Digital Commons Network^™

Comparative Demography And Dietary Resource Partitioning Of Two Wild Ranging Asiatic Equid Populations, Ellen Schulz, Thomas Kaiser, Annegret Stubbe, Michael Stubbe, Ravčigijn Samjaa, Nyamsuren Batsaikhan, Joachim Wussow

Erforschung biologischer Ressourcen der Mongolei / Exploration into the Biological Resources of Mongolia, ISSN 0440-1298

Tooth wear signatures allow inference on the dietary traits of herbivorous ungulates. Comparing dietary regimes of taxonomically closely related populations further allows inference on habitat structure and food availability. The mesowear method of tooth wear evaluation has opened up a pathway to reconstruct subtle differences in dietary behavior and resource partitioning based on skeletal material as the only source of information. Eighty cheek dentitions of Asian wild asses (Equus hemionus) from the Southern Gobi (Mongolia) and 61 dentitions of African free ranging donkeys (Equus asinus) from the Emirate Sharjah (United Arab Emirates) were investigated for their …

Administering The Clean Water Act: Do Regulators Have "Bigger Fish To Fry" When It Comes To Addressing The Practice Of Chumming On The Chesapeake Bay?, Hope M. Babcock

Georgetown Law Faculty Publications and Other Works

The Chesapeake Bay is one of the country's most productive estuaries. However, for decades the health of the Bay has been declining due in large part to nutrification. Excessive nutrients encourage algal blooms, which lower dissolved oxygen and increase turbidity in the Bay's waters. More than 40% of the Bay's main stern is now dead largely as a result of this problem. The practice of chumming, the discarding of baitfish, usually menhaden, over the sides of fishing boats to attract game fish like striped bass, is contributing to the Bay's nutrification problem because the decomposing chum raises the waters biological …

Eastward Ho: Phylogeographical Perspectives On Colonization Of Hosts And Parasites Across The Beringian Nexus [Guest Editorial], Eric Waltari, Eric P. Hoberg, Enrique P. Lessa, Joseph A. Cook

Harold W. Manter Laboratory of Parasitology: Faculty Publications

The response of Arctic organisms and their parasites to dramatic fluctuations in climate during the Pleistocene has direct implications for predicting the impact of current climate change in the North. An increasing number of phylogeographical studies in the Arctic have laid a framework for testing hypotheses concerning the impact of shifting environmental conditions on transcontinental movement. We review 35 phylogeographical studies of trans-Beringian terrestrial and freshwater taxa, both hosts and parasites, to identify generalized patterns regarding the number, direction and timing of trans-continental colonizations. We found that colonization across Beringia was primarily from Asia to North America, with many events …

Chlorophacinone Baiting For Belding’S Ground Squirrels, Craig A. Ramey, George H. Matschke, Richard M. Engeman

United States Department of Agriculture Wildlife Services: Staff Publications

The efficacy of using 0.01% chlorophacinone on steam-rolled oat (SRO) groats applied in CA alfalfa by spot-baiting/hand baiting around burrow entrances (~11.5 g) to control free-ranging Belding's ground squirrels (Spermophilus beldingi) were compared in 6 randomly assigned square treatment units (TUs). Four TUs were given the rodenticide and 2 treated with placebo bait. Each TU was a 0.4 ha square surrounded by a similarly treated 5.5 ha square buffer zone. Baits were applied on May 13 and re-applied, on May 20 and May 22, after 7 days of un-forecasted cool wet weather greatly reduced their above ground activity. Pesticide (EPA …

Parasites, Proteomics And Performance: Effects Of Gregarine Gut Parasites On Dragonfly Flight Muscle Composition And Function, Rudolf J. Schilder, James H. Marden

School of Biological Sciences: Faculty Publications

In previous work, we found that dragonflies infected with gregarine gut parasites have reduced muscle power output, loss of lipid oxidation in their flight muscles, and a suite of symptoms similar to mammalian metabolic syndrome. Here, we test the hypothesis that changes in muscle protein composition underlie the observed changes in contractile performance. We found that gregarine infection was associated with a 10-fold average reduction in abundance of a ~155·kDa fragment of muscle myosin heavy chain (MHC; ~206·kDa intact size). Insect MHC gene sequences contain evolutionarily conserved amino acid motifs predicted for calpain cleavage, and we found that calpain digestion …

