|National Parasite Collection|
Parasite Collections, Systematics and Biodiversity- A Context:
The US National Parasite Collection, A Century of Service:
The Agricultural Research Service of the US Department of Agriculture (USDA) has been the home for mission oriented and problem solving research on parasites and pathogens that directly or indirectly threaten animal health, food safety and the environment. A core facility within the current laboratory structure is the USNPC located at the Henry A. Wallace, Beltsville Agricultural Research Center near Washington, D.C.
Since 1892 the parasitological collections held by the USDA have been the focus for development of knowledge about the distribution of parasites, pathogens and diseases. The evolution of these collections has followed the expansion of research programs targeted to solve a number of emerging problems for agriculture during the last century. Concurrently, what is now the USNPC became the focal point for field and empirically based research emphasizing survey and inventory, systematics, biogeography, and ecology among a diverse assemblage of helminth and protozoan parasites of vertebrates and contributed to experimental studies to address the biology of an array of economically significant parasites. Thus, over the past century, the USNPC has served an essential and dual role for science and society in providing both a foundation of knowledge about the host and geographic distribution of parasites and in contributing to the resolution of a number of real world problems facing the farm and industrial production of food animals, food safety, and protection of the environment.
The USNPC, a national and international resource for systematic, taxonomic, diagnostic ecological and epidemiological research in parasitology has been continuously maintained by the USDA for over 100 years. The USNPC has served as a critical resource for all aspects of parasitology in North America and globally, and provides the foundation for all programs within the ARS and elsewhere that deal with the systematics and taxonomy of agriculturally and economically significant helminthic and protozoan parasites. The scope and depth of the Collection are unparalleled in North America. Current holdings are substantial and the collection is among the largest in the world (in excess of 100,000 lots, and over 20 million individual specimens; 3,000 holotypes, 7,000 type series) and accumulates about 1,000-1500 new lots of specimens annually. A primary role of the USNPC is acquisition, curation, and long-term maintenance of the specimens-based collections; and development and expansion of the collections database as an irreplaceable national archive. The specimen collection is linked to extensive documentation for host occurrence, geographic range, and other core data with which to assess the current and historical distribution of parasites and pathogens with a database accessed via the internet http://www.ars.usda.gov/ba/anri/apdl. . Contact the Curator and Staff of the USNPC at firstname.lastname@example.org.
A uniquely federal role is served as a center for diagnostics, identification and dissemination of information. Parasitologists in the ARS and others working in systematics and in veterinary, medical and wildlife parasitology have access to the necessary specimens and database to conduct studies on the identification, classification and distribution of parasitic helminths and protozoans. The specimens collections, accumulated over 150 years, are an historical baseline and resource for biodiversity research globally. The Collection is the foundation for proactive programs, prediction and prevention with respect to parasites and pathogens that pose risks to the health of animals, humans and the environment. A vision for the USNPC focuses on these issues- Serving society through biodiversity discovery and exploration, systematics, predictive classifications and interactive information systems for parasites that contribute to identification of new and emerging threats to animal health, food safety and the environment.
The USNPC serves a diverse and global constituency providing curation and access to specimens and databases that drive parasitological research. Combined resources of the USNPC its substantial sister-collections, including the Harold W. Manter Laboratory (University of Nebraska State Museum), the US National Tick Collection (Georgia Southern University), the Canadian Museum of Nature and other smaller taxonomically focused institutional facilities form the primary infrastructure for systematics, taxonomy and biodiversity of metazoan and protozoan parasites in North America. In the current environment we have an opportunity to formulate policy and seek synergistic interfaces within this community of systematics collections to further a broad goal of contributing to a comprehensive knowledge of parasite biodiversity at local, regional and global scales.
