Morphological and molecular identification of Dirofilaria immitis from Jackal (Canis aureus) in North Khorasan, northeast Iran

Background & objectives: The heartworm Dirofilaria immitis is an important mosquito-borne zoonotic nematode of domestic and wild mammals throughout the world, causing cardiopulmonary dirofilariasis. This parasite has been reported from carnivores in some provinces of Iran. However, in the present study, the occurrence of this filarial nematode is reported for the first time in wild canids of the North Khorasan Province, located in northeast Iran, based on morphological and molecular characteristics. Methods: The carcasses of 45 golden jackals (Canis aureus), 16 foxes (Vulpes vulpes), 15 dogs (Canis familiaris), and one wolf (Canis lupus) were necropsied between 2013 and 2014. Results: By gross examination, adult filarial nematodes were found in the cardiovascular system of four jackals (8.9%). The morphological characteristics of the recovered heartworms were compatible with D. immitis. DNA sequencing of the cytochrome c oxidase subunit I (cox1) gene of all four isolates was identical, showing 100% homology with several sequences registered in GenBank from other countries. No adult D. immitis was found in any of the other animals examined. Interpretation & conclusion: D. immitis is circulating in wildlife of the study area, suggesting the relevance of developing control programmes to prevent transmission of the disease to humans and domestic animals.