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Daniel A Grear

Dan Grear is a Wildlife Disease Ecologist at the National Wildlife Health Center.

I am interested in mechanisms that cause heterogeneities in pathogen transmission in wild animal disease systems and at the interface of wildlife, domestic animal, and human health. I lead investigations into wildlife mortality events and research that incorporates field studies with theoretical modeling of disease systems to identify key mechanisms that drive transmission dynamic.

Professional Experience

  • 2015 - Present Wildlife Disease Ecologist, U.S. Geological Survey, National Wildlife Health Center, Madison, WI

  • 2013 - 2015 Ecologist, U.S. Department of Agriculture, Veterinary Services, Center for Epidemiology and Animal Health, Fort Collins, CO

  • 2011 - 2014 Post-Doctoral Researcher, Colorado State University

Education and Certifications

  • 2011 Ph.D. Ecology, Pennsylvania State University

  • 2006 M.S. Wildlife Ecology, University of Wisconsin

  • 2002 B.S. Wildlife Ecology, University of Wisconsin

Affiliations and Memberships*

  • Member of the Ecological Society of America

  • Member of the Wildlife Society

  • Bsal Task Force Working Group Member

Science and Products

link
Aedes albopictus mosquito

Forecasting Mosquito Phenology in a Shifting Climate: Synthesizing Continental-scale Monitoring Data

Climate change is expected to have significant effects on the phenology of vectors of arthropod-borne diseases, particularly mosquitoes. However, forecasting the direction and magnitude of future phenological shifts requires a more detailed understanding of the climate drivers of mosquito phenology. Addressing this knowledge gap is particularly salient for mosquitoes, as they have the potential to
By
John Wesley Powell Center for Analysis and Synthesis
link

Forecasting Mosquito Phenology in a Shifting Climate: Synthesizing Continental-scale Monitoring Data

Climate change is expected to have significant effects on the phenology of vectors of arthropod-borne diseases, particularly mosquitoes. However, forecasting the direction and magnitude of future phenological shifts requires a more detailed understanding of the climate drivers of mosquito phenology. Addressing this knowledge gap is particularly salient for mosquitoes, as they have the potential to
Learn More
link
Northern gannet flying with mountains in background.

Avian Influenza

Avian influenza is a viral disease caused by various strains of avian influenza viruses that can be classified as low pathogenic avian influenza (LPAI) or highly pathogenic avian influenza (HPAI). It remains a global disease with potential high consequence with the potential to threaten wildlife, agriculture, and human health.
By
Ecosystems Mission Area, Biological Threats and Invasive Species Research Program, National Wildlife Health Center
link

Avian Influenza

Avian influenza is a viral disease caused by various strains of avian influenza viruses that can be classified as low pathogenic avian influenza (LPAI) or highly pathogenic avian influenza (HPAI). It remains a global disease with potential high consequence with the potential to threaten wildlife, agriculture, and human health.
Learn More
link
Scientist swabbing newt.

Batrachochytrium salamandrivorans (Bsal) Surveillance

Scientists of the USGS National Wildlife Health Center (NWHC) in collaboration with partners have developed risk assessments for Batrachochytrium salamandrivorans ( Bsal ) in the United States and have begun sampling high-risk locations for the fungus.
By
Ecosystems Mission Area, Biological Threats and Invasive Species Research Program, National Wildlife Health Center
link

Batrachochytrium salamandrivorans (Bsal) Surveillance

Scientists of the USGS National Wildlife Health Center (NWHC) in collaboration with partners have developed risk assessments for Batrachochytrium salamandrivorans ( Bsal ) in the United States and have begun sampling high-risk locations for the fungus.
Learn More
link
Image: Three-lined Salamander

Batrachochytrium salamandrivorans (Bsal)

Batrachochytrium salamandrivorans ( Bsal ) is an emerging pathogen capable of causing significant morbidity and mortality in salamanders.
By
Ecosystems Mission Area, Biological Threats and Invasive Species Research Program, National Wildlife Health Center
link

Batrachochytrium salamandrivorans (Bsal)

Batrachochytrium salamandrivorans ( Bsal ) is an emerging pathogen capable of causing significant morbidity and mortality in salamanders.
Learn More
Filter Total Items: 15

Indiana Amphibian Pathogen Surveillance data release

Data in this dataset were collected as a part of a surveillance project for reintroduction of a state endangered species in Indiana. This data was collected in the field by state biologists and sent to the USGS National Wildlife Health Center (NWHC) for testing of four amphibian pathogens, Batrachochytrium dendrobatidis (Bd), Batrachochytrium salamandrivorans (Bs), Ranavirus, and perkinsea. The da
By
National Wildlife Health Center

Avian disease screening of translocated sage grouse captured in Montana, USA

The purpose of this project is to determine the infectious status and exposure status of several diseases that have the potential to impact the health of greater sage grouse (Centrocercus urophasianus) captured in Montana, USA to be translocated to Alberta, Canada. Specific disease status to be tested include, infection with avian influenza virus (AIV), infection with Avian Paramyxovirus-1 (APMV1)
By
National Wildlife Health Center

Data Release for Replicate amphibian swab and standard dilution of artificial DNA data to assess qPCR and sampling detection error for Batrachochytrium dendrobatidis.

We generated a data set from by collecting duplicate swabs from all amphibian individuals sampled at 5 sites (96 individuals) and analyzed these duplicate swabs running 3 subsamples of the extracted DNA in separate qPCR reactions. The resulting data set included 2 swabs per individual with 1 qPCR result and a 2nd swab with 3 qPCR results for detection of Batrachochytrium dendrobatidis (Bd) DNA. We
By
National Wildlife Health Center

Avian morbidity and mortality data reported to the Wildlife Health Information Sharing Partnership - event reporting system (WHISPers) in the continental United States for events beginning on or between January 1, 2023 and December 31, 2023

Avian morbidity and mortality events reported in WHISPers that began in calendar year 2023. Events reported in WHISPers represent only those events that are reported to the USGS National Wildlife Health Center or the Southeastern Cooperative Wildlife Disease Studies at the University of Georgia, or that State, Federal, and Tribal partners voluntarily report into WHISPers, not legal, and marked as
By
National Wildlife Health Center

Serologic Survey of Selected Arthropod Borne Pathogens in Free-ranging Snowshoe Hares (Lepus americanus) Captured in Northern Michigan, USA