Grânulos De Amido E Fitólitos Em Cálculos Dentários Humanos: Contribuição Ao Estudo Do Modo De Vida E Subsistência De Grupos Sambaquianos Do Litoral Sul Do Brasil, Verônica Wesolowski, Sheila Maria Ferraz Mendonça De Souza, Karl Reinhard, Gregório Ceccantini

Karl Reinhard Publications

Este artigo tem por objetivo apresentar os resultados da recuperação e análise de micro-vestígios vegetais retidos em cálculos dentários de grupos de pescadores-coletores do litoral sul do Brasil. Apresenta também os resultados das relações mantidas entre grânulos de amido e cárie, e entre fitólitos e desgaste dentário.

Através da dissolução química de cálculos dentários foram recuperados microvestígios vegetais em todos os indivíduos estudados. Foi evidenciado o consumo de alimentos amiláceos em todas as séries esqueléticas estudadas, demonstrando independência entre dieta com aporte de produtos vegetais e utilização de cerâmica. Foram encontrados resultados sugestivos de padrões de escolha de alimentos diferenciados …

Integration Without Unification: An Argument For Pluralism In The Biological Sciences, Sandra D. Mitchell, Michael R. Dietrich

Dartmouth Scholarship

In this article, we consider the tension between unification and pluralism in biological theory. We begin with a consideration of historical efforts to establish a unified understanding of evolution in the neo‐Darwinian synthesis. The fragmentation of the evolutionary synthesis by molecular evolution suggests the limitations of the general unificationist ideal for biology but not necessarily for integrating explanations. In the second half of this article, we defend a specific variety of pluralism that allows for the integration required for explanations of complex phenomena without unification on a large scale.

A Coprological View Of Ancestral Pueblo Cannibalism, Karl Reinhard

Karl Reinhard Publications

As the object of my scientific study, I’ve chosen coprolites. It’s not a common choice, but to a paleonutritionist and archaeoparasitologist, a coprolite—a sample of ancient feces preserved by mineralization or simple drying—is a scientific bonanza. Analysis of coprolites can shed light on both the nutrition of and parasites found in prehistoric cultures. Dietary reconstructions from the analysis of coprolites can inform us about, for example, the origins of modern Native American diabetes. With regard to parasitology; coprolites hold information about the ancient emergence and spread of human infectious disease. Most sensational, however, is the recent role of coprolite analysis …

Viral Ecology And The Maintenance Of Novel Host Use, John Dennehy, Nicholas Friedenberg, Robert Holt, Paul Turner

Dartmouth Scholarship

Viruses can occasionally emerge by infecting new host species. However, the early phases of emergence can hinge upon ecological sustainability of the virus population, which is a product of both within‐host population growth and between‐host transmission. Insufficient growth or transmission can force virus extinction before the latter phases of emergence, where genetic adaptations that improve host use may occur. We examined the early phase of emergence by studying the population dynamics of RNA phages in replicated laboratory environments containing native and novel host bacteria. To predict the breadth of transmission rates allowing viral persistence on each species, we developed a …

Prevalence And Serovars Of Salmonella In The Feces Of Free-Ranging White-Tailed Deer (Odocoileus Virginianus) In Nebraska, David G. Renter, David P. Gnad, Jan M. Sargeant, Scott E. Hygnstrom

School of Natural Resources: Faculty Publications

To determine the prevalence and serovars of Salmonella in free-ranging deer, we cultured feces from white-tailed deer (Odocoileus virginianus) harvested by hunters during a regular firearm season in southeastern Nebraska (USA). We recovered Salmonella from 5 (1%; 95% confidence interval: 0.37– 2.20%) of 500 samples and identified four different Salmonella enterica serovars [Litchfield (1), Dessau (1), Infantis (2), and Enteritidis (1)]. Although the prevalence of Salmonella in free-ranging deer appears to be low, the serovars recovered are known to be pathogenic to humans and animals.

Proceedings Of The Western Australian Dhufish Workshop 2004, Mark Pagano, Terry Fuller

Fisheries Occasional Publications

The Western Australian Dhufish Workshop 2004 was a joint project between Recfishwest and the Western Australian Department of Fisheries.

