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

RESUMO

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 Säo 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 percent of the samples. When the PCR results were compared to those of histopathological leishmania detection, PCR showed superior results with 81.5 percent sensitivity and 95 percent CI of 68.0-95.1 percent. The Montenegro skin test (MST) was positive in 88.7 percent 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