Complete Genome Sequence of an Endemic Mycobacterium bovis Strain from Wood Bison in Wood Buffalo National Park, Canada

Mycobacterium bovis is the primary causative agent of bovine tuberculosis, a zoonotic infectious disease of concern for human health, livestock, and wildlife conservation. We report a complete genome sequence of an endemic Mycobacterium bovis strain affiliated with a wildlife reservoir of bovine tuberculosis found in wood bison in Wood Buffalo National Park, Canada.

Strategies for oocyte collection and in vitro embryo production in free-roaming bison herds

The study was conducted to test the feasibility of protocols for field collection of cumulus-oocyte complexes (COC) for in vitro embryo production (IVP) in wild bison. The study was done with captive wood bison during the anovulatory season. In Experiment 1, the efficiency of transvaginal ultrasound-guided COC collection was compared between bison restrained in a squeeze chute without sedation vs in lateral recumbency after chemical immobilization using a dart gun (n = 8/group). In Experiment 2, a 2 × 2 design was used to examine the effects of superstimulation treatment [single dose of equine chorionic gonodotrophin (eCG) vs multiple doses of follicle stimulating hormone (FSH)] and method of drug administration (manual injection vs field darting) on COC collection and IVP. In Experiment 1, no difference was detected between chute-restrained vs chemically immobilized groups in the time required to complete COC collections, the number of follicles aspirated (11.5 ± 1.9 vs 9.3 ± 1.8; P = 0.4) or the COC recovery rate [COC recovered/follicle aspirated; 58/92 (63%) vs 44/69 (64%); P = 0.9]. In Experiment 2, no differences were detected between superstimulation treatments (eCG vs FSH). The total number of follicles available for aspiration did not differ between manual injection and field darting (23.9 ± 2.7 vs 21.6 ± 1.9; P = 0.4). Compared with the random start unstimulated group, the embryo production rate was higher [18/132 (14%) vs 53/189 (28%); P = 0.04] after wave synchronization and superstimulation. Results suggest that COC collection is equally feasible in a recumbent position after chemical immobilization as those bison restrained in a standing position in a hydraulic chute. Ovarian superstimulation with a single-dose eCG protocol is as effective as a multiple-dose FSH protocol, and field darting is as effective as chute-side administration of superstimulation treatments. The strategies in the present study are ready to be incorporated into field collections in free-roaming bison herds.

22 Strategies for oocyte collection procedures in free-roaming bison herds

The study was conducted to test the feasibility of protocols for field collection of cumulus–oocyte complexes (COC) for invitro embryo production (IVP) in wild bison. The study was done with captive wood bison during the late anovulatory season (July). In Experiment 1, bison were assigned randomly to 2 groups (n=8/group) in which transvaginal ultrasound-guided COC collection was done in a chute without sedation or in lateral recumbency after chemical immobilization using a dart gun to compare collection efficiencies. In Experiment 2, a 2×2 design was used to examine the effects of superstimulation treatments [single-dose equine chorionic gonadotrophin (eCG) vs. multiple-dose FSH] and methods of drug administration (manual injection vs. field darting) on COC collection and IVP. Initial COC collection was done to serve as a non-superstimulated random start and to synchronize follicular wave emergence on the following day (Day 0; n=16). Half of the bison were given a single dose of 5000IU of eCG intramuscularly (IM) on Day −1. The other half were given 200mg of FSH IM on Day 0 and Day 2, followed by 2000IU human chorionic gonadotrophin IM on Day 4. Superstimulatory treatments were given by manual injection (chute restrained) to half of the bison in each group and by field darting in the other half. The COC were collected on Day 4 in the eCG group and Day 5 in the FSH group. Recovered COC were matured invitro for 25 to 28h at 38.8°C, fertilized (2×106 sperm mL−1) and co-incubated at 38.8°C in 5% O2, 5% CO2, and 90% N2 for 18h. Presumptive zygotes were denuded and cultured at 38.8°C in 5% O2, 5% CO2, and 90% N2. A commercially available IVF media set was utilised (IVF Bioscience). Data were compared by ANOVA and GLIMMIX. In Experiment 1, no difference was detected between chute-restrained vs. chemically immobilized groups in the time required to complete COC collection (6.9±1.0 vs. 8.9±1.0 min; P=0.2), the number of follicles aspirated (11.5±1.9 vs. 9.3±1.8; P=0.4), or the COC recovery rate [COC recovered/follicle aspirated; 58/92 (63%) vs. 44/69 (64%); P=0.9]. In Experiment 2, no differences were detected between superstimulation treatments (eCG vs. FSH) or method of drug administration (manual injection vs. field darting) for any endpoint. The number of medium (4.5–7.5 mm; 9.5±1.0 vs. 2.5±0.6; P<0.0001) and large (>8 mm; 8.6±0.8 vs. 3.4±1.5; P=0.004) follicles available was greater after superstimulation (groups combined) than without superstimulation (random start). Although there was no difference in the number of recovered compact COC between the superstimulated and non-superstimulated bison (8.9±1.3 vs. 6.2±1.7; P=0.2), the embryo production rate (number of embryos produced/number of COC matured) was greater after superstimulation than without superstimulation [54/189 (39%) vs. 19/108 (18%); P<0.05]. We conclude that COC collection in a field setting is feasible and minimum-handling superstimulation with a single dose of eCG is as effective as a multiple-dose FSH protocol for the invitro production of embryos in bison. This research was supported by NSERC and Vetoquinol.

