Sublethal effects of parasitism on ruminants can have cascading consequences for ecosystems.

Parasitic infections are common, but how they shape ecosystem-level processes is understudied. Using a mathematical model and meta-analysis, we explored the potential for helminth parasites to trigger trophic cascades through lethal and sublethal effects imposed on herbivorous ruminant hosts after infection. First, using the model, we linked negative effects of parasitic infection on host survival, fecundity, and feeding rate to host and producer biomass. Our model, parameterized with data from a well-documented producer­caribou­helminth system, reveals that even moderate impacts of parasites on host survival, fecundity, or feeding rate can have cascading effects on ruminant host and producer biomass. Second, using meta-analysis, we investigated the links between helminth infections and traits of free-living ruminant hosts in nature. We found that helminth infections tend to exert negative but sublethal effects on ruminant hosts. Specifically, infection significantly reduces host feeding rates, body mass, and body condition but has weak and highly variable effects on survival and fecundity. Together, these findings suggest that while helminth parasites can trigger trophic cascades through multiple mechanisms, overlooked sublethal effects on nonreproductive traits likely dominate their impacts on ecosystems. In particular, by reducing ruminant herbivory, pervasive helminth infections may contribute to a greener world.

Local thermal adaptation and local temperature regimes drive the performance of a parasitic helminth under climate change: The case of Marshallagia marshalli from wild ungulates.

Across a species' range, populations are exposed to their local thermal environments, which on an evolutionary scale, may cause adaptative differences among populations. Helminths often have broad geographic ranges and temperature-sensitive life stages but little is known about whether and how local thermal adaptation can influence their response to climate change. We studied the thermal responses of the free-living stages of Marshallagia marshalli, a parasitic nematode of wild ungulates, along a latitudinal gradient. We first determine its distribution in wild sheep species in North America. Then we cultured M. marshalli eggs from different locations at temperatures from 5 to 38°C. We fit performance curves based on the metabolic theory of ecology to determine whether development and mortality showed evidence of local thermal adaptation. We used parameter estimates in life-cycle-based host-parasite models to understand how local thermal responses may influence parasite performance under general and location-specific climate-change projections. We found that M. marshalli has a wide latitudinal and host range, infecting wild sheep species from New Mexico to Yukon. Increases in mortality and development time at higher temperatures were most evident for isolates from northern locations. Accounting for location-specific parasite parameters primarily influenced the magnitude of climate change parasite performance, while accounting for location-specific climates primarily influenced the phenology of parasite performance. Despite differences in development and mortality among M. marshalli populations, when using site-specific climate change projections, there was a similar magnitude of impact on the relative performance of M. marshalli among populations. Climate change is predicted to decrease the expected lifetime reproductive output of M. marshalli in all populations while delaying its seasonal peak by approximately 1 month. Our research suggests that accurate projections of the impacts of climate change on broadly distributed species need to consider local adaptations of organisms together with local temperature profiles and climate projections.

Sequential analysis of δ15 N in guard hair suggests late gestation is the most critical period for muskox calf recruitment.

RATIONALE: Analysis of stable isotopes in tissue and excreta may provide information about animal diets and their nutritional state. As body condition may have a major influence on reproduction, linking stable isotope values to animal demographic rates may help unravel the drivers behind animal population dynamics. METHODS: We performed sequential analysis of δ15 N values in guard hair from 21 muskoxen (Ovibos moschatus) from Zackenberg in high arctic Greenland. We were able to reconstruct the dietary history for the population over a 5-year period with contrasting environmental conditions. We examined the linkage between guard hair δ15 N values in 12 three-month periods and muskox calf recruitment to detect critical periods for muskox reproduction. Finally, we conducted similar analyses of the correlation between environmental conditions (snow depth and air temperature) and calf recruitment. RESULTS: δ15 N values exhibited a clear seasonal pattern with high levels in summer and low levels in winter. However, large inter-annual variation was found in winter values, suggesting varying levels of catabolism depending on snow conditions. In particular δ15 N values during January-March were linked to muskox recruitment rates, with higher values coinciding with lower calf recruitment. δ15 N values were a better predictor of muskox recruitment rates than environmental conditions. CONCLUSIONS: Although environmental conditions may ultimately determine the dietary δ15 N signal in muskox guard hairs, muskox calf recruitment was more strongly correlated with δ15 N values than ambient snow and temperature. The period January-March, corresponding to late gestation, appears particularly critical for muskox reproduction.