We conducted a serosurvey of snowshoe hares (Lepus americanus) for vector-borne pathogens in 2016-2017 that were captured in the Hiawatha National Forest in the eastern Upper Peninsula of Michigan, USA. At capture, in addition to age, sex, body weight of the hare and a blood sample data was collected on the ecological land type (USDA Forest Service. 2006. Hiawatha National Forest 2006 Forest Plan.
By
National Wildlife Health Center

Mercury concentrations in amphibian tissues across the United States, 2016-2021

Comma-separated values (.csv) file containing data related to amphibian sampling across the United States between 2016 and 2021. Data files contain mercury concentrations in amphibian and dragonfly tissues, mercury concentrations in sediment, as well as amphibian morphometrics, and habitat and climate characteristics where the samples were collected.
By
Forest and Rangeland Ecosystem Science Center

Paranannizziopsis spp. associated with skin lesions in wild snakes in North America and development of a real-time PCR assay for rapid detection of the fungus in clinical samples

The emergence of ophidiomycosis (or snake fungal disease) in snakes has prompted increased awareness of the potential impacts of fungal infections on wild reptile populations. Yet, aside from Ophidiomyces ophidiicola, little is known about other mycoses affecting wild reptiles. The closely related genus Paranannizziopsis has been associated with dermatomycosis in snakes and tuataras in captive col
By
National Wildlife Health Center

Student Network for Amphibian Pathogen Surveillance Data (ver. 2.0, April 2024)

Data in this dataset were collected as a part of the Student Network for Amphibian Pathogen Surveilance (SNAPs) program throughout the United States by undergraduate students in biology or ecology courses as a part of their curriculum throughout 2022. This data was collected in the field by students and sent to the USGS National Wildlife Health Center (NWHC) for testing of two amphibian fungal pat
By
National Wildlife Health Center

Population genetic analysis of the snake-infecting fungus, Ophidiomyces ophidiicola, in the eastern United States

Snake fungal disease (SFD; ophidiomycosis), caused by the pathogen Ophidiomyces ophidiicola (Oo), has been documented in wild snakes in North America and Eurasia, and is a potentially emerging disease in the eastern USA. However, a lack of historical disease data has made it challenging to determine whether Oo is a recent arrival to the USA or whether SFD emergence is due to other factors. Here, w
By
Biological Threats and Invasive Species Research Program, National Wildlife Health Center

Amphibian chytrid swab data from Mendocino County, California (2016 - 2020)

This dataset includes results from external skin swabbing of Rana boylii and Dicamptodon tenebrosus to test for the fungus Batrachochytrium dendrobatidis from Fox Creek in Mendocino County, California, in 2016-2020. Morphological measurements of swabbed animals were recorded, and Rana boylii had a unique identifier (pit tag) inserted beneath their skin for identification in future capture events.
By
Western Ecological Research Center (WERC)

Amphibian Chytrid Swab Data from Churchill County, Nevada (2019-2021)

This dataset includes results from external skin swabbing of Anaxyrus williamsi and Lithobates catesbeianus to test for the fungus Batrachochytrium dendrobatidis from the Dixie Valley in Churchill County, Nevada, in 2019-2021.
By
Western Ecological Research Center (WERC)

Evaluating regulations and surveillance as risk-mitigation to the emerging amphibian pathogen Bsal- Data release

Results of a literature search performed December 1, 2020. The tables in this document summarize the publications fitting in this search criteria and are split into the publications that update the list of international species that could carry Bsal (Appendix 1 Table S1). Number of individual live amphibians imported in categories of urodelan (salamander, newt, and related taxa) species restricted
By
Biological Threats and Invasive Species Research Program, National Wildlife Health Center
Dark colored newt on bright green vegetation.
Eastern newt (Notophthalmus viridescens) in Wisconsin
Eastern newt (Notophthalmus viridescens) in Wisconsin
Dark colored newt on bright green vegetation.

Eastern newt (Notophthalmus viridescens) in Wisconsin

Eastern newt (Notophthalmus viridescens) in Wisconsin

Eastern newt (Notophthalmus viridescens) in Wisconsin.

By
Ecosystems Mission Area, National Wildlife Health Center
Dark colored newt on bright green vegetation.

Eastern newt (Notophthalmus viridescens) in Wisconsin

Eastern newt (Notophthalmus viridescens) in Wisconsin

Eastern newt (Notophthalmus viridescens) in Wisconsin.

By
Ecosystems Mission Area, National Wildlife Health Center
Filter Total Items: 38

Serologic survey of selected arthropod-borne pathogens in free-ranging snowshoe hares (Lepus americanus) captured in Northern Michigan, USA

Snowshoe hares (Lepus americanus) in the Upper Peninsula (UP) of Michigan, USA, occupy the southern periphery of the species' range and are vulnerable to climate change. In the eastern UP, hares are isolated by the Great Lakes, potentially exacerbating exposure to climate-change-induced habitat alterations. Climate change is also measurably affecting distribution and prevalence of vector-borne pat
Authors
Erik K. Hofmeister, Eric Clark, Melissa Lund, Daniel A. Grear
By
Ecosystems Mission Area, National Wildlife Health Center

Chytrid infections exhibit historical spread and contemporary seasonality in a declining stream-breeding frog

Species with extensive geographical ranges pose special challenges to assessing drivers of wildlife disease, necessitating collaborative and large-scale analyses. The imperilled foothill yellow-legged frog (Rana boylii) inhabits a wide geographical range and variable conditions in rivers of California and Oregon (USA), and is considered threatened by the pathogen Batrachochytrium dendrobatidis (Bd
Authors
A.M. Belasen, R.A. Peek, A.J. Adams, I.D. Russell, M.E. De León, Michael J. Adams, J. Bettaso, K.G.H. Breedveld, A. Catenazzi, C.P. Dillingham, Daniel A. Grear, Brian J. Halstead, P.G. Johnson, Patrick M. Kleeman, M.S. Koo, C.W. Koppl, J.D. Lauder, G. Padgett-Flohr, J. Piovia-Scott, K.L. Pope, V. Vredenburg, M. Westphal, K. Wiseman, S.J. Kupferberg
By
Ecosystems Mission Area, National Wildlife Health Center, Western Ecological Research Center (WERC)

Paranannizziopsis spp. infections in wild snakes and a qPCR assay for detection of the fungus

The emergence of ophidiomycosis (or snake fungal disease) in snakes has prompted increased awareness of the potential effects of fungal infections on wild reptile populations. Yet, aside from Ophidiomyces ophidiicola, little is known about other mycoses affecting wild reptiles. The closely related genus Paranannizziopsis has been associated with dermatomycosis in snakes and tuataras in captive col
Authors
Jeffrey M. Lorch, Megan Winzeler, Julia S. Lankton, Stephen Raverty, Heindrich N Snyman, Helen M. Schwantje, Caeley Thacker, Susan Knowles, Hugh Y Cai, Daniel A. Grear
By
Ecosystems Mission Area, National Wildlife Health Center