Not playing by the rules: Unusual patterns in the epidemiology of parasites in a natural population of feral horses (Equus caballus) on Sable Island, Canada

Sable Island, Nova Scotia, Canada hosts one of few natural populations of feral horses (Equus caballus) never exposed to anthelmintics. Coproculture revealed cyathostomes, Strongylus equinus, S. edentatus, and S. vulgaris, with S. equinus (unusually) dominating in adult horses and cyathostomes dominating in young horses (<3 years of age). We examined 35 horses found dead in the springs of 2017 and 2018, as well as fecal samples from live horses in spring (n = 45) and summer 2018 (n = 236) using McMaster fecal flotation and Baermann larval sedimentation on fresh samples, and modified Wisconsin flotation and sucrose gradient immunofluorescent assay for Giardia and Cryptosporidium on frozen samples. Mean strongyle fecal egg counts were 666 eggs per gram (EPG) in dead horses, 689 EPG in live horses in spring, and 1105 EPG in summer; domestic horses are usually treated at counts exceeding 200 EPG. Adult horses (unusually) had patent infections with the lungworm Dictyocaulus arnfieldi and ascarids (Parascaris spp.), and in spring, dead horses had 5 times higher odds of having patent ascarid infections than live horses, likely due to malnutrition and corresponding immunodeficiency. Fecal prevalence and intensity of D. arnfieldi and Parascaris spp. were significantly higher in young horses, and in spring versus summer. A higher proportion of fecal samples were positive for strongyle and ascarid eggs using a centrifugal flotation technique on previously frozen feces, as compared to a passive flotation method on fresh feces. Eggs of the tapeworm Paranoplocephala mamillana were present in fecal samples from 28% of live, and 42% of dead, horses in spring. This research represents several new geographic records (S. edentatus, D. arnfieldi, and Eimeria leuckarti), provides insight into unusual patterns of parasite epidemiology in a nutrition-limited environment, and has conservation and biosecurity implications for this unique equine population, as well as for parasite management in domestic horses.

Comparison of multilocus sequence types found among North American isolates of Mycoplasma bovis from cattle, bison, and deer, 2007-2017

A prior multilocus sequence typing (MLST) study reported that Mycoplasma bovis isolates from North American bison possess sequence types (STs) different from those found among cattle. The 42 bison isolates evaluated were obtained in 2007 or later, whereas only 19 of 94 (~20%) of the available cattle isolates, with only 1 from North America, were from that same time. We compared STs of additional, contemporary, North American cattle isolates with those from bison, as well as isolates from 2 North American deer, all originating during the same timeframe, to more definitively assess potential strain-related host specificity and expand our understanding of the genetic diversity of M. bovis. From 307 isolates obtained between 2007 and 2017 (209 from cattle, 96 from bison, 2 from deer), we identified 49 STs, with 39 found exclusively in cattle and 5 exclusively in bison. Four STs were shared between bison and cattle isolates; one ST was found in cattle and in a deer. There was no clear association between ST and the health status of the animal of origin. An MLST-based phylogeny including 41 novel STs identified in our study reveals that STs found in bison fall within several divergent lineages that include STs found exclusively in cattle.

