Emerging Parasitic Infections in Arctic Ungulates (original) (raw)
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Advances in parasitology, 2012
Parasites play an important role in the structure and function of arctic ecosystems, systems that are currently experiencing an unprecedented rate of change due to various anthropogenic perturbations, including climate change. Ungulates such as muskoxen, caribou, moose and Dall's sheep are also important components of northern ecosystems and are a source of food and income, as well as a focus for maintenance of cultural traditions, for northerners. Parasites of ungulates can influence host health, population dynamics and the quality, quantity and safety of meat and other products of animal origin consumed by people. In this article, we provide a contemporary view of the diversity of nematode, cestode, trematode, protozoan and arthropod parasites of ungulates in arctic and subarctic North America and Greenland. We explore the intricate associations among host and parasite assemblages and identify key issues and gaps in knowledge that emerge in a regime of accelerating environment...
Global warming is changing the dynamics of Arctic host–parasite systems
Proceedings of The Royal Society B: Biological Sciences, 2005
Global climate change is altering the ecology of infectious agents and driving the emergence of disease in people, domestic animals, and wildlife. We present a novel, empirically based, predictive model for the impact of climate warming on development rates and availability of an important parasitic nematode of muskoxen in the Canadian Arctic, a region that is particularly vulnerable to climate
Climate change and Arctic parasites
Trends in Parasitology, 2015
Climate is changing rapidly in the Arctic. This has important implications for parasites of Arctic ungulates, and hence for the welfare of Arctic peoples who depend on caribou, reindeer, and muskoxen for food, income, and a focus for cultural activities. In this Opinion article we briefly review recent work on the development of predictive models for the impacts of climate change on helminth parasites and other pathogens of Arctic wildlife, in the hope that such models may eventually allow proactive mitigation and conservation strategies. We describe models that have been developed using the metabolic theory of ecology. The main strength of these models is that they can be easily parameterized using basic information about the physical size of the parasite. Initial results suggest they provide important new insights that are likely to generalize to a range of host-parasite systems. A new need for understanding the relationship between weather and disease transmission A principle motivation of this article is to encourage more ecologists to come and work in the Arctic [1] because the region is in many ways the definitive environment in which to study the impacts of climate change: Arctic animal communities are relatively simple compared to temperate, Mediterranean, or tropical systems, and the rates of climate change are significantly faster. Although the weather is extreme, it exhibits substantial annual variation, and this allows models of host-parasite systems to be parameterized and tested across a wide range of natural temperature and humidity gradients. The work has important implications for conservation of Arctic ungulates and their parasites, and hence for the welfare of Arctic peoples who depend on caribou, reindeer, and muskoxen for food, income, and a focus for cultural activities [2-4]. We recognize this article focuses significantly on our own research rather than providing a balanced review of this topic, but this is very much an epiphenomenon of the small number of people working on host-parasite problems in the Arctic. Using weather to predict worm and vector borne disease outbreaks has a long history in domestic animal parasitology [5,6], but these studies were essentially curtailed when cheap drugs with limited side-effects made it less essential to accurately predict the timing of treatment of domestic livestock with helminth infections [7,8]. More recently, a need for a better understanding of how climate modifies transmission dynamics has resurfaced again for three reasons: (i) climate change is already beginning to alter host-parasite systems around the globe; (ii) climate change is progressing much more rapidly than was initially predicted, necessitating a need to implement mitigation strategies sooner rather than later [1]; and (iii) drug resistance has considerably reduced the efficacy of anti-parasitic drugs, resulting in a need to be much more efficient in how and when we target their use against parasites [9,10]. Comprehending the influence of climate change on disease outbreaks generally requires an understanding of how climate variability modifies the various mechanisms that determine the transmission dynamics of parasites. In general, climate change can impact disease transmission in four different ways [11]: (i) by directly affecting the rates of development, mortality, and reproduction in free-living parasites and parasites within ectothermic intermediate hosts; (ii) by affecting the development, mortality, and reproduction of vectors and intermediate hosts; (iii) by inducing behavioral changes in hosts, vectors and/or parasites that modify contact, and thus, transmission rates; and (iv) by changing host susceptibility, for example, through changes in host physiology, host stress, or host immunity. If we are to make accurate predictions of either the seasonal response of parasite dynamics to climate variation, or of changes in the overall distribution, structure, and dynamics of host-parasite systems in response to broad-scale inter-annual climatic trends, then we need to quantify each of these processes for a large variety of systems. This is a Herculean task! Are there any shortcuts? Recent work suggests that we might be able to use metabolic scaling rules to parameterize host-parasite models if we simply have information on host and parasite body size
A walk on the tundra: Host-parasite interactions in an extreme environment
International journal for parasitology. Parasites and wildlife, 2014
Climate change is occurring very rapidly in the Arctic, and the processes that have taken millions of years to evolve in this very extreme environment are now changing on timescales as short as decades. These changes are dramatic, subtle and non-linear. In this article, we discuss the evolving insights into host-parasite interactions for wild ungulate species, specifically, muskoxen and caribou, in the North American Arctic. These interactions occur in an environment that is characterized by extremes in temperature, high seasonality, and low host species abundance and diversity. We believe that lessons learned in this system can guide wildlife management and conservation throughout the Arctic, and can also be generalized to more broadly understand host-parasite interactions elsewhere. We specifically examine the impacts of climate change on host-parasite interactions and focus on: (I) the direct temperature effects on parasites; (II) the importance of considering the intricacies of ...
