Molecular Evidence for Local Acquisition of Human Alveolar Echinococcosis in Saskatchewan, Canada.

Alveolar echinococcosis (AE) is a life-threatening parasitic disease caused by the zoonotic cestode Echinococcus multilocularis. Our goals were to confirm infection, identify species, and analyze biogeographical origin of metacestode tissues from a suspected human AE case in Saskatchewan, Canada. We conducted polymerase chain reaction (PCR) targeting the nad1 mitochondrial gene for E. multilocularis and the rrnS ribosomal RNA gene for E. granulosus and conducted haplotype analysis at the nad2 locus. Our analysis confirmed AE and indicated that sequences matched infected Saskatchewan coyotes and European E3/E4 haplotypes. The patient had no travel history outside North America. This suggests autochthonous transmission of a European-type strain.

Parasite control in Canadian companion animal shelters and a cost-comparison of anthelmintics.

Animal shelters have limited resources and must accommodate large numbers of animals at unpredictable intake rates. These dogs and cats are often parasitized, which can adversely affect the health of animals and expose shelter workers and adoptive owners to zoonoses. We analyzed survey responses from rural (n = 32) and urban (n = 50) companion animal shelters across Canada, and compared the wholesale cost of commercially available anthelmintics to identify cost-effective methods of managing parasites within shelters. Almost all shelters employed nematocides (98% to 99%), but cestocides and ectoparasiticides were used less frequently. Shelters identified cost as an important consideration in choosing to perform fecal diagnostic testing and administer anthelmintics, and this motivated many shelters to selectively perform testing (66%) or never to test (32%), and to use drugs extralabel (80%).

Contrôle des parasites dans les refuges pour animaux de compagnie du Canada et comparaison des coûts des anthelminthiques. Les refuges pour animaux possèdent des ressources limitées et doivent héberger un grand nombre d'animaux à des taux d'accueil imprévisibles. Des produits antiparasitaires sont souvent administrés à ces chiens et chats, ce qui peut influencer négativement la santé des animaux et exposer les travailleurs et les propriétaires adoptifs aux zoonoses. Nous avons analysé les réponses à un sondage provenant de refuges pour animaux de compagnie en région rurale (n = 32) et urbaine (n = 50) à l'échelle du Canada et nous avons comparé le coût de gros des anthelminthiques disponibles dans le commerce pour identifier des méthodes économiques de gérer les parasites dans les refuges. Presque tous les refuges employaient des nématicides (98 % à 99 %), mais les cestocides et les ectoparasiticides étaient utilisés moins fréquemment. Les refuges ont identifié le coût comme une considération importante lors des décisions relatives aux analyses des fèces et à l'administration des anthelminthiques et cette situation a motivé beaucoup de refuges à réaliser des analyses de manière sélective (66 %) ou de ne jamais effectuer d'analyses (32 %) et d'utiliser des médicaments en dérogation des directives de l'étiquette (80 %).(Traduit par Isabelle Vallières).

Echinococcus multilocularis and Echinococcus canadensis in wolves from western Canada.

Echinococcus species are important parasites of wildlife, domestic animals and people worldwide; however, little is known about the prevalence, intensity and genetic diversity of Echinococcus tapeworms in Canadian wildlife. Echinococcus tapeworms were harvested from the intestines of 42% of 93 wolves (Canis lupus) from five sampling regions in the Northwest Territories, Manitoba and Saskatchewan, and visually identified to genus level by microscopic examination. Genetic characterization was successful for tapeworms from 30 wolves, and identified both Echinococcus canadensis and Echinococcus multilocularis in all sampling locations. Mixed infections of E. canadensis/E. multilocularis, as well as the G8/G10 genotypes of E. canadensis were observed. These findings suggest that wolves may be an important definitive host for both parasite species in western Canada. This represents the first report of wolves naturally infected with E. multilocularis in North America, and of wolves harbouring mixed infections with multiple species and genotypes of Echinococcus. These observations provide important information regarding the distribution and diversity of zoonotic species of Echinococcus in western North America, and may be of interest from public health and wildlife conservation perspectives.