Collections as Information Systems, the Future of the USNPC:
Components of a parasitological information system should include specimens-based biodiversity inventories, comprehensive species lists, validation of morphological information, summaries of key phylogenetically diagnostic characters, and total evidence systems incorporating morphological, molecular and genomic data. Development of integrated information systems linking parasite, host and geographic (geo-referenced) data and development of applications for geographic information systems (GIS) is another goal. In this context, specimen-based data can serve as historical or temporal baselines and archives for understanding the influence of environmental change or human intervention on the distribution of parasites and pathogens. Interactive information systems linking diagnostic keys with phylogenetic and epidemiological and biological information for access on the WWW are also central to this concept. In essence the logical course for growth and relevancy of parasite collections is in building the infrastructure for biodiversity bioinformatics with museum staff serving as "curators of information" where a series of interrelated data frameworks within and among museums collectively summarize our base of knowledge in a synergistic manner .
Biodiversity informatics represents a essential contribution through formulation of relational databases, and development of interactive information systems that represent the next step in managing and disseminating parasitological data derived from specimens-based collections. At a general level we can formulate and contribute to a new paradigm for parasite collections as information systems where we build a world of distributed databases linking specimens-based collections. Parasites thus become a window on the world revealing facets of biocomplexity, and further, become resources for documenting biodiversity as a general reference system for the dynamics of intricate biological associations.
The Challenge for Parasite Systematics:
Systematists are purveyors of basic information about species and it is the systematics community that collectively creates the foundations for biodiversity informatics. Systematists hold and codify their special knowledge in the form of species names that represent the physical and ecological characteristics of known organisms which are the essential elements of genealogical reference systems. Systematics also is the framework for comparative studies in basic and applied biology. In parasitology, systematics research is the predictive foundation for recognizing emergent and invasive species, documenting patterns of distribution for pathogens and disease, applied epidemiology, and successful intervention either through management or the use of therapeutic approaches. Further, accurate morphological characterization of parasites and phylogenetic frameworks are critical for the reliability of any capabilities for molecular diagnostics and comparative genomics. In a broader context, parasites are critically important as (1.) ecological and trophic indicators; (2.) historical indicators of phylogeny, ecology and biogeography; (3.) contemporary and historical probes for biodiversity research; and (4.) model systems to explore a range of theoretical issues in evolutionary biology, and ecosystem/community structure based on comparative approaches. Simply, in the absence of systematics, parasitology and biological science in general could not proceed.
Biodiversity as a Foundation:
There is nothing more fundamental than a comprehensive understanding of parasite biodiversity, including accurate taxonomy and species identity, evolutionary relationships, geographic distribution and host associations. Parasites satisfy the primary criteria for recognition of priority taxa to be included in survey and inventory. To reiterate these include: (1.) taxa that are intrinsically important to humans; (2.) taxa that are intrinsically important to ecosystems that humans want to preserve; (3.) taxa that provide efficient means of learning something of importance; (4.) taxa that are geographically widespread; and (5.) taxa that provide an opportunity for international networking. Parasites are admirably suited for inclusion in basic survey and inventory of other vertebrate and invertebrate taxa, and collectively provide substantially greater information than that derived from the study of free-living organisms alone, and concurrently continue to have substantial socioeconomic impacts on a global scale.
Incomplete documentation of the biodiversity of the global parasite fauna, from the level of species to populations, continues to hamper the development of relevant control measures, and parasites continue to exert significant repercussions for science and society. Accurate survey and inventory is critical with respect to recognizing the potential emergence of pathogens, and interactions between parasite faunas circulating in domestic and sylvatic hosts, and at the interface of agricultural or managed and wild ecosystems. Globalization of the economy indicates that narrow regional approaches to documentation of diversity for parasites and pathogens are no longer supportable or viable. Translocation and introduction of parasites continue as factors determining the continental and global distribution of pathogens and further emphasize the importance of systematics and taxonomy in providing a predictive framework for identification, documentation, and subsequent surveillance and monitoring. These issues again emphasize the importance of collections which serve as the foundations for inventories of the worlds biota, and reenforce the significance of development of our specimens-based resources as primary information systems for biodiversity.