Can intake data inform on impacts of repeated subsidized onsite spay-neuter clinics for dogs?

Objective: Subsidized dog care and population management programs (DPM) are often implemented for dog population control where for-profit veterinary care is inaccessible. However, impacts of such programs are rarely assessed. The goal of this project was to determine if and how previously collected intake data from ongoing high-volume spay-neuter clinics could be used to measure impacts of such DPM programs. Animals: We used intake data collected from 2008 to 2019 from spay-neuter clinics that had been delivered repeatedly over a 10-year period in 6 First Nations communities in Alberta, to assess changes in intake dog characteristics. Procedures: Numbers of dogs brought in for spay-neuter surgery or surrendered, and their ages, sexes, breeds, weights, and body condition scores were compared. Reasons for surrender were investigated and socioeconomic factors were investigated as possible drivers for community differences in clinic participation rates and clinic sex ratios. Results: Socioeconomic indicators did not differ between the 6 participating communities; however, the total number of clinics requested by communities varied. In early years, female dogs were more likely to be brought to the clinics to be spayed whereas, in later years, more males were seen. The age at which animals were brought in for spay or neuter decreased over time (P < 0.05) but the surrender age did not. Breed proportions of x-large, small, and x-small breeds varied over time for both spay-neuter and surrender dogs (P < 0.05), with large-breed dogs always being the most common. However, there was an increase in small and x-small breeds in the final years of the study. Finally, weight status, a calculated estimate of body condition of spay-neuter dogs, increased over time within large and medium breeds, whereas the body condition score of surrendered dogs shifted from "thin" to "ideal" over time. Conclusions and clinical relevance: This work highlights the potential and challenges of using intake data to assess impacts of spay-neuter clinics that occur repeatedly over many years in the same communities. Overall increased weight status, high participation rates, and reduction of age at intake suggest positive effects of the assessed spay-neuter programs.

Les données d'admission peuvent-elles renseigner sur les impacts des cliniques de stérilisation sur place pour les chiens répétées et subventionnées? Objectif: Des programmes subventionnés de soins canins et de gestion de la population (DPM) sont souvent mis en œuvre pour limiter la population canine là où les soins vétérinaires à but lucratif sont inaccessibles. Cependant, les impacts de ces programmes sont rarement évalués. L'objectif de ce projet était de déterminer si et comment les données d'admission précédemment collectées dans les cliniques de stérilisation à grand volume en cours pourraient être utilisées pour mesurer les impacts de tels programmes de DPM. Animaux: Nous avons utilisé les données d'admission recueillies de 2008 à 2019 dans des cliniques de stérilisation qui avaient été dispensées à plusieurs reprises sur une période de 10 ans dans 6 communautés des Premières Nations de l'Alberta, pour évaluer les changements dans les caractéristiques d'admission des chiens. Procédures: Le nombre de chiens amenés pour une chirurgie de stérilisation ou cédés, ainsi que leurs âges, sexes, races, poids et scores de condition physique ont été comparés. Les raisons de l'abandon ont été étudiées ainsi que les facteurs socio-économiques en tant que facteurs possibles des différences communautaires dans les taux de participation aux cliniques et les ratios des sexes entre les cliniques. Résultats: Les indicateurs socioéconomiques ne différaient pas entre les 6 communautés participantes; cependant, le nombre total de cliniques demandées par les communautés variait. Au cours des premières années, les chiennes étaient plus susceptibles d'être amenées aux cliniques pour être stérilisées, tandis que dans les années suivantes, davantage de mâles étaient vus. L'âge auquel les animaux ont été amenés pour la castration ou la stérilisation a diminué avec le temps (P < 0,05), mais pas l'âge d'abandon. Les proportions de races très grandes, petites et très petites variaient au fil du temps pour les chiens stérilisés et les chiens abandonnés (P < 0,05), les chiens de grande race étant toujours les plus courants. Cependant, il y a eu une augmentation des races petites et très petites au cours des dernières années de l'étude. Enfin, le statut pondéral, une estimation calculée de la condition corporelle des chiens stérilisés, a augmenté avec le temps au sein des races grandes et moyennes, tandis que le score de condition corporelle des chiens abandonnés est passé de « mince ¼ à « idéal ¼ au fil du temps. Conclusions et pertinence clinique: Ce travail met en évidence le potentiel et les défis liés à l'utilisation des données d'admission pour évaluer les impacts des cliniques de stérilisation qui se déroulent à plusieurs reprises sur de nombreuses années dans les mêmes communautés. L'augmentation globale du statut pondéral, les taux de participation élevés et la réduction de l'âge à l'admission suggèrent des effets positifs des programmes de stérilisation évalués.(Traduit par Dr Serge Messier).