Rural origin, age, and endoparasite fecal prevalence in dogs surrendered to the Regina Humane Society, 2013.

We report the results of fecal parasite surveillance in dogs surrendered to the Regina Humane Society, Saskatchewan, Canada, between May and November 2013. Overall, 23% of 231 dogs were infected with at least 1 intestinal parasite. Endoparasite infection was positively associated with rural origin (P = 0.002) and age (< 12 months; P < 0.001).

Origine rurale, âge et prévalence des endoparasites fécaux chez les chiens livrés à la Regina Humane Society, 2013. Nous rapportons les résultats de la surveillance de parasites fécaux chez les chiens livrés à la Regina Humane Society (Saskatchewan, Canada) entre mai et novembre 2013. En tout, 23 % des 231 chiens ont été infectés avec au moins un parasite intestinal. L'infection aux endoparasites a été positivement associée à une origine rurale (P = 0,002) et à l'âge (< 12 mois; P < 0,001).(Traduit par Emilie Bouchard).

A retrospective investigation of feline gastrointestinal parasites in western Canada.

Between 1998 and 2008, feline fecal specimens were submitted to provincial veterinary diagnostic laboratories in Regina and Saskatoon, Saskatchewan, for sucrose centrifugation-flotation (n = 635), parasite identification (n = 17), and/or Giardia (n = 283) or Cryptosporidium (n = 266) commercial direct immunofluorescence assay (IFA). The most commonly detected parasites on flotation were Toxocara cati (4.7%), Isospora (3.8%), and taeniid eggs (Echinococcus or Taenia) (1.3%). Cats less than 2 years of age were twice as likely to have a positive parasite test as cats older than 2 years. Using IFA, Giardia was detected in 9.9% of samples, and Cryptosporidium in 2.3% of samples. Relative to IFA, flotation had sensitivity values of 39% and 50% for detection of Giardia and Cryptosporidium, respectively. Giardia and Isospora were detected in a higher proportion of samples in our study population than reported in the general cat population in western Canada. This study highlights the importance of sensitivity when interpreting diagnostic tests and provides information to guide region-specific recommendations for helminth parasite prevention and treatment.

Enquête rétrospective des parasites gastro-intestinaux félins dans l'Ouest canadien. Entre 1998 et 2008, des échantillons fécaux félins ont été soumis aux laboratoires de diagnostic vétérinaires provinciaux à Regina et à Saskatoon, en Saskatchewan, pour une centrifugation-flottaison par saccharose (n = 635), l'identification des parasites (n = 17), et/ou d'un essai par immunofluorescence direct commercial pour Giardia (n = 283) ou Cryptosporidium (n = 266). Les parasites les plus couramment détectés à la flottaison étaient Toxocara cati (4,7 %), Isospora (3,8 %) des œufs de ténia (Echinococcus ou Taenia) (1,3 %). Il était deux fois plus probable que les chats âgés de moins de 2 ans aient un test positif pour les parasites que les chats âgés de plus de 2 ans. À l'aide d'un essai par immunofluoresnce, Giardia a été détecté dans 9,9 % des échantillons et Cryptosporidium dans 2,3 % des échantillons. En rapport avec l'essai par immunofluorescence, la flottaison avait des valeurs de sensibilité de 39 % et de 50 % pour la détection de Giardia et de Cryptosporidium, respectivement. Giardia et Isospora ont été détectés dans une proportion supérieure d'échantillons dans notre population étudiée comparativement à celle des résultats signalés dans la population générale de chats de l'Ouest canadien. Cette étude souligne l'importance de la sensibilité lors de l'interprétation des tests diagnostiques et des renseignements pour guider des recommandations spécifiques à des régions pour la prévention et le traitement du parasite helminthe.(Traduit par Isabelle Vallières).

Identification of Trichinella taxa by ITS-1 amplicon next-generation sequencing with an improved resolution for detecting underrepresented genotypes in mixed natural infections.

