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One Health programs and trajectories are now the apparent standard for exploring the occurrence and distribution of emerging pathogens and disease. By definition, One Health has been characterized as a broadly inclusive, collaborative, and transdisciplinary approach with connectivity across local to global scales, which integrates the medical and veterinary community to recognize health outcomes emerging at the environmental nexus for people, animals, plants, and their shared landscapes. One Health has been an incomplete model, conceptually and operationally, focused on reactive and response-based foundations, to limit the impact of emerging pathogens and emerging infectious diseases and, as such, lacks a powerful proactive capacity. A proactive, predictive One Health is necessary, emanating in part from geographically/taxonomically broad and temporally deep biological collections of pathogen-host assemblages. The DAMA protocol (Document, Assess, Monitor, Act), the operational extension of the Stockholm paradigm (SP), accomplishes this task by encompassing holistic and strategic biological sampling of reservoir host assemblages and pathogens at environmental interfaces and more extensively through resurveys, with development of informatics resources digitally linked to physical specimens held in publicly accessible museum biorepositories. Archives of specimens are the foundations for accumulating interrelated archives of information (the baselines against which change can be identified and tracked), with collections serving as fundamental resources for biodiversity informatics under the conceptual evolutionary and ecological umbrella of the SP. A cultural and conceptual transformation is essential among the diverse practitioners in the One Health community, one that recognizes the necessity of placing pathogens in an evolutionary, ecological, and environmental context by integrating specimens and associated informatics into an infrastructure and networks for actionable information. As a community, it is essential to abandon response-based business as usual while looking forward toward proactive transboundary approaches that maximize our conceptual and taxonomic view of diversity across interconnected planetary scales that influence the complexity of pathogen-host interfaces. Evolution, where the past always influences the present and the future, defines our trajectory, as the need for sustained archives that describe the biosphere becomes more acute with each passing day.

Orthostrongylus macrotis (Dikmans, 1931) is a protostrongylid lungworm in wild ungulates from western North America, including mule and Columbia black-tailed deer, pronghorn, and rarely moose and elk. The lack of morphological data for certain developmental stages of O. macrotis and the unresolved taxonomic status of the genus indicate a more detailed morphological characterization of the species is necessary. We provide a detailed description of first-stage larvae (L1) of O. macrotis including morphological, morphometric, and molecular data. Species identity was confirmed based on molecular sequence data from the internal transcribed spacer subunit 2 (ITS-2) and large subunit (28S) rDNA. A fragment of the cytochrome oxidase c subunit 1 (COI) was also sequenced, followed by the determination of genetic distance and phylogenetic analyses. Integrated data describing L1 of O. macrotis contributes to a broader understanding of the parasite fauna of wild ungulates from North America and may be of relevance for a future revision of the genus. Further, we outline information for differentiation among species of North American protostrongylids, with typical spike-tailed L1s, circulating among free-ranging and semi-domestic ungulates.

The unusual genetic diversity of the Omicron strain has led to speculation about its origin. The mathematical modelling platform developed for the Stockholm Paradigm (SP) indicates strongly that it has retro-colonized humans from an unidentified nonhuman mammal, likely originally infected by humans. The relationship between Omicron and all other SARS-CoV-2 variants indicates oscillations among hosts, a core part of the SP. Such oscillations result from the emergence of novel variants following colonization of new hosts, replenishing and expanding the risk space for disease emergence. The SP predicts that pathogens colonize new hosts using pre-existing capacities. Those events are thus predictable to a certain extent. Novel variants emerge after a colonization and are not predictable. This makes it imperative to take proactive measures for anticipating emerging infectious diseases (EID) and mitigating their impact. The SP suggests a policy protocol, DAMA, to accomplish this goal. DAMA comprises: DOCUMENT to detect pathogens before they emerge in new places or colonize new hosts; ASSESS to determine risk; MONITOR to detect changes in pathogen populations that increase the risk of outbreaks and ACT to prevent outbreaks when possible and minimize their impact when they occur.

Although logistically challenging to study, the Arctic is a bellwether for global change and is becoming a model for questions pertinent to the persistence of biodiversity. Disruption of Arctic ecosystems is accelerating, with impacts ranging from mixing of biotic communities to individual behavioral responses. Understanding these changes is crucial for conservation and sustainable economic development. Genomic approaches are providing transformative insights into biotic responses to environmental change, but have seen limited application in the Arctic due to a series of limitations. To meet the promise of genome analyses, we urge rigorous development of biorepositories from high latitudes to provide essential libraries to improve the conservation, monitoring, and management of Arctic ecosystems through genomic approaches.

Marshallagia marshalli is a multi-host gastrointestinal nematode that infects a variety of artiodactyl species from temperate to Arctic latitudes. Eggs of Marshallagia are passed in host faeces and develop through three larval stages (L1, L2, and L3) in the environment. Although eggs normally hatch as L1s, they can also hatch as L3s. We hypothesised that this phenotypic plasticity in hatching behaviour may improve fitness in subzero and highly variable environments, and this may constitute an evolutionary advantage under current climate change scenarios. To test this, we first determined if the freeze tolerance of different free-living stages varied at different temperatures (−9 °C, −20 °C and −35 °C). We then investigated if there were differences in freeze tolerance of M. marshalli eggs sourced from three discrete, semi-isolated, populations of wild bighorn and thinhorn sheep living in western North America (latitudes: 40°N, 50°N, 64°N). The survival rates of eggs and L3s were significantly higher than L1s at −9 °C and −20 °C, and survival of all three stages decreased significantly with increasing freeze duration and decreasing temperature. The survival of unhatched L1s was significantly higher than the survival of hatched L1s. There was no evidence of local thermal adaptation in freeze tolerance among eggs from different locations. We conclude that developing to the L3 in the egg may result in a fitness advantage for M. marshalli, with the egg protecting the more vulnerable L1 under freezing conditions. This phenotypic plasticity in life-history traits of M. marshalli might be an important capacity, a potential exaptation capable of enhancing parasite fitness under temperature extremes.

