Canadian Journal of Zoology
Intestinal parasites of wolves (Canis lupus L. 1758) in northern and western Canada
Journal: Canadian Journal of Zoology
Manuscript ID cjz-2016-0017.R1
Manuscript Type: Article
Date Submitted by the Author: 08-Apr-2016
Complete List of Authors: Schurer, Janna; University of Saskatchewan, Veterinary Microbiology; University of Washington, Occupational and Environmental Health Sciences Pawlik, Michael; University of Saskatchewan Huber, Anna;Draft University of Saskatchewan Elkin, Brett; Government of the Northwest Territories, Environment and Natural Resources Cluff, Dean; Government of the Northwest Territories, Department of Environment and Natural Resources Pongracz, Jodie; Government of the Northwest Territories Gesy, Karen; University of Saskatchewan Wagner, Brent; University of Saskatchewan Dixon, Brent; Health Canada Merks, Harriet; Health Canada Bal, Mandeep; Guru Angad Dev Veterinary & Animal Sciences University Jenkins, Emily; University of Saskatchewan
PARASITOLOGY < Discipline, MOLECULAR GENETICS < Discipline, Keyword: Zoonoses
https://mc06.manuscriptcentral.com/cjz-pubs Page 1 of 28 Canadian Journal of Zoology
P a g e | 1
Intestinal parasites of wolves ( Canis lupus L., 1758) in northern and western Canada
Janna M. Schurer, Michael Pawlik, Anna Huber, Brett Elkin, H. Dean Cluff, Jodie Pongracz, Karen Gesy,
Brent Wagner, Brent Dixon, Harriet Merks, Mandeep S. Bal, Emily J. Jenkins
JMS, MP, AH, KG, BW, EJJ - Department of Veterinary Microbiology, University of Saskatchewan, Canada
BE, HDC, JP - Environment and Natural Resources, Government of the Northwest Territories, Canada
BD, HM - Health Canada, Canada
MSB – Guru Angad Dev Veterinary & Animal Sciences University, India
Corresponding Author: Janna M Schurer, 52Draft Campus Drive, Saskatoon, SK, S7N 5B4, email: [email protected] , telephone: 306-202-0827, fax: 306-966-7244
https://mc06.manuscriptcentral.com/cjz-pubs Canadian Journal of Zoology Page 2 of 28
P a g e | 2
Intestinal parasites of wolves ( Canis lupus ) in northern and western Canada
Janna M. Schurer, Michael Pawlik, Anna Huber, H. Brett Elkin, Dean Cluff, Jodie Pongracz, Karen Gesy,
Brent Wagner, Brent Dixon, Mandeep Bal, Emily J. Jenkins
Abstract:
Gray wolves ( Canis lupus L., 1758) are mobile opportunistic predators that can be infected by a wide range of parasites, with many acquired via predator-prey relationships. Historically, many of these parasites were identified only to genus or family, but genetic tools now enable identification of parasite fauna to species and beyond. We examined 191 intestines from wolves harvested for other purposes from regions in the Northwest Territories, British Columbia, Saskatchewan, and Manitoba. Adult helminths were collected from intestinal contents for morphological and molecular identification, and for a subset of wolves, fecal samples wereDraft also analyzed to detect helminth eggs and protozoan (oo)cysts. Using both detection methods, we found that 83% of 191 intestines contained one or more parasite species, including cestodes (Taenia spp. , Echinococcus spp., and Diphyllobothrium sp.), nematodes ( Uncinaria stenocephala, Trichuris spp. , Physaloptera spp. , and Toxascaris leonina ), a trematode ( Alaria sp.), and protozoa ( Sarcocystis spp. , Giardia spp. , and Cryptosporidium spp.).
Molecular characterization identified one species of Diphyllobothrium (D. latum ), three species of Taenia
(T. krabbei, T. hydatigena, and T. multiceps ), and two Giardia assemblages (B and C). These results demonstrate the diverse diet of wolves, and illustrate the possibility of parasite spillover among wildlife, domestic animals, and people.
Key Words:
Wolf; Canis lupus ; parasite; post-mortem; Canada; zoonotic
https://mc06.manuscriptcentral.com/cjz-pubs Page 3 of 28 Canadian Journal of Zoology
P a g e | 3
Introduction:
Gray wolves ( Canis lupus L., 1758), including tundra and timber wolves, are large canids native to North
America and Eurasia that can disperse hundreds to thousands of kilometers in the wild (Merrill and
Mech 2000; Mech and Boitani 2004). Despite predator reduction programs that extirpated these canids
from many regions of Canada by the 1950s, the wolf population appears to have recovered, and is now
broadly distributed across the country except for the Maritime provinces and the island of
Newfoundland (Vila et al. 1999; Darimont and Paquet 2000; Mech and Boitani 2004). Gray wolves face
both natural and anthropogenic challenges to survival including prey availability, inter-species
competition, disease, habitat fragmentation, hunting/trapping, vehicle accidents, and changing
environmental and climatic conditions. As apex predators, they play a critical role in maintaining ecosystem health by limiting species in lowerDraft trophic levels, and contributing to species biodiversity throughout the food web (Darimont and Paquet 2000). The health status of gray wolves is also relevant
to the health of people, livestock and companion animals because pathogens move between these
groups in a complex web of direct and indirect pathways.
Gray wolves generally depend upon a primary ungulate prey species in their diet, but feed
opportunistically on a variety of secondary prey species, according to season and availability (Kuyt 1972;
Mech and Boitani 2004). Outside of denning season, tundra wolves generally follow migratory prey,
while timber wolves generally protect a territory year-round, hunting suitable prey within a defined area
(Musiani et al. 2007). Timber wolves residing in Riding Mountain National Park (RMNP), in southern
Manitoba (MB), predate elk ( Cervus elaphus canadensis (Erxleben, 1777)) most frequently, followed by
moose ( Alces alces L., 1958), white-tailed deer ( Odocoileus virginianus (Zimmermann, 1780)), and
snowshoe hare ( Lepus americanus (Erxleben, 1777); Sallows 2007). In other areas of Canada, wolves
primarily prey on Sitka black-tailed deer ( O. hemionus sitkensis (Merriam, 1898); Darimont and Paquet
https://mc06.manuscriptcentral.com/cjz-pubs Canadian Journal of Zoology Page 4 of 28
P a g e | 4
2000), caribou ( Rangifer tarandus L., 1958; Musiani et al. 2007), mule deer ( O. hemionus (Rafinesque,
1817)), muskoxen ( Ovibos moschatus (Zimmermann, 1780); Gray 1983), or moose (Peterson and Page
1988). Secondary prey include bison ( Bison bison L. 1958), beaver ( Castor canadensis (Kuhl, 1820)) and various rodents, mustelids, ursids, lagomorphs, and spawning fish (Darimont and Paquet 2000; Darimont and Reimchen 2002), especially when ungulate populations are scarce (Darimont and Reimchen 2002;
Garrott et al. 2007). Many of these prey species act as intermediate or paratenic hosts for parasites that utilize wolves as definitive hosts. In addition to parasites acquired from prey through indirect life cycles, wolves are exposed to numerous parasites that have a direct fecal-oral life cycle. The result of this diverse diet and environmental exposure is that tundra and timber wolves are exposed to a broad range of parasites, including at least 28 nematode species, 27 cestode species, 16 trematode species, one acanthocephalan, as well as protozoans (CraigDraft and Craig 2005). Common parasites of Canadian wolves include taeniid spp. cestodes, nematodes ( Toxascaris leonina and Uncinaria stenocephala), the intestinal fluke Alaria , and coccidian protozoa such as Sarcocystis spp. (Choquette et al. 1973; Craig and Craig
2005; Stronen et al. 2011; Bryan et al. 2012).
