Veterinary Preventive Medicine, Epidemiology, and Public Health Commons^™

Alternatives To Corn For Baiting Wild Pigs, Justin A. Foster, Lee H. Williamson, John C. Kinsey, Ryan L. Reitz, Kurt C. Vercauteren, Nathan P. Snow

USDA Wildlife Services: Staff Publications

We examined dietary preferences of wild pigs to discern possible bait alternatives to corn. Captive trials were conducted during spring and fall 2021 in the Wild Pig Research Facility at Kerr Wildlife Management Area, Hunt, Texas, USA. We conducted 2‐choice tests by allowing wild pigs to feed ad libitum on soybeans, split peas, mealworms, and peanuts (spring 2021), and oats, acorns, earthworms, and peanuts (fall 2021), always with corn available as a second choice for reference. In each trial, we used proportion of test bait eaten versus total bait eaten, and relative access to both food sources as indices of …

Genomic Regions Associated With Pseudorabies Virus Infection Status In Naturally Infected Feral Swine (Sus Scrofa), Courtney F. Bowden, Jennifer N. Kiser, Ryan S. Miller, Alexandra C. Buckley, Paola M. Boggiatto, Rachael M. Giglio, Vienna R. Brown, Dorian Garrick, Holly L. Neibergs, Antoinette J. Piaggio, Scott E. Speidel, Timothy J. Smyser

USDA Wildlife Services: Staff Publications

Pseudorabies virus (PRV)—the causative agent of Aujeszky’s disease—was eliminated from commercial pig production herds in the United States (US) in 2004; however, PRV remains endemic among invasive feral swine (Sus scrofa). The circulation of PRV among abundant, widespread feral swine populations poses a sustained risk for disease spillover to production herds. Risk–based surveillance has been successfully implemented for PRV in feral swine populations in the US. However, understanding the role of host genetics in infection status may offer new insights into the epidemiology and disease dynamics of PRV that can be applied to management strategies. Genetic mechanisms underlying …

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

USDA 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 …

Assessment Of Spilled Toxic Bait By Wild Pigs And Potential Risk To Non-Target Species, John C. Kinsey, Justin A. Foster, Nathan P. Snow, Jason D. Wishart, Linton D. Staples, Janis K. Bush, Kurt V. Vercauteren

USDA Wildlife Services: Staff Publications

Background

In 2018, a sodium nitrite (SN)-based toxic bait for invasive wild pigs (hereafter wild pigs; Sus scrofa), was evaluated to determine its effectiveness in reducing local wild pig populations in Texas. Localized population reductions of > 70% were achieved, but spillage of bait outside wild pig-specific feeders (bait stations) caused by feeding wild pigs resulted in the deaths of non-target animals. To evaluate risks to non-target animals, we tested whether bait presentation influenced the total amount of bait spilled by wild pigs and estimated the associated risk to non-target species.

Results

We found that bait spilled outside bait stations …

A Social Network Analysis Of Actors Involved In Wild Pig (Sus Scrofa) Management In Missouri, Hailey E. Ellis, Meredith J. Grady, Lauren Jaebker, Alan D. Bright, Keith M. Carlisle

USDA Wildlife Services: Staff Publications

Wild pigs (Sus scrofa) cause significant damage to agriculture and native ecosystems and can transmit diseases to animals and people. Management responses designed to reduce population numbers are needed to mitigate these threats. Identifying networks of key actors, including the ways in which they interact, is valuable for purposes of better understanding opportunities or constraints that generate or impede effective management responses. The goal of our study was to understand the network of organizations, and the personnel working within them, that were active in wild pig management, research, or policy initiatives in Missouri during 2018–2020 by 1) identifying …

The Influence Of Income And Loss On Hunters' Attitudes Towards Wild Pigs And Their Management, Samantha Leivers, Keith M. Carlisle, Rachel L. Connally, Maureen G. Frank, John M. Tomeček

USDA Wildlife Services: Staff Publications

Wild pigs (Sus scrofa) are one of the most pervasive invasive species in North America. Wild pigs pose a threat to crops, livestock, and the environment, but also provide recreational hunting opportunities. There are avenues for some stakeholder groups to generate income from wild pigs, however, stakeholders vary in attitudes towards wild pigs and their management. We investigated whether financial loss and income resulting from wild pigs influenced hunter stakeholder attitudes towards their management in Texas. We examined how land use influenced hunting landowner attitudes towards wild pigs. We analyzed 22,176 responses (8,707 landowners, 13,469 nonlandowners) fromTexas hunters …

Wild Pig Removal Reduces Pathogenic Bacteria In Low-Order Streams, Sara A. Bolds, B. Graeme Lockaby, Latif Kalin, Stephen S. Ditchkoff, Mark D. Smith, Kurt Vercauteren

USDA Wildlife Services: Staff Publications

Invasive wild pig populations have undergone enormous increases in the United States and particularly across the southern U.S. in recent years. High fecundity rates and abilities to adapt quickly to varied habitats have enabled pig populations to become entrenched and difficult to eliminate. The pigs cause many negative impacts on ecosystems including degradation of water quality through infusion of fecal contamination and other non-point source pollutants. Our goal was to determine the effects of pig removal on water quality in streams that were known to be significantly polluted by pig activity Bolds (J Environ Qual 50: 441–453, 2021). We compared …

