectal mucosae for the molecular diagnosis of FeLV. Whole blood and oral, conjunctival, and rectal swabs were collected from a total of 145 cats. All samples were subjected to the amplification of a fragment of the gene of proviral DNA. Compared to blood samples used in this study as a reference, the accuracies for each PCR were 91.72, 91.23, and 85.50% for samples obtained by oral, conjunctival, and rectal swabs, respectively. The diagnostic sensitivity and specificity were 86.11 and 97.26% for the oral swabs, 90 and 92.59% for the conjunctival swabs, and 74.24 and 95.77% for the rectal swabs, respectively. The kappa values for oral, conjunctival, and rectal swabs were 0.834, 0.824, and 0.705, respectively. The diagnosis of these samples showed the presence of proviral DNA of FeLV in oral and conjunctival mucosae. In conclusion, mucosal samples for the molecular diagnosis of FeLV are an excellent alternative to venipuncture and can be safely used. It is faster, less laborious, less expensive, and well received by the animal.