The advent of molecular tools has resulted in many parasites being taxonomically re-classified and/or identified to levels beyond that possible by morphological examination (e.g., subspecies, genotypes, subgenotypes, and assemblages). With a few recent exceptions (Bryan et al. 2012; Schurer et al. 2014 b), surveys of wolves in Canada have reported parasites only to genus or species level, depending on whether samples were collected by necropsy or fecal examination. The present study surveyed wolves from 8 regions in 3 provinces (British Columbia [BC], Saskatchewan [SK], Manitoba [MB]) and the
Northwest Territories (NT), each with distinct differences in wolf dietary preferences, prey availability, and proximity to human settlements. We report gastrointestinal helminth and protozoa distribution and prevalence in these areas, including Taenia species, Echinococcus species and genotypes , and Giardia
https://mc06.manuscriptcentral.com/cjz-pubs Page 5 of 28 Canadian Journal of Zoology
P a g e | 5
duodenalis assemblages. These baselines are increasingly relevant for ecologists, veterinarians, and
those concerned with public health aspects of these parasites, as rapid environmental change in
northwestern Canada may be redrawing the boundaries of hosts and parasites alike.
Materials and Methods:
Gross examination
Hunters and trappers obtained 191 wolves from the Northwest Territories ( N=143), British Columbia ( N
=28), Saskatchewan ( N =17), and Manitoba ( N =3), Canada for purposes other than research, between
2010 and 2014 (Figure 1). Intestines were stored at -20˚C until shipped to the University of
Saskatchewan, where they were frozen at -80˚C for at least 5 days prior to examination in order to inactivate eggs of Echinococcus , which areDraft potentially infective for people (Eckert et al. 2001). We harvested helminths from the intestines using the scraping, filtration, and counting technique (SFCT)
(Gesy et al. 2013), and stored them in 70% ethanol until they could be identified to genus by
morphological examination. The intensity of Echinococcus cestodes was estimated as per (Gesy et al.
2013). Where possible, we obtained feces from the rectum, colon, and/or distal ileum, and stored them
at -20˚C prior to conducting fecal egg counts (FEC). Parasite ova and/or cysts were identified and
quantified for 4 grams (wet weight) of feces using a modified Stoll double centrifugation fecal flotation
(Nielsen et al. 2010). Giardia and Cryptosporidium (oo)cysts were quantified for 1 gram of feces using a
sucrose gradient flotation and commercial immunofluorescence assay (Waterborne Inc., New Orleans,
LA; Olson et al. 1997).
Wolf sampling sites in the Northwest Territories
Wolf samples were collected in four NT ecozones (Figure 1; Ecosystem Classification Group 2007;
Ecosystem Classification Group 2008; Ecosystem Classification Group 2010; Ecosystem Classification
https://mc06.manuscriptcentral.com/cjz-pubs Canadian Journal of Zoology Page 6 of 28
P a g e | 6
Group 2012). In the north, wolves sampled were from the Tundra Plains and Tundra Cordillera ecozones where summers are very short and cold, and winters are extremely cold and long (mean annual temperatures (MAT) -9 ˚C to -11˚C; Ecosystem Classification Group 2010). Continuous permafrost exists throughout these nearly treeless landscapes that are dominated by dwarf shrub tundra on uplands
(Ecosystem Classification Group 2010).
Samples came from wolves in the northern, mid, and southern areas of the large Taiga Plain ecozone.
The Taiga Plain ecozone ranges from very short cool summers and very cold winters in the north to warm moist summers and very cold and snowy winters in the south (MAT -8˚C to -13˚C in the north to -
1˚C to -4.5˚C in the south; Ecosystem Classification Group 2007). Permafrost is continuous in the north to discontinuous in the south and peatlandsDraft are extensive throughout. The highly variable climate results in forests that range from very open stunted forests of black ( Picea mariana (Mill.) B.S.P.) and white spruce ( P. glauca (Moench) Voss) with understory that is lichen in the north to closed canopy mixed-wood forest of aspen ( Populus L.) and white spruce with jack pine ( Pinus banksiana Lamb.) on drier sites in the south (Ecosystem Classification Group 2007).
There were also samples from the Taiga Shield ecozone, which has a climate of very short cool summers, very cold winters (mean annual temp -4˚C to -9˚C) towards treeline to warm moist summers, and very cold and snowy winters (mean annual temperature -3˚C to -4˚C) further southwest (Ecosystem
Classification Group 2008). Permafrost ranges along the gradient from widespread and continuous to discontinuous. Near treeline, trees only occur in small stands along lakeshores, lower slopes, eskers and gullies. At treeline, there are very open and usually stunted black and white spruce woodlands that progress to a closed-canopied mixed wood forests of aspen, white spruce and jack pine in the southwest
(Ecosystem Classification Group 2008).
https://mc06.manuscriptcentral.com/cjz-pubs Page 7 of 28 Canadian Journal of Zoology
P a g e | 7
Molecular methods - cestodes
We extracted DNA from cestodes for PCR analysis using two methods. For Taenia and Diphyllobothrium ,
we macerated approximately 0.1 gram of tissue from 1-2 specimens per host using needle tip scissors,
and extracted DNA using the DNeasy Blood and Tissue Kit (Qiagen Inc., Valencia, CA). For Echinococcus ,
we randomly selected three intact cestodes from each infected wolf, placed each in separate petri
dishes containing 500 μL lysis buffer for 10 mins, and extracted DNA as per Catalano et al. (2012).
Amplification of Taenia and Echinococcus DNA focused on regions of the nicotinamide adenosine
dinucleotide dehydrogenase subunit 1 (NAD1) and cytochrome c oxidase subunit 1 (CO1) mitochondrial
genes, with lengths of 471 and 446 base pairs, respectively (Bowles et al. 1992; Bowles and McManus 1993). A separate 437 bp region of the CO1Draft mitochondrial gene was used to amplify Diphyllobothrium - specific DNA (Wicht et al. 2010). These PCR products were resolved by electrophoresis (110V, 25 min)
on a 1.5% agarose gel stained with RedSafe nucleic acid (ChemBio Ltd, Herfordshire, UK), and viewed
under UV light. Samples that produced positive bands were purified (QIAquick PCR Purification Kit,
Qiagen Inc., Valencia, CA), sequenced in both directions using the same primers as the original
amplifications (Macrogen Inc., Seoul, Korea), and then assembled, edited and aligned using Staden
v4.10. Consensus sequences were identified by comparison to previously published sequences in
GenBank (National Center for Biotechnology Information) by BLAST search (blastn).
