Molecular characterization of Leishmania infection in canine.

Background: Canine leishmaniasis is an infectious protozoan disease transmitted by sand fly bites. The parasite infects the macrophages of vertebrates during the amastigote stage.

Aim: This study aimed to detect the causative species for infections between dogs with Leishmania in Iraq and to determine the relationship between isolates that infect Iraqi animals and other animals worldwide.

Methods: Fifty dogs of various breeds, ranging from 1 month to 7 years old of both sexes. Then, blood samples were collected from the cephalic vein into an EDTA tube; DNA was extracted using a commercial kit. Afterward, conventional PCR was performed using universal primers to detect 18S in Leishmania.

Results: Most dog infections were caused by Leishmania infantum. The age of the infected dogs ranged from a few months to 7 years. Our results indicate that most infections with Leishmiania spp. occurred between older males and younger females. Most dogs were asymptomatic, and a small percentage exhibited clinical signs, such as skin lesions, rough coats, hair loss, and onychogryphosis. To confirm the results and gain insight into the origin of the positive L. infantum isolates, 10 samples were sequenced. Interestingly, L. infantum isolates were typical of those recorded in Brazil, France, and the USA, except for one isolate, which was slightly different from the detected isolates. Therefore, our results showed that most infections were between older males rather than younger females, and the DNA sequencing results indicated that only 1 isolate out of 10 had a different demographic origin.

Conclusion: Dogs in this study were infected mainly with L. infantum without any clinical signs; most isolates resemble those recorded in Brazil, France, and the USA.