Comparison of the specificity of PCR and the histopathological detection of leishmania for the diagnosis of American cutaneous leishmaniasis

Abstract

More precise and rapid diagnostic methods for American cutaneous leishmaniasis (ACL) are necessary because of the growing number of cases observed in Brazil, including the northeastern region of the State of São Paulo. We applied PCR to 54 skin or mucosal biopsies from patients with a clinical and/or laboratory diagnosis of ACL using primers 13A and 13B, with positive results being obtained for 82% of the samples. When the PCR results were compared to those of histopathological leishmania detection, PCR showed superior results with 81.5% sensitivity and 95% CI of 68.0-95.1%. The Montenegro skin test (MST) was positive in 88.7% of patients. Since MST cannot be used as a diagnostic tool in endemic areas, the present results strongly suggest the use of PCR for the etiological confirmation of ACL, with emphasis on the mucosal form. Correspondence

Polymerase chain reaction with two molecular targets in mucosal leishmaniasis' diagnosis: a validation study

“…Most of the studies report case series with PCR made by non blind observers. None of the reports estimate inter-observer agreement (Pirmez et al 1999, Medeiros et al 2002, Oddone et al 2004, Disch et al 2005.…”

Polymerase chain reaction with lesion scrapping for the diagnosis of human American tegumentary leishmaniasis

“…The polymerase chain reaction (PCR) is able for detecting so little quantities as 1 phentogram (10 -15 g) of Leishmania DNA, equivalent to 1/10 of parasite (Gontijo & Carvalho 2003), offering an alternative way for the demonstration of parasites in clinical samples (Belli et al 1998, Medeiros et al 2002, Oliveira et al 2005. The objective of this work was to compare the PCR in lesion scrapping with other techniques used for the ATL diagnosis in patients in the northern region of Paraná.…”

L. (L.) chagasi in aids and visceral leishmaniasis (kala-azar) co-infection

“…The demonstration of granulomatous inflammatory infiltration with presence of lymphocyte cells can justify the absence of parasites on histopathological exam. Our experience has been showing the presence of amastigotes forms in nearly 50% of skin biopsies 14 . The literature shows numerous amastigotes forms identified in skin samples from nodules in aids-VL co-infection 6,8,10 .…”

“…One fragment of the cutaneous biopsy was used in PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) for leishmania identification. A specific pair of primers for a sequence of 120 bp of kDNA minicircle, common to all leishmania species, was used, as described elsewhere 9,14 . The analysis of the PCR product digested by HaeIII enzyme suggested the species L. (L.) chagasi, since its pattern was similar to the L. (L.) chagasi maintained in culture (Fig.…”