Molecular methods – Giardia
Molecular methods to identify G. duodenalis assemblages were performed on a subset of positive
samples from NT and SK ( N=35), using a PCR assay targeting a 292 bp region of the 16S-rRNA gene.
Specifically, DNA was extracted from cysts concentrated in a sucrose suspension using the DNeasy Blood
and Tissue Kit (Qiagen Inc., Mississauga, ON), using a protocol modified as follows: 100 μL of the
https://mc06.manuscriptcentral.com/cjz-pubs Canadian Journal of Zoology Page 8 of 28
P a g e | 8
suspended cysts were transferred to 1.5 mL microcentrifuge tubes containing 300 μL lysis buffer. Tubes
were subjected to five freeze/thaw cycles followed by overnight incubation with 20 μL of proteinase K
(20 mg/ml) at 56°C. Manufacturer’s instructions were then followed to purify the DNA. Nucleic acid
was eluted with 100 μL of elution buffer. Positive control, G. duodenalis cysts (Waterborne, Inc., New
Orleans, LA), and negative control, RNase/DNase-free water (Life Technologies, Carlsbad, CA), were also
extracted in parallel. Nested-PCR was performed to amplify a fragment of the Giardia 16S rRNA gene as
described in Appelbee et al. (2003). DNA sequencing of the PCR products was performed using a 3130xl
Genetic Analyzer (Applied Biosystems, Foster City, CA). PCR products were purified and bi-directional
sequencing was performed using the same primers as the original amplifications. DNA sequences were
assembled, edited and aligned using SeqScape v2.5 (ABI). Resulting consensus sequences were then aligned with representative sequence dataDraft from G. duodenalis assemblages, and trimmed to identical lengths of 189 bp for 16S rRNA, using Bioedit v7.1.3.0. Consensus sequences were compared to
reference sequences in GenBank using NCBI standard nucleotide BLAST (blastn).
Statistical analysis and mapping
Data were entered into a spreadsheet and analysed using SPSS (version 19; IMB Corporation, Armonk,
New York, USA). Age was categorized as juvenile (<12 mos) or adult (≥12 mos), and wolves were
considered to be infected if parasite adults or ova were observed by FEC or SFCT. A two-sided Fisher’s
Exact test at the 5% level was conducted to determine if gender and age were statistically associated
with parasite infection, and if parasite prevalence differed between geographic regions. Freeman-
Halton’s extension was used when contingency tables were greater than 2x2. Four fecal samples with
extremely high numbers of Sarcocystis sarcocysts were not quantified, and were omitted from the
overall intensity calculation.
https://mc06.manuscriptcentral.com/cjz-pubs Page 9 of 28 Canadian Journal of Zoology
P a g e | 9
Precise geographic coordinates for wolf-kill locations were only reported for a subset of samples. To
illustrate sampling regions for the remaining samples, we mapped the closest city or town to the
reported wolf location. Sampling sites were mapped using ArcGIS (version 10; Esri, Redlands, California,
USA).
Results:
Of the 191 wolves (83 female, 106 male, two unreported), 15 were juvenile, 102 were adult, and 74 had
unreported age. We observed at least one parasite species in 63% of 191 intestines (Table 1), which was
not statistically different ( P=0.82) from the 64% infection prevalence (not including protozoa) observed
in a subset of fecal samples ( N =151). Combining both methods to include protozoans showed that 83% (95% CI: 78-83%) of wolves were infected withDraft at least one gastrointestinal parasite, and that species richness in infected animals ranged from one to seven species (Figure 2).
Analysis of gut contents revealed six helminth genera (Diphyllobothrium spp., Taenia spp. , Echinococcus
spp. , Toxascaris leonina, Uncinaria stenocephala , and Alaria sp.), with cestodes observed most
frequently, followed by nematodes and flukes. Overall, 71 of 191 (37%) wolves were infected by
Echinococcus, with a median intensity of 2,258 ± 24,397 cestodes per infected wolf (range: 15-149,600).
DNA was successfully amplified from at least one adult cestode in 54 of 71 (76%) infected wolves.
Among BC wolves, 25 of 28 (89%) were infected with Echinococcus , including E. canadensis G8 (6 of 28;
21%), E. canadensis G10 (13 of 28; 46%), and E. multilocularis (3 of 28; 11%). Echinococcus results
obtained by gut necropsy from all SK/MB and 73 NT wolves are reported elsewhere (Schurer et al.
2014 b). Of the remaining NT wolves, nine of 70 were infected with Echinococcus (13%), including E.
canadensis G8 (1 of 70; 1%) and E. canadensis G10 (9 of 70; 13%). The minimum prevalence for all
wolves, including those reported elsewhere, was as follows: 46 of 191 (24%) E. canadensis G10 , 15 of
https://mc06.manuscriptcentral.com/cjz-pubs Canadian Journal of Zoology Page 10 of 28
P a g e | 10
191 (8%) E. multilocularis , and 12 of 191 (6%) E. canadensis G8 (15). Infection prevalence was
significantly different between NT, BC and SK/MB (P-value < 0.001). Mixed taeniid infections were
present in BC, NT, SK and MB, and were characterized as E. canadensis-E. multilocularis (6%) , E.
canadensis G8 -G10 (5%), T. multiceps -T. hydatigena (1%), and Echinococcus-Taenia (20%). Taenia spp.
cestodes were present in 36% of wolves and were identified, in order of descending frequency, as T.
krabbei , T. hydatigena , and T. multiceps . Of the five wolves (3% overall) infected with Diphyllobothrium,
four harboured D. latum . Mixed infections of D. latum with T. krabbei were also seen ( N =2). The
similarity of aligned PCR sequences to those previously catalogued in GenBank was generally high: T. krabbei (99-100%), T. hydatigena (98-100%), T. multiceps (96-97%), D. latum (99-100%), E. canadensis
G8 (98-99%), E. canadensis G10 (97-100%), E. multilocularis (98-100%). One Echinococcus isolate targeted by the CO1 had lower similarity –Draft with 93% shared identity to E. canadensis G10 - and was not successfully sequenced with ND1 primers. Giardia sp., Taenia spp., Echinococcus spp., and D. latum
sequences were submitted to GenBank and were assigned accession numbers as follows: KX058165-
KX058193, xxxxxxxx-xxxxxxxx.