Actualizing Cultural Humility: An Exploratory Study of Veterinary Students' Participation in a Northern Community Health Rotation.

Rotations in diverse, marginalized communities may offer health care students opportunities to develop cultural humility through different clinical experiences and activities. Through the actualization of cultural humility, veterinarians may offer accessible, affordable, culturally proficient, high-quality care to all their patients with a better understanding of how cultural differences affect the animal patient's health, well-being, and care. The purpose of this study was to explore whether participation in a community rotation in remote northern Indigenous communities promotes cultural humility among final-year veterinary students. Small groups of University of Calgary veterinary students travel annually to the Sahtu Settlement Area of the Northwest Territories, Canada, to participate in the Northern Community Health Rotation (NCHR). During the 4-week rotation, students spend 2.5 weeks providing veterinary services to domestic animals in five communities in the Sahtu. Eleven veterinary students who attended the NCHR between 2015 and 2020 answered exploratory open-ended questions in an online survey. Responses highlight areas of learning that contributed to their development of cultural humility. The rotation appears successful in increasing students' confidence working with people from diverse cultures, offering students opportunities to implement a client-centered approach, and advancing their capacity to recognize and challenge their preconceived biases about Indigenous cultures and animal ownership. These experiences are important to the acquisition of cultural humility for veterinary care providers.

Association of Environmental Factors with Seasonal Intensity of Erysipelothrix rhusiopathiae Seropositivity among Arctic Caribou.

Several caribou (Rangifer tarandus) populations have been declining concurrently with increases in infectious diseases in the Arctic. Erysipelothrix rhusiopathiae, a zoonotic bacterium, was first described in 2015 as a notable cause of illness and death among several Arctic wildlife species. We investigated epidemiologic and environmental factors associated with the seroprevalence of E. rhusiopathiae in the Arctic and found that seropositivity was highest during warmer months, peaking in September, and was highest among adult males. Summer seroprevalence increases tracked with the oestrid index from the previous year, icing and snowing events, and precipitation from the same year but decreased with growing degree days in the same year. Seroprevalence of E. rhusiopathiae varied more during the later years of the study. Our findings provide key insights into the influence of environmental factors on disease prevalence that can be instrumental for anticipating and mitigating diseases associated with climate change among Arctic wildlife and human populations.

Exposure of the Gulf of St. Lawrence grey seal Halichoerus grypus population to potentially zoonotic infectious agents.

The population of grey seals Halichoerus grypus in Canadian waters is currently used as a commercial source of meat for human consumption. As with domestic livestock, it is important to understand the occurrence in these seals of infectious agents that may be of public health significance and thus ensure appropriate measures are in place to avoid zoonotic transmission. This study examined the prevalence of antibodies against Brucella spp., Erysipelothrix rhusiopathiae, 6 serovars of Leptospira interrogans, and Toxoplasma gondii in 59 grey seals and determined by polymerase chain reaction (PCR) the presence of these potentially zoonotic agents in specific organs and tissues of seropositive animals. The presence of encysted Trichinella spp. larvae was also investigated by digestion of tongue, diaphragm and other muscle samples, but none were detected. Seroprevalence against Brucella spp. and E. rhusiopathiae was low (5 and 3%, respectively). All 59 seals tested had antibodies against L. interrogans, but no carrier of this bacterium was detected by PCR. Seroprevalence against T. gondii was 53%, and DNA of this protozoan was detected by PCR in 11/30 (37%) seropositive animals. Standard sanitary measures mandatory for commercialization of meat products for human consumption should greatly reduce the potential for exposure to these infectious agents. However, special consideration should be given to freezing seal meat for at least 3 d to ensure destruction of tissue cysts of T. gondii.