Arctic parasitology: why should we care?
Trends in Parasitology, 2011
The significant impact on human and animal health from parasitic infections in tropical regions is well known, but parasites of medical and veterinary importance are also found in the Arctic. Subsistence hunting and inadequate food inspection can expose people of the Arctic to foodborne parasites. Parasitic infections can influence the health of wildlife populations and thereby food security. The low ecological diversity that characterizes the Arctic imparts vulnerability. In addition, parasitic invasions and altered transmission of endemic parasites are evident and anticipated to continue under current climate changes, manifesting as pathogen range expansion, host switching, and/or disease emergence or reduction. However, Arctic ecosystems can provide useful models for understanding climate-induced shifts in host-parasite ecology in other regions.
Invasion, establishment, and range expansion of two parasitic nematodes in the Canadian Arctic
Global change biology, 2013
Climate warming is occurring at an unprecedented rate in the Arctic and is having profound effects on host-parasite interactions, including range expansion. Recently, two species of protostrongylid nematodes have emerged for the first time in muskoxen and caribou on Victoria Island in the western Canadian Arctic Archipelago. Umingmakstrongylus pallikuukensis, the muskox lungworm, was detected for the first time in 2008 in muskoxen at a community hunt on the southwest corner of the island and by 2012, it was found several hundred kilometers east in commercially harvested muskoxen near the town of Ikaluktutiak. In 2010, Varestrongylus sp., a recently discovered lungworm of caribou and muskoxen was found in muskoxen near Ikaluktutiak and has been found annually in this area since then. Whereas invasion of the island by U. pallikuukensis appears to have been mediated by stochastic movement of muskoxen from the mainland to the southwest corner of the island, Varestrongylus has likely bee...
Polar Biology, 2018
Documenting how climate change will affect Arctic ecosystems and food web dynamics requires an understanding of current sources of variation in species distributions, frequency, and abundance. Host-parasite interactions are expected to be altered in the coming decades under warming conditions. However, in many Polar Regions, there is little information describing parasite-host assemblages. We examine how gastrointestinal helminths of northern common eider ducks (Somateria mollissima sedentaria) in the low Arctic vary with host age, sex and sampling year. We found that the prevalence of an acanthocephalan (Profilicollus sp.) varied in eiders with age, sex and year, while a cestode (Microsomacanthus sp.) varied with host sex. Two other species of endohelminths (Lateriporus sp., Corysonoma sp.) were not found to vary with sex, age or sampling year, and another species (Microphallus sp.) did not vary with sex or age. Our results highlight the complexity inherent in Arctic host-parasite assemblages, and the need for more detailed studies to better understand how changing climatic conditions may affect species distributions, frequency or abundance.
International Journal for Parasitology, 2012
Parasitic nematodes are found in almost all wild vertebrate populations but few studies have investigated these host-parasite relationships in the wild. For parasites with free-living stages, the external environment has a major influence on life-history traits, and development and survival is generally low at subzero temperatures. For reindeer that inhabit the high Arctic archipelago of Svalbard, parasite transmission is expected to occur in the summer, due to the extreme environmental conditions and the reduced food intake by the host in winter. Here we show experimentally that, contrary to most parasitic nematodes, Marshallagia marshalli of Svalbard reindeer is transmitted during the Arctic winter. Winter transmission was demonstrated by removing parasites in the autumn, using a novel delayed-release anthelmintic bolus, and estimating re-infection rates in reindeer sampled in October, February and April. Larval stages of nematodes were identified using molecular tools, whereas adult stages were identified using microscopy. The abundance of M. marshalli adult worms and L4s increased significantly from October to April, indicating that reindeer were being infected with L3s from the pasture throughout the winter. To our knowledge, this study is the first to experimentally demonstrate over-winter transmission of a gastro-intestinal nematode parasite in a wild animal. Potential mechanisms associated with this unusual transmission strategy are discussed in light of our knowledge of the life-history traits of this parasite.