Broad-scale assessment of methylmercury in adult amphibians

Mercury (Hg) is a toxic contaminant that has been mobilized and distributed worldwide and is a threat to many wildlife species. Amphibians are facing unprecedented global declines due to many threats including contaminants. While the biphasic life history of many amphibians creates a potential nexus for methylmercury (MeHg) exposure in aquatic habitats and subsequent health effects, the broad-scal

Authors
Brian J. Tornabene, Blake R. Hossack, Brian J. Halstead, Collin A. Eagles-Smith, Michael J. Adams, Adam R. Backlin, Adrianne Brand, Colleen Emery, Robert N. Fisher, Jillian Elizabeth Fleming, Brad Glorioso, Daniel A. Grear, Evan H. Campbell Grant, Patrick M. Kleeman, David Miller, Erin L. Muths, Christopher Pearl, Jennifer Rowe, Caitlin Teresa Rumrill, J. Hardin Waddle, Megan Winzeler, Kelly L. Smalling
By
Ecosystems Mission Area, Water Resources Mission Area, Contaminant Biology, Toxic Substances Hydrology, Eastern Ecological Science Center, Forest and Rangeland Ecosystem Science Center, Fort Collins Science Center, National Wildlife Health Center, New Jersey Water Science Center, Northern Rocky Mountain Science Center, Western Ecological Research Center (WERC), Wetland and Aquatic Research Center

Keeping the heat on: Weighted surveillance for Chytrid fungus (Batrachochytirum dendrobatidis) in Dixie Valley toads (Anaxyrus [= Bufo] williamsi)

Introduced fungal pathogens have caused declines and extinctions of naïve wildlife populations across vertebrate classes. Consequences of introduced pathogens to hosts with small ranges might be especially severe because of limited redundancy to rescue populations and lower abundance that may limit the resilience of populations to perturbations like disease introduction. As a complement to biosecu
Authors
Matthew J. Forrest, Brian J. Halstead, Daniel A. Grear, Patrick M. Kleeman, Brian D. Todd, Oliver J. Miano, Kris D. Urquhart
By
Ecosystems Mission Area, National Wildlife Health Center, Western Ecological Research Center (WERC)

Epistylis spp. infestation in two species of mud turtles (Kinosternon spp.) in the American Southwest

The protistan genus Epistylis contains freshwater colonial species that attach to aquatic organisms in an epibiotic or parasitic relationship. They are known to attach to the epidermis and shells of aquatic turtles, but have not been reported to cause heavy infestations or morbidity in turtles. We documented heavy infestations of Epistylis spp. in several populations of Sonoran mud turtles (Kinost
Authors
Audrey K. Owens, Jennifer A. Smith, Rebecca A. Cole, Jeffrey M. Lorch, Daniel A. Grear
By
Ecosystems Mission Area, National Wildlife Health Center

The population genetics of the causative agent of snake fungal disease indicate recent introductions to the USA

Snake fungal disease (SFD; ophidiomycosis), caused by the pathogen Ophidiomyces ophiodiicola (Oo), has been documented in wild snakes in North America and Eurasia, and is considered an emerging disease in the eastern United States of America. However, a lack of historical disease data has made it challenging to determine whether Oo is a recent arrival to the USA or whether SFD emergence is due to
Authors
Jason T. Ladner, Jonathan M. Palmer, Cassandra L. Ettinger, Jason E. Stajich, Terence M. Farrell, Brad M. Glorioso, Becki Lawson, Steven J. Price, Anne G. Stengle, Daniel A. Grear, Jeffrey M. Lorch
By
Ecosystems Mission Area, National Wildlife Health Center, Wetland and Aquatic Research Center

Quarterly wildlife mortality report October 2021

The USGS National Wildlife Health Center (NWHC) Quarterly Mortality Report provides brief summaries of epizootic mortality and morbidity events by quarter. The write-ups, highlighting epizootic events and other wildlife disease topics of interest, are published in the Wildlife Disease Association quarterly newsletter. A link is provided in this WDA newsletter to the Wildlife Health Information Sha
Authors
Bryan J. Richards, Daniel A. Grear, Shelby Jo Weidenkopf
By
Ecosystems Mission Area, National Wildlife Health Center

Acute mortality in California tiger salamander (Ambystoma californiense) and Santa Cruz long-toed salamander (Ambystoma macrodactylum croceum) caused by Ribeiroia ondatrae (Class: Trematoda)

In early September 2019, a morbidity and mortality event affecting California tiger salamanders (Ambystoma californiense) and Santa Cruz long-toed salamanders (Ambystoma macrodactylum croceum) in late stages of metamorphosis was reported at a National Wildlife Refuge in Santa Cruz County, California, U.S.A. During the postmortem disease investigation, severe integumentary metacercarial (Class: Tre
Authors
Saskia Keller, Constance Roderick, Christopher Caris, Daniel A. Grear, Rebecca A. Cole
By
Ecosystems Mission Area, National Wildlife Health Center

Highly pathogenic avian influenza virus H5N2 (Clade 2.3.4.4) challenge of mallards age appropriate to the 2015 midwestern poultry outbreak

BackgroundThe 2015 highly pathogenic avian influenza virus (HPAIV) H5N2 clade 2.3.4.4 outbreak in upper midwestern U.S. poultry operations was not detected in wild birds to any great degree during the outbreak, despite wild waterfowl being implicated in the introduction, reassortment, and movement of the virus into North America from Asia. This outbreak led to the demise of over 50 million domesti
Authors
Jeffrey S. Hall, Daniel A. Grear, Scott Krauss, Patrick Seiler, Robert J. Dusek, Sean Nashold, Robert G. Webster
By
Ecosystems Mission Area, National Wildlife Health Center

Evaluation of regulatory action and surveillance as preventive risk-mitigation to an emerging global amphibian pathogen Batrachochytrium salamandrivorans (Bsal)

The emerging amphibian pathogen Batrachochytrium salamandrivorans (Bsal) is a severe threat to global urodelan (salamanders, newts, and related taxa) biodiversity. Bsal has not been detected, to date, in North America, but the risk is high because North America is one of the global hotspots for urodelan biodiversity. The North American and United States response to the discovery of Bsal in Europe
Authors
Daniel A. Grear, Brittany A. Mosher, Katherine Richgels, Evan H. Campbell Grant
By
Ecosystems Mission Area, Eastern Ecological Science Center, National Wildlife Health Center