The workshop incorporated presentations from the Department of Fisheries, Recfishwest, the Western Australian Fishing Industry Council, Murdoch University and Challenger TAFE to showcase current knowledge relating to the iconic dhufish in Western Australia. The perspectives of a recreational fisher, a commercial wetline operator and a metropolitan charter boat operator were also presented.

Through information sharing and discussion the workshop provided a platform to better understand the fundamental issues that underpin current and future management arrangements for this valuable resource. Both commercial …

Parelaphostrongylus Odocoilei In Columbia Black-Tailed Deer From Oregon, Jack A. Mortenson, Arthur Abrams, Benjamin M. Rosenthal, Detiger Dunams, Eric P. Hoberg, Robert J. Bildfell, Richard L. Green

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Documenting the occurrence of Parelaphostrongylus odocoilei has historically relied on the morphological examination of adult worms collected from the skeletal muscle of definitive hosts, including deer. Recent advances in the knowledge of protostrongylid genetic sequences now permit larvae to be identified. Dorsal-spined larvae (DSLs) collected in 2003–2004 from the lung and feces of six Columbian black-tailed deer (Odocoileus hemionus columbianus) from Oregon were characterized genetically. The sequences from unknown DSLs were compared to those from morphologically validated adults and larvae of P. odocoilei at both the second internal transcribed spacer (ITS-2) of ribosomal DNA and the mitochondrial cytochrome …

Sl1 Rna Gene Recovery From Enterobius Vermicularis Ancient Dna In Pre-Columbian Human Coprolites, Alena M. Iñiguez, Karl Reinhard, Marcelo Luiz Carvalho Gonçalves, Luiz Fernando Ferreira, Adauto Araújo, Ana Carolina Paulo Vincente

Karl Reinhard Publications

Enterobius vermicularis, pinworm, is one of the most common helminths worldwide, infecting nearly a billion people at all socio-economic levels. In prehistoric populations the paleoparasitological findings show a pinworm homogeneous distribution among hunter-gatherers in North America, intensified with the advent of agriculture. This same increase also occurred in the transition from nomad hunter-gatherers to sedentary farmers in South America, although E. vermicularis infection encompasses only the ancient Andean peoples, with no record among the pre-Colombian populations in the South American lowlands. However, the outline of pinworm paleo epidemiology has been supported by microscopic finding of eggs recovered from coprolites. …

The Amphibian Tree Of Life, Darrel R. Frost, Taran Grant, Julián Faivovich, Raoul H. Bain, Alexander Haas, Célio F.B. Haddad, Rafael O. De Sá

Biology Faculty Publications

The evidentiary basis of the currently accepted classification of living amphibians is discussed and shown not to warrant the degree of authority conferred on it by use and tradition. A new taxonomy of living amphibians is proposed to correct the deficiencies of the old one. This new taxonomy is based on the largest phylogenetic analysis of living Amphibia so far accomplished. We combined the comparative anatomical character evidence of Haas (2003) with DNA sequences from the mitochondrial transcription unit H1 (12S and 16S ribosomal RNA and tRNAValine genes, ø 2,400 bp of mitochondrial sequences) and the nuclear genes histone H3, …

Comparing Immune Responses Of Juvenile And Adult Northern Fence Lizards, Sceloporus Undulatus, Zaïna Sandrine Kabange

All-Inclusive List of Electronic Theses and Dissertations

Sex steroid hormones affect behavior and morphological traits important in sexual selection. Steroid hormones also play a role in the development and functioning of immune system components. The immunocompetence handicap hypothesis (Folstad and Karter, 1992) proposes that tradeoffs, mediated by plasma levels of testosterone, exist between the immune system and elaboration of secondary sexual traits. Endocrine-immune interactions are well documented in birds and mammals, and steroid hormones can be immunoenhancing or immunosuppressive. Relatively little work has examined the ontogeny of immune function, and the interactions between steroid hormones and the immune system in reptiles. The first experiment addressed the question …

Electrocution Of An Adult White-Tailed Deer, Christopher S. Deperno, Benjamin J. Bigalke, Jonathan A. Jenks, Brian S. Haroldson, Robert G. Osborn

The Prairie Naturalist

On 16 May 2002, an adult female white-tailed deer (Odocoileus virginianus) died after becoming entangled in an electric fence in southeast Minnesota. The deer (#393) was captured 30 January 2000 as part of a cooperative, long-term deer mortality study being conducted in southern Minnesota (Bigalke et al. 2002, Brinkman 2003, Brinkman et al. 2002). Although fence entanglements occur, they do not account for significant losses in white-tailed deer populations (Matschke et al. 1984). Nixon et al. (1991) documented mortality of two fawns with broken cervical vertebrae that had collided with fences, but did not distinguish the type of …

