Veterinary Microbiology and Immunobiology Commons^™

Feral Swine As Indirect Indicators Of Environmental Anthrax Contamination And Potential Mechanical Vectors Of Infectious Spores, Rachel M. Maison, Maggie R. Priore, Vienna R. Brown, Michael Bodenchuk, Bradley R. Borlee, Richard Bowen, Angela M. Bosco-Lauth

United States Department of Agriculture Wildlife Services: Staff Publications

U.S. government work

Optimal R&D Investment In The Management Of Invasive Species, William Haden Chomphosy, Dale T. Manning, Stephanie A. Shwiff, Stephan Weiler

United States Department of Agriculture Wildlife Services: Staff Publications

Invasive alien species (IAS) threaten world biodiversity, ecosystem services, and economic welfare. While existing literature has characterized the optimal control of an established IAS, it has not considered how research and development (R&D) into new removal methods or technologies can affect management decisions and costs over time. R&D can lower the costs of control in a management plan and creates an intertemporal trade-off between quick but costly control and gradual but cheaper removal over time. In this paper, we develop and solve a continuous time dynamic optimization model to study how investment in R&D influences the optimal control of an …

Highly Pathogenic Avian Influenza A(H5n1) Virus Outbreak In New England Seals, United States, Wendy Puryear, Kaitlin Sawatzki, Nichola Hill, Alexa Foss, Jonathon J. Stone, Lynda Doughty, Dominique Walk, Katie Gilbert, Maureen Murray, Elena Cox, Priya Patel, Zak Mertz, Stephanie Ellis, Jennifer Taylor, Deborah Fauquier, Ainsley Smith, Robert A. Digiovanni, Adriana Van De Guchte, Ana Silvia Gonzalez-Reiche, Zain Khalil, Harm Van Bakel, Mia K. Torchetti, Kristina Lantz, Julianna B. Lenoch, Jonathan Runstadler

United States Department of Agriculture Wildlife Services: Staff Publications

We report the spillover of highly pathogenic avian influenza A(H5N1) into marine mammals in the northeastern United States, coincident with H5N1 in sympatric wild birds. Our data indicate monitoring both wild coastal birds and marine mammals will be critical to determine pandemic potential of influenza A viruses.

An Evaluation Of Avian Influenza Virus Whole-Genome Sequencing Approaches Using Nanopore Technology, Hon S. Ip, Sarah Uhm, Mary Lea Killian, Mia K. Torchetti

United States Department of Agriculture Wildlife Services: Staff Publications

As exemplified by the global response to the SARS-CoV-2 pandemic, whole-genome sequencing played an important role in monitoring the evolution of novel viral variants and provided guidance on potential antiviral treatments. The recent rapid and extensive introduction and spread of highly pathogenic avian influenza virus in Europe, North America, and elsewhere raises the need for similarly rapid sequencing to aid in appropriate response and mitigation activities. To facilitate this objective, we investigate a next-generation sequencing platform that uses a portable nanopore sequencing device to generate and present data in real time. This platform offers the potential to extend in-house sequencing …

Environmental Transmission Of Influenza A Virus In Mallards, Kim M. Pepin, Clinton B. Leach, Nicole L. Barrett, Jeremy W. Ellis, Kaci K. Vandalen, Colleen T. Webb, Susan A. Shriner

United States Department of Agriculture Wildlife Services: Staff Publications

Abstract

Influenza A viruses present a major challenge for animal and human health. They circulate widely in wild waterfowl and frequently spillover into poultry, emphasizing the need for risk-based surveillance in wild birds and an understanding of the relative importance of different transmission mechanisms. We addressed this objective with a replicated (N = 6) experimental infection study in which we serially exposed eight cohorts of four naïve contact mallards to an experimentally infected mallard and a shared water pool. Viral concentration in the water was a better predictor of transmission than several direct measures of viral shedding in the …

