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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Animal Parasitic Diseases Laboratory » Research » Publications at this Location » Publication #312709

Title: A combined parasitological molecular approach for noninvasive characterization of parasitic nematode communities in wild hosts

Author
item BUDISCHAK, SARAH - University Of Georgia
item Hoberg, Eric
item Abrams, Arthur - Art
item JOLLES, ANNA - Oregon State University
item EZENWA, VANESSA - University Of Georgia

Submitted to: Molecular Ecology Resources
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/22/2015
Publication Date: 2/26/2015
Citation: Budischak, S.A., Hoberg, E.P., Abrams, A., Jolles, A.E., Ezenwa, V.O. 2015. A combined parasitological molecular approach for noninvasive characterization of parasitic nematode communities in wild hosts. Molecular Ecology Resources. DOI:10.1111/1755-0998.12382.

Interpretive Summary: Accurate estimates or representation of parasite diversity in domestic or free-ranging wildlife host animals has historically relied on often laborious and difficult methods developed to recover and collect adult parasites from animals examined after death. Such parasites are then available for authoritative identification often combining morphological and molecular methodologies. We describe development and application of a method that initially links morphology and sequences from identified adult parasites to identify larval stages. Most hosts are concurrently or sequentially infected with multiple parasites, thus fully understanding interactions between individual parasite species and their hosts depends on accurate characterization of the parasite community. For parasitic nematodes, non-invasive methods for obtaining quantitative, species-specific infection data in wildlife are unreliable. Consequently, characterization of gastrointestinal nematode communities of wild hosts has largely relied on lethal sampling to isolate and enumerate adult worms directly from the tissues of dead hosts. The necessity of lethal sampling severely restricts the host species that can be studied, the adequacy of sample sizes to assess diversity, the geographic scope of collections, and the research questions that can be addressed. Focusing on gastrointestinal nematodes of wild African buffalo, we evaluated whether accurate characterization of nematode communities could be made using a non-invasive technique that combined conventional parasitological approaches with molecular barcoding. To establish the reliability of this new method, we compared estimates of gastrointestinal nematode abundance, prevalence, richness and community composition derived from lethal sampling with estimates derived from our non-invasive approach. Our non-invasive technique accurately estimated total and species-specific worm abundance, as well as worm prevalence and community composition when compared to the lethal sampling method. Importantly, the rate of parasite species discovery was similar for both methods, and only a modest number of barcoded larvae (n = 10) were needed to capture key aspects of parasite community composition. Overall, this new non-invasive strategy offers numerous advantages over lethal sampling methods for studying nematode-host interactions in wildlife, and can readily be applied to a range of study systems. Our study has substantial implications for disease ecologists, veterinarians, conservation biologists and others who require reliable estimates of parasite faunal structure but for logistical reasons cannot directly study host animals by necropsy. Further, these methods allow for near simultaneous assessment of diversity across large geographic expanses and from multiple host animals a possibility that has seldom been realized.

Technical Abstract: Most hosts are concurrently or sequentially infected with multiple parasites, thus fully understanding interactions between individual parasite species and their hosts depends on accurate characterization of the parasite community. For parasitic nematodes, non-invasive methods for obtaining quantitative, species-specific infection data in wildlife are unreliable. Consequently, characterization of gastrointestinal nematode communities of wild hosts has largely relied on lethal sampling to isolate and enumerate adult worms directly from the tissues of dead hosts. The necessity of lethal sampling severely restricts the host species that can be studied, the adequacy of sample sizes to assess diversity, the geographic scope of collections, and the research questions that can be addressed. Focusing on gastrointestinal nematodes of wild African buffalo, we evaluated whether accurate characterization of nematode communities could be made using a non-invasive technique that combined conventional parasitological approaches with molecular barcoding. To establish the reliability of this new method, we compared estimates of gastrointestinal nematode abundance, prevalence, richness and community composition derived from lethal sampling with estimates derived from our non-invasive approach. Our non-invasive technique accurately estimated total and species-specific worm abundances, as well as worm prevalence and community composition when compared to the lethal sampling method. Importantly, the rate of parasite species discovery was similar for both methods, and only a modest number of barcoded larvae (n = 10) were needed to capture key aspects of parasite community composition. Overall, this new non-invasive strategy offers numerous advantages over lethal sampling methods for studying nematode-host interactions in wildlife, and can readily be applied to a range of study systems.