An unusual case of Erysipelothrix rhusiopathiae prosthetic joint infection from the Canadian Arctic: whole genome sequencing unable to identify a zoonotic source.

BACKGROUND: Erysipelothrix rhusiopathiae is a zoonotic pathogen that causes erysipeloid and is most frequently associated with exposure to domestic swine. Infection of native and prosthetic joints is a rarely reported manifestation. CASE PRESENTATION: We describe a case of E. rhusiopathiae prosthetic joint infection in a woman with a history of exposure to wild animals in the Canadian Arctic. Patient management involved a 1-stage surgical revision exchange with an antibiotic impregnated cement spacer and 6 weeks of intravenous penicillin G followed by 6 weeks of oral amoxicillin. Ten previously reported cases of E. rhusiopathiae joint infection are reviewed. Recent increases in mortality due to infection with this organism among host animal populations in the Canadian Arctic have generated concern regarding a potential increase in human infections. However, whole genome sequencing (WGS) of the organism was unable to identify a zoonotic origin for this case. CONCLUSIONS: Consideration should be given to E. rhusiopathiae as a cause of joint infections if the appropriate epidemiologic and host risk factors exist. Expanded use of WGS in other potential animal hosts and environmental sources may provide important epidemiologic information in determining the source of human infections.

Historical biogeography among species of Varestrongylus lungworms (Nematoda: Protostrongylidae) in ungulates: episodic expansion and host colonization linking Eurasia and North America.

Varestrongylus lungworms (Nematoda: Protostrongylidae) include 10 nominal species that parasitize wild and domesticated artiodactyles. Eight species are endemic to the western Palearctic and Eurasia, whereas two are limited in distribution to the Nearctic. Complex host associations, primarily among Cervidae and Bovidae (Caprinae), and biogeography were explored based on direct comparisons of parasite and host phylogenies to reveal the historical development of this fauna. Diversification among Varestrongylus species has an intricate history extending over the Pliocene and Quaternary involving episodic processes for geographic and host colonization: (1) Varestrongylus has origins in Eurasia with independent expansion events into bordering ecozones; (2) cervids are ancestral hosts; (3) the caprine-associated V. pneumonicus is basal and a result of an independent host colonization event; (4) secondary diversification, linked to sequential and independent host colonization events, occurred within cervids (V. sagittatus + V. tuvae; V. alpenae; and V. capreoli, V. alces + V. eleguneniensis); (5) at least two additional host colonization events into caprines occurred, followed or not by diversification (V. qinghaiensis + V. longispiculatus; V. capricola, respectively); (6) two independent events of geographic expansion into North America from Eurasia with cervids in the late Pliocene and early Pleistocene are postulated (V. alpenae, V. eleguneniensis). Comparisons based on phylogenetic hypotheses derived from comparative morphology and molecular inference for these nematodes are consistent with the postulated history for coevolutionary and biogeographic history. Episodes of geographic and host colonization, often in relation to rapid shifts in climate and habitat perturbation, have dominated the history of diversification of Varestrongylus.

Varestrongylus (Nematoda: Protostrongylidae), lungworms of ungulates: a phylogenetic framework based on comparative morphology.

