Veterinary Infectious Diseases Commons^™

European Starling Nest‐Site Selection Given Enhanced Direct Nest Predation Risk, Bradley Blackwell, Thomas W. Seamans, Morgan Pfeiffer, Bruce N. Buckingham

USDA Wildlife Services: Staff Publications

The European starling (Sturnus vulgaris) is recognized, outside its native range, as an invasive species, and efforts to deter its nesting have generally been unsuccessful. Enhancing perceived risk at the nest site is a little‐explored route in developing a nest deterrent. Specifically, nest predation risk affects site selection, reproduction, antipredator behavior, and fitness in nesting birds. We questioned whether perceived predation risk as related to a snake model positioned inside a nest box, in striking form, moving, and present throughout the period of cavity site selection would induce European starlings to avoid or delay nest construction. We conducted our study …

Efficacy And Risks From A Modified Sodium Nitrite Toxic Bait For Wild Pigs, Nathan P. Snow, Jason Wishart, Justin A. Foster, Linton D. Staples, Kurt C. Vercauteren

USDA Wildlife Services: Staff Publications

BACKGROUND: Wild pigs (Sus scrofa) are a destructive invasive species throughout many regions of the world. In 2018, a field evaluation of an early prototype of a sodium nitrite (SN) toxic bait in the United States revealed wild pigs dropped large amounts of the toxic bait outside the pig-specific bait stations while feeding, and thus subsequent hazards for non-target animals. We modified the SN-toxic bait formulation, the design of the bait station, and the baiting strategy to reduce dropped bait. We tested the modifications in Queensland, Australia (December 2018), Alabama, USA (August 2019), and Texas, USA (March 2020) …

Powassan Virus Experimental Infections In Three Wild Mammal Species, Nicole M. Nemeth, J. Jeffrey Root, Airn E. Hartwig, Richard A. Bowen, Angela M. Bosco-Lauth

USDA Wildlife Services: Staff Publications

Powassan virus (POWV) is a tick-borne virus maintained in sylvatic cycles between mammalian wildlife hosts and ticks (primarily Ixodes spp.). There are two currently recognized lineages, POWV-lineage 1 (POWV-L1) and deer tick virus (DTV; lineage 2), both of which can cause fatal neurologic disease in humans. Increased numbers of human case reports in the northeastern and north central United States in recent years have fueled questions into POWV epidemiology. We inoculated three candidate wildlife POWV reservoir hosts, groundhogs (Marmota monax), striped skunks (Mephitis mephitis), and fox squirrels (Sciurus niger), with either POWV-L1 or DTV. …

Evaluating Lethal Toxicant Doses For The Largest Individuals Of An Invasive Vertebrate Predator With Indeterminate Growth, Shane R. Siers, Scott M. Goetz, Rachel M. Volsteadt, Melia G. Nafus

USDA Wildlife Services: Staff Publications

The brown treesnake (Boiga irregularis) was accidentally introduced to Guam and caused severe ecological and economic damages. Acetaminophen is an effective, low-risk oral toxicant for invasive brown treesnakes, and an automated aerial delivery system (ADS) has been developed for landscape-scale toxic bait distribution. A fixed dose of 80 mg of acetaminophen within a tablet inserted into a dead neonatal mouse (DNM) was lethal for all brown treesnakes in previous trials; however, these trials did not include very large individuals which are difficult to acquire for testing. Because most reptiles continue to grow throughout their lifespan, a small number …

Toxoplasma Gondii Prevalence In Carnivorous Wild Birds In The Eastern United States, Sawsan Ammar, Liberty Wood, Chunlei Su, Maria Spriggs, Justin Brown, Kyle Van Why, Richard Gerhold

USDA Wildlife Services: Staff Publications

Toxoplasma gondii is an important zoonotic protozoan parasite that can infect all warm-blooded animals including mammals and birds. Raptors can be intermediate hosts for T. gondii and the infection may be dependent on their feeding habits. In this study, we investigated the seroprevalence of T. gondii in ten raptor species from Florida, Pennsylvania, and Tennessee followed by a parasite bioassay on select seropositive samples. From a total of 155 raptors, we detected T. gondii antibodies using a modified agglutination test (cutoff 1:25) in 32 (20.6%) birds. The T. gondii seroprevalence was 44.8% in Falconiformes (13/29), 75% in Strigiformes (15/20), and …

