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United States Department of Agriculture

Agricultural Research Service

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2009 Annual Report

1a. Objectives (from AD-416)
Objective 1: Define higher-level genealogical relationships among strongylate nematodes through analyses of morphological and molecular data as a basis for identification of species and populations of trichostrongyloids and metastrongyloids. Objective 2: Define faunal diversity, exploring history, geography (biogeography), host associations (coevolution) and population genetics (phylogeography) for parasitic nematodes and other helminths in ungulates across North America, Eurasia and globally. Objective 3: Build specimen collections and informatics resources of the U.S. National Parasite Collection.

1b. Approach (from AD-416)
Generality of Phylogenetic Approaches: Comparative phylogenetics is inherently long-term, hierarchical and complex and resides at the core of all approaches outlined in this project (9). Research is largely empirical and hypothesis driven, involving articulation, integration and analyses of comparative morphological and molecular databases. The revolution of phylogenetic systematics has transformed systematic parasitiology and its linkage to animal health, medicine and biodiversity research. Development of phylogenetically informative databases is cumulative, typically involving extensive and detailed description and revision as a first-level process to provide a comparable array of structural, meristic and other characters, and phylogenetically informative sequences from nuclear and mitochondrial loci, across both higher-level and species-level taxa. Hierarchical approaches- e.g., sequential top-down research programs, have proven to be particularly effective beginning with resolution of relationships for higher taxa that form the foundations for eventual elucidation of species-level phylogeny. Robust phylogenies for parasitic groups (the focus of Objective 1) provide the basis for analyses of cospeciation, historical biogeography and phylogeography (the focus of Objective 2) applied to elucidating patterns of host-parasite association, geographic distribution and disease. Phylogenetic studies will address crown clades of nematodes among Strongylida represented by the superfamilies Metastrongyloidea, and Trichostrongyloidea. Investigations will emphasize resolution of relationships at levels extending from putative monophyletic taxa within each major taxon to the level of species and populations as outlined in detail in subsequent sections. Systematic analyses will follow established methodology as exemplified in recent studies. Represented is an integrated program linking research (Objectives 1 & 2) and the U.S. National Parasite Collection (Objective 3). Integration is defined by the following model: (Obj. 1) Specimens with definitive identifications based on morphology from field-based research, including vouchers and type materials, are linked to frozen tissue collections and DNA products as a basis for comprehensive taxonomic revision, description (diagnostic characters), and phylogenetic analyses of specific parasite groups; (Obj. 2) Results of phylogenetic analyses are used as a foundation for historical explorations of biogeography and coevolution and definition of faunal structure over time; and (Obj. 3) Primary specimens, host information, and spatial and temporal data are archived and databased in the USNPC, with results of analyses, diagnostic capacity, images, etc., being integrated in synoptic summaries for parasite and host associations. These archives further summarize the results of phylogenetic, phylogeographic and historical studies.

3. Progress Report
Research activities focused on systematics of the medium stomach worms and protostrongylid lungworms and muscleworms in ruminants using integrated methods combining comparative morphology and molecular analyses of nuclear and mitochondrial DNA. Results were disseminated to user communities through publications in journals, and invited lectures at meetings or in academia. Collections activities for the U.S. National Parasite Collection (USNPC) focused on continuing acquisition of specimens (862 lots of specimens) and loans in the national and international community (342 lots to 40 researchers). Series of photomicrographs were provided to 5 researchers in lieu of international loans of irreplaceable type specimens. Over 400 lots of specimens (396 type and voucher slides; several hundred vials) were rehabilitated or repaired. The USNPC continues as one of the largest specimens-based collection in the world, and as an active and vital cornerstone for parasitological research globally and nationally. Other activities included (1) writing and editing of substantial sections of a white-paper (to be released through the Office of Science Technology Policy) dealing with systematics for the Interagency Taskforce on Invasive Terrestrial Animals and Pathogens (ITAP); and (2) training and mentoring graduate students at Cornell University, the University New Mexico and the University of Calgary, Canada.

4. Accomplishments
1. Developed new diagnostic characters for 2 genera and described a new species of medium stomach worm in ungulates. Medium stomach worms, particularly those referred to the subfamily Ostertagiinae are among the most pathogenic roundworm parasites in ungulates throughout the world. Diversity for the global fauna remains incompletely defined, although the potential for long-range translocation (intercontinental) with introductions of hosts and parasites has been documented. We developed new diagnostic criteria for species of 2 genera (Longistrongylus, Pseudomarshallagia) based on patterns of cuticular ridges on the body surface of adult nematodes and provided a comprehensive review of these characters in the subfamily. Further, using these ridge systems, we described a new and cryptic species of medium stomach worms in ungulates. These observations continue to expand our knowledge about diversity for the medium stomach worms and the morphological attributes which are critical for identification and diagnostics. Survey and inventory in conjunction with detailed systematic and taxonomic analyses serve as baselines for understanding diversity and for documenting the range of species that may be inadvertently introduced and become invasive in North America.

Review Publications
Santin-Duran, M., Alunda, J.M., Hoberg, E.P., De La Fuente, C. 2009. Age distribution and seasonal dynamics of abomasal helminths in wild red deer from central Spain. Journal of Parasitology. 94:1031-1037.

Hoberg, E.P., Abrams, A. 2008. Hamulonema gen. nov. for ostertagia kenyensis and teladorsagia hamata in the ostertagiine fauna (nematoda: trichostrongyloidea) from african ungulates. Journal of Parasitology. 94:866-879.

Hoberg, E.P., Polley, L., Jenkins, E.J., Kutz, S.J. 2008. Pathogens of domestic and free-ranging ungulates: Global climate change in temperate to boreal latitudes across North America. Proceedings of the World Association of Office International Des Epizooties. 27:511-528.

Kutz, S., Schock, D., Brook, R., Hoberg, E.P. 2008. Cimate change and infectious diseases in wildlife. The Wildlife Professional. Fall Issue: 42-46.

Koehler, A., Torres-Perez, F., Hoberg, E.P., Cook, J.A. 2009. Molecular view of the superfamily Dioctophymatoidea (Nematoda). Comparative Parasitology. 76(1):100-104.

Koehler, A.A., Hoberg, E.P., Dokuchaev, N.E., Tranbenkova, N.A., Whitman, J.S., Nagorsen, D.W., Cook, J.A. 2009. Phylogiography of a Holarctic nematode: Soboliphyme baturini among Mustelids: Climate change, episodic colonization and diversification in a complex host-parasite system. Biological Journal of the Linnean Society, London. 97(3):467-708.

Hoberg, E.P., Pilitt, P.A., Galbreath, K.E. 2009. Why Museums Matter: A tale of pinworms (Oxyuroidea: Heteroxynematidae)among pikas (Ochotona princeps and O. collaris) in the American West. Journal of Parasitology. 95:490-501.

Last Modified: 2/23/2016
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