Epidemiological study and risk factors of internal parasite infections in wild boar (Sus scrofa) in Mazandaran Province, northern Iran

Background/objective Given the importance of zoonotic diseases among wildlife, domestic animals, and humans, and the role of wild animals as natural reservoirs of many pathogens, this study was designed to investigate the epidemiology and identify risk factors associated with internal parasitic infections in wild boar (Sus scrofa) in Mazandaran province.Methods From January 2021 to December 2023, 15 wild boars, including 6 males and 9 females, that died in Mazandaran Province, northern Iran, were collected, those that were killed in car accidents or illnesses, and transferred to the Veterinary Parasitology Laboratory of Semnan University, Semnan, Iran, for parasite examination. The contents of the gastrointestinal (GI) tract were sieved, and the mucosa was examined for parasites. For the liver, the bile duct was examined, and for the lungs, the bronchi of both lobes were cut off, and all the parasites in this area were found, sieved, and washed, so that all the remaining worms were collected in the sieve. For muscle examination, several methods were used, including the squash prep test, tissue digestion, pathological assay, and Dab smear.Results All of the boars had at least one parasite, and 13 species of helminths and protozoa were identified. Eight species of nematodes were identified, including Ascarops strongylina (33.3%), Globocephalus urosubulatus (26.6%), Gongylonema pulchrum (6.6%), Metastrongylus apri (53.3%), Metastrongylus pudendotectus (46.6%), Oesophagostomum dentatum (20%), Physocephalus sexalatus (33.3%), and Trichuris suis (6.6%). Moreover, two species of trematodes (Dicricoelium dendriticum (13.3%) and Fasciola hepatica (6.6%)), one species of Acanthocephala (Macracanthorhynchus hirudinaceus (86.6%)), and one protozoan (Sarcocyst spp. (26.6%)) were identified. In addition, larvae of Taenia hydatigena were observed.Conclusion Wild boar populations in Mazandaran province exhibit a high prevalence of internal parasitic infections, indicating the active presence of parasitic cycles in the region's natural habitats.