Changes In Wild Pig (Sus Scrofa) Relative Abundance, Crop Damage, And Environmental Impacts In Response To Control Efforts, Joseph W. Treichler, Kurt C. Vercauteren, Charles R. Taylor, James C. Beasley

United States Department of Agriculture Wildlife Services: Staff Publications

Background

As the population and range of wild pigs (Sus scrofa) continue to grow across North America, there has been an increase in environmental and economic damages caused by this invasive species, and control efforts to reduce damages have increased concomitantly. Despite the expanding impacts and costs associated with population control of wild pigs, the extent to which wild pig control reduces populations and diminishes environmental and agricultural damages are rarely quantified.The goal of this study is to quantify changes in wild pig relative abundance and subsequent changes in damages caused by invasive wild pigs in response to …

Individual‑Level Patterns Of Resource Selection Do Not Predict Hotspots Of Contact, Anni Yang, Raoul Boughton, Ryan S. Miller, Nathan P. Snow, Kurt C. Vercauteren, Kim C. Pepin, George Wittemyer

United States Department of Agriculture Wildlife Services: Staff Publications

Contact among animals is crucial for various ecological processes, including social behaviors, disease transmission, and predator–prey interactions. However, the distribution of contact events across time and space is heterogeneous, influenced by environmental factors and biological purposes. Previous studies have assumed that areas with abundant resources and preferred habitats attract more individuals and, therefore, lead to more contact. To examine the accuracy of this assumption, we used a use-available framework to compare landscape factors influencing the location of contacts between wild pigs (Sus scrofa) in two study areas in Florida and Texas (USA) from those influencing non-contact space use. …

Comparison Of Daily Activity Patterns Across Seasons Using Gps Telemetry And Camera Trap Data For A Widespread Mammal, David W. Wolfson, Peter E. Schlichting, Raoul K. Boughton, Ryan S. Miller, Kurt C. Vercauteren, Jesse S. Lewis

United States Department of Agriculture Wildlife Services: Staff Publications

Daily activity patterns of animals can be dynamic across seasons in response to changing environmental conditions. Daily activity, though, has rarely been evaluated in relation to multiple factors (for example, seasons, demographics, and data collection methods), which could be important for understanding what drives activity patterns. Here, we evaluated the daily activity patterns of a widespread invasive species, wild pigs (Sus scrofa), across two ecologically different study areas at Buck Island Ranch, Florida, and Tejon Ranch, California (United States), from 2015 to 2018. Using GPS telemetry data (62 individuals in Florida, 21 individuals in California) and detections from …

Are Rabid Raccoons (Procyon Lotor) Ready For The Rapture? Determining The Geographic Origin Of Rabies Virus-Infected Raccoons Using Radcapture And Microhaplotypes, Matthew W. Hopken, Antoinette J. Piaggio, Zaid Abdo, Richard B. Chipman, Clara P. Mankowski, Kathleen M. Nelson, Mikaela Samsel Hilton, Christine Thurber, Mirian T. N. Tsuchiya, Jesús E. Maldonado, Amy T. Gilbert

United States Department of Agriculture Wildlife Services: Staff Publications

North America is recognized for the exceptional richness of rabies virus (RV) wildlife reservoir species. Management of RV is accomplished through vaccination targeting mesocarnivore reservoir populations, such as the raccoon (Procyon lotor) in eastern North America. Raccoons are a common generalist species, and populations may reach high densities in developed areas, which can result in contact with humans and pets with potential exposures to the raccoon variant of RV throughout the eastern United States. Understanding the spatial movement of RV by raccoon populations is important for monitoring and refining strategies supporting the landscape-level control and local elimination of …

Type And Frequency Of Wild Pig-Domestic Livestock Contacts And Operator Concern For Disease Spread, Sophie C. Mckee, Daniel F. Mooney, Ryan S. Miller

