Dirofilaria repens believed to be D. immitis: An erratic localization case in a golden jackal (Canis aureus)

Dirofilariosis is a widespread mosquito-borne disease that primarily affects dogs, the main reservoir, but it can also infect other mammalian hosts. Dirofilaria immitis is the causative agent of a cardiopulmonary disease in dogs, whereas Dirofilaria repens typically inhabits subcutaneous tissues and is often associated with subclinical infections. Nevertheless, D. repens shows a greater tendency for aberrant localization in atypical anatomical sites. We report a rare case of cardiac localization of D. repens in a golden jackal from the Friuli Venezia Giulia region, Northeastern Italy. The golden jackal also presented a calcified nodular lesion on the calcaneal region of the right hind limb heel, in which a filiform worm was recovered. Species identification was achieved through morphometric identification, complemented by PCR amplification of the COI and 12S rRNA genes and phylogenetic analyses. This represents only the second documented case of aberrant cardiac localization of D. repens in a wild canid, following a report in a wolf from Kazakhstan. This finding highlights the importance of accurate identification, even when the anatomical location might itself suggest a diagnosis. Moreover, the ecological and anatomical plasticity of D. repens underscores the importance of including wild canids in epidemiological surveillance programs, particularly considering the expanding distribution of both the parasite and the golden jackal across Europe.