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United States Department of Agriculture

Agricultural Research Service

2008 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 muscle worms 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 (2200 lots of specimens) and loans in the international community (1200 lots). 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. This projects relates to National Program 103, Component VII Countermeasures to Prevent and Control Parasitic Diseases.

1. Characterized and named a new genus and species of medium stomach worms 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 diagnosed and new genus and described a new species of previously medium stomach worms in African Buffalo and provided a comprehensive review of generic and species diversity for the African fauna. These observations substantially change our knowledge of diversity for the medium stomach worms, and further identifies Africa as a significant center for unique genera and species in the global fauna. 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. This accomplishment aligns with National Program NP 103 (Animal Health), focusing on priorities established in the Animal Health Action Plan: Component 1 Biodefense Research- (a) Emerging diseases, and Component VII Countermeasures to Prevent and Control Parasitic Diseases- (a) Drug resistant gastrointestinal parasitic diseases.

2. Developed models to describe and predict responses by pathogens of ungulates to climate change and environmental perturbation in North America. Nematode pathogens in ruminants represent a mosaic fauna of multiple origins (endemic versus introduced) in North America. Evolutionary history for different components of this fauna, derived from detailed studies of systematics, lead to predictions for how parasites will respond in a regime of climate change. Haemonchine and Cooperiine nematodes evolved in African ungulates, have been introduced to North America and are currently constrained in their distributions by temperature and humidity. Shifting isotherms (warming temperatures) and increased precipitation associated with global climate change are predicted to promote rapid northward expansion with new geographic and host distributions for populations of these livestock parasites. Emergent disease can result from a new ecological context for these and other host-parasite assemblages as a consequence of climate change, exacerbated by developing and broadened resistance to most classes of anthelmintics among these nematodes. Our research responds to the urgency to document and understand the health, agricultural, societal and economic impact of pathogens and emerging infectious diseases in a regime of climate change and ecological perturbation. This accomplishment aligns with National Program NP 103 (Animal Health), focusing on priorities established in the Animal Health Action Plan: Component 1 Biodefense Research- (a) Emerging diseases, and Component VII Countermeasures to Prevent and Control Parasitic Diseases- (a) Drug resistant gastrointestinal parasitic diseases.

5.Significant Activities that Support Special Target Populations

6.Technology Transfer

Number of Non-Peer Reviewed Presentations and Proceedings4

Review Publications
Koehler, A.A., Hoberg, E.P., Dokuchaev, N.E., Cook, J.A. 2007. Geographic and host range of the nematode Soboliphyme baturini across Beringia. Journal of Parasitology. 93:1070-1083.

Brooks, D., Hoberg, E.P. 2007. How will global climate change affect parasites? Trends in Parasitology. 23: 571-574.

Brooks, D.R., Hoberg, E.P. 2008. Darwin's Necessary Misfit and the Sloshing Bucket: The Evolutionary Biology of Emerging Infectious Diseases. Outreach and Education in Evolution. 1:2-9.

Hoberg, E.P., Abrams, A., Ezenwa, V.O. 2008. An exploration of diversity among the Ostertagiinae: Africanastrongylus buceros GEN. NOV. ET SP. NOV. (Nematoda: Trichostrongyloidea) in African Buffalo (Syncerus caffer). Journal of Parasitology. 94:230-251.

Muzaffar, S.B., Hoberg, E.P., Jones, I.A. 2007. First record of Alcataenia larina larina (Cestoda: Dilepididae) in Atlantic Puffins (Aves, Alcidae, Fratercula arctica) from Newfoundland, Canada. Comparative Parasitology. 74:380-382.

Hoberg, E.P., Abrams, A. 2007. Emended description and redetermination of Sarwaria caballeroi n. comb. (Nematoda: Ostertaginae) with Details of the Synlophe and Esophageal Characters. Journal of Parasitology. 93:1140-1150.

Asmundsson, I.M., Mortenson, J.A., Hoberg, E.P. 2008. Muscleworms, Parelaphostrongylus andersoni (Nematoda: Protostrongylidae), discovered in Columbia white-tailed deer from Oregon and Washington: Implications for biogeography and host associations. Journal of Wildlife Diseases. 44: 16-27.

Hoberg, E.P., Polley, L., Jenkins, E.J., Kutz, S.J., Veitch, A., Elkin, B. 2008. Integrated Approaches and Empirical Models for Investigation of Parasitic Disease in Northern Wildlife. Emerging Infectious Diseases. 14:10-17.

Last Modified: 4/16/2014
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