Fatal infection with Versteria sp. in a muskrat, with implications for human health

Abstract

The Taeniidae tapeworms are a family of helminths that have a similar life cycle, with intermediate hosts developing characteristic cysts in visceral organs. We describe here a case in Pennsylvania, USA, of fatal Versteria infection in a muskrat ( Ondatra zibethicus), which, to our knowledge, has not been reported to develop disease associated with infection. Postmortem examination revealed widespread tissue loss and replacement by solid-bodied cestode larvae with minimal adjacent inflammation in many visceral organs, most severe in the lungs, liver, and brain. Key morphologic features via histology included cephalic structures and short rostellar hooklets, which are characteristic for the genus. Genetic characterization confirmed the cestode as being an undescribed lineage of Versteria that has been implicated as the cause of severe morbidity and mortality in humans and nonhuman primates in North America. Considering the zoonotic significance of this pathogen, our report expands on the limited literature regarding disease caused by Versteria and emphasizes the need to identify the causative tapeworm more accurately, especially in rodent intermediate hosts given that previous reports do not have molecular confirmation of species.

A new species of Versteria (Cestoda: Taeniidae) parasitizing Galictis cuja (Carnivora: Mustelidae) from Patagonia, Argentina: Morphological and molecular characterization

“…Recently, Niedringhaus et al (2021) reported a fatal infection by cysticerci of Versteria sp. in a muskrat Ondatra zibethicus (L.) in Pennsylvania, USA; remarkably, in the same locality where a case of human cysticercosis was reported ( Lehman et al, 2019b ).…”

“…Moreover, it was integrated into the clade which also included Versteria sp. from the orangutan and from humans ( Niedringhaus et al, 2021 ). Unfortunately, the sequence of Versteria sp.…”

“…This species was included in Versteria because it is morphologically very similar to V. mustelae , although molecular data are not available ( Nakao et al, 2013 ). Up to now, species of Versteria are known to use mustelids and procyonids as definitive hosts and rodents as intermediate hosts ( Lavikainen, 2014 ; Niedringhaus et al, 2021 ).…”

“…reported from Wisconsin (host Mustela erminea L.) closely related with V. mustelae ; and the other one is a “zoonotic” lineage of Versteria sp. reported from M. erminea , Neogale vison (Schreber), a captive orangutan, and humans from Colorado, Oregon, Wisconsin (Zoo) and Pennsylvania ( Lee et al, 2016 ; Niedringhaus et al, 2021 ). None of these North American species are morphologically described, although they are molecularly characterized through cytochrome c oxidase subunit 1 gene (cox1) ( Goldberg et al, 2014 ; Lee et al, 2016 ; Lehman et al, 2019b ).…”

“…Additionally, two cases of metacestodes infection in humans by a species of Versteria were reported in Atlantic Canada and Pennsylvania, identified through the mitochondrial 12S rRNA gene and 18 rRNA gene, without morphological description ( Barkati et al, 2019 ; Deplazes et al, 2019 ). The taxonomic uncertainty of this group complicates the understanding of the natural history of the two Versteria species occurring in North America given that ancient reports of V. mustelae in both definitive and intermediate hosts in this region ( Skinker, 1935 ; Locker, 1955 ; Freeman, 1956 ; Verster, 1969 ) could be any of these species (see Niedringhaus et al, 2021 ).…”