Species of the genus Arostrilepis were discovered and definitively identified for the first time in rodents from geographically disparate localities along the Appalachian Mountain range of eastern North America (West Virginia, Virginia, and Maine). These are the first confirmed records for species of Arostrilepis occurring east of the Rocky Mountains and the Mississippi River in North America. Arostrilepis gardneri n. sp. is described on the basis of specimens obtained from two phylogenetically divergent rodent hosts: Southern Red-Backed Vole Myodes gapperi (Cricetidae: Arvicolinae) (from West Virginia) and the Woodland Jumping Mouse Napaeozapus insignis (Dipodidae: Zapodinae) (West Virginia, Virginia, and Maine). Additionally, in a mixed infection, specimens of Arostrilepis insperata n. sp. were also found in a Southern Red-Backed Vole from West Virginia. These previously unknown species are primarily distinguished from congeners based on shape, dimensions, and spination (pattern, shape, and size of spines) of the cirrus. Specimens of A. gardneri n. sp. are further characterized by the relative position and length of the cirrus-sac, arrangement of the testes, and relative size of the external seminal vesicle and seminal receptacle. Specimens of A. insperata n. sp. are structurally most similar to A. macrocirrosa from the western Nearctic and Palearctic but with consistently greater dimensions for the cirrus-sac, testes, and seminal receptacle. Phylogenetic analysis of Arostrilepis spp. using partial sequences of the mitochondrial cytochrome b gene and the nuclear second ribosomal internal transcribed spacer strongly supported the status of A. gardneri n. sp. and A. insperata n. sp. within an unresolved clade of congeners in Red-Backed Voles (Myodini and species of Myodes). Our observations extend the known geographic distribution for species of Arostrilepis to the Appalachian Mountains in either a disjunct or possibly continuous but patchy range across North America. Prior observations, summarizing field and museum collections, had suggested that geographic ranges for a diverse assemblage of Arostrilepis in North America were largely restricted to the north-western region of the continent, with historical connections to Beringia and Eurasia. Recognition of a more extensive distribution is consistent with a history of episodic biotic expansion and isolation under a dynamic of taxon pulses for arvicoline rodents and an associated parasite fauna in the Nearctic during the Quaternary. Occurrence in a dipodid rodent represents an event of host colonization from an arvicoline source.

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic reveals a major gap in global biosecurity infrastructure: a lack of publicly available biological samples representative across space, time, and taxonomic diversity. The shortfall, in this case for vertebrates, prevents accurate and rapid identification and monitoring of emerging pathogens and their reservoir host(s) and precludes extended investigation of ecological, evolutionary, and environmental associations that lead to human infection or spillover. Natural history museum biorepositories form the backbone of a critically needed, decentralized, global network for zoonotic pathogen surveillance, yet this infrastructure remains marginally developed, underutilized, underfunded, and disconnected from public health initiatives. Proactive detection and mitigation for emerging infectious diseases (EIDs) requires expanded biodiversity infrastructure and training (particularly in biodiverse and lower income countries) and new communication pipelines that connect biorepositories and biomedical communities. To this end, we highlight a novel adaptation of Project ECHO’s virtual community of practice model: Museums and Emerging Pathogens in the Americas (MEPA). MEPA is a virtual network aimed at fostering communication, coordination, and collaborative problem-solving among pathogen researchers, public health officials, and biorepositories in the Americas. MEPA now acts as a model of effective international, interdisciplinary collaboration that can and should be replicated in other biodiversity hotspots. We encourage deposition of wildlife specimens and associated data with public biorepositories, regardless of original collection purpose, and urge biorepositories to embrace new specimen sources, types, and uses to maximize strategic growth and utility for EID research. Taxonomically, geographically, and temporally deep biorepository archives serve as the foundation of a proactive and increasingly predictive approach to zoonotic spillover, risk assessment, and threat mitigation.

Despite the economic, social and ecological importance of the ostertagiine abomasal nematode Marshallagia marshalli, little is known about its life history traits and its adaptations to cope with environmental extremes. Conserved species-specific traits can act as exaptations that may enhance parasite fitness in changing environments. Using a series of experiments, we revealed several unique adaptations of the free-living stages of M. marshalli that differ from other ostertagiines. Eggs were isolated from the feces of bighorn sheep (Ovis canadensis) from the Canadian Rocky Mountains and were cultured at different temperatures and with different media. Hatching occurred primarily as L1s in an advanced stage of development, morphologically very similar to a L2. When cultured at 20 °C, however, 2.86% of eggs hatched as L3, with this phenomenon being significantly more common at higher temperatures, peaking at 30 °C with 28.95% of eggs hatching as L3s. After hatching, free-living larvae of M. marshalli did not feed nor grow as they matured from L1 to infective L3. These life history traits seem to be adaptations to cope with the extreme environmental conditions that Marshallagia faces across its extensive latitudinal distribution in North America and Eurasia. In order to refine the predictions of parasite dynamics under scenarios of a changing climate, basic life history traits and temperature-dependent phenotypic behaviour should be incorporated into models for parasite biology.

