Pediatric visceral leishmaniasis: a retrospective study to propose the diagnostic tests algorithm in southern Iran

Area of Science:

• Medical Parasitology
• Infectious Diseases
• Pediatric Diagnostics

Background:

• Visceral leishmaniasis (VL), caused by Leishmania infantum, is a significant health concern in Iran, particularly affecting young children.
• Accurate, timely, and minimally invasive diagnostic methods are essential for effective VL management in pediatric populations.

Purpose of the Study:

• To evaluate and compare the diagnostic performance of quantitative PCR (qPCR), indirect immunofluorescent antibody test (IFAT), and rK39-rapid diagnostic test (rK39-RDT) for VL detection in children.
• To identify an optimal diagnostic algorithm for VL in children, balancing invasiveness and diagnostic robustness.

Main Methods:

• A retrospective study involving 415 children with suspected VL, 50 healthy children from endemic areas, 46 healthy individuals from non-endemic areas, and 47 patients with non-VL diseases.
• Diagnostic testing included qPCR, IFAT, and rK39-RDT.
• Performance metrics such as sensitivity and specificity were calculated for each test and for combined approaches.

Main Results:

• Quantitative PCR (qPCR) demonstrated the highest sensitivity (92.2%), followed by IFAT (82.4%) and rK39-RDT (77.5%).
• qPCR and IFAT showed 100% specificity, while rK39-RDT had 98.6% specificity.
• Combining qPCR with either IFAT or rK39-RDT achieved a diagnostic sensitivity of 98% for VL.
• A combination of rK39-RDT and IFAT offered a sensitivity of 93.1%, comparable to qPCR alone, for laboratories lacking molecular facilities.

Conclusions:

• Quantitative PCR (qPCR) is a highly sensitive and specific diagnostic tool for VL in children.
• Integrating serological tests (IFAT, rK39-RDT) with qPCR enhances overall VL detection rates.
• For resource-limited settings, a combination of IFAT and rK39-RDT provides a viable alternative for sensitive VL diagnosis in children.