At a more fundamental level- parasites are the integrative core of biodiversity survey and inventory. Parasites yield insights into the origins and continuity of biotas, and the historical, phylogenetic, ecological and biogeographic and temporal connectivity across and within ecosystems (the linkage of macro and microevolutionary processes, and temporal and geographic scale). Parasites are critical in developing a synoptic understanding of the history and structure of the biosphere. Substantial contributions by parasitological research to biodiversity inventories extend from the accretion of novel information from standard surveys established over the past 200 years, to sophisticated research programs for systematics, ecology, biogeography and evolutionary biology, based on both organismal and molecular approaches.
The U.S. National Parasite Collection (USNPC) provides permanent preservation for type* and voucher specimens of helminths and other parasites of animals for future reference. The collections database is also made available on-line consequently specific data-standards are outlined below for information that should accompany specimens at the time of submission. All donors are notified of the catalogue numbers assigned to the specimens they contribute. Donors are requested to include their full address, phone and fax numbers, and e-mail address.
Scientists are encouraged to deposit their material early enough to receive numbers for inclusion in their manuscripts. It is mandatory that the specimens be received before numbers are assigned to them. All specimens in a type series* must be labeled clearly. Designation of specimens on a slide containing others may be accomplished by drawing a line around the specimen with a diamond pencil on the lower surface of the slide. Ideally, different specimens should be mounted separately. Parasites should be marked for location in histological tissue sections with a diamond pencil or inedible marker.
* See below for description of type specimens.
Additional data: (1) fixatives; (2) stains; (3) clearing and mounting media; (4) identifier of host; (5) if host specimens are deposited, location of host specimen(s), museum collection numbers (for type specimens, symbiotype, museum collection and number); (6) location of additional parasite specimens in other collections (museum and accession numbers); (7) other parasites present, prevalence or intensity; and (8) information on publication and journal. These data should be indicated clearly in a letter included in the package containing the specimens; a copy should be sent also under separate cover, or by e-mail or FAX. LABELS ON SLIDES OR IN BOTTLES ARE NOT ADEQUATE FOR PROVIDING SPECIMEN DATA.
TYPE SPECIMENS AND TYPE SERIES:
Additional information is required for the deposit of specimens for taxonomic purposes. Parasitologists proposing new taxa should be familiar with the 4th Edition of The International Code of Zoological Nomenclature and particularly with the section entitled “Types and the Species Group.” Copies of the code are available from the Treasurer, American Association for Zoological Nomenclature, c/o Department of Vertebrate Zoology, National Museum of Natural History, MRC 159, Smithsonian Institution, Washington, D.C. 20560.
If an author proposes a new species, all the specimens on which it is based, except for ones the author refers to as variants are regarded as the type series. The following names are used in designating specimens in the type series.
Holotype: The single specimen designated as the name-bearing type of a species or subspecies in the original publication, or the single specimen on which a taxon was based when no type was specified.
Paratype: Each specimen in a type series used in the description of a species other than the holotype. Scientists are encouraged to designate and deposit paratypes. These are utilized for study whenever possible in place of a holotype to avoid unnecessary handling and possible damage to holotype.
Allotype: A paratype specimen of the opposite sex from the holotype in parasites in which the sexes are separate and identifiable usually nematodes and acanthocephalans. Allotype designations are not regulated by the code.
Syntype: Each specimen in a type series from which neither a holotype nor a lectotype has been designated.
Lectotype: A syntype, designated as the single name-bearing type specimen after the original publication of a species or subspecies name.
Paralectotype: Each of the original syntypes remaining after the designation of a lectotype.
Neotype: A single specimen designated as the name-bearing type of a species or subspecies taxon for which no holotype, (or lectotype), syntypes, or prior neotype are believed to exist. A neotype should be chosen if possible from any surviving paratypes or paralectotypes. If no paratypes or paralectotypes are available, a specimen from the type host and/or the type locality is preferred.
Hapantotype: One or more preparations of directly related individuals representing differing stages in the life cycle together forming a name-bearing type, generally applied in an extant species of Protozoa.