A Monkey’S Tale: The Origin Of Plasmodium Vivax As A Human Malaria Parasite, Ananias A. Escalante, Omar E. Cornejo, Denise E. Freeland, Amanda C. Poe, Ester Durrego, William E. Collins, Altaf A. Lal

Harold W. Manter Laboratory of Parasitology: Library Materials

The high prevalence of Duffy negativity (lack of the Duffy blood group antigen) among human populations in sub-Saharan Africa has been used to argue that Plasmodium vivax originated on that continent. Here, we investigate the phylogenetic relationships among 10 species of Plasmodium that infect primates by using three genes, two nuclear (β-tubulin and cell division cycle 2) and a gene from the plastid genome (the elongation factor Tu). We find compelling evidence that P. vivax is derived from a species that inhabited macaques in Southeast Asia. Specifically, those phylogenies that include P. vivax as an ancient lineage from …

Feral Cats: An Overview, Margaret R. Slater, Stephanie Shain

State of the Animals 2005

Humans and cats have a long and complex history together. Since the nineteenth century, contradictory ideas about the need to protect and care for cats have moved us toward a shift in ideas, values, and behaviors to a more benign perception of cats than was generally the case in previous centuries. In some quarters, but not all, even feral cats have begun to be seen as worthy of our study and humane treatment. In many countries, the welfare of all cats has become a focus of public concern, but nowhere is the shift in values reflected more than in the …

Morbidity And Mortality Factors In Pre-Fledged Florida Sandhill Crane (Grus Canadensis Pratensis) Chicks, Robert J. Dusek, Marilyn G. Spalding, Donald J. Forrester, Nicholas Komar, Jonathan F. Day

Proceedings of the North American Crane Workshop

One hundred and fifteen Florida sandhill crane (Grus canadensis pratensis) chicks were captured in Osceola and Lake Counties, Florida in 1998 - 2000 and examined for evidence of disease. Evidence of Eimeria gruis and/or E. reichenowi infection was found in 52% of chicks examined. Ten chicks were positive for antibodies to St. Louis encephalitis virus and 1 of these chicks was also positive for antibodies to eastern equine encephalitis virus. Predation was the most commonly identified cause of mortality. An unidentified microfilaria, and an unknown protozoan were detected in blood smears from crane chicks. A number of other …

Possible Recent Range Expansion Of Alcataenia Longicervica (Eucestoda: Dilepididae) Parasitic In Murres Uria Spp. (Alcidae) Into The North Atlantic [Short Communications], Sabir B. Muzaffar, Eric P. Hoberg, Ian L. Jones

Harold W. Manter Laboratory of Parasitology: Faculty Publications

A wide range of helminths has been recorded from murres Uria spp. (Threlfall 1971, reviewed by Hoberg 1984a, Muzaffar & Jones 2004). Of the cyclophyllidean cestodes that parasitize murres, the genus Alcataenia Spasskaya 1971 (Dilepididae) is represented by ten species, eight of which are restricted and specific to the auks; the other two species occur in gulls (Laridae). The intermediate hosts of Alcataenia are euphausiid crustaceans such as species of Thysanoessa (Shimazu 1975), which also form an important dietary component of breeding and wintering murres, particularly Thick-billed Murres Uria lomvia (Gaston & Noble 1985, Birkhead & Nettleship 1987, Elliot et …

Caudal Polymorphism And Cephalic Morphology Among First-Stage Larvae Of Parelaphostrongylus Odocoilei (Protostrongylidae: Elaphostrongylinae) In Dall’S Sheep From The Mackenzie Mountains, Canada, Eric P. Hoberg, Emily J. Jenkins, Benjamin Rosenthal, Mayee Wong, Eric F. Erbe, Susan J. Kutz, Lydden Polley

