Pediatric visceral leishmaniasis diagnosis in Tunisia: comparative study between optimised PCR assays and parasitological methods

There has been a steady increase of visceral leishmaniasis during the past 20 years in Tunisia. In this study, we assess the value of two optimised PCR versus those of classical methods for the diagnosis of human visceral leishmaniasis. 106 samples were collected from 53 cases of pediatric visceral leishmaniasis. Peripheral blood and bone marrow samples were analysed both by parasitological methods (direct examination, leukocytoconcentration (LCC) and culture) and by PCR methods with two primer pair (R221/R332 and Lei 70L/Lei 70R). We diagnosed visceral leishmaniasis in all patients: 44 cases were diagnosed by culture (83%), 42 by direct examination of bone marrow (79%), 17 by LCC (32%), and 53 positive cases with both PCR assays (R221/R332 and/or Lei 70L/Lei 70R) (100%). Regarding each PCR assay, for blood samples, the difference between the sensitivities of PCR Lei 70L/Lei 70R (86,8%) and PCR R221/R332 (17%) is statistically significant with p-value 0.025. For bone marrow, the sensitivities of the two PCR methods were respectively 96,2% (Lei 70L/Lei 70R) and 75,5% (R221/R332). On the whole, PCR Lei 70L/Lei 70R was more effective than PCR R221/R332 and conventional methods for the two biological samples. Moreover, the requirement of less invasive sample using blood has the advantage of being repeatable for screening and for post therapeutic monitoring

Pediatric visceral leishmaniasis diagnosis in Tunisia: comparative study between optimised PCR assays and parasitological methods

There has been a steady increase of visceral leishmaniasis during the past 20 years in Tunisia. In this study, we assess the value of two optimised PCR versus those of classical methods for the diagnosis of human visceral leishmaniasis. 106 samples were collected from 53 cases of pediatric visceral leishmaniasis. Peripheral blood and bone marrow samples were analysed both by parasitological methods (direct examination, leukocytoconcentration (LCC) and culture) and by PCR methods with two primer pair (R221/R332 and Lei 70L/Lei 70R). We diagnosed visceral leishmaniasis in all patients: 44 cases were diagnosed by culture (83%), 42 by direct examination of bone marrow (79%), 17 by LCC (32%), and 53 positive cases with both PCR assays (R221/R332 and/or Lei 70L/Lei 70R) (100%). Regarding each PCR assay, for blood samples, the difference between the sensitivities of PCR Lei 70L/Lei 70R (86,8%) and PCR R221/R332 (17%) is statistically significant with p-value 0.025. For bone marrow, the sensitivities of the two PCR methods were respectively 96,2% (Lei 70L/Lei 70R) and 75,5% (R221/R332). On the whole, PCR Lei 70L/Lei 70R was more effective than PCR R221/R332 and conventional methods for the two biological samples. Moreover, the requirement of less invasive sample using blood has the advantage of being repeatable for screening and for post therapeutic monitoring

Polymerase chain reaction of peripheral blood as a tool for the diagnosis of visceral leishmaniasis in children

The diagnosis of visceral leishmaniasis (VL) generally requires the use of invasive tests for the collection of infected tissue (aspirates of bone marrow, spleen, liver or lymph nodes). This difficulty has led to the search for safer and less painful techniques to confirm the occurrence of the disease in children. Polymerase chain reaction (PCR) is a method that is advantageous in that it allows the use of peripheral blood samples for diagnosis. This paper reports the utilisation of PCR on peripheral blood samples to diagnose VL in 45 children in Mato Grosso do Sul, Brazil. This technique is compared with methods carried out using tissue collected by invasive procedures, including direct microscopy, culture and detection of Leishmania DNA by PCR in bone marrow aspirates. The results show that PCR of peripheral blood provides great sensitivity (95.6%) that is similar to that from the PCR of bone marrow aspirates (91.1%) and higher than that achieved with microscopy (80%) or culture (26.7%) methods. PCR of peripheral blood proved to be a suitable tool for the diagnosis of VL in children because it is highly sensitive and safe, with tissue collection being less invasive than in traditional tests