United States Department of Agriculture Wildlife Services: Staff Publications

Wild pigs (Sus scrofa) can levy substantial costs to domestic livestock operations and global supply chains due to disease introduction. Producers can take defensive action to avert these costs, but the factors influencing these decisions are not well understood. We examined survey data to characterize the type and frequency of contacts between wild pigs and domestic livestock and investigated the determinants of farm operator concern for disease introduction using an ordered logit model. We found that operators with livestock kept in buildings were more concerned about disease than those with livestock kept in fenced areas or that roam …

Echinococcus Species Infections Among Wild Canids In Pennsylvania, Usa, Kayla Garrett, Justin Brown, Ryan K. A. Grunert, Jonathan Hunte, Mark G. Ruder, Kyle Van Why, Michael J. Yabsley, Christopher A. Cleveland

United States Department of Agriculture Wildlife Services: Staff Publications

Echinococcus species are zoonotic tapeworms that can impact the health of wildlife, domestic animals, livestock, and humans. Two species of interest in North America are Echinococcus multilocularis and Echinococcus canadensis (Echinococcus granulosus sensu lato). The primary wildlife definitive hosts for E. multilocularis and E. canadensis are similar, including red foxes (Vulpes vulpes), gray foxes (Urocyon cinereoargenteus), coyotes (Canis latrans), and wolves (Canis lupus). These two Echinococcus spp. use different intermediate hosts, including small mammals for E. multilocularis and artiodactylids for E. canadensis. Although historically absent from …

Raccoon Densities Across Four Land Cover Types In The Southeastern United States, Jocab E. Hill, James L. Helton, David A. Bernasconi, Wesley C. Dixon, Matt T. Hamilton, Richard B. Chipman, Amy T. Gilbert, James C. Beasley, Guha Dharmarajan, Olin E. Rhodes Jr.

United States Department of Agriculture Wildlife Services: Staff Publications

Raccoons (Procyon lotor) are the primary reservoir for rabies virus in eastern North America. Management of rabies in raccoons is achieved primarily with the use of oral rabies vaccination (ORV) and effective ORV bait densities are determined in part by the densities of raccoons. Decisions regarding ORV bait densities, however, are limited by an incomplete understanding of raccoon densities across the spectrum of landscapes they occupy. We carried out a markrecapture study of raccoons on the Savannah River Site in South Carolina, USA, from 2017–2019, to develop sex‐ and landscape‐specific raccoon density estimates across 4 rural land cover …

Understory Arthropod Diversity In A Mixed Dryland Ecosystem, Hawai‘I, Matthew J. Madeiros, William P. Haines, Clare E. Aslan, Aaron B. Shiels, Asa Aue, Christina T. Liang

United States Department of Agriculture Wildlife Services: Staff Publications

Tropical drylands are among the most threatened ecosystems worldwide, and fewer than 10% of tropical dry forests in Hawai‘i remain intact. Terrestrial arthropods comprise most of the endemic fauna on many islands, including Hawai‘i, where they provide ecosystem services such as pollination, decomposition, and a reliable prey base for predators. The objective of our study was to measure understory arthropod diversity and relative abundances in two common habitat types within dryland Hawai‘i—a non-native grassland, dominated by Cenchrus setaceus (fountain grass) with few native shrubs, and a native woodland, dominated by Metrosideros polymorpha (‘ōhi‘a). We used generalized additive models to examine …

Range-Wide Sources Of Variation In Reproductive Rates Of Northern Spotted Owls, Jeremy T. Rockweit, Julianna M. Jenkins, James E. Hines, James D. Nichols, Katie M. Dugger, Alan B. Franklin, Peter C. Carlson, William L. Kendall, Damon B. Lesmeister, Christopher Mccafferty, Steven H. Ackers, L. Steven Andrews, Larissa L. Bailey, Jesse Burgher, Kenneth P. Burnham, Tara Chestnut, Mary M. Conner, Raymond J. Davis, Krista E. Dilione, Eric D. Forsman, Elizabeth M. Glenn, Scott A. Gremel, Keith A. Hamm, Dale R. Herter, J. Mark Higley, Rob B. Horn, David W. Lamphear, Trent L. Mcdonald, Janice A. Reid, Carl J. Schwarz, David C. Simon, Stan G. Sovern, James K. Swingle, J. David Wiens, Heather Wise, Charles B. Yackulic