Species of Trichinella are a globally distributed assemblage of nematodes, often with distinct host ranges, which include people, domestic, and wild animals. Trichinella spp. are important in northern Canada, where dietary habits of people and methods of meat preparation (drying, smoking, fermenting as well as raw) increase the risk posed by these foodborne zoonotic parasites. Outbreaks in the arctic and subarctic regions of Canada and the United States are generally attributed to T. nativa (T2) or the T6 genotype, when genetic characterization is performed. We report the discovery of Trichinella pseudospiralis (T4), a non-encapsulated species, in a wolverine (Gulo gulo) from the Northwest Territories of Canada. This parasite has been previously reported elsewhere from both mammals and carnivorous birds, but our findings represent new host and geographic records for T. pseudospiralis. Multiplex PCR and sequencing of fragments of Cytochrome Oxidase Subunit I (COI) and D3 rDNA confirmed the identification. Phylogenetically, Canadian isolates linked with each other and others derived from Palearctic or Neotropical regions, but not elsewhere in the Nearctic (continental USA). We suggest that migratory birds might have played a role in the dispersal of this pathogen 1000's of km to northwestern Canada. Wolverines are not typically consumed by humans, and thus should not pose a direct food safety risk for trichinellosis. However, the current finding suggests that they may serve as an indicator of a broader distribution for T. pseudospiralis. Along with infection risk already recognized for T. nativa and Trichinella T6, our observations emphasize the need for further studies using molecular diagnostics and alternative methods to clarify if this is a solitary case, or if T. pseudospiralis and other freeze susceptible species of Trichinella (such as T. spiralis) circulate more broadly in wildlife in Canada, and elsewhere., Graphical abstract (Picture of wolverine: Wolverine picture: credit to Gustaf Samelius, Snow Leopard Trust, Seattle, Washington 98103, USA).Image 1, Highlights • First documentation of Trichinella pseudospiralis on the mainland of Canada. • Second molecular characterization of T. pseudospiralis from Canada. • Northernmost observation of T. pseudospiralis from North America. • Most closely related to isolates from Palearctic and Neotropics, not Nearctic.

Haemonchus contortus, in common with many nematode species, has extremely high levels of genetic variation within and between field populations derived from distant geographical locations. MHco10(CAVR), MHco3(ISE) and MHco4(WRS) are genetically divergent H. contortus strains, originally derived from Australia, Kenya and South Africa, respectively, that have been maintained by numerous rounds of in vivo experimental infection of sheep. In order to explore potential pre-zygotic competition or post-zygotic incompatibility between the strains, we have investigated the ability of MHco10(CAVR) to interbreed with either MHco3(ISE) or MHco4(WRS) during dual strain co-infections. Sheep were experimentally co-infected with 4,000 infective larvae (L3) per os of the MHco10(CAVR) strain and an equal number of either the MHco3(ISE) or the MHco4(WRS) strain L3. The adult worm establishement rates and the proportions of F1 progeny resulting from intra- and inter-strain mating events were determined by admixture analysis of microsatellite multi-locus genotypes. Although there was no difference in adult worm establishment rates, the proportions of F1 progeny of both the MHco10(CAVR) x MHco3(ISE) and MHco10(CAVR) x MHco4(WRS) dual strain co-infections departed from Mendelian expectations. The proportions of inter-strain hybrid F1 progeny were lower than the expected 50%, suggesting either pre-zygotic competition or post-zygotic incompatibility between the co-infecting strains. To investigate this further, both eggs and hatched first stage larvae (L1) of broods from single adult female worms recovered from each dual co-infection were genotyped. Unhatched eggs from the broods revealed no inter-strain hybrid genotype deficit, suggesting there is no pre-zygotic competition between the strains. In contrast, there was a deficit in L1 inter-strain hybrid genotypes in the broods derived from MHco3(ISE) or MHco4(WRS) maternal parents, but not from MHco10(CAVR) maternal parents. This suggests that hybrid progeny of MHco10(CAVR) paternal parents have reduced post-zygotic development and/or viability consistent with incipient speciation of the MHco10(CAVR) strain. The presence of mating barriers between allopatric H. contortus strains has important implications for parasite ecology, including the ability of newly introduced anthelmintic resistant parasite populations to compete and interbreed with populations already established in a region.

Museum specimens play an increasingly important role in predicting the outcomes and revealing the consequences of anthropogenically driven disruption of the biosphere. As ecological communities respond to ongoing environmental change, host–parasite interactions are also altered. This shifting landscape of host–parasite associations creates opportunities for colonization of different hosts and emergence of new pathogens, with implications for wildlife conservation and management, public health, and other societal concerns. Integrated archives that document and preserve mammal specimens along with their communities of associated parasites and ancillary data provide a powerful resource for investigating, anticipating, and mitigating the epidemiological, ecological, and evolutionary impacts of environmental perturbation. Mammalogists who collect and archive mammal specimens have a unique opportunity to expand the scope and impact of their field work by collecting the parasites that are associated with their study organisms. We encourage mammalogists to embrace an integrated and holistic sampling paradigm and advocate for this to become standard practice for museum-based collecting. To this end, we provide a detailed, field-tested protocol to give mammalogists the tools to collect and preserve host and parasite materials that are of high quality and suitable for a range of potential downstream analyses (e.g., genetic, morphological). Finally, we also encourage increased global cooperation across taxonomic disciplines to build an integrated series of baselines and snapshots of the changing biosphere. Los especímenes de museo desempeñan un papel cada vez más importante tanto en la descripción de los resultados de la alteración antropogénica de la biosfera como en la predicción de sus consecuencias. Dado que las comunidades ecológicas responden al cambio ambiental, también se alteran las interacciones hospedador-parásito. Este panorama cambiante de asociaciones hospedador-parásito crea oportunidades para la colonización de diferentes hospedadores y para la aparición de nuevos patógenos, con implicancias en la conservación y manejo de la vida silvestre, la salud pública y otras preocupaciones de importancia para la sociedad. Archivos integrados que documentan y preservan especímenes de mamíferos junto con sus comunidades de parásitos y datos asociados, proporcionan un fuerte recurso para investigar, anticipar y mitigar los impactos epidemiológicos, ecológicos y evolutivos de las perturbaciones ambientales. Los mastozoólogos que recolectan y archivan muestras de mamíferos, tienen una oportunidad única de ampliar el alcance e impacto de su trabajo de campo mediante la recolección de los parásitos que están asociados con los organismos que estudian. Alentamos a los mastozoólogos a adoptar un paradigma de muestreo integrado y holístico y abogamos para que esto se convierta en una práctica estándarizada de la obtención de muestras para museos. Con este objetivo, proporcionamos un protocolo detallado y probado en el campo para brindar a los mastozoólogos las herramientas para recolectar y preservar materiales de parásitos y hospedadores de alta calidad y adecuados para una gran variedad de análisis subsecuentes (e.g., genéticos, morfológicos, etc.). Finalmente, también abogamos por una mayor cooperación global entre las diversas disciplinas taxonómicas para construir una serie integrada de líneas de base y registros actuales de nuestra cambiante biosfera.