Phototype: A set of photographs (usually of sporulated oocysts) of a new protozoan taxon. For format for depositing phototypes see Bandoni and Duszynski, 1988.
Another name occasionally used is Hypotype, a described or figured specimen used in a publication to extend or correct the knowledge of a previously defined species.
PACKAGING SPECIMENS FOR MAILING
Specimens must be packaged in strong containers and surrounded by shockproof absorbent material sufficient to withstand severe blows in transit and to absorb fluid in case specimen vials are broken. Screw caps on glass vials should be taped/parafilmed in place to prevent loosening in transit. Individual vials should be placed in separate small plastic bags. Slides must be completely dry and individually wrapped in paper (approximately 3” x 5”) before being placed in a slide box with shock-absorbing material between them. This procedure prevents fragments of one broken slide from hitting and breaking adjacent slides and greatly facilitates the recovery and reconstruction of damaged specimens and slide fragments. Wooden and flexible plastic slide boxes are preferred to inflexible hard plastic boxes. A letter containing the information about the specimens should be included in the package and a copy sent under separate cover. Address specimens to: U.S. National Parasite Collection, USDA, ARS, ANRI, Bldg. 1180, BARC-East, 10300 Baltimore Avenue, Beltsville, MD 20705-2350.
1. International Code for Zoological Nomenclature 4th Edition.
2. Bandoni, S. M. and D. W. Duszynski, 1988. A plea for improved presentation of type material for Coccidia. Journal of Parasitology 74:519-523.
The specimens in the U.S. National Parasite Collection (USNPC) were deposited for permanent preservation. They are not available as gifts or on loan for teaching, demonstrations, or student collections. Type specimens are available for study at the U.S. National Parasite Collection in Beltsville, Maryland, and on loan under certain conditions for 60 days, for essential comparisons when the original description of a species is thought to be inaccurate or inadequate. A strong justification is required for risking types, especially the name-bearing specimens, in the mail. Requests for concurrent loan of both holotype and paratypes of a single species are discouraged. Holotype specimens are rarely loaned, and only in extraordinary circumstances. Graduate students requiring specimens for comparative purposes may obtain them through their major professor, who must request, receive, and be responsible for their safekeeping and return. Investigators requesting the loan of type material should indicate in their request the collection number (if known from published descriptions; or from the USNPC webpage), original scientific name of the parasite, author’s name, and date of description. Requestors can search the database from a button at the base of the homepage. Requestors are reminded that the specimens are entered under their original names and records are by class, genus, and species/subspecies for the parasites only. Other groupings such as families cannot be searched. All generic synonyms must be included in requests for specimens.
Biosystematics research at the U.S. National Parasite Collection develops new information and concepts for parasite biodiversity and systematics, encompassing classification, geographic distribution, host association, identification and diagnosis of helminths and protozoans based on analyses of morphological and molecular variation. Strategic research for internal parasites in ruminants, other food animals, wild reservoir hosts, and equines supports programs for animal health, food safety and protection of the environment. Emerging pathogens, host-parasite systems at the interface of agricultural and natural ecosystems and those responding to global change create the focus for studies among parasite groups of veterinary and medical importance, emphasizing domestic and exotic hosts, new farm animals, and aquaculture. A primary repository for parasite biodiversity nationally and globally, the U.S. National Parasite Collection, acquires specimens and curates critical collections. Primary information systems, databases and historical baselines from the USNPC provide a framework to recognize and predict impacts of parasites and pathogens posing threats to the health of animals, humans and the environment.
A VISION FOR THE USNPU: Systematics, predictive classifications and interactive information systems for parasites identify new and emerging threats to animal health, food safety and protection of the environment.