Rabies Post-Exposure Healthcare-Seeking Behaviors And Perceptions: Results From A Knowledge, Attitudes, And Practices Survey, Uganda, 2013, Sarah C. Bonaparte, Laura Adams, Barnabas Bakamutumaho, Galileu Barbosa Costa, Julie M. Cleaton, Amy Gilbert, Modupe Osinubi, Emily G. Pieracci, Sergio Recuenco, Victor Tugumizemu, Joseph Wamala, Ryan M. Wallace

USDA Wildlife Services: Staff Publications

Background Rabies is a viral disease of animals and people causing fatal encephalomyelitis if left untreated. Although effective pre- and post-exposure vaccines exist, they are not widely available in many endemic countries within Africa. Since many individuals in these countries remain at risk of infection, post-exposure healthcare-seeking behaviors are crucial in preventing infection and warrant examination.

Methodology A rabies knowledge, attitudes, and practices survey was conducted at 24 geographically diverse sites in Uganda during 2013 to capture information on knowledge concerning the disease, response to potential exposure events, and vaccination practices. Characteristics of the surveyed population and of the canine-bite …

Oral Rabies Vaccination Of Small Indian Mongooses (Urva Auropunctata) With Onrab Via Ultralite Baits, Are R. Berentsen, Israel Leinbach, Mel J. Rivera-Rodriguez, Amy T. Gilbert

USDA Wildlife Services: Staff Publications

The Ontario Rabies Vaccine (ONRAB) is a human adenovirus rabies glycoprotein recombinant oral vaccine immunogenic for small Indian mongooses when delivered by direct instillation into the oral cavity. We offered Ultralite baits containing ~1.8 mL 109.5 TCID50 ONRAB oral rabies vaccine to 18 mongooses, while 6 mongooses were offered identical baits in placebo form. We collected sera from individual mongooses at days 0, 14 and 30 post vaccination (pv) and quantified rabies virus neutralizing antibodies (RVNA) using the rapid fluorescent focus inhibition test, with titers greater than or equal to 0.1 IU/mL considered positive. All study subjects were RVNA negative …

The Consequences Of Predators Without Prey, Mitchell A. Parsons, Thomas M. Newsome, Julie K. Young

USDA Wildlife Services: Staff Publications

Rapid and ongoing environmental change is leading to scenarios where marine and terrestrial predators are persisting without prey, either by scavenging or using anthropogenic foods. Despite investigations into the effects of predator presence or absence on prey behavior and ecology, little research has assessed the effect of prey absence on predators. Here, we synthesize research on scavenging and the use of anthropogenic resources by marine and terrestrial predators; hypothesize how the use of these resources may change predator behavior with respect to their social structure, space use, life history, and individual behavioral traits; and illustrate how these changes are likely …

Space Use In Free-Ranging Canids: Are Gonadal Hormones Required For Territory Maintenance?, Eric M. Gese, Patricia A. Terletzky

USDA Wildlife Services: Staff Publications

Fertility control among carnivores has been used to reduce depredations on livestock and wild neonates, population control, modify behavior, inhibit genetic introgression, and reduce human–wildlife conflicts. Although there is considerable knowledge on techniques to sterilize carnivores, there is little information concerning how the absence of gonadal hormones influences behavior, space use, and survival of wild canids. We examined territorial fidelity, home-range size and overlap, and survival of 179 surgically sterilized free-ranging canids (124 coyotes (Canis latrans Say, 1823), 55 coyote – red wolf (Canis rufus Audubon and Bachman, 1851) hybrids) with gonadal hormones present (tubal-ligated females (n = 70), vasectomized …

Relative Acceptance Of Brodifacoum Pellets And Soft Bait Sachets By Polynesian Rats (Rattus Exulans) On Wake Atoll, Peter J. Kappes, Shane R. Siers

USDA Wildlife Services: Staff Publications

Removing invasive rats from island ecosystems using rodenticides has proven conservation benefits and is an important management tool for conserving and restoring island ecosystems. However, rodenticide-based eradications can fail if not all rats consume enough bait to result in lethal toxicosis. A recent post-operational review of a failed attempt to eradicate rats from Wake Atoll suggested that some individuals may not have ingested a lethal dose of rodenticide due to potential dietary and/or sensory preferences developed via regular access to anthropogenic food sources. These food sources may be higher in fats and oils, possessing different sensory properties (e.g., softer, chewier, …

Reproductive Trade-Offs In The Colorado Checkered Whiptail Lizard (Aspidoscelis Neotesselatus): An Examination Of The Relationship Between Clutch And Follicle Size, Hannah E. Caracalas, S. S. French, S. B. Hudson, B. M. Kluever, A. C. Webb, D. Eifler, A. J. Lehmicke, Lise M. Aubry