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 (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. Graphical Abstract

Emerging infectious diseases (EIDs) increasingly threaten global food security and public health. Despite technological breakthroughs, we are losing the battle with (re)emerging diseases as treatment costs and production losses rise. A horizon scan of diseases of crops, livestock, seafood and food-borne illness suggests these costs are unsustainable. The paradigm of coevolution between pathogens and particular hosts teaches that emerging diseases occur only when pathogens evolve specific capacities that allow them to move to new hosts. EIDs ought to be rare and unpredictable, so crisis response is the best we can do. Alternatively, the Stockholm Paradigm suggests that the world is full of susceptible but unexposed hosts that pathogens could infect, given the opportunity. Global climate change, globalized trade and travel, urbanization and land-use changes (often associated with biodiversity loss) increase those opportunities, making EID frequent. We can, however, anticipate their arrival in new locations and their behaviour once they have arrived. We can 'find them before they find us', mitigating their impacts. The DAMA (Document, Assess, Monitor, Act) protocol alters the current reactive stance and embodies proactive solutions to anticipate and mitigate the impacts of EID, extending human and material resources and buying time for development of new vaccinations, medications and control measures.

We begin resolution of the Tetrabothrius jagerskioeldi–species complex with descriptions of Tetrabothrius alcae n. sp. based on numerous specimens, primarily in murres (species of Uria), from the greater North Pacific basin and Tetrabothrius sinistralis n. sp. based on cestodes in guillemots (species of Cepphus) from the central Bering Sea and West Greenland. These tetrabothriids are characterized, among 44 species of Tetrabothrius in avian hosts, by attributes of the scolex, male and female organ systems, structure and dimensions of the vitelline gland, numbers of testes, configuration of the genital atrium, genital papillae and the male and female atrial canals, position of the genital ducts relative to the poral osmoregulatory canals, structure, dimensions and position of the vaginal seminal receptacle, and dimensions of the embryophore and oncosphere, in addition to a broader array of characters. Remarkably, T. alcae, T. sinistralis, and a cryptic complex had remained unrecognized for the past century, given that these species are unequivocally differentiated by multiple suites of unique structural attributes relative to T. jagerskioeldi. Alcids and cestodes of the T. jagerskioeldi–complex are restricted to cold marine systems of advection and upwelling along coastal margins adjacent to the continental shelf or are associated with archipelagos (especially the Aleutian Arc), isolated islands and rocky headlands of the Bering Sea, Chukchi Sea, Gulf of Alaska, Sea of Okhotsk, and Sea of Japan. Tetrabothrius alcae, T. jagerskioeldi, and T. sinistralis may occur in sympatry but with minimal overlap in the faunas associated with murres (Alcini) and guillemots (Cepphini). Transmission for cestodes and persistence of this fauna is expected to be associated with pelagic and neritic systems adjacent to colony sites in zones where critical prey species are concentrated or secondarily dispersed downstream by predictable advective and upwelling processes and become available to foraging birds. Faunal assembly represents the outcomes of oscillating climate, shifting ranges (breakdown in isolation, ecological fitting, and exploration modes for cestodes) and the changing interfaces for resource availability maintained by trophic and habitat overlaps. Dynamics at these ecotones constitute the nexus of opportunity and capacity for infection by species of Tetrabothrius among avian hosts where capacity appears broad and opportunity is ecologically restricted in space and prevatime. Life history pathways for cestodes are tied to trophic associations and dynamics at mesoscales across marine domains and provinces. Resilience and connectivity through ecological fitting strongly suggest the influence of multiple trophic pathways for transmission and persistence of this complex fauna through differing assemblages of zooplankters, fishes, and cephalopods depending on locality, oceanographic conditions, and temporal variability. Changing conditions, especially ecological perturbations driven by climate oscillations, directly determine production cycles and distributions of micro- and macro-zooplankton, forage fishes, cephalopods, and trophic structure in high-latitude marine ecosystems. Expanding regimes of accelerating change emphasize the critical importance of field collections, archives, and baselines to assess biological outcomes across temporal and spatial scales. Parasite assemblages reveal macro- to meso-scale connectivity serving as adjuncts and proxies in recognizing and understanding outcomes for episodes of environmental oscillation and directional atmospheric and oceanic warming in marine ecosystems.

