Cutaneous Leishmaniasis in Khyber Pakhtunkhwa Province of Pakistan: Clinical Diversity and Species-Level Diagnosis

Abstract

This study primarily aimed to identify the causative species of cutaneous leishmaniasis (CL) in the Khyber Pakhtunkhwa Province of Pakistan and to distinguish any species-specific variation in clinical manifestation of CL. Diagnostic performance of different techniques for identifying CL was assessed. Isolates of Leishmania spp. were detected by in vitro culture, polymerase chain reaction (PCR) on DNA extracted from dried filter papers and microscopic examination of direct lesion smears from patients visiting three major primary care hospitals in Peshawar. A total of 125 CL patients were evaluated. Many acquired the disease from Peshawar and the neighboring tribal area of Khyber Agency. Military personnel acquired CL while deployed in north and south Waziristan. Leishmania tropica was identified as the predominant infecting organism in this study (89.2%) followed by Leishmania major (6.8%) and, unexpectedly, Leishmania infantum (4.1%). These were the first reported cases of CL caused by L. infantum in Pakistan. PCR diagnosis targeting kinetoplast DNA was the most sensitive diagnostic method, identifying 86.5% of all samples found positive by any other method. Other methods were as follows: ribosomal DNA PCR (78.4%), internal transcribed spacer 2 region PCR (70.3%), culture (67.1%), and microscopy (60.5%). Clinical examination reported 14 atypical forms of CL. Atypical lesions were not significantly associated with the infecting Leishmania species, nor with "dry" or "wet" appearance of lesions. Findings from this study provide a platform for species typing of CL patients in Pakistan, utilizing a combination of in vitro culture and molecular diagnostics. Moreover, the clinical diversity described herein can benefit clinicians in devising differential diagnosis of the disease.

Figure 1.

Geographical distribution of cutaneous leishmaniasis (CL) cases reported in the study. Map shows adjoining regions of Khyber Pakhtunkhwa Province. Areas shaded gray are agencies within the Federally Administrated Tribal Areas (FATA). Dot on the map represents the isolation site of one or more strains. Size of the dot is proportional to number of strains represented by it.

Figure 2.

Atypical forms of cutaneous leishmaniasis (CL) lesions reported. (A) Psoraisiform, (i and ii) dry type, (iii) mixed type; (B) ecthymatous, mixed-type; (C) (i and ii) cellulitis like, mixed type. (D) (i and ii) Verruciform, dry type; (E) mycetomatous, mixed type; (F) lupoid, (i) mixed type and (ii) dry type; (G) keloidal, dry type; (H) squamous cell carcinoma like, wet type; (I) discoid lupus erythematosus like, dry type; (J) paronychial, dry type; (K) chanciform, wet type; (L) basal cell carcinoma like, mixed type; (M) erysipeloid, dry type; (N) typical (i and ii) wet type; and (O) typical (i and ii) mixed-type. LT = Leishmania tropica; LM = Leishmania major; LF = Leishmania infantum; L = Leishmania spp.; NA = no spp. identified.