United States Department of Agriculture Wildlife Services: Staff Publications

We conducted a range-wide investigation of the dynamics of site-level reproductive rate of northern spotted owls using survey data from 11 study areas across the subspecies geographic range collected during 1993–2018. Our analytical approach accounted for imperfect detection of owl pairs and misclassification of successful reproduction (i.e., at least one young fledged) and contributed further insights into northern spotted owl population ecology and dynamics. Both nondetection and state misclassification were important, especially because factors affecting these sources of error also affected focal ecological parameters. Annual probabilities of site occupancy were greatest at sites with successful reproduction in the previous year …

Evaluation Of Roost Culling As A Management Strategy For Reducing Invasive Rose‑Ringed Parakeet (Psittacula Krameri) Populations, C. Janes Anderson, Leonard A. Brennan, William P. Bukoski, Steven C. Hess, Clayton D. Hilton, Aaron B. Shiels, Shane Siers, Bryan M. Kluever, Page E. Klug

United States Department of Agriculture Wildlife Services: Staff Publications

Rose-ringed parakeets (Psittacula krameri) are one of the most widespread invasive avian species worldwide. This species was introduced to the island of Kaua‘i, Hawai‘i, USA, in the 1960s. The rapidly increasing population has caused substantial economic losses in the agricultural and tourism industries. We evaluated the efficacy of a roost culling program conducted by an independent contractor from March 2020 to March 2021. We estimated island-wide minimum abundance was 10,512 parakeets in January 2020 and 7,372 in April 2021. Over 30 nights of culling at four roost sites, approximately 6,030 parakeets were removed via air rifles with 4,415 …

Social Network Analysis Of White-Tailed Deer Scraping Behavior: Implications For Disease Transmission, Michael E. Egan, Kim M. Pepin, Justin Fischer, Scott R. Hygnstrom, Kurt C. Vercauteren, Guillaume Bastille-Rousseau

United States Department of Agriculture Wildlife Services: Staff Publications

Host contact structure affects pathogen transmission in host populations, but many measures of host contact do not distinguish contacts that are relevant to pathogen transmission from those that are not. Scrapes are sites for chemical communication by white-tailed deer (Odocoileus virginianus) during the breeding season and potential sites of transmission of prions, the causative agent of chronic wasting disease (CWD). Scrape-related behaviors vary in their probability of transmitting prions to or from the environment, suggesting that behavior be combined with contact structure to better reflect potential heterogeneity in prion transmission at scrapes. We recorded visits and behaviors by …

High Winds And Melting Sea Ice Trigger Landward Movement In A Polar Bear Population Of Concern, Annie Kellner, Todd C. Atwood, David C. Douglas, Stewart W. Breck, Colorado State University - Fort Collins

United States Department of Agriculture Wildlife Services: Staff Publications

Some animal species are responding to climate change by altering the timing of events like mating and migration. Such behavioral plasticity can be adaptive, but it is not always. Polar bears (Ursus maritimus) from the southern Beaufort Sea subpopulation have mostly remained on ice year-round, but as the climate warms and summer sea ice declines, a growing proportion of the subpopulation is summering ashore. The triggers of this novel behavior are not well understood. Our study uses a parametric time-to-event model to test whether biological and/or time-varying environmental variables thought to influence polar bear movement and habitat selection …

Space Use And Movements Of Southeastern Breeding Double-Crested Cormorants (Nannopterum Auritum) In The United States, Leah L.K. Moran, Brian S. Dorr, Katie C. Hanson-Dorr, R. J. Moore, Scott A. Rush

