Comparison of three methods for diagnosis of cutaneous leishmaniasis

Leishmaniasis is one of the infectious parasitic diseases of highest incidence in the world. Cutaneous Leishmaniasis (CL) has long been reported in Shiraz, Southern Iran. There is a need to find a sensitive and specific method for treatment and control of the disease.

We have compared the sensitivity of the conventional methods microscopy and cultivation of lesion scrapes against PCR amplification of parasite kinetoplast DNA from these samples. The samples (n=219) were obtained from the patients clinically suspected of CL. The smears were stained with Giemsa for microscopy and cultured in Novy-Nicolle-McNeal (NNN) blood agar for promastigote growth. For PCR, the dry smears were scraped off the slides and DNA was extracted.

The positive rates from 219 specimens were 76.71%, 50.68%, and 93.61% for microscopy, cultivation, and PCR, respectively. The highest correlation was found between PCR and microscopy method (P=0.014). In PCR assay, 95.61%, 3.9%, and 0.49% of the samples were identified as Leishmania major, L. tropica, and dermatropic L. infantum, respectively.

The PCR method appears to be the most sensitive for the diagnosis of CL and is valuable for identifying the other species of Leishmania with confusing dermatropic signs.