USDA Wildlife Services: Staff Publications

Life history theory predicts that there should be an inverse relationship between offspring size and number, because individuals cannot simultaneously maximize both when resources are limited. Although extensively studied in avian species, the occurrence and determinants of reproductive tradeoffs in oviparous reptiles are far less understood, particularly in parthenogenetic species. We studied this trade-off in the Colorado Checkered Whiptail, Aspidoscelis neotesselatus, a female-only parthenogenetic lizard. Using data previously collected in 2018 and 2019, we tested for clutch and egg size trade-offs and determined whether this relationship could be influenced by female size and aspects of physiological condition. Physiological condition …

Differing Alterations Of Odor Volatiles Among Pathogenic Stimuli, Patrick Millet, Talia Martin, Maryanne Opiekun, Gary K. Beauchamp, Bruce A. Kimball

USDA Wildlife Services: Staff Publications

Alterations of the volatile metabolome (the collection of volatiles present in secretions and other emanations) that occur in response to inflammation can be detected by conspecifics and chemometric analyses. Using a model system where mouse urinary metabolites are altered by treatment with lipopolysaccharide (found in the outer cell membrane of gram-negative bacteria), we hypothesized that alteration of body odor volatiles will vary according to the pathogen responsible for inducing the inflammation. We tested this hypothesis by treating mice with different immunogens that engage different immune signaling pathways. Results suggest that alterations of body odor volatiles resulting from inflammation do contain …

Occurrence Of Mesocarnivores In Montane Sky Islands: How Spatial And Temporal Overlap Informs Rabies Management In A Regional Hotspot, Amanda M. Veals, John Koprowski, David L. Bergman, Kurt C. Vercauteren, David B. Wester

USDA Wildlife Services: Staff Publications

Interspecific interactions among mesocarnivores can influence community dynamics and resource partitioning. Insights into these interactions can enhance understanding of local ecological processes that have impacts on pathogen transmission, such as the rabies lyssavirus. Host species ecology can provide an important baseline for disease management strategies especially in biologically diverse ecosystems and heterogeneous landscapes. We used a mesocarnivore guild native to the southwestern United States, a regional rabies hotspot, that are prone to rabies outbreaks as our study system. Gray foxes (Urocyon cinereoargenteus), striped skunks (Mephitis mephitis), bobcats (Lynx rufus), and coyotes (Canis latrans) share large portions of their geographic ranges …

A Novel Technique To Improve Capture Success Of Common Ravens, Lindsey R. Perry, Terrah M. Owens, Zachary T. Slick, Jimmy Taylor, Jonathan B. Dinkins

USDA Wildlife Services: Staff Publications

Traditional trapping techniques for common ravens (Corvus corax; raven) require significant effort, often produce low capture rates, and cannot be used in some situations. We designed a 3-m noose pole to secure ravens from nocturnal roost locations while using a strobe spotlight to temporarily disorient them. We collected measures of trapping efficiency and contrasted them with padded leghold traps also used in the study. We effectively implemented our noose pole method in July and August of 2018, 2019, and 2020 in the Baker and Cow Lakes sage-grouse (Centrocercus urophasianus) Priority Areas of Conservation in eastern Oregon, USA, which yielded trapping …

Recolonizing Carnivores: Is Cougar Predation Behaviorally Mediated By Bears?, Kristin N. Engebretsen, Jon P. Beckmann, Carl W. Lackey, Alyson M. Andreasen, Cody Schroeder, Pat Jackson, Julie K. Young

USDA Wildlife Services: Staff Publications

Conservation and management efforts have resulted in population increases and range expansions for some apex predators, potentially changing trophic cascades and foraging behavior. Changes in sympatric carnivore and dominant scavenger populations provide opportunities to assess how carnivores affect one another. Cougars (Puma concolor) were the apex predator in the Great Basin of Nevada, USA, for over 80 years. Black bears (Ursus americanus) have recently recolonized the area and are known to heavily scavenge on cougar kills. To evaluate the impacts of sympatric, recolonizing bears on cougar foraging behavior in the Great Basin, we investigated kill sites of 31 cougars between …

Food Habits Of Wintering Double-Crested Cormorants In The Mississippi Delta, Terrel W. Christie, Brian S. Dorr, J. Brian Davis, Luke A. Roy, Carole R. Engle, Katie Hanson-Dorr, Anita M. Kelly