High species diversity of trichostrongyle parasite communities within and between Western Canadian commercial and conservation bison herds revealed by nemabiome metabarcoding

Background

Many trichostrongylid nematode species are reported to infect bison, some of which are major causes of disase and production loss in North American bison herds. However, there is little information on the species distribution and relative abundance of these parasites in either commercial or conservation herds. This is largely because trichostrongylid nematode species cannot be distinguished by visual microscopic examination of eggs present in feces. Consequently, we have applied ITS2 rDNA nemabiome metabarcoding to describe the trichostrongyle parasite species diversity in 58 bison production groups derived from 38 commercial North American plains bison (Bison bison bison) herds from across western Canada, and two bison conservation herds located in Elk Island National Park (EINP) [plains bison and wood bison (Bison bison athabascae)] and one in Grasslands National Park (GNP) (plains bison).

Results

We report much higher infection intensities and parasite species diversity in commercial bison herds than previously reported in beef cattle herds grazing similar latitudes. Predominant trichostrongyle parasite species in western Canadian commercial bison herds are those commonly associated with Canadian cattle, with Ostertagia ostertagi being the most abundant followed by Cooperia oncophora. Combined with high fecal egg counts in many herds, this is consistent with significant clinical and production-limiting gastrointestinal parasitism in western Canadian bison herds. However, Haemonchus placei was the most abundant species in five of the production groups. This is both surprising and important, as this highly pathogenic blood-feeding parasite has not been reported at such abundance, in any livestock species, at such northerly latitudes. The presence of Trichostrongylus axei as the most abundant parasite in four herds is also unusual, relative to cattle. There were striking differences in parasite communities between the EINP and commercial bison herds. Most notably, Orloffia bisonis was the predominant species in the wood bison herd despite being found at only low levels in all other herds surveyed.

Conclusions

This study represents the most comprehensive description of parasite communities in North American bison to date and illustrates the power of deep amplicon sequencing as a tool to study species diversity in gastrointestinal nematode communities.

Electronic supplementary material

The online version of this article (10.1186/s13071-018-2880-y) contains supplementary material, which is available to authorized users.

Surveillance for Echinococcus canadensis genotypes in Canadian ungulates

The geographic and host distribution, prevalence and genotypes of Echinococcus canadensis in wild ungulates in Canada are described to better understand the significance for wildlife and public health. We observed E. canadensis in 10.5% (11/105) of wild elk (wapiti; Cervus canadensis) in Riding Mountain National Park, Manitoba, examined at necropsy, over two consecutive years (2010–2011). Molecular characterization of hydatid cyst material from these elk, as well as three other intermediate wildlife host species, was based on sequence of a 470 bp region of the NADH dehydrogenase subunit 1 (NAD1) mitochondrial gene. In moose [Alces alces], elk, and caribou [Rangifer tarandus] from northwestern Canada, the G10 genotype was the only one present, and the G8 genotype was detected in a muskox (Ovibos moschatus) from northeastern Canada. On a search of the national wildlife health database (1992–2010), cervids with hydatid cysts were reported in all provinces and territories except the Atlantic provinces, from which wolves [Canis lupis] are historically absent. Of the 93 cervids with records of hydatid cysts, 42% were elk, 37% were moose, 14% were caribou, and 6% were white-tailed and mule deer [Odocoileus virginianus and Odocoileus hemonius]. In these animals, 83% of cysts were detected in lungs alone, 8% in both lungs and liver, 3% in liver alone, and 6% in other organs. These observations can help target surveillance programs and contribute to a better understanding of ecology, genetic diversity, and genotype pathogenicity in the Echinococcus granulosus species complex.