United States Department of Agriculture Wildlife Services: Staff Publications

Abstract: Seasonal movements of Double-crested Cormorants (Nannopterum auritum) have been studied at breeding and wintering sites in the southeastern United States, but little information exists on the movements of these birds within and from their southern breeding sites in lacustrine systems. Since 2001, cormorants have established nesting colonies on islands in Guntersville Reservoir in Alabama, USA. Following the movements of tagged cormorants using satellite telemetry, we found that the mean home range during the 2017 breeding season (May–August) was 41.76 km², with a core use area of 6.36 km². The mean home range used …

Disease Progression And Serological Assay Performance In Heritage Breed Pigs Following Brucella Suis Experimental Challenge As A Model For Naturally Infected Feral Swine, Vienna R. Brown, Ryan S. Miller, Courtney F. Bowden, Timothy J. Smyser, Nicholas A. Ledesma, Aim E. Hartwig, Paul Gordy, Aaron M. Anderson, Stephanie M. Porter, Kate Alexander, Zane Gouker, Tom Gidlewski, Richard A. Bowen, Angela M. Bosco-Lauth

United States Department of Agriculture Wildlife Services: Staff Publications

Invasive feral swine (Sus scrofa) are one of the most important wildlife species for disease surveillance in the United States, serving as a reservoir for various diseases of concern for the health of humans and domestic animals. Brucella suis, the causative agent of swine brucellosis, is one such pathogen carried and transmitted by feral swine. Serology assays are the preferred field diagnostic for B. suis infection, as whole blood can be readily collected and antibodies are highly stable. However, serological assays frequently have lower sensitivity and specificity, and few studies have validated serological assays for B. suis in feral swine. …

Evaluation Of The Effect Of Hydrated Lime On The Scavenging Of Feral Swine (Sus Scrofa) Carcasses And Implications For Managing Carcass-Based Transmission Of African Swine Fever Virus, Courtney F. Bowden, James Grinolds, Gregory Franckowiak, Loma Mccallister, Joe M. Halseth, Matthew Cleland, Travis Guerrant, Michael J. Bodenchuk, Robert Miknis, Michael C. Marlow, Vienna R. Brown

United States Department of Agriculture Wildlife Services: Staff Publications

African swine fever (ASF) is a devastating hemorrhagic disease marked by extensive morbidity and mortality in infected swine. The recent global movement of African swine fever virus (ASFV) in domestic and wild swine (Sus scrofa) populations has initiated preparedness and response planning activities within many ASF-free countries. Within the US, feral swine are of utmost concern because they are susceptible to infection, are wide-spread, and are known to interact with domestic swine populations. African swine fever virus is particularly hardy and can remain viable in contaminated carcasses for weeks to months; therefore, carcass-based transmission plays an important role in the …

H7n9 Influenza A Virus Transmission In A Multispecies Barnyard Model, Angela M. Bosco-Lauth, Anna Rodriguez, Rachel M. Maison, Stephanie M. Porter, J. Jeffrey Root

United States Department of Agriculture Wildlife Services: Staff Publications

Influenza A viruses are a diverse group of pathogens that have been responsible for millions of human and avian deaths throughout history. Here, we illustrate the transmission potential of H7N9 influenza A virus between Coturnix quail (Coturnix sp.), domestic ducks (Anas platyrhynchos domesticus), chickens (Gallus gallus domesticus), and house sparrows (Passer domesticus) co-housed in an artificial barnyard setting. In each of four replicates, individuals from a single species were infected with the virus. Quail shed virus orally and were a source of infection for both chickens and ducks. Infected chickens transmitted the virus to quail but not to ducks or …