Investigations of intercontinental dispersal between Asia and North America reveal complex patterns of geographic expansion, retraction and isolation, yet historical reconstructions are largely limited by the depth of the record that is retained in patterns of extant diversity. Parasites offer a tool for recovering deep historical insights about the biosphere, improving the resolution of past community-level interactions. We explored biogeographic hypotheses regarding the history of dispersal across Beringia, the region intermittently linking Asia and North America, through large-scale multi-locus phylogenetic analyses of the genus Schizorchis , an assemblage of host-specific cestodes in pikas (Lagomorpha: Ochotonidae). Our genetic data support palaeontological evidence for two separate geographic expansions into North America by Ochotona in the late Tertiary, a history that genomic evidence from extant pikas does not record. Pikas descending from the first colonization of Miocene age persisted into the Pliocene, subsequently coming into contact with a second wave of Nearctic colonists from Eurasia before going extinct. Spatial and temporal overlap of historically independent pika populations provided a window for host colonization, allowing persistence of an early parasite lineage in the contemporary fauna following the extinction of its ancestral hosts. Empirical evidence for ancient ‘ghost assemblages' of hosts and parasites demonstrates how complex mosaic faunas are assembled in the biosphere through episodes of faunal mixing encompassing parasite lineages across deep and shallow time.

Rapid climate warming in the Arctic results in multifaceted disruption of biodiversity, faunal structure, and ecosystem health. Hypotheses have linked range expansion and emergence of parasites and diseases to accelerating warming globally but empirical studies demonstrating causality are rare. Using historical data and recent surveys as baselines, we explored climatological drivers for Arctic warming as determinants of range expansion for two temperature-dependent lungworms, Umingmakstrongylus pallikuukensis and Varestrongylus eleguneniensis, of muskoxen (Ovibos moschatus) and caribou (Rangifer tarandus), in the Canadian Arctic Archipelago from 1980 through 2017. Our field data shows a substantial northward shift of the northern edge of the range for both parasites and increased abundance across the expanded ranges during the last decade. Mechanistic models parameterized with parasites’ thermal requirements demonstrated that geographical colonization tracked spatial expansion of permissive environments, with a temporal lag. Subtle differences in life histories, thermal requirements of closely related parasites, climate oscillations and shifting thermal balances across environments influence faunal assembly and biodiversity. Our findings support that persistence of host-parasite assemblages reflects capacities of parasites to utilize host and environmental resources in an ecological arena of fluctuating opportunity (alternating trends in exploration and exploitation) driving shifting boundaries for distribution across spatial and temporal scales.

Altres ajuts: Natural Sciences and Engineering Research Council of Canada 316189-2012-RGPIN. Beringian Coevolution Project (BCP), National Science Foundation DEB 0196095 i 0415668 An understanding of the mechanisms influencing prenatal characteristics is fundamental to comprehend the role of ecological and evolutionary processes behind survival and reproductive success in animals. Although the negative influence of parasites on host fitness is undisputable, we know very little about how parasitic infection in reproductive females might influence prenatal factors such as fetal development and sex allocation. Using an archival collection of Dall's sheep (Ovis dalli dalli), a capital breeder that depends on its body reserves to overcome the arctic winter, we investigated the direct and indirect impacts of the parasite community on fetal development and sex allocation. Using partial least squares modelling, we observed a negative effect of parasite community on fetal development, driven primarily by the nematode Marshallagia marshalli. Principal component analysis demonstrated that mothers with low parasite burden and in good body condition were more likely to have female versus male fetuses. This association was primarily driven by the indirect effect of M. marshalli on ewe body condition. Refining our knowledge of the direct and indirect impact that parasite communities can have on reproduction in mammals is critical for understanding the effects of infectious diseases on wildlife populations. This can be particularly relevant for species living in ecosystems sensitive to the effects of global climate change.

Natural history collections spanning multiple decades provide fundamental historical baselines to measure and understand changing biodiversity. New technologies such as next generation DNA sequencing have considerably increased the potential of museum specimens to address significant questions regarding the impact of environmental changes on host and parasite/pathogen dynamics. We developed a new technique to identify intestinal helminth parasites and applied it to shrews (Eulipotyphla: Soricidae) because they are ubiquitous, occupy diverse habitats, and host a diverse and abundant parasite fauna. Notably, we included museum specimens preserved in various ways to explore the efficacy of using metabarcoding analyses that may enable identification of helminth symbiont communities from historical archives. We successfully sequenced the parasite communities (using 12S mtDNA, 16S mtDNA, 28S rDNA) of 23 whole gastrointestinal tracts. All gastrointestinal tracts were obtained from the Museum of Southwestern Biology, USA, and from recent field collections, varying both in time since fixation (ranging from 4 months to 16 years) and preservation method (70% or 95% ethanol stored at room temperature, or flash frozen in liquid nitrogen and stored at −80 °C). Our proof of concept demonstrates the feasibility of applying next generation DNA sequencing techniques to authoritatively identify the parasite/pathogen communities within whole gastrointestinal tracts from museum specimens of varying age and fixation, and the value of future preservation of host-associated whole gastrointestinal tracts in public research archives. This powerful approach facilitates future comparative examinations of the distributions and interactions among multiple associated groups of organisms through time and space.

Horizontal gene transfer (HGT) has played an important role in the evolution of nematodes. Among candidate genes, cyanase, which is typically found only in plants, bacteria and fungi, is present in more than 35 members of the Phylum Nematoda, but absent from free-living and clade V organisms. Phylogenetic analyses showed that the cyanases of clade I organismsTrichinellaspp.,Trichurisspp. andSoboliphyme baturini(Subclass: Dorylaimia) represent a well-supported monophyletic clade with plant cyanases. In contrast, all cyanases found within the Subclass Chromadoria which encompasses filarioids, ascaridoids and strongyloids are homologous to those of bacteria. Western blots exhibited typical multimeric forms of the native molecule in protein extracts ofTrichinella spiralismuscle larvae, where immunohistochemical staining localized the protein to the worm hypodermis and underlying muscle. RecombinantTrichinellacyanase was bioactive where gene transcription profiles support functional activityin vivo. Results suggest that: (1) independent HGT in parasitic nematodes originated from different Kingdoms; (2) cyanase acquired an active role in the biology of extantTrichinella; (3) acquisition occurred more than 400 million years ago (MYA), prior to the divergence of the Trichinellida and Dioctophymatida, and (4) early, free-living ancestors of the genusTrichinellahad an association with terrestrial plants.

