Comparison of PCR-based methods for the diagnosis of cutaneous leishmaniasis in two different epidemiological scenarios: Spain and Morocco.

BACKGROUND: Cutaneous leishmaniasis (CL) is a disfiguring and stigmatising disease occurring in more than 70 countries across the world including Spain and Morocco. The use of sensitive tests that can differentiate Leishmania species is advised.

OBJECTIVE: To evaluate the influence of the epidemiological scenario on the reliability of the PCR techniques and contribute to the selection of the most efficient one for CL diagnosis.

METHODS: The sensitivities of parasitological methods and four PCRs were compared in cutaneous samples from 77 patients from Spanish (PSH) and Moroccan hospitals (PMH). Exudates and fresh or paraffin-embedded tissue biopsies were used.

RESULTS: None of the PCRs used in this study allowed the diagnosis of all CL cases, showing also some drawbacks. Lmj4/Uni21-PCR displayed the best sensitivity with PMH, but it did not provide positive results in PSH with CL confirmed by other PCRs. Conversely, JW13/JW14-PCR and L. infantum-PCR-ELISA displayed good sensitivities with PSH that were not achieved with PMH. Nested-ITS-1-PCR did not show enough sensitivity with paraffin-embedded tissue biopsies. False-negative results were obtained in 19% of PSH due to unspecific hybridizations of ITS-1 primers with human chromosome1.

CONCLUSIONS: PCR should be routinely used in patients with cutaneous lesions compatible with CL and furthermore, the combination of two PCR techniques is advisable. The selection of these PCRs will be influenced by the epidemiological scenario: In areas where L. infantum is endemic, the use of the PCR-ELISA joint with JW13/JW14-PCR seems an appropriate choice, whereas in areas such as Morocco, Lmj4/Uni21 and ITS-1 provide satisfactory results.