Quarterly wildlife mortality report January 2021

The USGS National Wildlife Health Center (NWHC) Quarterly Mortality Report provides brief summaries of epizootic mortality and morbidity events by quarter. The write-ups, highlighting epizootic events and other wildlife disease topics of interest, are published in the Wildlife Disease Association quarterly newsletter. A link is provided in this WDA newsletter to the Wildlife Health Information Sha
Authors
Bryan J. Richards, Barbara Bodenstein, Daniel A. Grear, Hon S. Ip, Anne Ballmann, Julia S. Lankton, Valerie I. Shearn-Bochsler
By
Ecosystems Mission Area, National Wildlife Health Center

Non-USGS Publications**

Gorsich EE, Luis AD, Buhnerkempe MG, Grear DA, Portacci K, Miller RS, Webb CT. 2016. Mapping US cattle shipment networks: Spatial and temporal patterns of trade communities from 2009 to 2011. Preventive Veterinary Medicine, 134, 82-91.
Lavelle MJ, Kay SL, Pepin KM, Grear DA, Campa H, VerCauteren K. 2016. Evaluating wildlife-cattle contact rates to improve the understanding of dynamics of bovine tuberculosis transmission in Michigan, USA. Preventive Veterinary Medicine, 135, 28-36.
Scott A, B McCluskey, M Brown-Reid, DA Grear, P Pitcher, G Ramos, D Spencer. 2016. Porcine epidemic diarrhea virus introduction into the United States: Root cause investigation. Preventive Veterinary Medicine, 123, 192-201. doi: 10.1016/j.prevetmed.2015.11.013
Glaser L, M Carstensen, S Shaw, S Robbe-Austerman, A Wunschmann, DA Grear, T Stuber, B Thomsen. 2016. Descpriptive epidemiology and whole genome sequencing analysis for an outbreak of bovine tuberculosis in beef cattle and white-tailed deer in Northwestern Minnesota. PLoS ONE, e0145735.
McClure RSM, CL Burdett, ML Farnsworth, MW Lutman, DM Theobold, PD Riggs, DA Grear, RS Miller. 2015. Modeling and mapping the probability of occurrence of invasive wild pigs across the contiguous United States. PLoS ONE 10(8): e0133771. doi:10.1371/journal.pone.0133771
Pepin KM, CB Leach, C Marques-Toledo, KH Laass, KS Paixao, AD Luis, DTS Hayman, NG Johnson, MG Buhnerkempe, S Carver, DA Grear, K Tsao, AE Eiras, and CT Webb. 2015. Utility of mosquito surveillance data for spatial prioritization of vector control against dengue viruses in three Brazilian cities. Parasites and Vectors, 8, 98.
Tsao K, S Robbe-Austerman, RS Miller, K Portacci, DA Grear, and CT Webb. 2014. Sources of bovine tuberculosis in the United States. Infection, Genetics, and Evolution. 114, 201-212.
Luong LT, DA Grear, and PJ Hudson. 2014. Manipulation of host-resource dynamics impacts transmission of trophically transmitted parasites. International Journal for Parasitology, 44, 737-742.
Grear DA, J Kaneene, J Averill, and CT Webb. 2014. Local cattle movements in response to ongoing bovine TB zonation and regulations. Preventive Veterinary Medicine, 114, 201-212.
Buhnerkempe MG, MJ Tildesley, T Lindström, DA Grear, RS Miller, K Portacci, M Keeling, U Wennergren, and CT Webb. 2014. The impact of movements and animal density on continental scale cattle disease outbreaks in the United States. PLoS one, e91724.
Grear DA, LT Luong, and PJ Hudson. 2013. Network transmission inference: host behavior and parasite life-cycle make social networks meaningful in disease ecology, Ecological Applications, 23, 1906-1914.
Buhnerkempe, MG, DA Grear, RS Miller, K Portacci, J Lombard, and CT Webb. 2013. A national-scale picture of U.S. cattle movements obtained from Interstate Certificates of Veterinary Inspection data. Prev. Vet. Med., 112, 318-329.
Lindström T, DA Grear, MG Buhnerkempe, CT Webb, RS Miller, K Portacci, and U Wennergren. 2013. Bayesian approach for modeling cattle movements in the United States: scaling up a partially observed network. PLoS ONE,8, e53432. doi:10.1371/journal.pone.0053432
Grear DA, LT Luong, and PJ Hudson. 2012. Sex-biased transmission of a complex life-cycle parasite: why males matter. Oikos, 121, 1446-1453. doi: 10.1111/j.1600-0706.2012.20358.x
Blanchong, JA, DA Grear, BV Weckworth, DP Keane, KT Scribner, and MD Samuel. 2012. Effects of chronic wasting disease on reproduction and fawn harvest vulnerability in Wisconsin white-tailed deer. Journal of Wildlife Diseases, 48, 361-370.
Rogers K, S Robinson, MD Samuel, and DA Grear. 2011. Diversity and distribution of white-tailed deer mtDNA lineages in CWD outbreak areas in southern Wisconsin, USA. Journal of Toxicology and Environmental Health, 74, 1521-1535. doi: 10.1080/15287394.2011.618980
Grear DA and PJ Hudson. 2011. The dynamics of macroparasite host-self-infection: a study of the patterns and processes of pinworm (Oxyuridae) aggregation. Parasitology, 138, 619-617. doi: 10.1017/S0031182011000096.
Grear DA, MD Samuel, K Scribner, BV Weckworth, and JA Langenberg. 2010. Influence of genetic relatedness and spatial proximity on CWD transmission among female white-tailed deer. Journal of Applied Ecology, 47, 532-540.
Luong, LT, SE Perkins, DA Grear, A Rizzoli, and PJ Hudson. 2010. The relative importance of host characteristics and co-infection in generating variation in Heligmosomoides polygyrus fecundity. Parasitology, 137, 1003-1012.
Grear DA, SE Perkins, and PJ Hudson. 2009. Does elevated testosterone result in increased exposure and transmission of parasites? Ecology Letters, 12, 528-537.
Luong, LT, DA Grear, and PJ Hudson. 2009. Male hosts are responsible for the transmission of a trophically transmitted parasite, Pterygodermatites peromysci to the intermediate host in the absence of sex-biased infection. International Journal for Parasitology, 39, 1263-1268.
Grear DA, MD Samuel, JA Langenberg, and D Keane. 2006. Demographic patterns and harvest vulnerability of chronic wasting disease infected white-tailed deer in Wisconsin. Journal of Wildlife Management, 70, 546-553.