The specific status of Echinococcus canadensis has long been controversial, mainly because it consists of the mitochondrial lineages G6, G7, G8 and G10 with different host affinity: G6 (camel strain) and G7 (pig strain) with domestic cycles and G8 (cervid strain) and G10 (Fennoscandian cervid strain) with sylvatic or semi-domestic cycles. There is an argument whether the mitochondria] lineages should be recognised as separate species which correspond to the biological or epidemiological aggregation. In the present study, the specific status of E. canadensis was investigated using mitochondrial DNA and single copy nuclear DNA markers. Nucleotide sequences of complete mitochondrial cytochrome c oxidase subunit 1 (cox1) and partial nuclear phosphoenolpyruvate carboxykinase (pepck) and DNA polymerase delta (pold) were determined for 48 isolates of E. canadensis collected from different hosts in a wide range of regions. The mitochondrial phylogeny of cox1 showed that all the isolates were clearly divided into three clades corresponding to G6/G7, G8 and G10. Five and three alleles were confirmed at pepck and pold loci, respectively. These alleles were generally divided into two groups corresponding to G6/G7 or G8 and G10. However, allele sharing was confirmed among individuals belonging to different lineages. The allele sharing occurred primarily in regions where different mitochondrial DNA lineages were found in sympatry. The resultant nuclear mitochondrial discordance suggests the genetic exchangeability among E. canadensis isolates belonging to different lineages. An apparently mosaic parasite fauna that reflects faunal mixing due to natural and anthropogenic disturbance, including introductions and invasion, precludes us from designating each of G6/G7, G8 and G10 into a different species. (C) 2017 Australian Society for Parasitology.

The Beringian Coevolution Project (BCP), a field program underway in the high northern latitudes since 1999, has focused on building key scientific infrastructure for integrated specimen-based studies on mammals and their associated parasites. BCP has contributed new insights across temporal and spatial scales into how ancient climate and environmental change have shaped faunas, emphasizing processes of assembly, persistence, and diversification across the vast Beringian region. BCP collections also represent baseline records of biotic diversity from across the northern high latitudes at a time of accelerated environmental change. These specimens and associated data form an unmatched resource for identifying hidden diversity, interpreting past responses to climate oscillations, documenting contemporary conditions, and anticipating outcomes for complex biological systems in a regime of ecological perturbation. Because of its dual focus on hosts and parasites, the BCP record also provides a foundation for comparative analyses that can document the effects of dynamic change on the geographic distribution, transmission dynamics, and emergence of pathogens. By using specific examples from carnivores, eulipotyphlans, lagomorphs, rodents, ungulates, and their associated parasites, we demonstrate how broad, integrated field collections provide permanent infrastructure that informs policy decisions regarding human impact and the effect of climate change on natural populations.

Hookworms belonging to the genus Ancylostoma (Dubini, 1843) cause ancylostomiasis, a disease of considerable concern in humans and domestic and wild animals. Molecular and epidemiological data support evidence for the zoonotic potential among species of Ancylostoma where transmission to humans is facilitated by rapid urbanization and increased human-wildlife interactions. It is important to assess and describe these potential zoonotic parasite species in wildlife, especially in hosts that have physiological similarities to humans and share their habitat. Moreover, defining species diversity within parasite groups that can circulate among free-ranging host species and humans also provides a pathway to understanding the distribution of infection and disease. In this study, we describe a previously unrecognized species of hookworm in the genus Ancylostoma in the giant panda, including criteria for morphological and molecular characterization. The hookworm specimens were obtained from a wild giant panda that died in the Fengtongzai Natural Reserve in Sichuan Province of China in November 2013. They were microscopically examined and then genetically analyzed by sequencing the nuclear internal transcribed spacer (ITS, ITS1-5.8S-ITS2) and mitochondrial cytochrome c oxidase subunit 1 (cox1) genes in two representative specimens (one female and one male, FTZ1 and FTZ2, respectively). Ancylostoma ailuropodae n. sp. is proposed for these hookworms. Morphologically the hookworm specimens differ from other congeneric species primarily based on the structure of the buccal capsule in males and females, characterized by 2 pairs of ventrolateral and 2 pairs of dorsolateral teeth; males differ in the structure and shape of the copulatory bursa, where the dorsal ray possesses 2 digitations. Pairwise nuclear and mitochondrial DNA comparisons, genetic distance analysis, and phylogenetic data strongly indicate that A. ailuropodae from giant pandas is a separate species which shared a most recent common ancestor with A. ceylanicum Looss, 1911 in the genus Ancylostoma (family Ancylostomatidae). Ancylostoma ailuropodae n. sp. is the fourth species of hookworm described from the Ursidae and the fifteenth species assigned to the genus Ancylostoma. A sister-species association with A. ceylanicum and phylogenetic distinctiveness from the monophyletic Uncinaria Frolich, 1789 among ursids and other carnivorans indicate a history of host colonization in the evolutionary radiation among ancylostomatid hookworms. Further, phylogenetic relationships among bears and a history of ecological and geographical isolation for giant pandas may be consistent with two independent events of host colonization in the diversification of Ancylostoma among ursid hosts. A history for host colonization within this assemblage and the relationship for A. ailuropodae n. sp. demonstrate the potential of this species as a zoonotic parasite and as a possible threat to human health. The cumulative morphological, molecular and phylogenetic data presented for A. ailuropodae n. sp. provides a better understanding of the taxonomy, diagnostics and evolutionary biology of the hookworms.

