Occurrence of Cross-Reaction Between Canine Visceral Leishmaniasis and Ehrlichiosis By Enzyme-Linked Immunosorbent Assay (ELISA), Indirect Immunofluorescent Antibody Test (IFAT) and Immunochromatographic Dipstick Test
M.F. Zanette1; V.M.F. Lima1; M.D. Lauenti2 ; J.P. Vides1; D.L. Silva1; C.N. Rossi1; F.A. Ikeda-Garcia1; F.A. Rosa1; L.S.V. Sobrinho1; D.C. Costa1; S.H.V. Perri1; M.K. Hagiwara2; M. Marcondes1
The diagnosis of canine leishmaniasis is a complex task for the clinician because the disease can adopt a broad spectrum of clinical features and the laboratory findings, such as renal and liver function, hematology and urinalysis are frequently not conclusive. Therefore, the detection of specific anti-Leishmania circulating antibodies by means of serologic methods became the most valuable tool for the diagnosis in Brazil. However, the specificity of the serological tests may be harmed due to the occurrence of cross-reaction among diseases such as ehrlichiosis. Thus, the aim of this work was to determine the occurrence of cross-reaction between Ehrlichia canis and Leishmania chagasi antigens, by ELISA, indirect immunofluorescent antibody test (IFAT) and immunochromatographic dipstick test. The ELISA and indirect immunofluorescence assay were performed using L. chagasi promastigote antigen while the immunochromatographic test employed rK39 antigen. The study was carried out with a group of 13 experimentally E. canis infected dogs. Of the 13 sera samples tested for visceral leishmaniasis, one (7,7%) were positive by ELISA and by immunochromatographic test and all of them were found to be negative by indirect immunofluorescence test. According to the results obtained in the present study it was possible to conclude that cross- reaction between Ehrlichia canis and Leishmania chagasi antigens may occur and, among the three methods assessed, the indirect immunofluorescence test seemed to be the best choice when double infection with E. canis and L. chagasi is suspected.