Varestrongylus Bhalerao, 1932 comprises ten valid lungworm species infecting wild and domestic ungulates from Eurasia and North America. Here, we present a phylogenetic hypothesis for the genus based on morphological characters in a broader context for the family Protostrongylidae and discuss species relationships and aspects of character evolution. Phylogenetic analysis of 25 structural attributes, including binary and multistate characters, among the 10 species of Varestrongylus resulted in one fully resolved most parsimonious tree (61 steps; consistency index = 0.672, retention index = 0.722, and consistency index excluding uninformative characters = 0.667). Varestrongylus forms a monophyletic clade and is the sister of Pneumostrongylus, supporting recognition of the subfamily Varestrongylinae. Monophyly for Varestrongylus is diagnosed by six unequivocal synapomorphies, all associated with structural characters of the copulatory system of males. Varestrongylus pneumonicus is basal, and sister to all other species within the genus, which form two subclades. The subclade I contains V. sagittatus + V. tuvae and V. qinghaiensis + V. longispiculatus. Subclade II contains V. alpenae, V. capricola, V. capreoli, and V. eleguneniensis + V. alces. Both subclades are diagnosed by two unambiguous synapomorphies. Highlighted is the continuing importance of phylogenetic assessments based on comparative morphology as a foundation to explore the structure of the biosphere across space and time.

Discovery of herpesviruses in Canadian wildlife.

Herpesviruses (HVs) have a wide range of hosts in the animal kingdom. The result of infection with HVs can vary from asymptomatic to fatal diseases depending on subtype, strain, and host. To date, little is known about HVs naturally circulating in wildlife species and the impact of these viruses on other species. In our study, we used genetic and comparative approaches to increase our understanding of circulating HVs in Canadian wildlife. Using nested polymerase chain reaction targeting a conserved region of the HV DNA polymerase gene, we analyzed material derived from wildlife of western and northern Canada collected between February 2009 and Sept 2014. For classification of new virus sequences, we compared our viral sequences with published sequences in GenBank to identify conserved residues and motifs that are unique to each subfamily, alongside phylogenetic analysis. All alphaherpesviruses shared a conserved tryptophan (W856) and tyrosine (Y880), betaherpesviruses all shared a serine (S836), and gammaherpesviruses had a conserved glutamic acid (E835). Most of our wildlife HV sequences grouped together with HVs from taxonomically related host species. From Martes americana, we detected previously uncharacterized alpha- and beta-herpesviruses.

Participatory science and innovation for improved sanitation and hygiene: process and outcome evaluation of project SHINE, a school-based intervention in Rural Tanzania.

BACKGROUND: Diarrheal disease is a major cause of mortality and morbidity in low and middle income countries with children being disproportionately affected. Project SHINE (Sanitation & Hygiene INnovation in Education) is a grassroots participatory science education and social entrepreneurship model to engage youth and the wider community in the development of sustainable strategies to improve sanitation and hygiene. METHODS: Based in rural and remote Tanzania, this pilot study engaged pastoralist high-school students and communities in the development and evaluation of culturally and contextually relevant strategies to improve sanitation and hygiene. Using a train-the-trainer approach, key activities included teacher workshops, school-based lessons, extra-curricular activities, community events and a One Health sanitation science fair which showcased projects related to water, sanitation and hygiene in relation to human and animal health. The process and outcome of the study were evaluated through qualitative interviews and focus group discussions with diverse project participants, as well as pre- and post- questionnaires completed by students on knowledge, attitudes and practices concerning sanitation and hygiene. RESULTS: The questionnaire results at baseline and follow-up showed statistically significant improvements on key measures including a decrease in unhygienic behaviors, an increase in the perceived importance of handwashing and intention to use the toilet, and increased communication in the social network about the importance of clean water and improved sanitation and hygiene practices, however there were no significant changes in sanitation related knowledge. Qualitative data highlighted strong leadership emerging from youth and enthusiasm from teachers and students concerning the overall approach in the project, including the use of participatory methods. There was a high degree of community engagement with hundreds of community members participating in school-based events. Sanitation science fair projects addressed a range of pastoralist questions and concerns regarding the relationship between water, sanitation and hygiene. Several projects, such as making soap from local materials, demonstrate potential as a sustainable strategy to improve health and livelihoods in the long-term. CONCLUSIONS: The Project SHINE model shows promise as an innovative capacity building approach and as an engagement and empowerment strategy for youth and communities to develop locally sustainable strategies to improve sanitation and hygiene.

Genomic analysis of the multi-host pathogen Erysipelothrix rhusiopathiae reveals extensive recombination as well as the existence of three generalist clades with wide geographic distribution.