**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.

Preventive actions in response to the Bsal threat reduced Bsal risk in the U.S.

Preventive actions in response to the Bsal threat reduced Bsal risk in the U.S.

Import regulations and a large surveillance effort have reduced the risk of Batrachochytrium salamandrivorans (Bsal) introduction to the United States...

Read Article
A Unified Research Strategy for Disease Management

A Unified Research Strategy for Disease Management

As wildlife diseases increase globally, an understanding of host-pathogen relationships can elucidate avenues for management and improve conservation...

Read Article

Science and Products

link
Aedes albopictus mosquito

Forecasting Mosquito Phenology in a Shifting Climate: Synthesizing Continental-scale Monitoring Data

Climate change is expected to have significant effects on the phenology of vectors of arthropod-borne diseases, particularly mosquitoes. However, forecasting the direction and magnitude of future phenological shifts requires a more detailed understanding of the climate drivers of mosquito phenology. Addressing this knowledge gap is particularly salient for mosquitoes, as they have the potential to
By
John Wesley Powell Center for Analysis and Synthesis
link

Forecasting Mosquito Phenology in a Shifting Climate: Synthesizing Continental-scale Monitoring Data

Climate change is expected to have significant effects on the phenology of vectors of arthropod-borne diseases, particularly mosquitoes. However, forecasting the direction and magnitude of future phenological shifts requires a more detailed understanding of the climate drivers of mosquito phenology. Addressing this knowledge gap is particularly salient for mosquitoes, as they have the potential to
Learn More
link
Northern gannet flying with mountains in background.

Avian Influenza

Avian influenza is a viral disease caused by various strains of avian influenza viruses that can be classified as low pathogenic avian influenza (LPAI) or highly pathogenic avian influenza (HPAI). It remains a global disease with potential high consequence with the potential to threaten wildlife, agriculture, and human health.
By
Ecosystems Mission Area, Biological Threats and Invasive Species Research Program, National Wildlife Health Center
link

Avian Influenza

Avian influenza is a viral disease caused by various strains of avian influenza viruses that can be classified as low pathogenic avian influenza (LPAI) or highly pathogenic avian influenza (HPAI). It remains a global disease with potential high consequence with the potential to threaten wildlife, agriculture, and human health.
Learn More
link
Scientist swabbing newt.

Batrachochytrium salamandrivorans (Bsal) Surveillance

Scientists of the USGS National Wildlife Health Center (NWHC) in collaboration with partners have developed risk assessments for Batrachochytrium salamandrivorans ( Bsal ) in the United States and have begun sampling high-risk locations for the fungus.
By
Ecosystems Mission Area, Biological Threats and Invasive Species Research Program, National Wildlife Health Center
link

Batrachochytrium salamandrivorans (Bsal) Surveillance

Scientists of the USGS National Wildlife Health Center (NWHC) in collaboration with partners have developed risk assessments for Batrachochytrium salamandrivorans ( Bsal ) in the United States and have begun sampling high-risk locations for the fungus.
Learn More
link
Image: Three-lined Salamander

Batrachochytrium salamandrivorans (Bsal)

Batrachochytrium salamandrivorans ( Bsal ) is an emerging pathogen capable of causing significant morbidity and mortality in salamanders.
By
Ecosystems Mission Area, Biological Threats and Invasive Species Research Program, National Wildlife Health Center
link

Batrachochytrium salamandrivorans (Bsal)

Batrachochytrium salamandrivorans ( Bsal ) is an emerging pathogen capable of causing significant morbidity and mortality in salamanders.
Learn More
Filter Total Items: 15

Indiana Amphibian Pathogen Surveillance data release

Data in this dataset were collected as a part of a surveillance project for reintroduction of a state endangered species in Indiana. This data was collected in the field by state biologists and sent to the USGS National Wildlife Health Center (NWHC) for testing of four amphibian pathogens, Batrachochytrium dendrobatidis (Bd), Batrachochytrium salamandrivorans (Bs), Ranavirus, and perkinsea. The da
By
National Wildlife Health Center

Avian disease screening of translocated sage grouse captured in Montana, USA

The purpose of this project is to determine the infectious status and exposure status of several diseases that have the potential to impact the health of greater sage grouse (Centrocercus urophasianus) captured in Montana, USA to be translocated to Alberta, Canada. Specific disease status to be tested include, infection with avian influenza virus (AIV), infection with Avian Paramyxovirus-1 (APMV1)
By
National Wildlife Health Center

Data Release for Replicate amphibian swab and standard dilution of artificial DNA data to assess qPCR and sampling detection error for Batrachochytrium dendrobatidis.

We generated a data set from by collecting duplicate swabs from all amphibian individuals sampled at 5 sites (96 individuals) and analyzed these duplicate swabs running 3 subsamples of the extracted DNA in separate qPCR reactions. The resulting data set included 2 swabs per individual with 1 qPCR result and a 2nd swab with 3 qPCR results for detection of Batrachochytrium dendrobatidis (Bd) DNA. We
By
National Wildlife Health Center

Avian morbidity and mortality data reported to the Wildlife Health Information Sharing Partnership - event reporting system (WHISPers) in the continental United States for events beginning on or between January 1, 2023 and December 31, 2023

Avian morbidity and mortality events reported in WHISPers that began in calendar year 2023. Events reported in WHISPers represent only those events that are reported to the USGS National Wildlife Health Center or the Southeastern Cooperative Wildlife Disease Studies at the University of Georgia, or that State, Federal, and Tribal partners voluntarily report into WHISPers, not legal, and marked as
By
National Wildlife Health Center

Serologic Survey of Selected Arthropod Borne Pathogens in Free-ranging Snowshoe Hares (Lepus americanus) Captured in Northern Michigan, USA

We conducted a serosurvey of snowshoe hares (Lepus americanus) for vector-borne pathogens in 2016-2017 that were captured in the Hiawatha National Forest in the eastern Upper Peninsula of Michigan, USA. At capture, in addition to age, sex, body weight of the hare and a blood sample data was collected on the ecological land type (USDA Forest Service. 2006. Hiawatha National Forest 2006 Forest Plan.
By
National Wildlife Health Center

Mercury concentrations in amphibian tissues across the United States, 2016-2021

Comma-separated values (.csv) file containing data related to amphibian sampling across the United States between 2016 and 2021. Data files contain mercury concentrations in amphibian and dragonfly tissues, mercury concentrations in sediment, as well as amphibian morphometrics, and habitat and climate characteristics where the samples were collected.
By
Forest and Rangeland Ecosystem Science Center

