Cross-Reaction of Sera from Patients with Various Infectious Diseases with Leishmania infantum

Objective: To compare and evaluate the application of indirect fluorescent antibody (IFA) and counterimmunoelectrophoresis (CIEP) for laboratory identification of visceral leishmaniasis. Materials and Methods: Serum samples from patients with malaria (Plasmodium vivax, n = 86; Plasmodium falciparum, n = 38), brucellosis (n = 26), tuberculosis (n = 31) and typhoid fever (n = 35) were examined for the presence of antibody to Leishmaniainfantum antigen using IFA and CIEP tests. Results: Using IFA, false-positive results were malaria (P. vivax 19.8%, P. falciparum 13.2%), tuberculosis (6.4%), brucellosis (3.8%), and typhoid fever (2.8%). Using CIEP, a lower percentage of false-positives was observed only among malaria patients (P. vivax 2.3%, P. falciparum 2.6%). Serum samples from patients with other infectious diseases were negative in the CIEP test. Conclusion: Based on the results of this study, the CIEP technique is recommended for immunodiagnosis of visceral leishmaniasis, especially in regions where malaria, brucellosis and tuberculosis are prevalent.