Fecal analysis and intestinal examination both indicated that taeniids ( Taenia and Echinococcus ) and T. leonina were the dominant gastrointestinal helminths of wolves in the sample regions. Slightly less prevalent were Giardia sp. , Cryptosporidium spp. , Alaria sp., and Sarcocystis spp. (range: 18-25%). Least common, and with limited distributions were Diphyllobothrium sp. , U. stenocephala, Physaloptera spp. , and Trichuris spp. (range 1-8%) . Molecular analysis of Giardia demonstrated that most infections were zoonotic Assemblage B only (33 of 35 samples in NT and SK), but that two wolves (one each in NT and
SK) harboured mixed infections of Assemblage B and canid-specific Assemblage C.
https://mc06.manuscriptcentral.com/cjz-pubs Page 11 of 28 Canadian Journal of Zoology
P a g e | 11
Overall infection status (by either method) was not significantly correlated to age ( P=0.16) or gender
(P=0.56). Age class was not a risk factor for infection by Echinococcus spp. (P=0.77), Taenia spp.
(P=0.23), T. leonina (P=0.55), Sarcocystis spp. (P=0.15), Giardia spp. (P=1.0) or Cryptosporidium spp.
(P=0.22). Gender was also not associated with infection by individual parasites [ Echinococcus (P=0.36),
Taenia (P=0.65), Toxascaris (P=0.74), Diphyllobothrium (P=0.16), Alaria (P=0.24), Sarcocystis (P=0.15),
Giardia (P=0.26) or Cryptosporidium (P=0.63)]. Parasite genera observed by fecal flotation but not
detectable by intestinal examination included Trichuris, Physaloptera, Sarcocystis, Giardia, and
Cryptosporidium .
At the province/territory level (Tables 1-2), we observed statistically significant geographic differences in parasite prevalence for Echinococcus spp.,Draft Taenia spp., and Sarcocystis spp. In NT, significant differences in parasite prevalence occurred among ecozones for D. latum, T. multiceps , and Alaria sp.
(Table 3). While E. canadensis was distributed across all ecozones of the NT and was present in all
provinces, E. multilocularis was detected only in the Taiga Plains/Taiga Cordillera ecozone in NT and Fort
St. John in BC. Taenia krabbei was also widely distributed, whereas T. hydatigena was absent from two
NT ecozones, and T. multiceps was found only in Tundra Plains. No significant differences in T. leonina
prevalence were observed at the province/territory or ecozone level.
Discussion:
Our study reports baseline endoparasite prevalence estimates for wolves in several regions of western
Canada, using molecular techniques to identify species and genotypes, when required. Such
information will become increasingly important for those using One Health approaches to investigate
pathogen transmission dynamics among animals, people and the environment. Our study demonstrated
statistically similar helminth prevalence using fecal flotation and gastrointestinal necropsy (64% and
https://mc06.manuscriptcentral.com/cjz-pubs Canadian Journal of Zoology Page 12 of 28
P a g e | 12
63%, respectively). In situations where canid necropsy is unacceptable (e.g., zoological specimens, pets, free ranging wildlife of conservation concern), fecal flotation is a non-invasive technique with high sensitivity for detecting certain endoparasite species such as T. leonina (Liccioli et al. 2012). Using sensitive techniques (such as sucrose gradient concentration and immunofluorescence assays) and in the hands of experienced users, it has the added benefit of detecting protozoa not visible to the naked eye on necropsy or commonly observed using basic fecal flotation techniques. In comparison to necropsy, fecal analysis is less time intensive, less expensive, and carries less risk of exposure to biological hazards if eggs and cysts contained in stool samples are inactivated at -80˚C prior to processing. However, there are several advantages to necropsy such as the relative ease in detecting and recovering taeniid cestodes (identified morphologically, if specimens are fresh and of good quality, or by molecular methods, which are especiallyDraft useful when sample quality and handling are not optimal for parasite morphology) and distinguishing among mixed infections of parasite species shedding morphologically indistinguishable eggs. Taeniid cestodes ( Taenia and Echinococcus spp.) cannot be differentiated on the basis of egg morphology, eggs may not float consistently in routine fecal tests, and extraction of DNA from eggs can be challenging. As well, some helminths shed eggs sporadically or produce eggs that crack during freezing (such as hookworm eggs of Ancylostoma and Uncinaria spp.), and so infection intensity for these species is more accurately estimated by intestinal necropsy (Liccioli et al. 2012; Schurer et al. 2014 a).
This study confirms the sympatric distribution of E. canadensis G8 and G10 genotypes in western
Canada, and broadens the known distribution of wolves as definitive hosts for E. multilocularis to
include BC (Wang et al. 1989; Rausch 1995; Craig and Craig 2005; Thompson et al. 2006; Schurer et al.
2014 b). We demonstrate that G8 and G10 not only co-exist within geographic locales, but that co-
infection of wolves with multiple taeniid genera, species, and genotypes occurs. Mixed infections of
https://mc06.manuscriptcentral.com/cjz-pubs Page 13 of 28 Canadian Journal of Zoology
P a g e | 13
Echinococcus species (6%), E. canadensis genotypes (5%), Taenia species (1%), and of Echinococcus and
Taenia (20%) were all observed; however, we did not conduct PCR on all Taenia , Diphyllobothrium , or
Echinococcus adults, and such estimates undervalue the true prevalence of mixed infection. This
supports laboratory based studies demonstrating that adaptive immunity against recurrent taeniid
infection is unlikely to occur in canids (D. Jenkins and Rickard 1985). Echinococcus was present in more
wolves than any other parasite, highlighting the importance of wolves in maintaining the sylvatic
predator-prey life cycle. Domestic dogs, particularly those with access to carcasses and not regularly
dewormed, can act as bridging hosts between wildlife and people, serving as a source of Echinococcus
infection for both. Dogs do not experience adverse health effects from infection by adult Echinococcus
cestodes; however, ingestion of eggs of E. multilocularis shed in feces of wild canids can result in infection with the larval form (alveolar echinococcDraftosis), which has a poor clinical prognosis (Peregrine et al. 2012; Skelding et al. 2014). We report an Echinococcus infection prevalence (37%) that is higher than
previous reports from MB, BC and NT (Choquette et al. 1973; Stronen et al. 2011; Bryan et al. 2012),
which might be explained by differences in sampling techniques or changing environmental, ecological
or climatic conditions. The high prevalence of E. canadensis relative to E. multilocularis likely
demonstrates the preference among wolves for ungulate prey relative to rodents, but may also be
explained by the smaller geographic distribution of E. multilocularis in North America, defined by two
focal regions (i.e., the northern tundra zone and the north central region), although this may be
changing with detection of the parasite in new regions such as BC (Eckert et al. 2001; Mech and Boitani
2004; Schurer et al. 2013).
