Hiding in plain sight: discovery and phylogeography of a cryptic species of Trichinella (Nematoda: Trichinellidae) in wolverine (Gulo gulo)

Authors

Rajnish Sharma, University of SaskatchewanFollow
Peter C. Thompson, Beltsville Agricultural Research CenterFollow
Eric P. Hoberg, University of New Mexico, Albuquerque
W. Brad Scandrett, Saskatoon Laboratory
Kelly Konecsni, Saskatoon Laboratory
N. Jane Harms, Government of Yukon
Piia M. Kukka, Government of Yukon
Thomas S. Jung, Government of Yukon & University of Alberta
Brett Elkin, Government of the Northwest Territories
Robert Mulders, Government of the Northwest Territories
Nicholas C. Larter, Government of the Northwest Territories
Marsha Branigan, Government of the Northwest Territories
Jodie Pongracz, Government of the Northwest Territories
Brent Wagner, University of Saskatchewan
Pratap Kafle, University of Saskatchewan
Vladislav A. Lobanov, Saskatoon Laboratory
Benjamin M. Rosenthal, Beltsville Agricultural Research Center
Emily J. Jenkins, University of Saskatchewan

Date of this Version

3-24-2020

Citation

2020 Authors

Comments

R. Sharma et al. / International Journal for Parasitology 50 (2020) 277–287

Abstract

Understanding parasite diversity and distribution is essential in managing the potential impact of para- sitic diseases in animals and people. Imperfect diagnostic methods, however, may conceal cryptic species. Here, we report the discovery and phylogeography of a previously unrecognized species of Trichinella in wolverine (Gulo gulo) from northwestern Canada that was indistinguishable from T. nativa using the stan- dard multiplex PCR assay based on the expansion segment 5 (ESV) of ribosomal DNA. The novel genotype, designated as T13, was discovered when sequencing the mitochondrial genome. Phylogenetic analyses of the mitochondrial genome and of 15 concatenated single-copy orthologs of nuclear DNA indicated a com- mon ancestor for the encapsulated clade is shared by a subclade containing Trichinella spiralis and Trichinella nelsoni, and a subclade containing T13 and remaining taxa: T12 + (T2 + T6) + [(T5 + T9) + (T 3 + T8)]. Of 95 individual hosts from 12 species of mammalian carnivores from northwestern Canada from which larvae were identified as T. nativa on multiplex PCR, only wolverines were infected with T13 (14 of 42 individuals). These infections were single or mixed with T. nativa and/or T6. Visual examination and motility testing confirmed that T13 is encapsulated and likely freeze-tolerant. We developed a new Polymerase Chain Reaction-Restriction Fragment Length Polymorphism which unequivocally distinguishes between T13 and T. nativa. We propose Trichinella chanchalensis n. sp. for T13, based on significant genetic divergence from other species of Trichinella and broad-based sampling of the Trichinella genome. Exploration of Alaskan and Siberian isolates may contribute to further resolution of a phylogeo- graphically complex history for species of Trichinella across Beringia, including Trichinella chanchalensis n. sp. (T13)