The molecular epidemiology of Cryptosporidium and Giardia infections in coyotes from Alberta, Canada, and observations on some cohabiting parasites

Coyotes from southern Alberta and Saskatchewan, Canada, were examined for the presence of Giardia and Cryptosporidium and cohabiting helminths. Toxascaris was present in over 90% of the 70 animals examined, and Taenia sp. in 6.5-25% of the two groups of animals studied. Giardia (12.5-21.7%) and Cryptosporidium (0-17.4%) were also common and molecular characterisation revealed both zoonotic and host-adapted genotypes of Giardia, whereas the Cryptosporidium proved to be a variant of the canine species C. canis. The seasonal variation observed in the occurrence of Cryptosporidium may be related to stress-induced shedding of the parasite.

Wildlife reservoirs for bovine tuberculosis (Mycobacterium bovis) in Canada: strategies for management and research

In Canada, there are two known regional foci where wildlife populations are infected with bovine tuberculosis (Mycobacterium bovis) and considered to be disease reservoirs. Free-ranging populations of wood bison (Bison bison athabascae) in and around Wood Buffalo National Park (WBNP) and wapiti (Cervus elaphus manitobensis) in and around Riding Mountain National Park (RMNP) are infected with bovine tuberculosis. In this paper, we provide an overview of these diseased wild ungulate populations and the complexities of attempting to manage issues relating to bovine tuberculosis in and around protected areas. We do not describe the quantitative science and epidemiological data in detail from these case histories, but instead compare and contrast these two cases from a broader perspective. This is achieved by reviewing the context and process by which a diverse group of stakeholders engage and develop strategies to address the controversial problems that diseased wildlife populations often present. We suggest that understanding the factors that drive the strategic-level management processes is equally important for addressing a wildlife disease problem as the tactical-level issues, such as design and implementation of technically sound field research and management programs. Understanding the experiences within the WBNP and RMNP areas, particularly the strategies that have failed or succeeded, may prove useful to understanding and improving management approaches when wildlife are infected with M. bovis. Applying this understanding is consistent with the principles of adaptive management in which we learn from previous experiences to develop better strategies for the future.

Molecular and morphological characterization of Echinococcus in cervids from North America

Many issues concerning the taxonomy of Echinococcus have been resolved in recent years with the application of molecular tools. However, the status of Echinococcus maintained in transmission cycles involving cervid intermediate hosts remains to be determined. The recent characterization of the parasite from cervids in Finland has highlighted the paucity of data available, particularly that from North America. In this study, we have characterized a large number of Echinococcus isolates from cervids from Western Canada on the basis of morphology and molecular genetic techniques. Our results support earlier studies suggesting that Echinococcus of cervid origin is phenotypically and genetically distinct to Echinococcus maintained in domestic host assemblages, and also confirms that Echinococcus of cervid origin does not constitute a genetically homogeneous group. However, our data do not support the existence of 2 distinct genotypes (strains/subspecies) with separate geographical distributions. Our data appear to support the existence of only 1 species in cervids, but additional isolates from cervids and wolves in other endemic regions should be characterized before a final decision is made on the taxonomic status of Echinococcus in cervids.

Antibodies to selected pathogens in free-ranging terrestrial carnivores and marine mammals in Canada

Antibody titres to selected pathogens (canine adenovirus [CAV-2], feline herpesvirus [FHV], phocine herpesvirus [PHV-1], canine distemper virus, dolphin morbillivirus [DMV], phocine distemper virus [PDV], parainfluenza virus type 3 [PI3], rabies virus, dolphin rhabdovirus [DRV], canine coronavirus, feline coronavirus, feline leukaemia virus, Borrelia burgdorferi and Toxoplasma gondii) were determined in whole blood or serum samples from selected free-ranging terrestrial carnivores and marine mammals, including cougars (Fellis concolor), lynxes (Fellis lynx), American badgers (Taxidea taxus), fishers (Martes pennanti), wolverines (Gulo gulo), wolves (Canis lupus), black bears (Ursus americanus), grizzly bears (Ursus arctos), polar bears (Ursus maritimus), walruses (Odobenus rosmarus) and belugas (Delphinapterus leucas), which had been collected at several locations in Canada between 1984 and 2001. Antibodies to a number of viruses were detected in species in which these infections have not been reported before, for example, antibodies to CAV-2 in walruses, to PDV in black bears, grizzly bears, polar bears, lynxes and wolves, to DMV in grizzly bears, polar bears, walruses and wolves, to PI3 in black bears and fishers, and to DRV in belugas and walruses.