Red Fox (Vulpes vulpes) and Wolf (Canis lupus) as a Reservoir of Cryptosporidium spp. and Giardia intestinalis in Poland

Infections with zoonotic pathogens have received increasing attention in recent years, as reflected in the literature of both veterinary and human medicine. <i>Cryptosporidium</i> and <i>Giardia</i> are recognised as the principal causes of waterborne outbreaks worldwide, but there is still limited data on the role of wild carnivores, such as red foxes and wolves, as reservoir hosts and in disseminating these pathogens in the environment. The aim of the current project was to analyse the prevalence and abundance of <i>Cryptosporidium</i> and <i>Giardia</i> infections in foxes from seven voivodeships and in wolves from the Warmia-Masuria Voivodeship in Poland and to conduct a phylogenetic analysis of the detected parasites. For the detection of both parasites, we used the commercial immunofluorescent assay MeriFluor <i>Cryptosporidium</i>/<i>Giardia</i>. For <i>Cryptosporidium</i> detection we also applied modified Ziehl-Neelsen (ZN) staining of faecal smears and, following PCR amplification, sequenced the <i>18S</i> rDNA locus. For <i>Giardia</i> detection, we sequenced the glutamate dehydrogenase (<i>gdh</i>) gene. In total, 117 and 69 faecal samples obtained from red foxes and wolves, respectively, were screened for the presence of <i>Cryptoporidium</i>/<i>Giardia</i>. In red foxes, prevalence was 38.5% and 15.4% for <i>Cryptosporidium</i> spp. and <i>G. intestinalis</i>, respectively. In wolves, the prevalence of <i>Cryptosporidium</i> spp. was 14.5%, and only one sample was <i>Giardia</i>-positive. <i>Cryptosporidium canis</i>, <i>Cryptosporidium</i> sp. vole genotype, <i>C. baileyi</i> and <i>Cryptosporidium</i> sp. were identified in red foxes, while <i>C. canis</i> and <i>Cryptosporidium</i> sp. were detected in wolves. Our results indicate that red foxes and grey wolves act as reservoir hosts of <i>Cryptosporidium</i> spp. and <i>G. intestinalis</i> in natural areas in Poland.