Writing Statistical Methods For Ecologists, Amy J. Davis, Shannon Kay

United States Department of Agriculture Wildlife Services: Staff Publications

The Methods section is a key component of any ecology research publication containing detailed information on how the data were collected and analyzed. However, descriptions of which statistical methods were used and how they were applied can substantially vary and may not provide enough information for the analyses to be reproducible. Computational and statistical programming advances have allowed ecological researchers without a strong statistical or mathematical background to access and use increasingly complex statistical methods. Thus, statistical methods are written by and need to be accessible to researchers across a range of quantitative expertise. Poorly written Methods sections can incorrectly …

Variance In Offspring Sex Ratio And Maternal Allocation In A Highly Invasive Mammal, Sarah M. Chinn, Timothy J. Smyser, James C. Beasley

United States Department of Agriculture Wildlife Services: Staff Publications

Skewed sex ratios at birth are widely reported in wild populations, however, the extent to which parents are able to modulate the sex ratio of offspring to maximize their own fitness remains unclear. This is particularly true for highly polytocous species as maximizing fitness may include trade-offs between sex ratio and the size and number of offspring in litters. In such cases, it may be adaptive for mothers to adjust both the number of offspring per litter and offspring sex to maximize individual fitness. Investigating maternal sex allocation in wild pigs (Sus scrofa) under stochastic environmental conditions, we predicted that …

Perturbations Highlight Importance Of Social History In Parakeet Rank Dynamics, Annemarie Van Der Marel, Xavier Francis, Claire L. O'Connell, Cesar O. Estien, Chelsea Carminito, Virginia Darby Moore, Nickolas Lormand, Bryan M. Kluever, Elizabeth A. Hobson

United States Department of Agriculture Wildlife Services: Staff Publications

Dominance hierarchies can provide many benefits to individuals, such as access to resources or mates, depending on their ranks. In some species, rank can emerge as a product of a group’s history of social interactions. However, it can be difficult to determine whether social history is critical to rank in observation-based studies. Here, we investigated rank dynamics in three captive groups of monk parakeets (Myiopsitta monachus). We used experimental social perturbations to test whether social history shapes rank emergence in these groups. Using targeted removals and reintroductions, we tested whether differently ranked individuals could re-take their ranks in hierarchies after …

Distribution Of The Misfolded Isoform Of The Prion Protein In Peripheral Tissues And Spinal Cord Of Rocky Mountain Elk (Cervus Elaphus Nelsoni) With Naturally Occurring Chronic Wasting Disease, Terry R. Spraker, Thomas Gidlewski, J. G. Powers, T. A. Nichols, M. A. Wild

United States Department of Agriculture Wildlife Services: Staff Publications

Chronic wasting disease (CWD) is an infectious transmissible spongiform encephalopathy of cervids associated with the presence of a misfolded prion protein (PrPCWD). Progression of PrPCWD distribution has been described using immunohistochemistry and histologic changes in a single section of brain stem at the level of the obex resulting in scores from 0 (early) to 10 (terminal) in elk with naturally occurring CWD. Here we describe the spread and distribution of PrPCWD in peripheral tissues and spinal cord in 16 wild and 17 farmed Rocky Mountain elk (Cervus elaphus nelsoni) with naturally occurring CWD and correlate these findings with obex scores. …

Predator Telemetry Informs Temporal And Spatial Overlap With Stocked Salmonids In Lake Huron, David G. Fielder, Todd A. Hayden, Thomas R. Binder, Brian S. Dorr, Heidi A. Currier

United States Department of Agriculture Wildlife Services: Staff Publications

Double-Crested Cormorants (Phalacrocorax auratus), Walleyes (Sander vitreus), and Lake Trout (Salvelinus namaycush) are migratory predators that undergo extensive movements in Lake Huron. Stocking of juvenile salmonid fish (Oncorhynchus and Salmo sp.) is an important component of fishery management in Lake Huron and assessing the spatial and temporal extent of predator movements is a useful consideration for determining when and where to stock juvenile fish to reduce predation and maximize survival. Previous investigation indicated that some Walleyes migrate to the main basin of Lake Huron in spring from Saginaw Bay. Similarly, telemetry studies of Lake Trout movement in Lake Huron have …

