Diagnosis of Cutaneous Leishmaniasis: Why Punch When You Can Scrape?

Abstract

Abstract. Cutaneous leishmaniasis (CL) has been introduced to the Leishmania under-endemic Lebanese population in an uncontrolled manner as a result of recent large-scale displacement of refugees from endemic Syria. Accordingly, a quick and reliable method to diagnose CL is essential. Matched punch biopsies and air-dried scrapings on 72 patients were obtained. Scrapings were collected in two forms: thick drop (N = 33) or thin smear (N = 39). Clinical information was recorded. Sections of punch biopsies and scrapings were stained and examined microscopically. Polymerase chain reaction (PCR) was performed on both scraping forms and biopsies. The diagnostic sensitivity of the tests performed revealed that microscopy in conjunction with PCR on punch biopsies was the most sensitive test (93%) overall. However, taken individually, microscopy and PCR yielded the highest sensitivities when performed on drop scrapings (63% and 85%, respectively), and not smear scrapings (38% and 56%, respectively) as compared with the punch biopsies (44% and 83%, respectively). Microscopic concordance for punch biopsies and drop scrapings was present in 25 of 33 cases. Concordance was predicted only by the high/low parasitic index (PI: 3.1 ± 1.7 and 0.4 ± 0.5, respectively; P 0.05). Herein, we optimized a novel rapid method for reliable diagnosis of CL based on drop scrapings with good agreement with the gold standard punch biopsy technique.

Cutaneous leishmaniasis: an evolving disease with ancient roots

“…In our study, all cases that failed microscopically to show organisms were proven to CL after PCR analysis. Combining microscopic with molecular studies previously yielded a sensitivity of 93% . In short, we strongly support the use of molecular diagnosis means when the clinical setting supports CL and microscopic examination fails to confirm it.…”

“…Combining microscopic with molecular studies previously yielded a sensitivity of 93%. 10 In short, we strongly support the use of molecular diagnosis means when the clinical setting supports CL and microscopic examination fails to confirm it. Though ideal, a multimodal approach combining histopathology, culture, and PCR raises the issue of costeffectiveness, especially in the concerned endemic areas.…”

“…All patients received punch biopsies of the lesions. A team of trained physicians collected the samples according to previously described protocols . The 4 mm punch biopsies were taken from the border of the lesion of every patient.…”

“…A team of trained physicians collected the samples according to previously described protocols. 10 The 4 mm punch biopsies were taken from the border of the lesion of every patient. They were stored in tightly sealed formalin-filled tubes.…”

Semi-Quantitative, Duplexed qPCR Assay for the Detection of Leishmania spp. Using Bisulphite Conversion Technology

“…(See Supplementary Materials) Leishmania DNA-based detection in the laboratory is dominated by cPCR, nested PCR or qPCR. Conventional PCR has sensitivities ranging from 56% to 100%, depending on clinical specimen and gene target [8,22]. In nested PCR, an inner and outer set of primers are designed and tested in two rounds to increase sensitivity and specificity [23].…”