BACKGROUND: Knowledge about how bacterial populations are structured is an important prerequisite for studying their ecology and evolutionary history and facilitates inquiry into host specificity, pathogenicity, geographic dispersal and molecular epidemiology. Erysipelothrix rhusiopathiae is an opportunistic pathogen that is currently reemerging in both the swine and poultry industries globally. This bacterium sporadically causes mortalities in captive marine mammals, and has recently been implicated in large-scale wildlife die-offs. However, despite its economic relevance and broad geographic and host distribution, including zoonotic potential, the global diversity, recombination rates, and population structure of this bacterium remain poorly characterized. In this study, we conducted a broad-scale genomic comparison of E. rhusiopathiae based on a diverse collection of isolates in order to address these knowledge gaps. RESULTS: Eighty-three E. rhusiopathiae isolates from a range of host species and geographic origins, isolated between 1958 and 2014, were sequenced and assembled using both reference-based mapping and de novo assembly. We found that a high proportion of the core genome (58 %) had undergone recombination. Therefore, we used three independent methods robust to the presence of recombination to define the population structure of this species: a phylogenetic tree based on a set of conserved protein sequences, in silico chromosome painting, and network analysis. All three methods were broadly concordant and supported the existence of three distinct clades within the species E. rhusiopathiae. Although we found some evidence of host and geographical clustering, each clade included isolates from diverse host species and from multiple continents. CONCLUSIONS: Using whole genome sequence data, we confirm recent suggestions that E. rhusiopathiae is a weakly clonal species that has been shaped extensively by homologous recombination. Despite frequent recombination, we can reliably identify three distinct clades that do not clearly segregate by host species or geographic origin. Our results provide an essential baseline for future molecular epidemiological, ecological and evolutionary studies of E. rhusiopathiae and facilitate comparisons to other recombinogenic, multi-host bacteria.

Onchocerca lupi Nematodes in Dogs Exported from the United States into Canada.

The Onchocerca lupi nematode is an emerging helminth capable of infecting pets and humans. We detected this parasite in 2 dogs that were imported into Canada from the southwestern United States, a region to which this nematode is endemic. We discuss risk for establishment of O. lupi in Canada.

'WE CAN'T GET WORMS FROM COW DUNG': REPORTED KNOWLEDGE OF PARASITISM AMONG PASTORALIST YOUTH ATTENDING SECONDARY SCHOOL IN THE NGORONGORO CONSERVATION AREA, TANZANIA.

Records at the Endulen Hospital in the Ngorongoro Conservation Area (NCA), Tanzania, reveal that soil-transmitted helminth infections and protozoa are consistently in the top ten diagnoses for Maasai pastoralists, indicating a significant public health concern. Nevertheless, Maasai pastoralist adaptations to life in close proximity to livestock and to unreliable access to water raise important questions about experiences of, and resiliency to, parasitic infections. Though these infections are particularly prevalent among youth in low- and middle-income countries (LMIC), a focus on resiliency highlights local capacity to recover from and prevent illness. For instance, how is human parasitism perceived and experienced among communities displaying behaviours that studies have associated with transmission of diarrhoeal diseases, such as open defecation? Among these communities, how is parasitism seen to impact the health and development of children? And, what resources are available to endure or mitigate this heavy disease burden among affected communities? This study draws on formative research carried out in May 2014 in anticipation of an innovative school-based and youth-driven water, sanitation and hygiene education intervention rolled out in two boarding schools in the NCA in subsequent months. The initiative is grounded in a One Health approach to health promotion, drawing on partnerships in medicine, public health and veterinary medicine to appreciate the unique interactions between humans, animals and the environment that shape well-being among pastoralist communities. Qualitative data generated through group discussions with secondary school youth (n=60), Maasai teachers (n=6) and a women's group (n=8) in the NCA convey existing knowledge of the prevalence, prevention and treatment of human parasitism. An underlying principle of the larger initiative is to engage youth as creative agents of change in developing and sustaining locally relevant health promotion strategies. Findings highlight practical knowledge around certain 'neglected tropical diseases', namely helminths, among pastoralist communities in the NCA, in turn feeding into the development of the science fair and related interventions.

Evaluation of a portable oxygen concentrator to provide fresh gas flow to dogs undergoing anesthesia.

