Prevalence of intestinal helminths of red foxes (Vulpes vulpes) in central Europe (Poland): a significant zoonotic threat

Jacek Karamon, Joanna Dąbrowska, Maciej Kochanowski, Małgorzata Samorek-Pieróg, Jacek Sroka, Mirosław Różycki, Ewa Bilska-Zając, Jolanta Zdybel, Tomasz Cencek

The red fox (Vulpes vulpes) is widely distributed in the world; in central Europe, it is the most numerous wild species of the family Canidae. It can play the role of a definitive host for many intestinal parasites, including zoonotic helminths. Poland, with its geographical location (central Europe), is an interesting area for parasitological investigations of this species. The aim of this study was to evaluate and compare the prevalence of intestinal helminths in red foxes in different regions of Poland. Intestines of 473 red foxes from four different regions were examined using the sedimentation and counting technique (SCT). In addition, 344 samples of faeces were examined using flotation. Overall, intestinal helminths were found in 98.9% of red foxes. The average prevalence of detected parasites was as follows: Mesocestoides spp. (84.1%); hookworms (67.9%); Alaria alata (61.5%); Toxocara/Toxascaris (49.5%); Taenia spp. (42.5%); Echinococcus multilocularis (25.6%); and Trichuris vulpis (2.3%). The prevalence of the majority of parasite species was similar in each region. Significant differences between regions were observed in the case of E. multilocularis: a low prevalence in the south-western and northern regions (0% and 0.9%, respectively) and a high prevalence in the south-east and northeast (39.3% and 42.7%, respectively). In the case of A. alata, important differences were found between northern (96.5% and 93.7% in northern and northeast regions, respectively) and southern regions (15.2% and 24.7% for south-western and south-east regions, respectively). The percentage of positive samples obtained with coproscopic examination (except for Trichuris) was significantly lower than that obtained with SCT. Analysis of the prevalence estimated in individual regions with the use of both methods (flotation and SCT) showed a high correlation for all parasite species (except for Mesocestoides spp.). The flotation method also allowed us to detect the eggs of the lung nematode Eucoleus aerophilus (syn. Capillaria aerophila) (76.2% of positive foxes). This study showed a very high percentage of red foxes infected with intestinal helminths in different parts of Poland. Depending on the location, some differences were observed regarding the prevalence of dangerous zoonotic parasites, which should be considered in the assessment of infection risk for humans.