Rapid detection of Leishmania infantum infection in dogs: a comparative study using fast agglutination screening test (FAST) and direct agglutination test (DAT) in Iran

Canine visceral leishmaniasis (CVL) is not only a veterinary problem but has also a serious public health importance. Rapid detection of CVL is highly important for control of human visceral leishmaniasis in Iran. This study was aimed to compare the fast agglutination screening test (FAST) with direct agglutination test (DAT) as a standard serological test for the detection of anti-Leishmania antibodies on dog serum samples. DAT and FAST antigens were prepared in the School of Public Health, Tehran University of Medical Science. Altogether, 73 serum samples from Leishmania infantum infection dogs and 74 sera from healthy controls were collected from human VL/CVL endemic and non-endemic areas of Iran, respectively. All the sera were evaluated with both FAST and DAT techniques. A sensitivity of 98.60% (95% CI, 98.57-98.62) and specificity of 78.70% (95 CI%, 69.20-88.20) were found at a 1:160--(cut-off) titer when DAT confirmed cases were compared with healthy control. A good degree of agreement was observed between FAST and DAT (86.8%) by kappa analysis (p < 0.01). In conclusion, this study showed that FAST is very practical and simple diagnostic tool for the sero-diagnosis of CVL in endemic areas of Iran.