Cladogram of Subfamilies of the Trichostrongylidae (Hoberg & Lichtenfels, 1994, J. Parasitol. 80: 976-996)
Other Resources and Reference Materials
V. Mazzola. The National Parasite Collection. Agricultural Research Magazine, Nov. 1992. pp. 18-19.
J. Kluger. You'll Never Walk Alone. Discover. November, 1993. p. 49.
Mark Wexler. As the Worm Turns. Modern Maturity. July-August, 1995. Vol. 38, No. 4, p. 19.
Hank Becker. Fingerprinting Parasitic Worms. Agricultural Research Magazine, April, 1996, pp. 18-19.
Hank Becker. Searching for Parasitic Roots. Agricultural Research Magazine, Dec. 1996, pp. 4-7.
Mark Wexler. Solving Microscopic Mysteries. National Wildlife. Feb./March, 1997. 32(2):65.
Jennifer Ackerman. Parasites: A New Portrait. National Geographic. Oct., 1997. 192(4):72-91.
J.R. Lichtenfels, J.H. Kirkbride, Jr. and D.J. Chitwood, Eds. Systematic Collections of the Agricultural Research Service. Miscellaneous Publication No. 1343. Apr., 1998.
Developed illustrated identification keys to adult forms of large stomach worms (Haemonchus) of ruminants of North America, the most important nematode pathogens of sheep in southeastern United States and of cattle in warm, moist pastures. The keys employed newly discovered characters of the synlophe (surface cuticular ridges) and permit the morphological identification of single adult specimens of either sex for the first time.
Developed first phylogenetic classification of nematodes of the family Trichostrongylidae which includes most of the economically important nematode parasites of ruminants. This new classification of the subfamilies for the first time established monophyly for the family and subfamilies of these important groups, a prerequisite for further studies on their evolution.
Developed diagnostic probes specific for species of Trichinella. Species and subspecific populations from domestic hosts and wildlife can be identified without costly, time-consuming animal infections. This work revolutionized the identification of Trichinella, which cannot be identified morphologically, and contributed greatly to an understanding of the epidemiology of this important parasite of swine and other domestic animals and wildlife.
Developed diagnostic probes for species of the genera Ostertagia, Haemonchus, Cooperia and Nematodirus. The probes can be used for any developmental stage in the life cycle of the parasite including difficult to identify eggs and larvae. The results may lead to the development of cow-side diagnostic kits to determine the presence and intensity of infections in individual animals. This provides a means to tailor treatment to individual animals reducing the cost and the risk of environmental damage or the development of resistance to drugs.
Developed the Arctic Refugium Hypothesis which postulated that the Arctic and Subarctic were regions of evolutionary diversification rather than net extinction during the last million years. The hypothesis provides a framework for evaluating evolutionary relationships between hosts and parasites in the Holarctic, and is the focus of broad based studies in biodiversity.
Following the discovery of Nematodirus battus in sheep, the recently introduced pathogen was redescribed and APHIS personnel were trained for a nationwide survey of sheep. Five populations of this species from worldwide localities were studied using DNA sequences in an effort to determine the source of the importation and elucidate the mysterious history of this nematode that appeared as a serious pathogen of sheep in England in 1950 and was subsequently identified in Norway, The Netherlands, France, and in 1985 in the US and Canada. Results of the DNA studies indicate the probability of a European origin for the nematode and importation to the US through Canada.
Provided phylogenetic resolution among species of Taenia, economically and medically important tapeworms of humans and domesticated hosts. This information is critical to understanding the role of humans as hosts for these tapeworms. These data will be of significance in medicine and veterinary practice in providing more critical diagnostics and for understanding patterns of life cycles and host relationships for these species.
Developed a National Plan for Parasite Collections that proposed the development of collections of frozen parasite tissue and a database of available parasite germplasm. The demand for such parasite specimens is growing rapidly, but no such collections or databases have been developed. Developing such resources at existing parasite collections would use existing structures to provide new services to parasitologists and broaden the user community of the collections. The database of the U.S. Parasite Collection has been made available on the Internet.
