IDENTİFİCATİON OF LEİSHMANİA TROPİCA FROM PEDİATRİC VİSCERAL LEİSHMANİASİS İN SOUTHERN MEDITERRANEAN REGION OF TURKEY. Molecular characterization of pediatric visceral leishmaniasis

Abstract

Background;  Protozoa of the genus Leishmania are obligate intracellular parasites and Leishmania species cause a spectrum of species-specific clinical symptoms known as cutaneous, mucocutaneous and visceral leishmaniasis. Leishmania major and Leishmania tropica are known to cause cutaneous leishmaniasis, while Leishmania infantum and Leishmania donovani cause visceral leishmaniasis (VL). However, molecular studies in recent years have shown that Leishmania species cause different clinical symptoms.

Objectives; Our aim is to evaluate the relationship between clinical and molecular characterization of leishmania isolates in children with VL defined in Turkey, which is an intercontinental transitional region.

Methods; The clinical diagnosis of VL was confirmed by the detection of amastigotes in the bone marrow aspirate and/or the rK39 test and/or molecular methods (genus specific PCR, Real-Time PCR, ITS1 PCR-RFLP, DNA sequencing).

Results: Most of the VL patients were referred from the districts of Adana (53.3%) and others from neighboring provinces; Hatay (16.6%), Osmaniye (3%), Gaziantep (3%), Adıyaman (3%) and 20% case were Syrian emigrants. A total of 30 patients with a clinical diagnosis of VL were confirmed by different diagnostic methods. It was found that 93% positive with microscopic examination, 79.1% with rK39 dipstick test, and 60% with genus specific PCR assay in clinical samples. The Leishmania isolates were identified as L. infantum (40%), L. donovani (26.7%) and L. tropica (23.3%) using Real Time PCR, ITS1 PCR-RFLP and DNA sequencing. There was no cutaneous finding in any case in clinical examination. The most common clinical findings were fever (93.3%), splenomegaly (90%), followed by hepatomegaly (76.6%). The most common laboratory finding was thrombocytopenia (86.6%) followed by anemia (70%). Hemophagocytic lympho-histiocytosis was detected in bone marrow aspiration in two of our patients. Since pentavalent antimony salts treatment initially failed in four patients, it was necessary to switch to Liposomal-Amphotericin B treatment and was successfully treated. Conclusions: The presence of L. tropica in VL patients, despite the absence of cutaneous findings in any of the cases, shows that this strain can cause VL, contrary to conventional knowledge. In the Adana province, where this study was carried out, L. infantum from CL cases in previous studies should be taken into account and visceral spread in CL cases and accompanying cutaneous lesions in VL cases should be investigated in detail.

Key Words;

Visceral leishmaniasis, DNA Sequencing, Leishmania infantum, Leishmania donovani, Leishmania tropica