BACKGROUND: Amplicon-based next-generation sequencing (NGS) has rapidly gained popularity as a powerful method for delineating taxa in complex communities, including helminths. Here, we applied this approach to identify species and genotypes of zoonotic nematodes of the Trichinella genus. A known limitation of the current multiplex PCR (mPCR) assay recommended by the International Commission on Trichinellosis is that it does not differentiate Trichinella nativa from T. chanchalensis. METHODS: The new assay entails deep sequencing of an amplified variable fragment of the ribosomal cistron's (rDNA) internal transcribed spacer 1 using the Illumina platform. The assay was evaluated using first-stage larvae (L1) of select laboratory strains of various Trichinella taxa mixed in known proportions and then validated using archived L1 from 109 wildlife hosts. The species/genotypes of these L1 isolates from wildlife were previously determined using mPCR. RESULTS: NGS data analysis for Trichinella laboratory strains selected as representative of North American fauna revealed a sequence representation bias. Trichinella pseudospiralis, a non-encapsulated species, was the most underrepresented when mixed with T. spiralis, T. murrelli, T. nativa and Trichinella T6 in equal quantities. However, five L1 of T. pseudospiralis were readily revealed by NGS in a mix with 2000 L1 of T. nativa (1:400 ratio). From naturally infected wildlife, all Trichinella taxa revealed by mPCR were also identified by NGS in 103 of 107 (96.3%) samples amplified on both assays. NGS identified additional taxa in 11 (10.3%) samples, whereas additional taxa were revealed by mPCR in only four (3.7%) samples. Most isolates comprised single or mixed infections of T. nativa and Trichinella T6. On NGS, T. chanchalensis (T13) was detected in combination with Trichinella T6 in a wolverine (Gulo gulo) and in combination with T. nativa and Trichinella T6 in a marten (Martes americana) from the Northwest Territories, Canada. CONCLUSIONS: This new NGS assay demonstrates strong potential as a single assay for identifying all recognised Trichinella taxa as well as improved sensitivity for detecting under-represented and novel genotypes in mixed infections. In addition, we report a new host record for T. chanchalensis in American marten.

Intestinal infection with Echinococcus multilocularis in a dog.

OBJECTIVE: To raise veterinary awareness of a newly recognized parasitic threat to canine and human health, highlight the increasing availability of molecular parasitological diagnostics and the need to implement best practices of cestocidal use in high-risk dogs. ANIMAL: A young Boxer dog with vomiting and bloody diarrhea, suspected diagnosis of inflammatory bowel disease. CLINICAL PRESENTATION, PROGRESSION, AND PROCEDURES: Bloodwork revealed inflammation, dehydration, and protein loss, addressed with supportive therapy. Fecal culture revealed only Escherichia coli. On centrifugal flotation, tapeworm eggs (which could be Taenia or Echinococcus spp) and, unusually, adult cestodes of Echinococcus were observed. The referring veterinarian was contacted to initiate immediate treatment with a cestocide due to zoonotic potential. Diagnosis was confirmed with a coproPCR which has higher sensitivity for Echinococcus spp than fecal flotation alone. DNA was identical to an introduced European strain of E multilocularis currently emerging in dogs, people, and wildlife. Since dogs can also self-infect and develop hepatic alveolar echinococcosis (severe and often fatal), this was ruled out using serology and abdominal ultrasound. TREATMENT AND OUTCOME: Following cestocidal treatment, fecal flotation and coproPCR were negative for eggs and DNA of E multilocularis; however, coccidia were detected and diarrhea resolved following treatment with sulfa-based antibiotics. CLINICAL RELEVANCE: This dog was serendipitously diagnosed with E multilocularis, acquired through ingestion of a rodent intermediate host likely infected from foxes and coyotes. Therefore, as a dog at high risk of reexposure from eating rodents, regular (ideally monthly) treatment with a labeled cestocide is indicated going forward.

Novel molecular diagnostic (PCR) diagnosis and outcome of intestinal Echinococcus multilocularis in a dog from western Canada.