Harold W. Manter Laboratory of Parasitology: Faculty Publications

We demonstrate polymorphism in the structure of the tail among first-stage larvae of Parelaphostrongylus odocoilei (Protostrongylidae). Two distinct larvae, both with a characteristic dorsal spine, include (1) a morphotype with a kinked conical tail marked by three distinct transverse folds or joints and a symmetrical terminal tail spike and (2) a morphotype with a digitate terminal region lacking folds or joints and with an asymmetrical, subterminal tail spike. These divergent larval forms had been postulated as perhaps representing distinct species of elaphostrongyline nematodes. Application of a multilocus approach using ITS-2 sequences from the nuclear genome and COX-II sequences from the …

The Ecology And Relationships Of Chiropteran Ectoparasitic Communities Of Indiana, Christopher Michael Ritzi

All-Inclusive List of Electronic Theses and Dissertations

The ectoparasites of bats are an important and largely unstudied area of mammalian ecology. The structure of ectoparasitic communities on bats, and their interactions with their hosts, may help in the understanding of roosting ecology, pa1iurition, and other aspects of host natural history. In this study, a vigorous survey of the ectoparasitic fauna of the bats ofindiana was undertaken, to determine if changes in species composition has occurred over the past 30 years. This survey resulted in the recovery of 51,980 parasites of 13 families from 2,816 host individuals of l O species, documenting 16 new host records and 14 …

Human Health Effects Of A Changing Global Nitrogen Cycle, Alan R. Townsend, Robert W. Howarth, Fakhri A. Bazzaz, Mary S. Booth, Cory C. Cleveland, Sharon K. Collinge, Andrew P. Dobson, Paul R. Epstein, Elisabeth A. Holland, Dennis R. Keeney, Michael A. Mallin, Christine A. Rogers, Peter Wayne, Amir H. Wolfe

Ecosystem and Conservation Sciences Faculty Publications

Changes to the global nitrogen cycle affect human health well beyond the associated benefits of increased food production. Many intensively fertilized crops become animal feed, helping to create disparities in world food distribution and leading to unbalanced diets, even in wealthy nations. Excessive air- and water-borne nitrogen are linked to respiratory ailments, cardiac disease, and several cancers. Ecological feedbacks to excess nitrogen can inhibit crop growth, increase allergenic pollen production, and potentially affect the dynamics of several vector-borne diseases, including West Nile virus, malaria, and cholera. These and other examples suggest that our increasing production and use of fixed nitrogen …

References, L. David Mech, Luigi Boitani

United States Geological Survey, Northern Prairie Wildlife Research Center: Publications

Abrams, P. A. 2000. The evolution of predator-prey interactions. Annu. Rev. Ecol. Syst. 31:79-105.

Abuladze, K. I. 1964. Osnovy Tsestodologii. Vol. IV. Teniatylentochnye gel' minty zhivotnykh i cheloveka i vyzyvaevaniia. Nauka, Moscow. 530 pp.

Achuff, P. L., and R. Petocz. 1988. Preliminary resource inventory of the Arjin Mountains Nature Reserve, Xinjiang, People's Republic of China. World Wide Fund for Nature, Gland, Switzerland. 78 pp.

Ackerman, B. B., F. A. Leban, M. D. Samuel, and E. 0. Garton. 1990. User's manual for program Home Range. 2d ed. Technical Report no. 15. Forestry, Wildlife, and Range Experiment Station, University ofldaho, Moscow.

Acorn, …

Distribution And Prevalence Of Echinococcus Multilocularis In Wild Predators In Nebraska, Kansas, And Wyoming, S. T. Stroandt, D. R. Virchow, M. W. Dryden, Scott E. Hygnstrom, K. R. Kazacos

School of Natural Resources: Faculty Publications

To further determine the distribution and prevalence of Echinococcus multilocularis in the central United States, 245 wild canids (125 red foxes, 120 coyotes) and 33 bobcats were collected from Nebraska, Kansas, and Wyoming and examined for this parasite. Animals examined included 11 red foxes from the western panhandle of Nebraska; 5 red foxes and 30 coyotes from southern Nebraska; 56 red foxes and 1 coyote from northeastern Nebraska; 20 red foxes, 63 coyotes, and 13 bobcats from northern Kansas; 2 red foxes, 26 coyotes, and 20 bobcats from southern Kansas; and 31 red foxes from eastcentral Wyoming. Of these, 27 …

Morphological Variation Of Allocreadium Lobatum (Digenea: Allocreadiidae) In The Creek Chub, Semotilus Atromaculatus (Osteichthyes: Cyprinidae), In Nebraska, Usa, Monte S. Willis