Nine Taenia species are known to infect wolves in Canada, and of these we observed three: T. krabbei,
T. hydatigena, and T. multiceps (Craig and Craig 2005) . Taenia krabbei was most prevalent but occurred
only in BC and the NT, highlighting the importance of cervids such as moose, elk, and caribou as primary
https://mc06.manuscriptcentral.com/cjz-pubs Canadian Journal of Zoology Page 14 of 28
P a g e | 14
prey to those wolves (Jones and Pybus 2001; Craig and Craig 2005). In contrast, T. hydatigena, which is
transmitted by bovid, cervid or caprid intermediate hosts, was present in BC, SK, and 2 ecozones of the
NT, but at lower prevalence than T. krabbei . Caribou are possible intermediate hosts for Taenia
multiceps within the sampling regions. Suggestions that T. krabbei is most common in tundra wolves,
while T. hydatigena is most prevalent in timber wolves, conflict with dietary studies that suggest tundra wolves consume a greater variety of prey, including rodents, than timber wolves (Pimlott et al. 1969;
Kuyt 1972; Choquette et al. 1973; Craig and Craig 2005). The presence of E. multilocularis and T. hydatigena in both tundra and boreal regions suggests that wolves in both areas hunt opportunistically, utilizing ungulates as well as a wide variety of smaller prey. Piscivores are infected by Diphyllobothrium when they consume infected marine or freshwater fish (e.g., pike [ Esox lucius L., 1758], yellow perch [Perca flavescens (Mitchill, 1814)], and walleyeDraft [ Sander vitreus (Mitchill, 1818)]; Scholz et al. 2009). The presence of D. latum in NT was expected, as wolves may have direct and/or indirect access to freshwater and anadromous fish, but other surveys have also reported D. dendriticum (reviewed in E.
Jenkins et al. 2013). We did not detect Diphyllobothrium in BC, where D. nihonkaiense occurs in coastal wolves, even though three wolves in this survey were captured on Vancouver Island. This could be due to seasonal switching of primary prey (Darimont and Reimchen 2002), but is more likely explained by the fact that most BC samples were from non-coastal areas (Figure 1).
We observed four nematode species: T. leonina (most prevalent), U. stenocephala, Physaloptera spp. , and Trichuris spp. We did not observe Spirocerca, Dioctophyme renale , Eucoleus aerophilus , Filaroides osleri or Ancylostoma caninum, likely because they are relatively rare in Canada and because our isolation method was not optimized to detect all nematode species (Choquette et al. 1973; Craig and
Craig 2005; Bryan et al. 2012). Toxocara canis , a nematode common to young canids and transmitted through direct, peri-natal, and paratenic life cycles, was also not observed despite previous reports of
https://mc06.manuscriptcentral.com/cjz-pubs Page 15 of 28 Canadian Journal of Zoology
P a g e | 15
infected wolves in BC and MB (Bryan et al. 2012; Stronen et al. 2011). This suggests that wolves are less
suitable hosts than domestic dogs, which have been observed with moderate levels of toxocariasis in
close proximity to the sampling areas (Salb et al. 2008; Himsworth et al. 2010; Schurer et al. 2012). It is
also possible that Toxascaris life stages are better adapted to survival in cold arctic climates than
Toxocara , for which a northern distributional limit exists (E. Jenkins et al. 2013) .
The finding of Giardia Assemblage C was expected, as this assemblage is canid-specific and was
previously reported in wild coyotes ( Canis latrans (Say, 1823)) in Alberta and SK (Thompson et al. 2009).
Within western Canada, Assemblage B has been reported in BC wolves (Bryan et al. 2012); however,
between the two zoonotic assemblages (A and B), Assemblage A has been reported more often, with hosts including dogs (Salb et al. 2008; HimsworthDraft et al. 2010; Schurer et al. 2012), wolves (Bryan et al. 2012), coyotes (Thompson et al. 2009), muskoxen (Kutz et al. 2008) and cattle ( Bos taurus L., 1758;
Appelbee et al. 2003). The widespread geographic distribution and host range of zoonotic Giardia
assemblages suggests that pathogen sharing among people, wildlife and domestic animals occurs even
in remote areas; however, the direction of pathogen transmission remains unclear.
One limitation to our opportunistic sampling method was that geographic areas were not equally
represented. For MB in particular, we do not report a complete picture of parasite richness; those
parasites that were present at low prevalence may have remained unobserved. This study maximized
parasite detection by conducting fecal analysis and adult helminth parasite recovery from intestinal
necropsy; however, intensity estimates based on fecal flotation for some helminths (e.g., Uncinaria ),
may have appeared artificially low due to morphological changes in eggs that prevent detection or
identification after freezing (Schurer et al. 2014 a). Other endoparasites (ascarids, taeniids and
https://mc06.manuscriptcentral.com/cjz-pubs Canadian Journal of Zoology Page 16 of 28
P a g e | 16
Sarcocystis ) produce ova/cysts that tolerate extreme temperature conditions well, and infection can be accurately assessed by FEC (Schurer et al. 2014 a).
This study highlights the utility of combining fecal analysis and necropsy to estimate overall gastrointestinal parasitism, and the need for new, non-invasive techniques to detect parasites common to wolves. We observed a broad geographic distribution of certain zoonotic parasites ( Echinococcus,
Cryptosporidium, Giardia ), as well as localized differences in parasite diversity and prevalence. While prevalence of these helminth zoonoses appears to be decreasing in people across the Canadian North, there remain a disproportionate number of cases in northern Canadians relative to the rest of Canada, and this may exacerbate existing health disparities (Jenkins et al. 2013). There is increasing concern that these protozoans are already a significant Draftcontributor to human enteric illness in the Canadian North and that outbreaks may increase in frequency and magnitude in a rapidly changing northern climate.
For these reasons, there remains a need to determine baselines for parasite diversity in free-ranging wildlife, and to further characterize the occurrence and direction of pathogen transmission among wildlife, domestic animals, and people in northern environments, in order to better assess and manage current and emerging risks to animal and public health.
Acknowledgements:
We gratefully acknowledge Helen Schwantje, Karl Cox, Todd Shury, Chelsea Himsworth, Christine
Menno, Marsha Branigan, and the hunters and trappers who provided animal tissues. We also thank
Rajnish Sharma for technical support. Student training at the Zoonotic Parasite Research Unit was generously funded by the Public Health and the Agricultural Rural Ecosystem (PHARE), the Western
College of Veterinary Medicine Interprovincial Undergraduate Summer Student Fellowship, and the
Integrated Training Program in Infectious Diseases, Food Safety, and Public Policy (ITraP). Laboratory
https://mc06.manuscriptcentral.com/cjz-pubs Page 17 of 28 Canadian Journal of Zoology
P a g e | 17
funding was provided by the Natural Sciences and Engineering Research Council of Canada and the
Canadian Foundation for Innovation Leaders Opportunity Fund.
References:
Appelbee, A.J., Frederick, L.M., Heitman, T.L., and Olson, M.E. 2003. Prevalence and genotyping of
Giardia duodenalis from beef calves in Alberta, Canada. Vet. Parasitol. 112 : 289–94.
