Investigating Crithidia spp. in ulcer smear of patients suspected of leishmaniasis in Aq-Qala, Golestan province, Northern Iran, 2019-2020

Background: Cutaneous leishmaniasis (CL) is a parasitic infection that causes significant health problems. This study aimed to survey the prevalence of Leishmania and Crithidia spp. co-infection in the wounds of patients with suspected Leishmaniasis in Golestan Province, northern Iran. Methods: This retrospective descriptive study included 140 smears of patients suspected of CL who were referred to the Leishmaniasis Diagnostic Laboratory in Aq-Qala Health Center, Golestan Province, northern Iran, in 2019–2020. The sore smears, along with demographic and epidemiological data of patients, were obtained from the laboratory archives. DNA was extracted from Giemsa-stained smears, and PCR was performed on the ITS1 and GPDH genes for Leishmania and Crithidia spp., respectively. Results: In our research, 140 patients suspected of CL were studied. PCR results showed that 117 patients (83.5%) were positive for L. major, three patients (2.1%) were positive for L. tropica, and 20 patients (14.2%) were negative for the Leishmania parasite. One patient’s smear was positive for Crithidia species. Five patients (3.5%) had a history of treated leishmaniasis. The results indicated that 74.7% of the patients with one wound, 89.5% of the patients with two wounds, 96.4% of the patients with three wounds, 90.9% of the patients with four wounds, and 100% of the patients with five or more wounds were positive for L. major. Conclusion: More studies should be conducted in the field of simultaneous infection of Leishmania and Crithidia in humans. In addition, research on the effect of leishmaniasis treatments on Crithidia spp. can be useful.