Parasitology and Gray Wolves

Abstract

There is a lack of studies on the richness of Sarcocystis species in naturally infected grey wolves that serve as definitive hosts of these parasites. In this work, we used a nested PCR approach to examine the intestines of 13 grey wolves from Lithuania for the presence of Sarcocystis species that use canids as definitive host and ungulates as intermediate host. Under a light microscope, Sarcocystis spp. sporocysts/oocysts were found in 12 animals (92.3%). Based on comparisons of newly acquired cytochrome c oxidase subunit I (cox1) gene nucleotide sequences, we identified a total of 12 different Sarcocystis species (S. arieticanis, S. alces, S. capracanis, S. capreolicanis, S. gracilis, S. hjorti, S. iberica, S. linearis, S. miescheriana, S. pilosa, S. tenella and S. venatoria). This is the first report identifying four of them (S. alces, S. iberica, S. pilosa and S. venatoria) in the intestines of grey wolves. Two or more parasite species (up to nine different species per animal) were detected in 76.9% of the examined samples. This shows the significant role of the grey wolf in the life cycle of Sarcocystis species in the wild.

Abstract

European wolf populations have expanded their distribution ranges in recent decades and their spatial behaviour may contribute to the spread of Echinococcus spp. across Europe. In this study, the occurrence of Echinococcus granulosus sensu lato was monitored in the faecal samples from grey wolves from areas covering the substantial part of their range in Slovakia. Samples were collected from several geographical areas, including Poloniny National Park in the easternmost part of the country, as well as Muráň Plateau National Park, the Vepor Mountains and the Poľana Protected Landscape Area in central Slovakia. The overall occurrence of the parasite in 112 samples collected between 2014 and 2017 was 5.4%. Echinococcus canadensis (genotype G7), the main causative agent of human cystic echinococcosis in Central Europe, was confirmed in all six positive faeces through sequence analysis of the mitochondrial 12S rRNA gene. Geographically, five positive samples were derived from the Vepor Mountains and one from the Poľana Protected Landscape Area. The occurrence of E. canadensis G7, the primary cause of human cystic echinococcosis in Central Europe, in wolves in Slovakia indicates its presence in a sylvatic cycle, which may contribute to sustaining its circulation within the country.

Abstract
Over the past decades, the grey wolf (Canis lupus) has expanded its range across Italy, reclaiming historical habitats, including anthropized landscapes. This resurgence raises concerns regarding its potential role in maintaining and spreading pathogens. In this study, we focused on Dirofilaria immitis, the causative agent of canine heartworm disease, investigating its prevalence in wolves and exploring the environmental factors influencing infection risk. A total of 488 wolf carcasses collected from northern and central Italy between 2021 and 2024 were analysed. Morphological identification of adult nematodes was conducted using light and scanning electron microscopy, while molecular analyses of mitochondrial COI and 12S rRNA genes were performed to assess genetic variation. Spatial modelling was applied to evaluate infection risk based on environmental factors. D. immitis was detected in 3.5% of the sampled wolves, with prevalence varying among regions, reaching 5.2% in Emilia-Romagna. Microfilariae were identified in two cases, confirming the wolves’ potential role as competent hosts. Phylogenetic analysis revealed no significant genetic divergence between D. immitis from wolves and those previously recorded in dogs and other hosts. Spatial analysis indicated that infection risk was highest in low-altitude areas of the Po Valley, a historically endemic region for dirofilariosis. These findings suggest that the expanding wolf population may serve as a competent host for D. immitis, potentially influencing local epidemiology and complicating control efforts in domestic dogs. Continued surveillance is necessary to assess the impact of wildlife reservoirs on heartworm transmission and public heal