Bowles, J, Blair, D., and McManus, D.P. 1992. Genetic variants within the genus Echinococcus identified
by mitochondrial DNA sequencing. Mol. Biochem. Parasitol. 54 : 165–74.
Bowles, J, and McManus, D.P. 1993. NADH dehydrogenase 1 gene sequences compared for species and
strains of the genus Echinococcus . Int. J. Parasitol. 23 : 969–72. Bryan, H.M, Darimont, C.T., Hill, J.E., Paquet,Draft P.C., Wagner, B.A., and Smits, J.E. 2012. Seasonal and biogeographical patterns of gastrointestinal parasites in large carnivores: Wolves in a coastal
archipelago. Parasitology, 139 : 781–90.
Catalano, S, Lejuene, M., Liccioli, S., Verocai, G.G., Gesy, K.M., Jenkins, E.J., Kutz, S.J., Fuentealba, C.,
Duignan, P.J., and Massolo, A. 2012. Echinococcus multilocularis in urban coyotes, Alberta,
Canada. Emerg. Infect. Dis. 18:1625-1628.
Choquette, L.P.E., Gibson, G.G., Kuyt, E., and Pearson, A.M. 1973. Helminths of wolves, Canis lupus L., in
the Yukon and Northwest Territories. Can. J. Zool. 51 : 1087–91.
Craig, H.L., Craig, P.S. 2005. Helminth parasites of wolves ( Canis lupus ): A species list and an analysis of
published prevalence studies in Nearctic and Palaearctic populations. J. Helminthol. 79 : 55–103.
Darimont, C.T., and Paquet, P.C. 2000. The grey wolves ( Canis lupus ) of British Columbia’s coastal
rainforests: Findings from year 2000 pilot study and conservation assessment. Raincoast
Conservation Society, Victoria, BC. Available from
http://raincoast.org/files/publications/reports/wolfreport.pdf.
https://mc06.manuscriptcentral.com/cjz-pubs Canadian Journal of Zoology Page 18 of 28
P a g e | 18
Darimont, C.T., and Reimchen, T.E. 2002. Intra-hair stable isotope analysis implies seasonal shift to
salmon in grey wolf diet. Can. J. Zool. 80 : 1638–42.
Eckert, J., Gemmell, M.A., Meslin, F.-X., and Pawlowski, Z.S. 2001. WHO/OIE manual of Echinococcosis in
humans and animals: A public health problem of global concern. Organization for Animal Health
and World Health Organization, Geneva, Switzerland. Available from
http://apps.who.int/iris/bitstream/10665/42427/1/929044522X.pdf
Ecosystem Classification Group. 2007. Ecological Regions of the Northwest Territories - Taiga Plains.
Yellowknife, NT, Canada: Department of Environment and Natural Resources, Government of
the Northwest Territories.
Ecosystem Classification Group. 2008. Ecological Regions of the Northwest Territories - Taiga Shield. Yellowknife, NT, Canada: DepartmentDraft of Environment and Natural Resources, Government of the Northwest Territories.
Ecosystem Classification Group. 2010. Ecological Regions of the Northwest Territories - Cordillera.
Yellowknife, NT, Canada: Department of Environment and Natural Resources, Government of
the Northwest Territories.
Ecosystem Classification Group. 2012. Ecological Regions of the Northwest Territories - Southern Arctic.
Yellowknife, NT, Canada: Department of Environment and Natural Resources, Government of
the Northwest Territories.
Garrott, R.A., Bruggeman, J.E., Becker, M.S., Kalinowski, S.T., and White, P.J. 2007. Evaluating prey
switching in wolf-ungulate systems. Ecol. Appl. 17 : 1588–97.
Gesy, K.M., Pawlik, M., Kapronczai, L., Wagner, B.A., Elkin, B.T., Schwantje, H., and Jenkins, E.J. 2013. An
improved method for the extraction and quantification of adult Echinococcus from wildlife
definitive hosts. Parasitol. Res. 112 : 2075-2078.
https://mc06.manuscriptcentral.com/cjz-pubs Page 19 of 28 Canadian Journal of Zoology
P a g e | 19
Gray, D.R. 1983. Interaction between wolves and muskoxen on Bathurst Island, Northwest Territories,
Canada. Acta Zool. Fenn. 174 :255-257.
Himsworth, C.G., Skinner, S., Chaban, B., Jenkins, E.J., Wagner, B.A., Harms, N.J., Leighton, F.A.,
Thompson, R.C.A., and Hill, J.E. 2010. Short report: Multiple zoonotic pathogens identified in
canine feces collected from a remote Canadian Indigenous community. Am. J. Trop. Med. Hyg.
83 : 338–41.
Jenkins, D.J., and Rickard, M.D. 1985. Specific antibody responses to Taenia hydatigena, Taenia
pisiformis and Echinococcus granulosus in dogs. Aust. Vet. J. 62 : 72–78.
Jenkins, E.J., Castrodale, L.J., de Rosemond, S., Dixon, B., Elmore, S.A., Gesy, K.M., Hoberg, E., Polley, L.,
Schurer, J.M., Simard, M., and Thompson, R.C.A. 2013. Tradition and transition: Parasitic zoonoses in people and animals inDraft northern North American and Greenland. Adv. Parasitol. 82 : 33–204.
Jones, A, and Pybus, M.J. 2001. Taeniasis and echinococcosis. In Parasitic diseases of wild mammals.
Edited by W.M. Samuel, M.J. Pybus, and A.A. Kocan. Iowa State University Press, Ames, Iowa.
pp.150–92.
Kutz, S., Thompson, R.C.A., Polley, L., Kondola, K., Nagy, J., Wielinga, C.M., and Elkin, B.T. 2008. Giardia
Assemblage A: Human genotype in muskoxen in the Canadian Arctic. Parasit. Vectors, 1: 32.
Kuyt, E. 1972. Food habits and ecology of wolves on barren-ground caribou range in the Northwest
Territories. 21. Canadian Wildlife Services, Technical Report Series. Ottawa, Canada:
Environment Canada.
Liccioli, S., Catalano, S., Kutz, S.J., Lejuene, M., Verocai, G.G., Duignan, P.J., Fuentealba, C., Ruckstuhl,
K.E., and Massolo, A. 2012. Sensitivity of double centrifugation sugar fecal flotation for detecting
intestinal helminths in coyotes (Canis latrans ). J. Wildl. Dis. 48 : 717–23.
https://mc06.manuscriptcentral.com/cjz-pubs Canadian Journal of Zoology Page 20 of 28
P a g e | 20
Mech, L.D., and Boitani, L. 2004. Canids, foxes, wolves, jackals and dogs. In Status Survey and
Conservation Action Plan. Edited by C. Sillero-Zubiri, M. Hoffman, and D.W. Macdonald.
IUCN/SSC Canid Specialist Group. Available from
http://www.env.gov.bc.ca/fw/wildlife/management-
issues/docs/grey_wolf_management_plan.pdf.