OBJECTIVE: To describe the novel PCR diagnosis and outcome of intestinal Echinococcus multilocularis in a dog. ANIMAL: A 13-month-old female intact dog with naturally occurring intestinal E multilocularis. CLINICAL PRESENTATION, PROGRESSION, AND PROCEDURES: The 13-month-old dog initially presented with a reduced appetite and weight loss and then developed hematochezia. The clinical history included a lack of endoparasite preventive care (fecal testing, deworming), exposure to coyotes, fox, sheep, and rodents and the dog had intermittently been fed a raw food diet. Physical examination revealed a thin dog, with a 2/9 body condition score, that was otherwise clinically unremarkable. A fecal sample was submitted for screening for gastrointestinal parasites as part of an infectious disease assessment. The fecal PCR test reported detection of E multilocularis. This result was sequenced as the European haplotype E3/E4. Centrifugal flotation (same sample) did not detect taeniid eggs. TREATMENT AND OUTCOME: The dog was treated with metronidazole, maropitant, and milbemycin oxime/praziquantel. Clinical improvement was noted within 48 hours. No DNA of E multilocularis was detected in a fecal sample collected approximately 10 days after treatment. The dog's owner was advised to provide monthly deworming (praziquantel) for all dogs on the property and to contact their human health-care provider due to potential zoonotic exposure risk. CLINICAL RELEVANCE: Increasing detection of E multilocularis is occurring in dogs in Canada and the US. Alveolar echinococcosis can cause severe disease in dogs and humans. Fecal PCR detection and surveillance may alert practitioners to canine intestinal cases and allow dogs to serve as sentinels for human exposure risk.

California Serogroup Viruses in a Changing Canadian Arctic: A Review.

The Arctic is warming at four times the global rate, changing the diversity, activity and distribution of vectors and associated pathogens. While the Arctic is not often considered a hotbed of vector-borne diseases, Jamestown Canyon virus (JCV) and Snowshoe Hare virus (SSHV) are mosquito-borne zoonotic viruses of the California serogroup endemic to the Canadian North. The viruses are maintained by transovarial transmission in vectors and circulate among vertebrate hosts, both of which are not well characterized in Arctic regions. While most human infections are subclinical or mild, serious cases occur, and both JCV and SSHV have recently been identified as leading causes of arbovirus-associated neurological diseases in North America. Consequently, both viruses are currently recognised as neglected and emerging viruses of public health concern. This review aims to summarise previous findings in the region regarding the enzootic transmission cycle of both viruses. We identify key gaps and approaches needed to critically evaluate, detect, and model the effects of climate change on these uniquely northern viruses. Based on limited data, we predict that (1) these northern adapted viruses will increase their range northwards, but not lose range at their southern limits, (2) undergo more rapid amplification and amplified transmission in endemic regions for longer vector-biting seasons, (3) take advantage of northward shifts of hosts and vectors, and (4) increase bite rates following an increase in the availability of breeding sites, along with phenological synchrony between the reproduction cycle of theorized reservoirs (such as caribou calving) and mosquito emergence.

Toxoplasma gondii and related Sarcocystidae parasites in harvested caribou from Nunavik, Canada.

Caribou are keystone species important for human harvest and of conservation concern; even so, much is unknown about the impact of parasites on caribou health and ecology. The aim of this study was to determine the seroprevalence, tissue prevalence, and diversity of tissue-dwelling coccidian parasites (including Toxoplasma gondii, Neospora caninum and Sarcocystis spp.) in 88 migratory caribou (Rangifer tarandus) harvested for human consumption in two communities in Nunavik, Québec, Canada. Both T. gondii and N. caninum have potential to cause abortions and neurological disease in caribou. Seroprevalence for antibodies to T. gondii using ELISA on fluid from thawed hearts was 18% overall, and no DNA of T. gondii was detected in tissues, which has positive implications for food safety since this parasite is zoonotic. Seroprevalence for antibodies to N. caninum using competitive ELISA was 5%, and DNA of N. caninum was detected in only one heart sample. DNA of Sarcocystis, a non-zoonotic, related coccidian, was detected in tissue samples from 85% of caribou, with higher prevalence in heart (82%) than skeletal muscle (47%). This is the first time that Sarcocystis spp. from caribou in Canada have been identified to species level, many of which have been described in reindeer from Fennoscandia. The high prevalence and diversity of Sarcocystis spp. suggests intact trophic relationships between canids and caribou in Nunavik. Besnoitia spp. was serendipitously detected in three muscle samples, a parasite previously associated with skin lesions in caribou in Nunavik. Community-level differences in T. gondii exposure and prevalence of Sarcocystis spp. in skeletal muscle tissues may reflect differences in hunter selection of individual animals and muscles, or possibly regional differences in the ecology of carnivore definitive hosts for these parasites. Further work is needed to explore effects of tissue coccidians in caribou, their taxonomic classifications, and community level differences in parasite prevalence and diversity.