Paranannizziopsis spp. associated with skin lesions in wild snakes in North America and development of a real-time PCR assay for rapid detection of the fungus in clinical samples

The emergence of ophidiomycosis (or snake fungal disease) in snakes has prompted increased awareness of the potential impacts of fungal infections on wild reptile populations. Yet, aside from Ophidiomyces ophidiicola, little is known about other mycoses affecting wild reptiles. The closely related genus Paranannizziopsis has been associated with dermatomycosis in snakes and tuataras in captive col
By
National Wildlife Health Center

Student Network for Amphibian Pathogen Surveillance Data (ver. 2.0, April 2024)

Data in this dataset were collected as a part of the Student Network for Amphibian Pathogen Surveilance (SNAPs) program throughout the United States by undergraduate students in biology or ecology courses as a part of their curriculum throughout 2022. This data was collected in the field by students and sent to the USGS National Wildlife Health Center (NWHC) for testing of two amphibian fungal pat
By
National Wildlife Health Center

Population genetic analysis of the snake-infecting fungus, Ophidiomyces ophidiicola, in the eastern United States

Snake fungal disease (SFD; ophidiomycosis), caused by the pathogen Ophidiomyces ophidiicola (Oo), has been documented in wild snakes in North America and Eurasia, and is a potentially emerging disease in the eastern USA. However, a lack of historical disease data has made it challenging to determine whether Oo is a recent arrival to the USA or whether SFD emergence is due to other factors. Here, w
By
Biological Threats and Invasive Species Research Program, National Wildlife Health Center

Amphibian chytrid swab data from Mendocino County, California (2016 - 2020)

This dataset includes results from external skin swabbing of Rana boylii and Dicamptodon tenebrosus to test for the fungus Batrachochytrium dendrobatidis from Fox Creek in Mendocino County, California, in 2016-2020. Morphological measurements of swabbed animals were recorded, and Rana boylii had a unique identifier (pit tag) inserted beneath their skin for identification in future capture events.
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Western Ecological Research Center (WERC)

Amphibian Chytrid Swab Data from Churchill County, Nevada (2019-2021)

This dataset includes results from external skin swabbing of Anaxyrus williamsi and Lithobates catesbeianus to test for the fungus Batrachochytrium dendrobatidis from the Dixie Valley in Churchill County, Nevada, in 2019-2021.
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Western Ecological Research Center (WERC)

Evaluating regulations and surveillance as risk-mitigation to the emerging amphibian pathogen Bsal- Data release

Results of a literature search performed December 1, 2020. The tables in this document summarize the publications fitting in this search criteria and are split into the publications that update the list of international species that could carry Bsal (Appendix 1 Table S1). Number of individual live amphibians imported in categories of urodelan (salamander, newt, and related taxa) species restricted
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Biological Threats and Invasive Species Research Program, National Wildlife Health Center
Dark colored newt on bright green vegetation.
Eastern newt (Notophthalmus viridescens) in Wisconsin
Eastern newt (Notophthalmus viridescens) in Wisconsin
Dark colored newt on bright green vegetation.

Eastern newt (Notophthalmus viridescens) in Wisconsin

Eastern newt (Notophthalmus viridescens) in Wisconsin

Eastern newt (Notophthalmus viridescens) in Wisconsin.

By
Ecosystems Mission Area, National Wildlife Health Center
Dark colored newt on bright green vegetation.

Eastern newt (Notophthalmus viridescens) in Wisconsin

Eastern newt (Notophthalmus viridescens) in Wisconsin

Eastern newt (Notophthalmus viridescens) in Wisconsin.

By
Ecosystems Mission Area, National Wildlife Health Center
Filter Total Items: 38

Serologic survey of selected arthropod-borne pathogens in free-ranging snowshoe hares (Lepus americanus) captured in Northern Michigan, USA

Snowshoe hares (Lepus americanus) in the Upper Peninsula (UP) of Michigan, USA, occupy the southern periphery of the species' range and are vulnerable to climate change. In the eastern UP, hares are isolated by the Great Lakes, potentially exacerbating exposure to climate-change-induced habitat alterations. Climate change is also measurably affecting distribution and prevalence of vector-borne pat
Authors
Erik K. Hofmeister, Eric Clark, Melissa Lund, Daniel A. Grear
By
Ecosystems Mission Area, National Wildlife Health Center

Chytrid infections exhibit historical spread and contemporary seasonality in a declining stream-breeding frog

Species with extensive geographical ranges pose special challenges to assessing drivers of wildlife disease, necessitating collaborative and large-scale analyses. The imperilled foothill yellow-legged frog (Rana boylii) inhabits a wide geographical range and variable conditions in rivers of California and Oregon (USA), and is considered threatened by the pathogen Batrachochytrium dendrobatidis (Bd
Authors
A.M. Belasen, R.A. Peek, A.J. Adams, I.D. Russell, M.E. De León, Michael J. Adams, J. Bettaso, K.G.H. Breedveld, A. Catenazzi, C.P. Dillingham, Daniel A. Grear, Brian J. Halstead, P.G. Johnson, Patrick M. Kleeman, M.S. Koo, C.W. Koppl, J.D. Lauder, G. Padgett-Flohr, J. Piovia-Scott, K.L. Pope, V. Vredenburg, M. Westphal, K. Wiseman, S.J. Kupferberg
By
Ecosystems Mission Area, National Wildlife Health Center, Western Ecological Research Center (WERC)

Paranannizziopsis spp. infections in wild snakes and a qPCR assay for detection of the fungus

The emergence of ophidiomycosis (or snake fungal disease) in snakes has prompted increased awareness of the potential effects of fungal infections on wild reptile populations. Yet, aside from Ophidiomyces ophidiicola, little is known about other mycoses affecting wild reptiles. The closely related genus Paranannizziopsis has been associated with dermatomycosis in snakes and tuataras in captive col
Authors
Jeffrey M. Lorch, Megan Winzeler, Julia S. Lankton, Stephen Raverty, Heindrich N Snyman, Helen M. Schwantje, Caeley Thacker, Susan Knowles, Hugh Y Cai, Daniel A. Grear
By
Ecosystems Mission Area, National Wildlife Health Center

Broad-scale assessment of methylmercury in adult amphibians

Mercury (Hg) is a toxic contaminant that has been mobilized and distributed worldwide and is a threat to many wildlife species. Amphibians are facing unprecedented global declines due to many threats including contaminants. While the biphasic life history of many amphibians creates a potential nexus for methylmercury (MeHg) exposure in aquatic habitats and subsequent health effects, the broad-scal