Climate oscillations and episodic processes interact with evolution, ecology and biogeography to determine the structure and complex mosaic that is the biosphere. Parasites and parasite–host assemblages are key components in a general explanatory paradigm for global biodiversity. We explore faunal assembly in the context of Quaternary time frames of the past 2.6 million years, a period dominated by episodic shifts in climate. Climate drivers cross a continuum from geological to contemporary timescales and serve to determine the structure and distribution of complex biotas. Cycles within cycles are apparent, with drivers that are layered, multifactorial and complex. These cycles influence the dynamics and duration of shifts in environmental structure on varying temporal and spatial scales. An understanding of the dynamics of high-latitude systems, the history of the Beringian nexus (the intermittent land connection linking Eurasia and North America) and downstream patterns of diversity depend on teasing apart the complexity of biotic assembly and persistence. Although climate oscillations have dominated the Quaternary, contemporary dynamics are driven by tipping points and shifting balances emerging from anthropogenic forces that are disrupting ecological structure. Climate change driven by anthropogenic forcing has supplanted a history of episodic variation and is eliminating ecological barriers and constraints on development and distribution for pathogen transmission. A framework to explore interactions of episodic processes on faunal structure and assembly is the Stockholm Paradigm, which appropriately shifts the focus from cospeciation to complexity and contingency in explanations of diversity.

Accurate measures of nematode fecundity can provide important information for investigating parasite life history evolution, transmission potential, and effects on host health. Understanding differences among fecundity assessment protocols and standardizing methods, where possible, will enable comparisons across different studies and host and parasite species and systems. Using the trichostrongyle nematode Cooperia fuelleborni isolated from wild African buffalo (Syncerus caffer), we compared egg recovery and enumeration between two methods for measuring the fecundity of female worms. The first method, in utero egg count, involves visual enumeration of the eggs via microscopic inspection of the uterine system. The second method, ex utero egg count, involves dissolving the same specimens from above in a sodium chloride solution to release the eggs from the female's uterus, then enumeration under an inverted microscope. On average, the ex utero method resulted in 34% more eggs than the in utero method. However, results indicate that the two methods used to quantify parasitic nematode fecundity are highly correlated. Thus, while both methods are viable options for estimating relative nematode fecundity, we recommend caution in undertaking comparative studies that utilize egg count data collected using different methods. National Science Foundation Ecology of Infectious Diseases Grant [DEB-1102493, EF-0723928]; Georgia Museum of Natural History's Joshua Laerm Academic Support Award for Undergraduate Research; NSFNational Science Foundation (NSF) [DEB-1102493]; NSF Population of Infectious Diseases REU Program at the University of Georgia [DBI-1156707] Many thanks to South Africa National Parks Veterinary Services for assistance with the animal capture operations. We thank R. Spaan, J. Spaan, A. Majewska, J. Alagappan, C. Becker, B. Beechler, E. Belinfante, E. Gorsich, C. Gondhalekar, C. Hebbale, T. Lavelle, L. Leathers, L. Megow, T. Mowla, A. Petrelli, K. Raum, N. Rogers, K. Sakamoto, P. Snyder, and M. Smith for invaluable assistance in the field and in the lab. All animal protocols were approved by the UGA Institutional Animal Care and Use Committee (AUP#: A2013 08-017-Y1-A0; AUP#: A2010 10-190-Y3-A5). This work was funded by the National Science Foundation Ecology of Infectious Diseases Grant to VOE and AEJ (DEB-1102493, EF-0723928). LVA was supported by a Georgia Museum of Natural History's Joshua Laerm Academic Support Award for Undergraduate Research and an NSF REU supplement to DEB-1102493; JR was supported by the NSF Population of Infectious Diseases REU Program at the University of Georgia (DBI-1156707). Public domain – authored by a U.S. government employee

Background Although trichinellosis is known to cause thrombotic disease, serious thrombotic events are rare and have not been previously associated with Trichinella nativa infection. Methods Patient interviews and medical chart reviews were conducted on 10 men who became ill following consumption of a common source of black bear meat. Trichinella serology on patient sera as well as polymerase chain reaction (PCR) and larval identification of the meat samples was conducted. Results All 10 exposed individuals developed an acute illness clinically compatible with trichinellosis, characterized by fever, abdominal pain, and diarrhea, along with eosinophilia ranging from 0.9 × 109/L to 6.1 × 109/L. Within 2 weeks of the diarrheal illness, systemic symptoms developed in all exposed individuals characterized by fever, myalgia, periorbital edema, and fatigue. ST-elevation myocardial infarction and sinus venous tract thrombosis occurred as a complication of trichinellosis in 2 patients. Acute serology was nonreactive in all patients, though convalescent serology was reactive in 6 of 8 (75%) patients for whom sera was available. Multiplex PCR identified T. nativa from the bear meat, and was corroborated by microscopic larval identification. Conclusions We report a 100% attack rate of T. nativa from bear meat among those who were exposed, and demonstrate that this species can cause serious thrombotic complications of trichinellosis in humans. Education of hunters and the public regarding the importance of proper preparation of wild game prior to ingestion is warranted.