Merrill, S.B., and Mech, L.D. 2000. Details of extensive movements by Minnesota wolves ( Canis lupus ).
Am. Midl. Nat. 144 : 428–33.
Musiani, M., Leonard, J.A., Cluff, H.D., Gates, C.C., Mariani, S., Paquet, P.C., Vila, C. and Wayne, R.K.
2007. Differentiation of tundra/taiga and boreal coniferous forest wolves: Genetics, coat colour
and association with migratory caribou. Mol. Ecol. 16 : 4149–70. Nielsen, M.K., Vidyashankar, A.N., Andersen,Draft U.V., DeLisi, K., Pilegaard, K., and Kaplan, R.M. 2010. Effects of fecal collection and storage factors on strongylid egg counts in horses. Vet. Parasitol. 167 : 55–
61.
Olson, M.E., Thorlakson, C.L., Deselliers, L., Morck, D.W., and McAllister, T.A. 1997. Giardia and
Cryptosporidium in Canadian farm animals. Vet. Parasitol. 68 : 375–81.
Peregrine, A.S., Jenkins, E.J., Barnes, B., Johnson, S., Polley, L., Barker, I.K., de Wolf, B., and Gottstein, B.
2012. Alveolar hydatid disease ( Echinococcus multilocularis ) in the liver of a Canadian dog in
British Columbia, a newly endemic region. Can. Vet. J. 53 : 870–74.
Peterson, R.O., and Page, R.E. 1988. The rise and fall of Isle Royale wolves, 1975-1986. J. Mammal. 69 :
89–99.
Pimlott, D.H., Shannon, J.A., and Kolenosky, G.B. 1969. The ecology of the timber wolf in Algonquin
Provincial Park. 87. Research Report (Wildlife). Ontario Department of Lands and Forests:
Ottawa, Canada.
https://mc06.manuscriptcentral.com/cjz-pubs Page 21 of 28 Canadian Journal of Zoology
P a g e | 21
Rausch, R.L. 1995. Life cycle patterns and geographic distribution of Echinococcus species. In
Echinococcus and hydatid disease. Edited by R.C.A. Thompson and A.J. Lymbery. CAB
International, Wallingford, UK. pp.477.
Salb, A.L., Barkema, H.W., Elkin, B.T., Thompson, R.C.A., Whiteside, D.P., Black, S.R., Dubey, J.P., and
Kutz, S.J. 2008. Dogs as sources and sentinels of parasites in humans and wildlife, northern
Canada. Emerg. Infect. Dis. 14 : 60–63.
Sallows, T. 2007. Diet preference and parasites of grey wolves in Riding Mountain National Park of
Canada. M.Sc. thesis, University of Manitoba, Canada. Available from
http://mspace.lib.umanitoba.ca/bitstream/handle/1993/8030/Sallows_Diet_preference.pdf?se
quence=1&isAllowed=y. Scholz, T., Garcia, H.H., Kuchta, R., and Wicht,Draft B. 2009. Update on the human broad tapeworm (genus Diphyllobothrium ), including clinical relevance. Clin. Microbiol. Rev. 22 : 146–60.
Schurer, J.M., Davenport, L., Wagner, B.A., and Jenkins, E.J. 2014 a. Effects of sub-zero storage
temperature on endoparasites in canine and equine feces. Vet. Parasitol. 204 : 310–15.
Schurer, J.M., Elkin, B.T. and Jenkins, E.J. 2014 b. Echinococcus multilocularis and E. canadensis in wolves
from western Canada. Parasitology, 141 : 159–63.
Schurer, J.M., Hill, J.E., Fernando, C., and Jenkins, E.J. 2012. Sentinel surveillance for zoonotic parasites in
companion animals in Indigenous communities of Saskatchewan. Am. J. Trop. Med. Hyg. 87 :
495–98.
Schurer, J.M., Shury, T., Leighton, F.A., and Jenkins, E.J. 2013. Surveillance for Echinococcus canadensis
genotypes in Canadian ungulates. Int. J. Parasitol. Parasites Wildl. 2: 97–101.
Skelding, A., Brooks, A., Stalker, M., Mercer, N., de Villa, E., Gottstein, B., and Peregrine, A.S. 2014.
Hepatic alveolar hydatid disease ( Echinococcus multilocularis ) in a boxer dog from southern
Ontario. Can. Vet. J. 55 : 551–53.
https://mc06.manuscriptcentral.com/cjz-pubs Canadian Journal of Zoology Page 22 of 28
P a g e | 22
Stronen, A.V., Sallows, T., Forbes, G.J., Wagner, B.A., and Paquet, P.C. 2011. Diseases and parasites in
wolves of the Riding Mountain National Park region, Manitoba, Canada. J. Wildl. Dis. 47 : 222–27.
Thompson, R.C.A., Boxell, A.C., Ralston, B.J., Constantine, C.C., Hobbs, R.P., Shury, T., and Olson, M.E.
2006. Molecular and morphological characterization of Echinococcus in cervids from North
America. Parasitology, 132 : 439–47.
Thompson, R.C.A., Colwell, D.D., Shury, T., Appelbee, A.J., Read, C., Njiru, Z., and Olson, M.E. 2009. The
molecular epidemiology of Cryptosporidium and Giardia infections in coyotes from Alberta,
Canada, and observations on some cohabiting parasites. Vet. Parasitol. 159 : 167–70.
Vila, C., Amorim, I.R., Leonard, J.A., Posada, D., Castroviejo, J., Petrucci-Fonseca, F., Crandall, K.A.,
Ellegren, H., and Wayne, R.K. 1999. Mitochondrial DNA phylogeography and population history of the grey wolf Canis lupus . Mol. Ecol.Draft 8: 2089–2103. Wang, W., Wu, Y., and Ding, Z. 1989. The occurrence of Echinococcus multilocularis Leuckart, 1863 in fox
and wolf in Tacheng District, Xinjiang. Bull. Endem. Dis. 4: 8–12.
Wicht, B., Yanagida, T., Scholz, T., Ito, A., Jimenez, J.A., and Brabac, J. 2010. Multiplex PCR for differential
identification of broad tapeworms (Cestoda: Diphyllobothrium ) infecting humans. J. Clin.
Microbiol. 48 : 3111–16.
https://mc06.manuscriptcentral.com/cjz-pubs Page 23 of 28 Canadian Journal of Zoology
P a g e | 23
Table 1: Parasite prevalence, not including Echinococcus , in wolves (Canis lupus L., 1758) as observed by
intestinal necropsy and compared by province/territory.