Authors
Brian J. Tornabene, Blake R. Hossack, Brian J. Halstead, Collin A. Eagles-Smith, Michael J. Adams, Adam R. Backlin, Adrianne Brand, Colleen Emery, Robert N. Fisher, Jillian Elizabeth Fleming, Brad Glorioso, Daniel A. Grear, Evan H. Campbell Grant, Patrick M. Kleeman, David Miller, Erin L. Muths, Christopher Pearl, Jennifer Rowe, Caitlin Teresa Rumrill, J. Hardin Waddle, Megan Winzeler, Kelly L. Smalling
By
Ecosystems Mission Area, Water Resources Mission Area, Contaminant Biology, Toxic Substances Hydrology, Eastern Ecological Science Center, Forest and Rangeland Ecosystem Science Center, Fort Collins Science Center, National Wildlife Health Center, New Jersey Water Science Center, Northern Rocky Mountain Science Center, Western Ecological Research Center (WERC), Wetland and Aquatic Research Center

Keeping the heat on: Weighted surveillance for Chytrid fungus (Batrachochytirum dendrobatidis) in Dixie Valley toads (Anaxyrus [= Bufo] williamsi)

Introduced fungal pathogens have caused declines and extinctions of naïve wildlife populations across vertebrate classes. Consequences of introduced pathogens to hosts with small ranges might be especially severe because of limited redundancy to rescue populations and lower abundance that may limit the resilience of populations to perturbations like disease introduction. As a complement to biosecu
Authors
Matthew J. Forrest, Brian J. Halstead, Daniel A. Grear, Patrick M. Kleeman, Brian D. Todd, Oliver J. Miano, Kris D. Urquhart
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Ecosystems Mission Area, National Wildlife Health Center, Western Ecological Research Center (WERC)

Epistylis spp. infestation in two species of mud turtles (Kinosternon spp.) in the American Southwest

The protistan genus Epistylis contains freshwater colonial species that attach to aquatic organisms in an epibiotic or parasitic relationship. They are known to attach to the epidermis and shells of aquatic turtles, but have not been reported to cause heavy infestations or morbidity in turtles. We documented heavy infestations of Epistylis spp. in several populations of Sonoran mud turtles (Kinost
Authors
Audrey K. Owens, Jennifer A. Smith, Rebecca A. Cole, Jeffrey M. Lorch, Daniel A. Grear
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Ecosystems Mission Area, National Wildlife Health Center

The population genetics of the causative agent of snake fungal disease indicate recent introductions to the USA

Snake fungal disease (SFD; ophidiomycosis), caused by the pathogen Ophidiomyces ophiodiicola (Oo), has been documented in wild snakes in North America and Eurasia, and is considered an emerging disease in the eastern United States of America. However, a lack of historical disease data has made it challenging to determine whether Oo is a recent arrival to the USA or whether SFD emergence is due to
Authors
Jason T. Ladner, Jonathan M. Palmer, Cassandra L. Ettinger, Jason E. Stajich, Terence M. Farrell, Brad M. Glorioso, Becki Lawson, Steven J. Price, Anne G. Stengle, Daniel A. Grear, Jeffrey M. Lorch
By
Ecosystems Mission Area, National Wildlife Health Center, Wetland and Aquatic Research Center

Quarterly wildlife mortality report October 2021

The USGS National Wildlife Health Center (NWHC) Quarterly Mortality Report provides brief summaries of epizootic mortality and morbidity events by quarter. The write-ups, highlighting epizootic events and other wildlife disease topics of interest, are published in the Wildlife Disease Association quarterly newsletter. A link is provided in this WDA newsletter to the Wildlife Health Information Sha
Authors
Bryan J. Richards, Daniel A. Grear, Shelby Jo Weidenkopf
By
Ecosystems Mission Area, National Wildlife Health Center

Acute mortality in California tiger salamander (Ambystoma californiense) and Santa Cruz long-toed salamander (Ambystoma macrodactylum croceum) caused by Ribeiroia ondatrae (Class: Trematoda)

In early September 2019, a morbidity and mortality event affecting California tiger salamanders (Ambystoma californiense) and Santa Cruz long-toed salamanders (Ambystoma macrodactylum croceum) in late stages of metamorphosis was reported at a National Wildlife Refuge in Santa Cruz County, California, U.S.A. During the postmortem disease investigation, severe integumentary metacercarial (Class: Tre
Authors
Saskia Keller, Constance Roderick, Christopher Caris, Daniel A. Grear, Rebecca A. Cole
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Ecosystems Mission Area, National Wildlife Health Center

Highly pathogenic avian influenza virus H5N2 (Clade 2.3.4.4) challenge of mallards age appropriate to the 2015 midwestern poultry outbreak

BackgroundThe 2015 highly pathogenic avian influenza virus (HPAIV) H5N2 clade 2.3.4.4 outbreak in upper midwestern U.S. poultry operations was not detected in wild birds to any great degree during the outbreak, despite wild waterfowl being implicated in the introduction, reassortment, and movement of the virus into North America from Asia. This outbreak led to the demise of over 50 million domesti
Authors
Jeffrey S. Hall, Daniel A. Grear, Scott Krauss, Patrick Seiler, Robert J. Dusek, Sean Nashold, Robert G. Webster
By
Ecosystems Mission Area, National Wildlife Health Center

Evaluation of regulatory action and surveillance as preventive risk-mitigation to an emerging global amphibian pathogen Batrachochytrium salamandrivorans (Bsal)

The emerging amphibian pathogen Batrachochytrium salamandrivorans (Bsal) is a severe threat to global urodelan (salamanders, newts, and related taxa) biodiversity. Bsal has not been detected, to date, in North America, but the risk is high because North America is one of the global hotspots for urodelan biodiversity. The North American and United States response to the discovery of Bsal in Europe
Authors
Daniel A. Grear, Brittany A. Mosher, Katherine Richgels, Evan H. Campbell Grant
By
Ecosystems Mission Area, Eastern Ecological Science Center, National Wildlife Health Center

Quarterly wildlife mortality report January 2021

The USGS National Wildlife Health Center (NWHC) Quarterly Mortality Report provides brief summaries of epizootic mortality and morbidity events by quarter. The write-ups, highlighting epizootic events and other wildlife disease topics of interest, are published in the Wildlife Disease Association quarterly newsletter. A link is provided in this WDA newsletter to the Wildlife Health Information Sha
Authors
Bryan J. Richards, Barbara Bodenstein, Daniel A. Grear, Hon S. Ip, Anne Ballmann, Julia S. Lankton, Valerie I. Shearn-Bochsler
By
Ecosystems Mission Area, National Wildlife Health Center

