Serological Diagnosis of Feline Tegumentary Leishmaniasis by Indirect Immunofluorescence (IFI) and Enzyme-Linked Immunosorbent Assay (ELISA) in an Endemic Area in Brazil

Background: American tegumentary leishmaniasis (ATL) is a serious public health problem, and the participation of domestic cats in its epidemiological process has not yet been fully elucidated. Therefore, the standardization of monitoring methodologies of cat populations becomes important for the generation of information on the disease. In Brazil, ATL presents a wide geographical distribution, being Leishmania (Viannia) braziliensis its etiologic agent of ATL in Rio de Janeiro. The main objective of the present study was investigate the presence of specific anti-Leishmania (Viannia) braziliensis Immunoglobulin G (IgG) in 34 cats from an ATL endemic area in this municipality. Materials, Methods & Results: Sera from three cats from the study area naturally infected with Leishmania (Viannia) braziliensis were used as positive control. Analyses were performed with antigen preparations using indirect immunofluorescence (IFI) and enzyme-linked immunosorbent assay (ELISA). We found prevalence rates of 20.6% (7/34) in the IFI and 14.7% (5/34) in the ELISA. Specificity was 87.1% for the IFI and 93.5% for the ELISA, and both tests presented sensitivity of 100%. Concordance between the used tests was assessed as moderate. Discussion: By conducting a feline serological survey in an endemic area for ATL we provide information on the involvement of this species in such epidemiological process. In this context, the participation of the cat in cycles of leishmaniases has been highlighted by several authors; infection of the phlebotomine by parasites originated from this vertebrate host can already be demonstrated by xenodiagnosis and several cases of feline infection have been reported in endemic regions of several countries such as Brazil, Spain, France, Portugal, Greece, Iran, Israel and Italy. Therefore, the standardization of diagnostic techniques that support the screening and monitoring of such populations becomes of utmost importance. In fact, the use of the IFI and ELISA serological techniques, showing sensitivity and NPV of 100%, confirm the use of such tools in epidemiological surveys for the detection of anti-L. (V.) braziliensis antibodies in domestic cats, and these methodologies are frequently employed in canine surveys showing good results. The serological titers found in this study for Leishmania (V.) braziliensis are similar to those of studies carried out with cats in endemic areas of visceral leishmaniasis in Spain. This similarity shows that the titers can be high even when L. (V.). braziliensis is the etiological agent. It is worth mentioning that these values are significant when compared with those of canine studies carried out in ATL endemic regions. Ultimately, the sample refers to an ATL endemic region located in Brazil, one of the countries with the highest endemicity levels of cutaneous leishmaniasis in the world and, therefore, an important area for the implementation and evaluation of diagnostic techniques for the generation of data on the disease and its possible hosts. Thus, the present study provides information on the occurrence of ATL by Leishmania (V.) braziliensis in domestic cats; demonstrates that the methodologies employed were favorable to the use of such techniques as tools in epidemiological surveys for the diagnosis of feline tegumentary leishmaniasis; and paves the way for further studies on the subject.