Echinococcus multilocularis in urban coyotes, Alberta, Canada.

Echinococcus multilocularis is a zoonotic parasite in wild canids. We determined its frequency in urban coyotes (Canis latrans) in Alberta, Canada. We detected E. multilocularis in 23 of 91 coyotes in this region. This parasite is a public health concern throughout the Northern Hemisphere, partly because of increased urbanization of wild canids.

Alveolar hydatid disease (Echinococcus multilocularis) in the liver of a Canadian dog in British Columbia, a newly endemic region.

An adult dog that lived in central British Columbia was examined because of a history of lethargy and vomiting. Histology, immunohistochemistry, and polymerase chain reaction (PCR) examination of a hepatic mass confirmed the presence of an alveolar hydatid cyst, the first description of Echinococcus multilocularis in British Columbia. We provide recommendations for case management and remind practitioners in endemic areas of western Canada that dogs can serve as definitive and, rarely, intermediate hosts for E. multilocularis.

RésuméHydatidose alvéolaire(Echinococcus multilocularis)dans le foie d'un chien canadien en Colombie-Britannique, une région nouvellement endémique. Un chien adulte habitant dans le centre de la Colombie-Britannique a été examiné en raison d'une anamnèse d'abattement et de vomissements. L'histologie, l'immunohistochimie et l'amplification en chaîne par la polymérase d'une masse hépatique ont tous confirmé la présence d'un kyste hydatique, la première description d'Echinococcus multilocularis en Colombie-Britannique. Nous présentons des recommandations pour la gestion des cas et rappelons aux praticiens dans les régions endémiques de l'Ouest canadien que les chiens peuvent servir d'hôtes définitifs, et rarement, d'hôtes intermédiaires, pour E. multilocularis.(Traduit par Isabelle Vallières).

Combining deep sequencing and conventional molecular approaches reveals broad diversity and distribution of fleas and Bartonella in rodents and shrews from Arctic and Subarctic ecosystems.

BACKGROUND: Bartonella are intracellular bacteria that are transmitted via animal scratches, bites and hematophagous arthropods. Rodents and their associated fleas play a key role in the maintenance of Bartonella worldwide, with > 22 species identified in rodent hosts. No studies have addressed the occurrence and diversity of Bartonella species and vectors for small mammals in Arctic and Subarctic ecosystems, which are increasingly impacted by invasive species and climate change. METHODS: In this study, we characterized the diversity of rodent fleas using conventional PCR targeting the mitochondrial cytochrome c oxidase II gene (COII) and Bartonella species in rodents and shrews (n = 505) from northern Canada using conventional PCR targeting the ITS (intergenic transcribed spacer) region and gltA (citrate synthase) gene. Metagenomic sequencing of a portion of the gltA gene was completed on a subset of 42 rodents and four rodent flea pools. RESULTS: Year, total summer precipitation the year prior to sampling, average minimum spring temperature and small mammal species were significant factors in predicting Bartonella positivity. Occurrence based on the ITS region was more than double that of the gltA gene and was 34% (n = 349) in northern red-backed voles, 35% (n = 20) in meadow voles, 37% (n = 68) in deer mice and 31% (n = 59) in shrews. Six species of Bartonella were identified with the ITS region, including B. grahamii, B. elizabethae, B. washoensis, Candidatus B. rudakovii, B. doshiae, B. vinsonii subsp. berkhoffii and subsp. arupensis. In addition, 47% (n = 49/105) of ITS amplicons had < 97% identity to sequences in GenBank, possibly due to a limited reference library or previously unreported species. An additional Bartonella species (B. heixiaziensis) was detected during metagenomic sequencing of the gltA gene in 6/11 rodents that had ITS sequences with < 97% identity in GenBank, highlighting that a limited reference library for the ITS marker likely accounted for low sequence similarity in our specimens. In addition, one flea pool from a northern red-backed vole contained multiple species (B. grahamii and B. heixiaziensis). CONCLUSION: Our study calls attention to the usefulness of a combined approach to determine the occurrence and diversity of Bartonella communities in hosts and vectors.