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

Allocreadium lobatum Wallin 1909, a parasite of fresh-water fish, was originally described as having distinct lobate testes, and subsequent descriptions have left this original description unchanged. The present study quantifies the observation of distinctly non-lobate testes that could be categorized as round or asymmetrical in addition to the previously described lobate testes. Six hundred thirty-six A. lobatum were collected from 228 Semotilus atromaculatus over a 9 month period. Overall, 21.3%, 61.6%, and 16% were found to be round, asymmetrical, and lobate testes respectively (N = 1,071). Analysis of testis morphology found the increasing presence of lobate testis as …

Development Of The Muskox Lungworm, Umingmakstrongylus Pallikuukensis (Protostrongylidae), In Gastropods In The Arctic, Susan J. Kutz, Eric P. Hoberg, John Nishi, Lydden Polley

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Development of the muskox protostrongylid lungworm, Umingmakstrongylus pallikuukensis, in its slug intermediate host, Deroceras laeve, was investigated under field conditions in the Arctic. Every two weeks, from 19 June to 28 August 1997, groups of ten experimentally infected slugs were placed in tundra enclosures in a mesic sedge meadow near Kugluktuk, Nunavut, Canada. First-stage larvae (L1) infecting slugs on or before 17 July developed to third-stage larvae (L3) in 4–6 weeks. Intensity of L3 in slugs peaked at 6–8 weeks post infection (PI) and then progressively declined by 10, 12, and 48–50 weeks PI. Abundance of L3 in …

Detection Of Giardia Duodenalis Antigen In Coprolites Using A Commercially Available Enzyme-Linked Immunosorbent Assay, Marcelo Luiz Carvalho Gonçalves, Adauto Araújo, Rosemere Duarte, Joaquim Pereira Da Silva, Karl Reinhard, Françoise Bouchet, Luis Fernando Ferreira

Karl Reinhard Publications

The objective of this experiment was to assess the utility of a commercially available enzyme-linked immunosorbent assay (ELISA) kit for diagnosis of giardiasis in archaeological human remains. The kit, a monoclonal antibody assay, is used to detect the presence of Giardia-specific antigen 65 (GSA65) in human feces. We utilized the assay in ancient fecal material. The material included desiccated feces found in mummies or in archaeological sites, and sediments from latrines. A total of 83 specimens, previously examined microscopically for parasites, were examined. The ELISA detected 3 positive samples, dated to about 1200 AD, 1600 AD, and 1700 AD. …

Multidisciplinary Coprolite Analysis, Karl Reinhard, Dennis R. Danielson, Mark Daniels, Sérgio Augusto De Miranda Chaves

Karl Reinhard Publications

Coprolite analysis, as reviewed by Reinhard and Bryant (1992), contributes unique and detailed information regarding diet and parasitic disease. We present here an analysis of dietary components of coprolites from Bighorn Cave using macroscopic remains, pollen concentrations, and phytoliths. In addition, we analyzed Bighorn Cave coprolites for evidence of parasitic organisms, especially intestinal worms. Such analyses of coprolites have become important methods for reconstructing past dietary and medicinal practices. Pollen concentration and phytolith quantification techniques have recently been developed, but until this report no known attempt has been made to synthesize pollen, macroscopic, and phytolith data from a single coprolite …

Protostrongylus Stilesi (Nematoda: Protostrongylidae): Ecological Isolation And Putative Host-Switching Between Dall’S Sheep And Muskoxen In A Contact Zone, Eric P. Hoberg, Susan J. Kutz, John Nagy, Emily Jenkins, Brett Elkin, Marsha Branigan, Dorothy Cooley

Harold W. Manter Laboratory of Parasitology: Faculty Publications

The occurrence of Protostrongylus stilesi in a population of introduced muskoxen, Ovibos moschatus wardi, on the Arctic Coastal Plain, Yukon Territory (YT) and Northwest Territories (NT), Canada, is consistent with a contemporary colonization event from Dall’s sheep, Ovis dalli dalli, which indicates that host specificity may be ecologically based and contextual for this parasite. Colonization of muskoxen by P. stilesi may be a predictable event in zones of sympatry with Dall’s sheep; exposure to infection may coincide with occupation of winter ranges of Dall’s sheep by muskoxen during the summer season. Disruption of contemporary ecological isolating barriers can …