Non-USGS Publications**

Gorsich EE, Luis AD, Buhnerkempe MG, Grear DA, Portacci K, Miller RS, Webb CT. 2016. Mapping US cattle shipment networks: Spatial and temporal patterns of trade communities from 2009 to 2011. Preventive Veterinary Medicine, 134, 82-91.
Lavelle MJ, Kay SL, Pepin KM, Grear DA, Campa H, VerCauteren K. 2016. Evaluating wildlife-cattle contact rates to improve the understanding of dynamics of bovine tuberculosis transmission in Michigan, USA. Preventive Veterinary Medicine, 135, 28-36.
Scott A, B McCluskey, M Brown-Reid, DA Grear, P Pitcher, G Ramos, D Spencer. 2016. Porcine epidemic diarrhea virus introduction into the United States: Root cause investigation. Preventive Veterinary Medicine, 123, 192-201. doi: 10.1016/j.prevetmed.2015.11.013
Glaser L, M Carstensen, S Shaw, S Robbe-Austerman, A Wunschmann, DA Grear, T Stuber, B Thomsen. 2016. Descpriptive epidemiology and whole genome sequencing analysis for an outbreak of bovine tuberculosis in beef cattle and white-tailed deer in Northwestern Minnesota. PLoS ONE, e0145735.
McClure RSM, CL Burdett, ML Farnsworth, MW Lutman, DM Theobold, PD Riggs, DA Grear, RS Miller. 2015. Modeling and mapping the probability of occurrence of invasive wild pigs across the contiguous United States. PLoS ONE 10(8): e0133771. doi:10.1371/journal.pone.0133771
Pepin KM, CB Leach, C Marques-Toledo, KH Laass, KS Paixao, AD Luis, DTS Hayman, NG Johnson, MG Buhnerkempe, S Carver, DA Grear, K Tsao, AE Eiras, and CT Webb. 2015. Utility of mosquito surveillance data for spatial prioritization of vector control against dengue viruses in three Brazilian cities. Parasites and Vectors, 8, 98.
Tsao K, S Robbe-Austerman, RS Miller, K Portacci, DA Grear, and CT Webb. 2014. Sources of bovine tuberculosis in the United States. Infection, Genetics, and Evolution. 114, 201-212.
Luong LT, DA Grear, and PJ Hudson. 2014. Manipulation of host-resource dynamics impacts transmission of trophically transmitted parasites. International Journal for Parasitology, 44, 737-742.
Grear DA, J Kaneene, J Averill, and CT Webb. 2014. Local cattle movements in response to ongoing bovine TB zonation and regulations. Preventive Veterinary Medicine, 114, 201-212.
Buhnerkempe MG, MJ Tildesley, T Lindström, DA Grear, RS Miller, K Portacci, M Keeling, U Wennergren, and CT Webb. 2014. The impact of movements and animal density on continental scale cattle disease outbreaks in the United States. PLoS one, e91724.
Grear DA, LT Luong, and PJ Hudson. 2013. Network transmission inference: host behavior and parasite life-cycle make social networks meaningful in disease ecology, Ecological Applications, 23, 1906-1914.
Buhnerkempe, MG, DA Grear, RS Miller, K Portacci, J Lombard, and CT Webb. 2013. A national-scale picture of U.S. cattle movements obtained from Interstate Certificates of Veterinary Inspection data. Prev. Vet. Med., 112, 318-329.
Lindström T, DA Grear, MG Buhnerkempe, CT Webb, RS Miller, K Portacci, and U Wennergren. 2013. Bayesian approach for modeling cattle movements in the United States: scaling up a partially observed network. PLoS ONE,8, e53432. doi:10.1371/journal.pone.0053432
Grear DA, LT Luong, and PJ Hudson. 2012. Sex-biased transmission of a complex life-cycle parasite: why males matter. Oikos, 121, 1446-1453. doi: 10.1111/j.1600-0706.2012.20358.x
Blanchong, JA, DA Grear, BV Weckworth, DP Keane, KT Scribner, and MD Samuel. 2012. Effects of chronic wasting disease on reproduction and fawn harvest vulnerability in Wisconsin white-tailed deer. Journal of Wildlife Diseases, 48, 361-370.
Rogers K, S Robinson, MD Samuel, and DA Grear. 2011. Diversity and distribution of white-tailed deer mtDNA lineages in CWD outbreak areas in southern Wisconsin, USA. Journal of Toxicology and Environmental Health, 74, 1521-1535. doi: 10.1080/15287394.2011.618980
Grear DA and PJ Hudson. 2011. The dynamics of macroparasite host-self-infection: a study of the patterns and processes of pinworm (Oxyuridae) aggregation. Parasitology, 138, 619-617. doi: 10.1017/S0031182011000096.
Grear DA, MD Samuel, K Scribner, BV Weckworth, and JA Langenberg. 2010. Influence of genetic relatedness and spatial proximity on CWD transmission among female white-tailed deer. Journal of Applied Ecology, 47, 532-540.
Luong, LT, SE Perkins, DA Grear, A Rizzoli, and PJ Hudson. 2010. The relative importance of host characteristics and co-infection in generating variation in Heligmosomoides polygyrus fecundity. Parasitology, 137, 1003-1012.
Grear DA, SE Perkins, and PJ Hudson. 2009. Does elevated testosterone result in increased exposure and transmission of parasites? Ecology Letters, 12, 528-537.
Luong, LT, DA Grear, and PJ Hudson. 2009. Male hosts are responsible for the transmission of a trophically transmitted parasite, Pterygodermatites peromysci to the intermediate host in the absence of sex-biased infection. International Journal for Parasitology, 39, 1263-1268.
Grear DA, MD Samuel, JA Langenberg, and D Keane. 2006. Demographic patterns and harvest vulnerability of chronic wasting disease infected white-tailed deer in Wisconsin. Journal of Wildlife Management, 70, 546-553.

**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.

Preventive actions in response to the Bsal threat reduced Bsal risk in the U.S.

Preventive actions in response to the Bsal threat reduced Bsal risk in the U.S.

Import regulations and a large surveillance effort have reduced the risk of Batrachochytrium salamandrivorans (Bsal) introduction to the United States...

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A Unified Research Strategy for Disease Management

A Unified Research Strategy for Disease Management

As wildlife diseases increase globally, an understanding of host-pathogen relationships can elucidate avenues for management and improve conservation...

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*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government

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