Evidence of Arctic Fox (Vulpes lagopus) Survival Following Exposure to Rabies Virus.

The arctic fox variant of the rabies virus (RABV) is enzootic in the circumpolar north. Reports of abortive RABV exposures motivated a retrospective analysis of sera from 41 arctic foxes (Vulpes lagopus) captured at Karrak Lake in Nunavut, Canada, during 2011-15. Estimated RABV antibody prevalence among foxes was 15% (95% confidence interval, 7-28%).

Host and geographic differences in prevalence and diversity of gastrointestinal helminths of foxes (Vulpes vulpes), coyotes (Canis latrans) and wolves (Canis lupus) in Québec, Canada.

Wild canids are hosts to a wide range of parasites and can play a role in transmission of zoonoses. As many parasites are transmitted through food webs, and wild canids are at high trophic levels, parasite prevalence and diversity in wild canids can serve as excellent indicators of ecosystem health. Our main objectives were to update knowledge on the composition of gastrointestinal helminths in wild canids from Québec, Canada, and to describe differences in parasite prevalence and diversity among canid species and regions. Hunters and trappers provided whole carcasses of red foxes (Vulpes vulpes) (N = 176), and intestinal tracts of coyotes (Canis latrans) (N = 77) and gray wolves (Canis lupus) (N = 23) harvested for non-research purposes over the winter of 2016-2017. A modified Stoll's centrifugation sucrose flotation on feces of 250 wild canids was used, and eggs of one family and eight genera of parasitic helminths were recovered: diphyllobothriids, Taenia/Echinococcus spp., Capillaria spp., Toxascaris sp., Toxocara sp., Trichuris sp., Uncinaria sp., and Metorchis sp. Adult Taenia spp. cestodes were recovered from 61 of 276 (22%) canids. Six different species (T. hydatigena, T. twitchelli, T. crassiceps, T. polyacantha, T. krabbei, and T. pisiformis-"like") were differentiated based on DNA sequenced from 65 individual adult cestodes using primers for the nicotinamide adenosine dinucleotide dehydrogenase subunit 1 (ND1) and cytochrome c oxidase subunit 1 (CO1) mitochondrial DNA loci. Alaria sp. trematodes infected 89 of 276 canids (32%). A subset were identified as A. americana at the CO1 locus. The marine trematode Cryptocotyle lingua was reported for the first time in foxes in the province of Québec. These results help us understand more fully the predator-prey relationships within this group of canids. This baseline data in regional parasite prevalence and intensity is critical in order to detect future changes following ecological disturbances due to climate and landscape alterations.

Copro-polymerase chain reaction has higher sensitivity compared to centrifugal fecal flotation in the diagnosis of taeniid cestodes, especially Echinococcus spp, in canids.

