First report of the zoonotic nematode Baylisascaris procyonis in non-native raccoons (Procyon lotor) from Italy

Abstract

Baylisascaris procyonis is a nematode parasite of the raccoon (Procyon lotor), and it can be responsible for a severe form of larva migrans in humans. This parasite has been reported from many countries all over the world, after translocation of its natural host outside its native geographic range, North America. In the period between January and August 2021, 21 raccoons were cage-trapped and euthanized in Tuscany (Central Italy), in the context of a plan aimed at eradicating a reproductive population of this non-native species. All the animals were submitted for necroscopic examination. Adult ascariids were found in the small intestine of seven raccoons (prevalence 33.3%). Parasites have been identified as B. procyonis based on both morphometric and molecular approaches. The aim of the present article is to report the first finding of this zoonotic parasite from Italy, highlighting the sanitary risks linked to the introduction of alien vertebrate species in new areas. Graphical Abstract

Detection of Endoparasites in Non-Native Raccoons from Central Italy

“…Morphological and morphometric features of all the ascarids detected were consistent with those of B. procyonis : length 9–16 cm, width 1–3 mm, white-yellowish to tan-colored, with a prominent dark alimentary tract. Male parasites showed typical features of the genus Baylisascaris , such as the presence of cervical alae with cuticular bars, dorsal and subventral labial papillae distinctly double, pericloacal area rugosa, uniform spicules, and discrete precloacal and postcloacal groups of papillae on the tail [ 12 ]. Molecular analyses of twenty-five adult parasites (one for each positive raccoon) confirmed the phenotypic identification, resulting in a 100% coverage and identity with a B. procyonis -deposited sequence (GenBank accession number: MZ092853), and our previously deposited sequence (GenBank accession number: OU974763.1) [ 12 ].…”

“…Recovered parasites were preserved in 70% ethanol and subsequently submitted to morphologic and morphometric identification. In the case of ascarid parasites, fragments (approximately 1 cm long) of adult parasites (one specimen for each infected raccoon) were submitted for molecular identification using a next-generation sequencing (NGS)-based amplicon sequencing approach, as described by Lombardo et al in 2022 [ 12 ]. Moreover, from each raccoon, samples of rectal content, ileum, skeletal muscles (diaphragm and tibialis muscles), urine, and nasal (choanae) lavage fluid were also collected.…”

“…From the 1830s, following the spreading of the raccoons through the Old World, this parasite progressively increased its geographical range and, at present, it has been reported in non-native raccoon populations from many European countries, including Denmark [ 8 ], Austria [ 9 ], Poland [ 10 ] and Germany [ 11 ]. More recently, B. procyonis was reported in the Central Italy raccoon population by our research group [ 12 ]. As for other helminthic infections, numerous species other than B. procyonis were reported worldwide in raccoons, such as Strongyloides procyonis, Aonchotheca putorii , Ancylostoma sp., Uncinaria sp., Trichuris sp., Trichinella pseudospiralis [ 13 ], Trichinella T9 [ 14 ], Polymorphus minutus [ 15 ], Mesocestoides sp.…”

Wild Mesocarnivores as Reservoirs of Endoparasites Causing Important Zoonoses and Emerging Bridging Infections across Europe

“…The infected host sheds millions of eggs daily that become infective (containing the third-stage larva, L3) in approximately 10–12 days and remain infective for months or years [ 204 ]. In Europe, B. procyonis infection in raccoons has been documented in over 70% of raccoons in central Germany [ 196 , 205 ] and in 33.3% in Italy at necropsy [ 206 ]. Raccoons infected with B .…”

Microsatellite profiling of hosts from parasite-extracted DNA illustrated with raccoons (Procyon lotor) and their Baylisascaris procyonis roundworms

“…While not all European raccoon populations are parasitised by B. procyonis , the roundworm is currently increasing its geographic distribution [ 29 – 32 ]. For effective eradication and/or management actions, it is important to understand whether the parasite was introduced through a distinct founder event or through natural dispersal of infected raccoons [ 31 ].…”