Evaluating the performance of IFAT, RDT, and semi-nested PCR for detection of Leishmania infantum infection on sera samples in symptomatic dogs

Zoonotic visceral leishmaniosis is caused by Leishmania infantum in the Mediterranean region and the Middle East, and dogs are the main reservoirs of the disease. The aim of this study was to estimate the diagnostic results of indirect immunofluorescent antibody test (IFAT), rapid diagnostic test (RDT), and semi-nested PCR to detect L. infantum infection on sera samples of symptomatic dogs in an endemic area of Iran. In this study, 23 clinically infected dogs and 75 clinically suspected dogs were selected for the study and sera samples were examined using IFAT, RDT, and semi-nested PCR. Among clinically suspected dogs, 72% (54 /7 5), 26% (13/50), and 36% (27/75) of sera samples were positive for L. infantum by IFAT, semi-nested PCR, and RDT, respectively. A poor agreement was observed between IFAT and semi-nested PCR. A slight agreement was observed between IFAT with PCR and RT methods, and the worse agreement was observed between semi-nested PCR and RDT. The sensitivity and specificity of RDT and semi-nested PCR were calculated according the IFAT results on clinically suspected dogs. The RDT and semi-nested PCR showed a low sensitivity (35%, 38%), whereas the specificity was the highest (100%) in RDT and high (71%) in semi-nested PCR. The IFAT was shown the best results for the diagnoses of visceral leishmaniosis in symptomatic dogs. The RDT and semi-nested PCR had low sensitivity but high and moderate specificity were observed by RDT and semi-nested PCR, respectively. Based on the high-specificity results, RDT could be used as simple test for diagnoses of visceral leishmaniosis in symptomatic dogs.