Prompt and reliable diagnostic tests for taeniid infection in canids are important due to the risk of zoonoses like Echinococcus spp. Current diagnostic methods relying on fecal flotation lack sensitivity and specificity, but this has rarely been quantified due to the challenges in performing adult cestode recovery (the gold standard) in domestic dogs (Canis familiaris). Therefore, we recovered adult Taenia and Echinococcus spp. from intestines, as well as fecal/intestinal material from 484 wild canids trapped for fur in two Canadian provinces (276 foxes - primarily Vulpes vulpes, coyotes - Canis latrans, and wolves - Canis lupus in Québec and 208 coyotes in Saskatchewan). The performances of a newly developed coproPCR for tapeworm DNA detection in dogs, and centrifugal fecal flotation using Sheather's solution, were evaluated against adult cestode recovery. Overall, adult taeniid cestode prevalence (Taenia and/or Echinococcus) was 28 % (95 % CI: 23-33 %) in Québec (62 % (CI: 51-73%) of 74 coyotes, 65 % (CI: 44-82) of 23 wolves, and 11 % (CI: 7-16%) of 179 foxes) and 79 % (CI: 73-84%) of 208 coyotes in Saskatchewan. In Québec, E. canadensis and Taenia spp. were detected in coyotes and wolves, and foxes were only infected with Taenia spp., whereas Saskatchewan coyotes were predominantly infected with E. multilocularis (at significantly higher prevalence, but not intensity, than coyotes in Québec). Compared with centrifugal fecal flotation, the new coproPCR had at least double the sensitivity (58 % vs 23 % in QC coyotes, 57 % vs 23 % in QC wolves, 24 % vs 0% in QC foxes, and 80 % vs 25 % in SK coyotes). Notably, no taeniid eggs were detected on flotations from foxes infected with Taenia spp., and the new coproPCR had highest sensitivity in Saskatchewan coyotes, which were predominantly infected with E. multilocularis. CoproPCR has promising prospects for use in Veterinary clinics and diagnostic laboratories to detect taeniid cestode infections because of its higher sensitivity than faecal flotation methods. This is particularly important for zoonotic Echinococcus spp. where, from a public health perspective, false negatives are a much greater concern than false positives.

A repeatable and quantitative DNA metabarcoding assay to characterize mixed strongyle infections in horses.

Horses are ubiquitously infected by a diversity of gastro-intestinal parasitic helminths. Of particular importance are nematodes of the family Strongylidae, which can significantly impact horse health and performance. However, knowledge about equine strongyles remains limited due to our inability to identify most species non-invasively using traditional morphological techniques. We developed a new internal transcribed spacer 2 (ITS2) DNA metabarcoding 'nemabiome' assay to characterise mixed strongyle infections in horses and assessed its performance by applying it to pools of infective larvae from fecal samples from an experimental herd in Kentucky, USA and two feral horse populations from Sable Island and Alberta, Canada. In addition to reporting the detection of 33 different species with high confidence, we illustrate the assay's repeatability by comparing results generated from aliquots from the same fecal samples and from individual horses sampled repeatedly over multiple days or months. We also validate the quantitative potential of the assay by demonstrating that the proportion of amplicon reads assigned to different species scales linearly with the number of larvae present. This new tool significantly improves equine strongyle diagnostics, presenting opportunities for research on species-specific anthelmintic resistance and the causes and consequences of variation in mixed infections.

New geographic records for Echinococcus canadensis in coyotes and moose from Nova Scotia, Canada.

Echinococcus spp. tapeworms can cause serious diseases in mammals, including humans. Within the E. granulosus species complex, metacestodes produce unilocular cysts that are responsible for cystic echinococcosis in animal intermediate hosts. Canids are definitive hosts, harbouring adult cestodes in their intestines. Adult E. canadensis were recovered from the small intestine of 1 of 262 coyotes (Canis latrans) from Nova Scotia, Canada. Subsequently, we found unilocular cysts in lungs and livers of 4 of 8 sympatric moose (Alces alces) from Cape Breton Island. DNA was extracted from three cysts using the Qiagen DNeasy Blood and Tissue kit and assayed by polymerase chain reaction (PCR) with primers (cest4 and cest5) for a 117-bp region of the small subunit of ribosomal RNA of E. granulosus sensu lato, and further validated as E. canadensis G8 using primers targeting nicotinamide adenosine dinucleotide dehydrogenase subunit 1 (ND1) and cytochrome c oxidase subunit 1 (CO1) mitochondrial genes. These are the first records of E. canadensis in any of the three Maritime provinces, which include Nova Scotia, New Brunswick, and Prince Edward Island. The parasite was thought to be absent in this region due to extirpation of wolves (Canis spp.) in the 1800s. These findings suggest that further wildlife surveillance and risk assessment is warranted.

