Golden jackals (Canis aureus) as novel hosts for Angiostrongylus vasorum in Romania.

Angiostrongylus vasorum, commonly known as the French heartworm, is a metastrongyloid nematode infecting domestic and wild carnivores. While red foxes (Vulpes vulpes) are known as the primary reservoir hosts in Europe, recent studies suggest that golden jackals (Canis aureus) could also be considered as important reservoir hosts. Due to the rapid expansion of golden jackals in Europe, their role in the epidemiology of A. vasorum remains insufficiently explored. This study aimed to assess the occurrence of A. vasorum in golden jackals from Romania. Between October 2013 and November 2024, a total of 137 golden jackals were collected from 21 counties in Romania through legal hunting or roadkill. A full parasitological necropsy was performed (other data presented elsewhere), with the cardiorespiratory tract dissected for adult nematodes. First-stage larvae (L1) were isolated using the Baermann method. Morphological examination of nematodes and larvae was conducted using standard microscopy. Molecular identification of adult nematodes was carried out using PCR targeting the ITS-2 region, followed by sequencing and phylogenetic analysis. Additionally, histopathological analysis was performed on lung tissue. A. vasorum was identified in the pulmonary arteries of 2 out of 137 golden jackals (1.45 %). The presence of first-stage larvae in lung tissue confirmed their role as definitive hosts. Molecular sequencing revealed 100 % identity with A. vasorum isolated from Europe. Histopathological examination showed granulomatous pneumonia with parasitic eggs, larvae, and vascular changes associated with the infection. This study confirms golden jackals as suitable hosts for A. vasorum in Romania, indicating their potential role as reservoir hosts. Given the increasing overlap between jackals, domestic dogs, and red foxes, further surveillance is needed to understand the epidemiological implications of A. vasorum in wildlife and domestic animal health.