Fusion Of Visible And Thermal Images Improves Automated Detection And Classification Of Animals For Drone Surveys, B. Santhana Krishnan, Landon R. Jones, Jared A. Elmore, Sathishkumar Samiappan, Kristine O. Evans, Morgan Pfeiffer, Bradley Blackwell, Raymond Iglay

United States Department of Agriculture Wildlife Services: Staff Publications

Visible and thermal images acquired from drones (unoccupied aircraft systems) have substantially improved animal monitoring. Combining complementary information from both image types provides a powerful approach for automating detection and classification of multiple animal species to augment drone surveys. We compared eight image fusion methods using thermal and visible drone images combined with two supervised deep learning models, to evaluate the detection and classification of white-tailed deer (Odocoileus virginianus), domestic cow (Bos taurus), and domestic horse (Equus caballus). We classified visible and thermal images separately and compared them with the results of image fusion. …

Biodiversity Indices And Random Forests Reveal The Potential For Striped Skunk (Mephitis Mephitis) Fecal Microbial Communities To Function As A Biomarker For Oral Rabies Vaccination, Matthew W. Hopken, Darby Gilfillan, Amy Gilbert, Antoinette J. Piaggio, Mikaela Samsel Hilton, James Pierce, Bruce Kimball, Zaid Abdo

United States Department of Agriculture Wildlife Services: Staff Publications

Wildlife disease surveillance and monitoring poses unique challenges when assessing rates of population vaccination, immunity, or infection prevalence. Non-invasively detected biomarkers can help reduce risk to both animal and field personnel during wildlife disease management activities. In this study, we investigated the utility of fecal microbiome data collected from captive striped skunks (Mephitis mephitis) in predicting rabies virus vaccination and infection status. We sequenced the hypervariable region 4 (V4) of the bacterial 16S gene and estimated alpha and beta diversity across timepoints in three groups of skunks: vaccination then rabies virus infection, sham vaccination then rabies virus infection, and rabies …

Determination Of Residue Levels Of Rodenticide In Rodent Livers Offered Novel Diphacinone Baits By Liquid Chromatography-Tandem Mass Spectrometry, David A. Goldade, Shane Siers, Steven C. Hess, Robert T. Sugihara, Craig A. Riekena

United States Department of Agriculture Wildlife Services: Staff Publications

A specific and sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for the determination of the anticoagulant rodenticide diphacinone (DPN) in mouse and rat liver. Tissue samples were extracted with a mixture of water and acetonitrile containing ammonium hydroxide. The extracted sample was cleaned up with a combination of liquid-liquid partitioning and dispersive solid phase extraction. Chromatographic separation was achieved using a Waters X-Bridge BEH C-18 LC column (50 mm, 2.1 mm ID, 2.5 μm particle size) with detection on a triple quadrupole mass spectrometer in multiple reaction monitoring (MRM) mode. The monitored transition for DPN was m/z …

Controllable Factors Affecting Accuracy And Precision Of Human Identification Of Animals From Drone Imagery, Landon R. Jones, Jared A. Elmore, B. Santhana Krishnan, Sathishkumar Samiappan, Kristine O. Evans, Morgan B. Pfeiffer, Brad Blackwell, Raymond Iglay

United States Department of Agriculture Wildlife Services: Staff Publications

Surveying animal populations using drones (unoccupied aircraft systems [UAS]) provides numerous advantages; however, few best practices exist to survey animal communities with drones. Among myriad factors that can affect human identification and counts of animals from drone images, we focused on three factors typically controlled in the study design or by the drone pilot: flight altitude, camera angle, and time of day. Identifying interactions and patterns among these three variables represents an important first step to determining best survey practices. We used a drone to survey known numbers of eight animal decoy species, representing a range of body sizes and …