This study evaluated the ability of a portable oxygen concentrator (POC) to provide fresh gas to an anesthetic machine via an Ayre's T-piece or a Bain circuit. Fraction of inspired oxygen (FiO2) was compared at flows of 0.5 to 3.0 L/min. Measured FiO2 was 96% at flow rates ≥ 1 L/min. Mean battery life at 1.0, 2.0, and 3.0 L/min was 4.21 ± 0.45, 2.62 ± 0.37 and 1.5 ± 0.07 hours, respectively. The POC proved to be useful and effective during 2 power outages. The POC was sufficient to prevent rebreathing in 70% of dogs using a T-piece circuit and 20% of dogs with a Bain circuit. A significant negative correlation between inspired CO2 and O2 flow rates was noted. A significant positive correlation between inspired CO2 and ETCO2 was documented. The occurrence of hypercarbia was associated with low O2 flow. Battery back-up was essential during power outages. The POC can be effectively used for delivery of anesthesia.

Évaluation d'un concentrateur d'oxygène portable pour fournir une circulation de gaz frais aux chiens subissant une anesthésie. Cette étude a évalué la capacité d'un concentrateur d'oxygène portable (COP) à fournir du gaz frais à l'aide d'une pièce en T d'Ayre ou d'un circuit de Bain. La fraction d'oxygène inspiré (FiO2) a été comparée à des débits de 0,5 à 3,0 L/min. La FiO2 mesurée était de 96 % à des taux de débit de ≥ 1 L/min. La durée de vie moyenne de la batterie à 1,0, à 2,0 et à 3,0 L/min était de 4,21 ± 0,45, de 2,62 ± 0,37 et 1,5 ± 0,07 heures, respectivement. Le COP s'est avéré utile et efficace durant deux pannes d'électricité. Le COP a été suffisant pour prévenir la réinspiration chez 70 % des chiens en utilisant un circuit de pièce en T et un circuit de Bain chez 20 % des chiens. Une corrélation négative importante entre le CO2 inspiré et les taux de débit d'O2 a été observée. Une corrélation positive importante entre le CO2 inspiré et l' ETCO2 a été documentée. L'occurrence de l'hypercarbie était associée à un faible débit d'O2. Une batterie de secours était essentielle durant les pannes d'électricité. Le COP peut être efficacement utilisé pour fournir de l'anesthésie.(Traduit par Isabelle Vallières).

Pathogens at the livestock-wildlife interface in Western Alberta: does transmission route matter?

In southwestern Alberta, interactions between beef cattle and free-ranging elk (Cervus elaphus) may provide opportunities for pathogen transmission. To assess the importance of the transmission route on the potential for interspecies transmission, we conducted a cross-sectional study on four endemic livestock pathogens with three different transmission routes: Bovine Viral Diarrhea Virus and Bovine Herpesvirus 1 (predominantly direct transmission), Mycobacterium avium subsp. paratuberculosis (MAP) (indirect fecal-oral transmission), Neospora caninum (indirect transmission with definitive host). We assessed the occurrence of these pathogens in 28 cow-calf operations exposed or non-exposed to elk, and in 10 elk herds exposed or not to cattle. We characterized the effect of species commingling as a risk factor of pathogen exposure and documented the perceived risk of pathogen transmission at this wildlife-livestock interface in the rural community. Herpesviruses found in elk were elk-specific gamma-herpesviruses unrelated to cattle viruses. Pestivirus exposure in elk could not be ascertained to be of livestock origin. Evidence of MAP circulation was found in both elk and cattle, but there was no statistical effect of the species commingling. Finally, N. caninum was more frequently detected in elk exposed to cattle and this association was still significant after adjustment for herd and sampling year clustering, and individual elk age and sex. Only indirectly transmitted pathogens co-occurred in cattle and elk, indicating the potential importance of the transmission route in assessing the risk of pathogen transmission in multi-species grazing systems.

Variation in Muskox (Ovibos moschatus) Guard Hair Growth Rates: Implications for Measuring Chronological Biomarkers.