USDA Wildlife Services: Staff Publications

Given its ubiquity, it is not surprising that agriculture, including fin fish aquaculture, contributes to food webs worldwide and is used by numerous wildlife for foraging and meeting other needs. Double-crested Cormorants (Phalacrocorax auritus) impact United States commercial aquaculture and are considered the primary avian predator in catfish (Ictalurus spp.) aquaculture facilities in the Mississippi Delta. Recent changes in aquaculture practices, regulatory policies, and decreased overall hectares in production prompted this study that assessed cormorant consumption of catfish in relation to their night roosts through surveys and diet analysis. Cormorants were collected from night roosts from October …

The Evolutionary Consequences Of Human–Wildlife Conflict In Cities, Christopher J. Schell, Lauren Stanton, Julie K. Young, Lisa Angeloni, Joanna E. Lambert, Stewart W. Breck, Maureen H. Murray

USDA Wildlife Services: Staff Publications

Human–wildlife interactions, including human–wildlife conflict, are increasingly common as expanding urbanization worldwide creates more opportunities for people to encounter wildlife. Wildlife–vehicle collisions, zoonotic disease transmission, property damage, and physical attacks to people or their pets have negative consequences for both people and wildlife, underscoring the need for comprehensive strategies that mitigate and prevent conflict altogether. Management techniques often aim to deter, relocate, or remove individual organisms, all of which may present a significant selective force in both urban and nonurban systems. Managementinduced selection may significantly affect the adaptive or nonadaptive evolutionary processes of urban populations, yet few studies explicate the …

A Framework For Surveillance Of Emerging Pathogens At The Human-Animal Interface: Pigs And Coronaviruses As A Case Study, Kim M. Pepin, Ryan S. Miller, Mark Q. Wilber

USDA Wildlife Services: Staff Publications

Pigs (Sus scrofa) may be important surveillance targets for risk assessment and risk-based control planning against emerging zoonoses. Pigs have high contact rates with humans and other animals, transmit similar pathogens as humans including CoVs, and serve as reservoirs and intermediate hosts for notable human pandemics. Wild and domestic pigs both interface with humans and each other but have unique ecologies that demand different surveillance strategies. Three fundamental questions shape any surveillance program: where, when, and how can surveillance be conducted to optimize the surveillance objective? Using theory of mechanisms of zoonotic spillover and data on risk factors, …

Effects Of Social Structure And Management On Risk Of Disease Establishment In Wild Pigs, Anni Yang, Peter E. Schlichting, Bethany Wight, Wesley M. Anderson, Sarah M. Chinn, Mark Q. Wilber, Ryan S. Miller, James C. Beasley, Raoul Boughton, Kurt C. Vercauteren, George Wittemyer, Kim M. Pepin

USDA Wildlife Services: Staff Publications

1. Contact heterogeneity among hosts determines invasion and spreading dynamics of infectious disease, thus its characterization is essential for identifying effective disease control strategies. Yet, little is known about the factors shaping contact networks in many wildlife species and how wildlife management actions might affect contact networks.

2. Wild pigs in North America are an invasive, socially structured species that pose a health concern for domestic swine given their ability to transmit numerous devastating diseases such as African swine fever (ASF). Using proximity loggers and GPS data from 48 wild pigs in Florida and South Carolina, USA, we employed a …

Surveys For Ticks On Wildlife Hosts And In The Environment At Asian Longhorned Tick (Haemaphysalis Longicornis)-Positive Sites In Virginia And New Jersey, 2018, Seth A. White, Sarah N. Bevins, Mark G. Ruder, David Shaw, Stacey L. Vigil, Adam Randall, Thomas J. Deliberto, Kristen Dominguez, Alec T. Thompson, James W. Mertins, Jeffrey T. Alfred, Michael J. Yabsley

USDA Wildlife Services: Staff Publications

Haemaphysalis longicornis, the Asian longhorned tick (ALT), is native to eastern Asia, but it has become invasive in several countries, including Australia, New Zealand and recently in the eastern United States (US). To identify wild mammal and avian host species in the US, we conducted active wildlife surveillance in two states with known ALT infestations (Virginia and New Jersey). In addition, we conducted environmental surveys in both states. These surveillance efforts resulted in detection of 51 ALTinfested individuals from seven wildlife species, including raccoon (Procyon lotor), Virginia opossum (Didelphis virginiana), red fox (Vulpes vulpes …