High prevalence, intensity, and genetic diversity of Trichinella spp. in wolverine (Gulo gulo) from Yukon, Canada.

BACKGROUND: Species of Trichinella are globally important foodborne parasites infecting a number of domestic and wild vertebrates, including humans. Free-ranging carnivores can act as sentinel species for detection of Trichinella spp. Knowledge of the epidemiology of these parasites may help prevent Trichinella spp. infections in northern Canadian animals and people. Previous research on Trichinella spp. in wildlife from Yukon did not identify risk factors associated with infection, or the diversity and identity of species of Trichinella in regional circulation, based on geographically extensive sampling with large sample sizes. METHODS: In a cross-sectional study, we determined the prevalence, infection intensity, risk factors, and species or genotypes of Trichinella in wolverine (Gulo gulo) in two regions of Yukon, Canada, from 2013-2017. A double separatory funnel digestion method followed by mutiplex PCR and PCR-RFLP were used to recover and identify species of Trichinella, respectively. RESULTS: We found larvae of Trichinella in the tongues of 78% (95% CI 73-82) of 338 wolverine sampled. The odds of adult (≥ 2 years) and yearling (1 year) wolverine being Trichinella spp.-positive were four and two times higher, respectively, compared to juveniles (<1 year). The odds of Trichinella spp. presence were three times higher in wolverine from southeast than northwest Yukon. The mean intensity of infection was 22.6 ± 39 (SD, range 0.1-295) larvae per gram. Trichinella T6 was the predominant genotype (76%), followed by T. nativa (8%); mixed infections with Trichinella T6 and T. nativa (12%) were observed. In addition, T. spiralis was detected in one wolverine. Out of 22 isolates initially identified as T. nativa in multiplex PCR, 14 were analyzed by PCR-RFLP to distinguish them from T. chanchalensis, a recently discovered cryptic species, which cannot be distinguished from the T. nativa on multiplex PCR. Ten isolates were identified either as T. chanchalensis alone (n = 7), or mixed infection with T. chanchalensis and T. nativa (n = 2) or T. chanchalensis and Trichinella T6 (n = 1)]. CONCLUSIONS: Wolverine hosted high prevalence, high larval intensity, and multiple species of Trichinella, likely due to their scavenging habits, apex position in the food chain, and wide home range. Wolverine (especially adult males) should be considered as a sentinel species for surveys for Trichinella spp. across their distributional range.

Toxocara spp. in dogs and cats in Canada.

Toxocara spp. (T. canis and T. cati) are the dominant ascarids of domestic dogs and cats, respectively, in populated regions of southern Canada, where they pose animal and public health concerns. A review of the published literature indicated that prevalence of both parasites is declining in more recent studies (post 2000), likely due to changes in animal husbandry as well as use of anthelmintics. Geographically, prevalence was higher in the east (Atlantic), and in more southerly locations, possibly due to more favourable climate conditions for egg survival and development. At northern latitudes and in wild felids and canids in general, the non-zoonotic ascarid Toxascaris leonina appears to outcompete Toxocara spp.; however, T. leonina is rare in domestic cats in Canada. Prevalence of Toxocara spp. was higher in cats than dogs, shelter/rural/remote/feral/stray vs owned animals, and young vs adult animals, as has been observed in many other studies and regions of the world. While the regional prevalences in this review should be interpreted carefully in light of variation in diagnostic methods and study populations, they generally follow the same trends observed in a recent national study of shelter animals. This review is a timely summary of the state of the published knowledge on prevalence of Toxocara spp. in Canada, and highlights knowledge gaps to be addressed, including the northern distributional limits of these species in Canada, the potential for transmission to and from wildlife hosts, and the public health significance of the parasite in the mainstream Canadian population.