Segmental analyses of hair may be useful for measuring biomarkers over several seasons to years from a single sample. To attribute hair segments to specific time periods, a known chronological marker, or a hair growth rate, is needed. We examined guard hair growth rates of captive muskoxen (Ovibos moschatus) in Fairbanks, Alaska, USA. We sought to determine if a general growth rate could be applied across muskox populations, thus facilitating the use of segmental analyses for various biomarkers. We used archived samples from 16 muskoxen that had guard hairs sampled at six, 14, and 30 wk after shaving. We measured the lengths of 10 guard hairs per sample, calculated weekly and annual growth rates, and then fitted linear mixed-effects models to assess the effect of different covariates on hair growth rate. The period in which hair had been grown had a significant effect (P<0.05) on growth rate. Extrapolated annual hair growth rates were 277±40 mm/yr (weeks 0-6), 248±47 mm/yr (weeks 7-14), and 165±36 mm/yr (weeks 15-30), with an overall average rate of 210±14 mm/yr. These rates were significantly faster than those of free-ranging Greenland muskoxen-78 mm/yr as measured by stable isotope analyses-and varied intra-annually. This suggests that a universal growth rate cannot be generalized across muskox populations and time.

Assessing current visual tooth wear age estimation methods for Rangifer tarandus using a known age sample from Canada.

Age estimation is crucial for investigating animal populations in the past and present. Visual examination of tooth wear and eruption is one of the most common ageing methods in zooarchaeology, wildlife management, palaeontology, and veterinary research. Such approaches are particularly advantageous because they are non-destructive, can be completed using photographs, and do not require specialized training. Several tooth wear and eruption methods have been developed for Rangifer tarandus, a widely distributed and long-utilized species in the North. This paper evaluates the practicality and effectiveness of three existing visual tooth wear and eruption methods for this species using a large known-age sample from several caribou populations in northern Canada (Bluenose East, Bluenose West, Dolphin-Union, Qamanirjuaq, and Beverly herds). These methods are evaluated based on: (1) the amount of error and bias between estimated and actual ages, (2) suitable and interpretable results, (3) user-friendly and unambiguous procedures, and (4) which teeth and visual features of those teeth are used to record wear and eruption status. This study finds that the three evaluated methods all have variable errors and biases, and two show extensive biases when applied to older individuals. Demographic data is simpler to generate and more flexible to report when methods allow age to be estimated as a continuous or discrete variable, rather than as age ranges. The dentition samples used by two of the previously developed methods impact their applicability to other populations of Rangifer. In one existing method, individuals were unavailable from some age ranges leaving gaps when assigning ages. For another Rangifer-ageing method, the population utilized was too distinct in morphology or diet to be used with the Canadian caribou analyzed here. Additional refinement of tooth wear and eruption ageing methods will benefit zooarchaeological research on reindeer and caribou remains.

Patterns of gastrointestinal parasite infections in bighorn sheep, Ovis canadensis, with respect to host sex and seasonality.

Males and females in sexually dimorphic species show differences in their physiology and behaviour due to differences in energetic investment into reproduction and soma. This means that the two sexes may show different patterns of parasitism at different times of the year. In this study, we evaluate the abundance of fecal eggs and larvae of 5 parasite types (Strongyles, Nematodirus spp., Marshallagia marshalli., Protostrongylus spp. lungworms, and Eimeria spp.) in relation to season and sex in Rocky Mountain bighorn sheep (Ovis canadensis). We use fecal egg counts (FEC) as a proxy for infection intensity. Parasite FECs differed between male and female bighorn sheep and varied with season. We found pronounced fluctuations in fecal egg counts of various parasite species in males and females across different seasons and reproductive stages. Strongyle counts were significantly higher during late gestation and lactation/summer, and particularly pronounced in males. Nematodirus counts were highest during late gestation in females and during the rut in males. Marshallagia counts peaked during late gestation in females and during the rut in males. Protostrongylus spp. lungworm counts were highest during late gestation in females and in males during lactation/summer and the rut. Eimeria oocyst counts varied across seasons, with higher counts in males during the rut and in females during winter and late gestation. Additionally, significant differences in Strongyle counts were observed between coursing and tending rams, with tending rams exhibiting higher counts. We discuss why the sexes might differ in FECs and suggest that differences between FECs of the parasites across seasons may be due to different life cycles and cold tolerance of the parasites themselves.