Identification and phylogenetic analysis of Taenia spp. parasites found in wildlife in the Emilia-Romagna region, northern Italy (2017-2022)

Abstract

The recent expansion of the habitat of several wildlife species, comprising anthropized areas, is a relevant risk factor for many zoonotic diseases and should be considered in national and regional sanitary monitoring systems. We evaluated adult intestinal Taenia spp. parasites isolated from wild carnivores and cystic larval forms isolated from wild mammals analysed at the Istituto Zooprofilattico Sperimentale della Lombardia ed Emilia-Romagna (IZSLER) as part of the regional wildlife sanitary surveillance plan. Then, we assessed parasite species through molecular analysis (multiplex PCR followed by ribosomal 12S subunit gene sequencing) in order to update the epidemiological situation on Taeniids infection in the Emilia-Romagna wildlife, reporting the prevalence of each isolated species. The most commonly isolated species was Taenia serialis, which we detected in both wolves and foxes as definitive hosts and in roe deer as intermediate host. More attention on the distribution of Taeniids in wildlife should be paid, considering their potential zoonotic role: several Taenia spp. (Taenia solium, Taenia multiceps, Taenia serialis, Taenia brauni, Taenia glomerulatus) are known for causing coenurosis in humans, with possible severe or fatal outcomes.

Keywords: Cestodes; Phylogenetic analysis; Wildlife parasitology.

Graphical abstract

Fig. 1

Schematic representation of Taenia spp. life cycle in wildlife with accidental involvement of humans as intermediate hosts. Animals images taken from www.phylopic.org (Authors: Tracy Heath, Ferran Sayol, Anthony Caravaggi, Katy Lawler). The Figure was partly generated using Servier Medical Art, provided by Servier, licensed under a Creative Commons Attribution 3.0 unported license.

Fig. 2

– Distribution of different Taenia species in each host species considered.

Fig. 3

Distribution of wildlife species in which each Taenia spp. were detected.

Fig. 4

Percentage of isolation of different Taenia species.

Fig. 5

Geographical location of animals resulted positive for Taenia spp. Icons placed around circles are located in the same position, represented by the yellow point. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Fig. 6

Phylogenetic tree with the sequences of small ribosomal RNA subunit (rrnS) of T.hydatigena (yellow), T. serialis (orange), T. pisiformis (magenta), T. crassiceps (purple) sequenced at the IZSLER, compared with public sequences deposited in GenBank (black). The tree was obtained using the HKJ + G substitution model. Chain length = 10 million iterations. Node labels are posterior probabilities ≥0.9. Squares = sequence from intermediate host; circles = sequence from definitive host. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)