Visceral leishmaniosis in dogs from western Iran

Leishmania infantum is a sand fly-borne parasite, causing visceral and mucocutaneous leishmaniosis. Dogs are the main reservoir hosts and play a crucial role in the epidemiology of the infection. This study reports for the first time the presence of L. infantum in sick dogs from a western province of Iran, previously considered not endemic for this infection. From April 2024 to June 2025, six mongrel dogs with poor body condition and skin lesions were presented to veterinary clinics in Hamedan, Iran. Impression smears and scrapes of the suspected lesions were examined microscopically for Leishmania amastigotes. In addition, spleen, skin, and lymph node samples from two dead dogs were collected for histological examination. Genomic DNA was extracted from skin lesions and further tested for Leishmania spp. DNA by conventional PCR and sequencing. The infected dogs presented several clinical signs, including cachexia, muscle wasting, lymphadenopathy, muco-/cutaneous lesions, rough and dry hair coat, with alopecic regions characterized by hyperkeratosis, crusts and scales, desquamation, seborrheic dermatitis, and thick dandruff with bright reflections. Leishmania infantum amastigotes were observed in histological sections and/or impression smears of all dogs and further confirmed by DNA sequencing. The presence of L. infantum in dogs from an area of Iran previously considered not endemic, spotlighting the importance of regular surveillance programs in canine populations for implementing control and preventive measures to reduce the risk of infection in both human and animal settings.