Varestrongylus eleguneniensis (Nematoda; Protostrongylidae) is a recently described species of lungworm that infects caribou (Rangifer tarandus), muskoxen (Ovibos moschatus) and moose (Alces americanus) across northern North America. Herein we explore the geographic distribution of V. eleguneniensis through geographically extensive sampling and discuss the biogeography of this multi-host parasite. We analyzed fecal samples of three caribou subspecies (n = 1485), two muskox subspecies (n = 159), and two moose subspecies (n = 264) from across northern North America. Protostrongylid dorsal-spined larvae (DSL) were found in 23.8%, 73.6%, and 4.2% of these ungulates, respectively. A portion of recovered DSL were identified by genetic analyses of the ITS-2 region of the nuclear rDNA or the cytochrome oxidase c subunit I (COI) region of the mtDNA. We found V. eleguneniensis widely distributed among caribou and muskox populations across most of their geographic prange in North America but it was rare in moose. Parelaphostrongylus andersoni was present in caribou and moose and we provide new geographic records for this species. This study provides a substantial expansion of the knowledge defining the current distribution and biogeography of protostrongylid nematodes in northern ungulates. Insights about the host and geographic range of V. eleguneniensis can serve as a geographically extensive baseline for monitoring current distribution and in anticipating future biogeographic scenarios under a regime of accelerating climate and anthropogenic perturbation., Graphical abstract Image 1, Highlights • Varestrongylus eleguneniensis is a lungworm whose primary host is the caribou. • The muscleworm, Parelaphostrongylus andersoni, co-infects caribou across its range. • We expand the knowledge on distribution of the caribou lungworm and the muscleworm. • Muskoxen sympatric with caribou are infected with the caribou lungworm. • We discuss the biogeography of V. eleguneniensis and Rangifer across North America.

Gastrointestinal nematode (GIN) infections in cattle cause appetite suppression which leads to poor feed conversion, reduced weight gain and reduced milk production. Overuse and exclusive reliance on anthelmintic drugs has resulted in widespread resistance in many parasitic nematode species infecting livestock making control increasingly difficult. Wild ruminants are competent hosts of a number of nematode species that typically infect and are best adapted for cattle, sheep, and goats. Thus, the potential exists for wild ruminants to act as reservoirs in the translocation of domestic GIN, including those carrying anthelmintic resistance mutations as well as susceptible genotypes. The potential for parasite exchange is heightened by interfaces or ecotones between managed and wild rangelands, and by perturbations linked to climate warming that can increasingly alter the distributions of wild ungulates and their interactions with domestic and free-ranging ruminants. To investigate the extent to which wild ruminants harbour parasites capable of infecting domestic ruminants we first performed an epidemiological study of feces from wildlife hosts that spanned 16 states and included white-tailed deer (85 % of the samples), pronghorn, elk, mule deer, bighorn sheep, moose, cattle, and caribou across the United States. All samples were cultured to third stage larvae and nematode DNA was isolated and PCR amplified. Among the 548 wild ruminant samples received, 33 % (181 samples) were positive for nematode DNA, among which half (84 samples) contained DNA from GIN species commonly found in cattle. DNA from cattle GIN species was detected in 46 % of samples from the Northeast, 42 % from the Southeast, 10 % from the Midwest, 0 % from the Southwest and 11 % from the West. Deep amplicon sequencing of the ITS-2 rDNA indicated that Ostertagia and Trichostrongylus were present in 90 % and 69 % of the nematode DNA positive samples, respectively, whereas Haemonchus, Cooperia and Oesophagostomum were present in 26 %, 2 % and 10 % of the samples, respectively. These data clearly show that wild ruminants commonly harbour multiple parasite species whose primary hosts are domestic cattle, and suggest that further work is warranted to investigate their specific roles in the management of anthelmintic resistance.

Understanding parasite diversity and distribution is essential in managing the potential impact of parasitic diseases in animals and people. Imperfect diagnostic methods, however, may conceal cryptic species. Here, we report the discovery and phylogeography of a previously unrecognized species of Trichinella in wolverine (Gulo gulo) from northwestern Canada that was indistinguishable from T. nativa using the standard multiplex PCR assay based on the expansion segment 5 (ESV) of ribosomal DNA. The novel genotype, designated as T13, was discovered when sequencing the mitochondrial genome. Phylogenetic analyses of the mitochondrial genome and of 15 concatenated single copy orthologs of nuclear DNA indicated a common ancestor for the encapsulated clade is shared by a subclade containing Trichinella spiralis and Trichinella nelsoni, and a subclade containing T13 and remaining taxa: T12 + (T2 + T6) + [(T5 + T9) + (T3 + T8)]. Of 95 individual hosts from 12 species of mammalian carnivores from northwestern Canada from which larvae were identified as T. nativa on multiplex PCR, only wolverines were infected with T13 (14 of 42 individuals). These infections were single or mixed with T. nativa and/or T6. Visual examination and motility testing confirmed that T13 is encapsulated and likely freeze-tolerant. We developed a new Polymerase Chain Reaction-Restriction Fragment Length Polymorphism which unequivocally distinguishes between T13 and T. nativa. We propose Trichinella chanchalensis n. sp. for T13, based on significant genetic divergence from other species of Trichinella and broad-based sampling of the Trichinella genome. Exploration of Alaskan and Siberian isolates may contribute to further resolution of a phylogeographically complex history for species of Trichinella across Beringia, including Trichinella chanchalensis n. sp. (T13).

In PNAS, Jones et al. (1) provide an expert history of human–plague interactions across central Asia, and we support their thesis that zoonotic systems are best regulated using “control” rather than “eradication” strategies. Nonetheless, a control strategy is incomplete if it fails to acknowledge the critical role that modern biospecimen infrastructure plays in revealing historic and ongoing oscillations of host–pathogen systems. Recent environmental changes unique to central Asia (2), coupled with intensification of cultural and economic exchange in the region (i.e., China’s Belt and Road Initiative; ref. 3) demand approaches to pathogen control that are informed by the historic and … [↵][1]1To whom correspondence may be addressed. Email: bryansmclean{at}gmail.com. [1]: #xref-corresp-1-1