Prevalence N (%) 95% CI P-value 1
Province/Territory 2 NT BC SK/MB Total
Sample size 143 28 20 191
Toxascaris 25 (17) 6 (21) 3 (15) 34 (18) 13 -23 0.81
Diphyllobothrium 3 5 (3) 0 (0) 0 (0) 5 (3) 1-5 0.77
D. latum 4 4 (3) 0 (0) 0 (0) 4 (2) 0-4
Unidentified 1 (1) 0 (0) 0 (0) 1 (1) 0-1
Taenia 3 38 (27) 23 (28) 8 (40) 69 (36) 29 -43 <0.001 T. krabbei 4 26 (18) Draft16 (57) 0 (0) 42 (22) 16-28 T. hydatigena 4 6 (4) 6 (21) 1 (5) 13 (7) 4-11
T. multiceps 4 3 (2) 0 (0) 0 (0) 3 (2) 0-4
Unidentified 4 (3) 6 (21) 7 (35) 17 (9) N/A
Alaria 8 (6) 0 (0) 3 (15) 11 (6) 3-9 0.06
Uncinaria 1 (1) 0 (0) 0 (0) 1 (1) 0-1 1.0
Parasite Prevalence 5 75 (52) 28 (100) 17 (85) 120 (63) 56 -70 <0.001
1Fisher’s Exact Test; 2NT-Northwest Territories, BC-British Columbia, SK-Saskatchewan, MB-Manitoba;
3Based on morphological identification; 4Based on molecular identification; 5Percent wolves infected
with one or more adult helminth species observed during necropsy
https://mc06.manuscriptcentral.com/cjz-pubs Canadian Journal of Zoology Page 24 of 28
P a g e | 24
Table 2: Parasite prevalence in wolves (Canis lupus L., 1758) as observed by fecal flotation and compared by province/territory.
Prevalence N (%) 95% CI P-value 1 Median
Intensity 2
(min-max)
Province/Territory 3 NT BC SK/MB Total
Sample size 118 13 20 151
Toxascaris leonina 30 (25) 3 (23) 1 (5) 34 (23) 16 -30 0.13 70 (3 -2425)
Diphyllobothrium 13 (11) 0 (0) 0 (0) 13 (9) 4-14 0.22 118 (5 -4010)
Taeniid 20 (17) 10 (77) 12 (60) 42 (28) 21 -35 <0.001 68 (3 -9593) Alaria 25 (21) 0 (0) Draft5 (25) 30 (20) 14 -26 0.12 10 (3 -1535) Uncinaria 1 (1) 0 (0) 0 (0) 1 (1) 0-3 1.0 N/A
stenocephala
Sarcocystis 21 (18) 0 (0) 8 (40) 29 (19) 13 -25 0.01 2067 (147 -
7600)
Physaloptera 2 (2) 0 (0) 0 (0) 2 (1) 0-3 0.99 N/A
Trichuris 2 (2) 0 (0) 0 (0) 2 (1) 0-3 0.99 N/A
Giardia 34 (29) 1 (8) 3 (15) 38 (25) 18 -32 0.15 800 (2 -18476)
Cryptosporidium 14 (19) 4 N/A 6 (30) 20 (13) 8-18 0.36 367 (67 -1467)
Parasite 87 (74) 13 (100) 17 (85) 117 (77) 70 -84 0.06
Prevalence 5
1Fisher’s Exact Test; 2Eggs or cysts per gram feces; 3NT-Northwest Territories, MB-Manitoba, BC-British
Columbia, SK-Saskatchewan; 4Subset of NT samples analyzed for Cryptosporidium (N=93); 5Wolves infected with at least one gastrointestinal parasite observed by fecal analysis
https://mc06.manuscriptcentral.com/cjz-pubs Page 25 of 28 Canadian Journal of Zoology
P a g e | 25
Table 3: Comparison of parasite prevalence in Northwest Territory wolves (Canis lupus L., 1758; N=143)
by ecozone.
Ecozone Taiga Plains & Tundra Taiga Tundra P-value 1
Taiga Cordillera Plains Shield Cordillera
Fecal analysis or necropsy – N (%)
Sample Size 72 35 19 17
Toxascaris 19 (26) 11 (31) 8 (42) 5 (29) 0.6
Diphyllobothrium 11 (15) 0 (0) 3 (16) 1 (6) 0.04
Taenia 19 (26) 10 (29) 2 (11) 7 (41) 0.21
T. krabbei 11 (15) 7 (20) 2 (11) 6 (35) 0.23 T. hydatigena 5 (7) Draft1 (3) 0 (0) 0 (0) 0.59 T. multiceps 0 (0) 3 (9) 0 (0) 0 (0) 0.04
Echinococcus 23 (32) 4 (11) 3 (16) 2 (12) 0.06
E. canadensis G8 5 (7) 0 (0) 0 (0) 0 (0) 0.31
E. canadensis G10 12 (23) 4 (11) 2 (11) 2 (12) 0.91
E. multilocularis 6 (8) 0 (0) 0 (0) 0 (0) 0.19
Alaria 18 (25) 0 (0) 10 (53) 0 (0) <0.01
Fecal Analysis only – N (%)
Sample Size 65 23 19 11
Sarcocystis 16 (25) 1 (4) 4 (21) 0 (0) 0.05
Giardia 20 (31) 2 (9) 7 (37) 5 (45) 0.06
Cryptosporidium 11 (20) 2 N/A 3 (16) N/A 0.62
Parasite Prevalence 3 60 (83) 22 (63) 17 (89) 13 (76) 0.047
1Fisher’s Exact Test; 2N=54; 3Wolves infected with at least one gastrointestinal parasite
https://mc06.manuscriptcentral.com/cjz-pubs Canadian Journal of Zoology Page 26 of 28
Figure 1: Wolf sampling sites (circle - individual wolf; square – group of wolves)
Figure 2: Parasite richness in wolves ( Canis lupus L., 1758; N=193) from the Northwest Territories, British
Columbia, Saskatchewan, and Manitoba as determined by intestinal necropsy and fecal analysis (Bars -
95% confidence intervals).
Draft
https://mc06.manuscriptcentral.com/cjz-pubs Page 27 of 28 Canadian Journal of Zoology
NT Ecozones
Boreal Cordillera Northern Arctic Southern Arctic: Tundra Plains Sachs ^_Harbour Taiga Cordillera Tuktoyaktuk Taiga Plains ^_ ^_ Taiga Shield Inuvik ^_Ulukhaktok Tundra Cordillera Northwest northern limit of trees
Norman ^_ Wells Yukon Nunavut DraftTerritories
Fort ^_ Yellowknife Simpson ^_
Hay River ^_ British Fort Smith^_ o Fort 60 Smithers St.John
Alberta Key Prince Lake George Saskatchewan Manitoba Port Columbia Hardy Prince Albert Big River Pemberton National Tofino Park
Mill Bay Lamb Creek Riding Mountain National 0 125 250 500 Park km
https://mc06.manuscriptcentral.com/cjz-pubs Canadian Journal of Zoology Page 28 of 28
40
35
30
25
20
% wolves % 15
10
5
0 0 1 2 3 4 5 6 7 # parasite genera
Draft
https://mc06.manuscriptcentral.com/cjz-pubs