Objective: To establish PCR method for the detection of the asymptomatic infection of Leishmania infantum.
Methods: Six primer pairs were selected for detecting Chinese strain of L. infantum by optimizing conditions which affect amplification. Their sensitivity and specificity were compared by using DNAs extracted from human blood seeded with cultured L. infantum promastigotes (MHOM/CN/86/GS) as template. Blood samples of the inhabitants without symptoms of visceral leishmaniasis in the endemic area were analyzed with two selected primer pairs with good sensitivity and specificity.
Results: The specificity of all six primer pairs reached 100%, and the sensitivity varied among the primer pairs. The primer pairs RV1-RV2 (0.1 parasite/ml blood) and K13A-K13B (1 parasite/ml blood) were most sensitive. Leishmania DNA was detected in 33% (33/100) and 30% (30/100) human blood samples by RV1-RV2 and K13A-K13B primer pairs respectively.
Conclusion: This study suggests that RV1-RV2 and K13A-K13B primer pairs are suitable in detecting the asymptomatic infection of L. infantum, and the prevalence of the asymptomatic infection is high in human population in the endemic area.