Discovered and described a new pathogenic nematode from ostriches in North Carolina and Texas in a collaborative project with the College of Veterinary Medicine, North Carolina State University and the Texas Veterinary Medical Center, Texas A&M University. Nematodes may cause significant losses of valuable ostriches in the rapidly growing ratite industry in the United States. The nematode was apparently imported with ostriches from Africa and is now widespread in North America. This information is important to scientists, producers and the Animal and Plant Health Inspection Service who are interested in controlling the nematode and in preventing future importations of exotic pathogens.
Paired subcuticular glands with microscopic surface pores have been discovered near the vulva of female Trichostrongyloid nematodes and they are being investigated as a possible source of a sex attractant for male nematodes. The discovery was made during microscopic studies required to identify the economically important nematodes. If the new organ is determined to be a source of a sex attractant, a biological control might be developed that could reduce the cost of controlling the nematodes in meat and dairy animals. Such a biological control would be of considerable interest to producers, especially in organic and sustainable agricultural systems.
Collaborated with researchers in Scotland and Australia to identify nematode parasites of horses to be used to develop molecular probes that will permit nematode eggs in the feces of horses to be identified. The probes will be powerful research tools for determining which species are drug resistant or most pathogenic, for evaluating antiparasitic drugs and biological control agents, and for identifying the species causing larval cyathostomiasis, an emerging disease of horses.
Discovered a common synlophe pattern among genera of the Haemonchinae that significantly advanced the utility of this morphological character for identification and classification of these important nematode parasites of cattle, sheep, goats and deer. The Haemonchinae includes 3 genera, Haemonchus, Mecistocirrus and Ashworthius, commonly referred to as large stomach worms that cause significant production losses due to morbidity, mortality, cost of treatment and suboptimal use of contaminated pastures. The new information improved the ability of scientists to identify endemic and exotic species that threaten farmed ruminants. This information is essential to evaluate biological and chemical treatment and control agents, determine the importance of reservoir hosts such as wildlife, evaluate emerging or recently imported pathogens and to prevent the importation of others. .
Developed an international standard taxonomy for the strongylid nematode parasites of horses. Led an international team that revised and improved the standard system of names used for all research to diagnose and control the most pathogenic nematode parasites of horses. The information is essential for progress in developing diagnostic probes, biological control agents and antiparasitic drugs for larval cyathostomiasis, an emerging disease of horses worldwide.
Discovered a cryptic species of abomasal nematode in North American ruminants. This discovery and description of a new species of medium stomach worm, of the genus Teladorsagia, clearly indicates that we do not yet have a basic understanding of the species diversity of nematode pathogens in domestic and wild ruminants in North America. The new species was recognized on the basis of DNA sequence differences and comparative morphology. Previously, the long-spicule forms of medium stomach worms in domestic and wildlife species were believed to belong to a single species. This work is critical to understanding the interface between domestic and wild ruminants, and the potential for emerging disease related to these parasites within the context of global change.
Figures 1-6. Nematodirus spp. of North American domesticated ruminants. Diagrammatic drawings of anterior and cervical regions; right lateral views showing cephalic expansions, number and pattern of distribution of cuticular ridges, and positions of cervical papillae (cp), excretory pore (exp), and distal end of esophagus (es). 1. N. filicollis. 2. N. davtiani. 3. N. helvetianus. 4. N. oiratianus interruptus ssp. n. 5. N. abnormalis. 6. N. spathiger.
(Lichtenfels & Pilitt, 1983, Proc. Helminthol. Soc. Wash. 50: 261-274)
**Requests for specimens as well as comments and corrections are encouraged via email to the USNPC Curator.
Cooperia spp. of cattle & sheep
Cross section Haemonchus Similis
Libyostongylus dentatus n.sp. from ostriches
Nematodirus in Domestic Ruminants of North America
Ovejectors of Strongyloidea
Spicules of Ostertagiinae
Strongylus ssp. of horses
Synlophes of Ostertagiinae
Trichinella spiralis in muscle of a dog
Umingmakstrongylus pallikuukensis, cervical region