Behavioral States In Space And Time: Understanding Landscape Use By An Invasive Mammal, Steven M. Gray, John M. Humphreys, Robert A. Montgomery, Dwayne R. Etter, Kurt C. Vercauteren, Daniel B. Kramer, Gary J. Roloff

USDA Wildlife Services: Staff Publications

Animal movement models can be used to understand species behavior and assist with implementation of management activities. We explored behavioral states of an invasive wild pig (Sus scrofa) population that recently colonized central Michigan, USA, 2014–2018. To quantify environmental factors related to wild pig movement ecology and spatio‐temporal landscape use, we predicted wild pig behavioral states relative to land cover type, landscape structure (i.e., edge and patch cohesion), and weather conditions. We used global positioning system (GPS)‐collars and monitored 8 wild pigs from 2014–2018. We fit local convex hulls and calculated movement metrics revealing 3 wild pig behavioral states (resting, …

Adaptive Risk-Based Targeted Surveillance For Foreign Animal Diseases At The Wildlife-Livestock Interface, Ryan S. Miller, Sarah N. Bevins, Gericke Cook, Ross Free, Kim M. Pepin, Thomas Gidlewski, Vienna Brown

USDA Wildlife Services: Staff Publications

Animal disease surveillance is an important component of the national veterinary infrastructure to protect animal agriculture and facilitates identification of foreign animal disease (FAD) introduction. Once introduced, pathogens shared among domestic and wild animals are especially challenging to manage due to the complex ecology of spillover and spillback. Thus, early identification of FAD in wildlife is critical to minimize outbreak severity and potential impacts on animal agriculture as well as potential impacts on wildlife and biodiversity. As a result, national surveillance and monitoring programs that include wildlife are becoming increasingly common. Designing surveillance systems in wildlife or, more importantly, at …

Economic Damages Of Wild Pigs In Non-Traditional Areas: From The Fairway To The After Life, Sophie Mckee, Julie Elser, Maryfrances Miller, Lirong Liu, Ryan Miller, Steven S. Shwiff, Stephanie A. Shwiff

USDA Wildlife Services: Staff Publications

Invasive wild pigs are widely known to cause damage to agricultural properties and commodities, but less has been reported about damages to other types of property. A survey was distributed to golf courses and cemeteries across Texas to explore the extent of damage these properties experience. While both property types reported significant damages, golf courses were found to experience more damage than cemeteries. Using average reported costs and predicted county-level damage, total costs for all golf courses and cemeteries across the state were estimated to exceed $1.6 million USD per year.

Towards A More Comprehensive Understanding Of Wild Pig (Sus Scrofa) Impacts On Agricultural Producers: Insights From A Texas Case Study, Keith M. Carlisle, Nicole Didero, Sophie Mckee, Julie Elser, Stephanie A. Shwiff

USDA Wildlife Services: Staff Publications

This research investigates the impacts of invasive wild pigs (Sus scrofa Linneaus) on agricultural producers in Texas, with the aim of identifying and describing all categories of wild pig impacts and quantifying the extent of producers’ over- or underestimation of their total wild pig-related costs in 2018, as compared to calculations based upon data subsequently provided by the producers about individual wild pig-related costs and losses. Based on interviews with 23 producers in 16 Texas counties, we identified more than 20 discrete categories of negative impacts and negligible positive impacts associated with wild pigs. Among them were categories that have …

Rooting Out Genetic Structure Of Invasive Wild Pigs In Texas, Anna M. Mangan, Antoinette J. Piaggio, Michael J. Bodenchuk, Courtney F. Pierce, Timothy J. Smyser

USDA Wildlife Services: Staff Publications

Invasive wild pigs (Sus scrofa), also called feral swine or wild hogs, are recognized as among the most destructive invasive species in the world. Throughout the United States, invasive wild pigs have expanded rapidly over the past 40 years with populations now established in 38 states. Of the estimated 6.9 million wild pigs distributed throughout the United States, Texas supports approximately 40% of the population and similarly bears disproportionate ecological and economic costs. Genetic analyses are an effective tool for understanding invasion pathways and tracking dispersal of invasive species such as wild pigs and have been used recently …

Risks Of Introduction And Economic Consequences Associated With African Swine Fever, Classical Swine Fever And Foot-And-Mouth Disease: A Review Of The Literature, Vienna Brown, Ryan S. Miller, Sophie C. Mckee, Karina H. Ernst, Nicole M. Didero, Rachel M. Maison, Meredith J. Grady, Stephanie A. Shwiff

USDA Wildlife Services: Staff Publications

African swine fever (ASF), classical swine fever (CSF) and foot-and-mouth disease (FMD) are considered to be three of the most detrimental animal diseases and are currently foreign to the U.S. Emerging and re-emerging pathogens can have tremendous impacts in terms of livestock morbidity and mortality events, production losses, forced trade restrictions, and costs associated with treatment and control. The United States is the world's top producer of beef for domestic and export use and the world's third-largest producer and consumer of pork and pork products; it has also recently been either the world's largest or second largest exporter of pork …

Anthraquinone Repellent Seed Treatment On Corn Reduces Feeding By Wild Pigs, Nathan P. Snow, Joseph M. Halseth, Scott J. Werner, Kurt C. Vercauteren

USDA Wildlife Services: Staff Publications

Wild pigs (Sus scrofa) are a destructive invasive species that cause extensive damage to agriculture throughout many regions of the world. In particular wild pigs damage corn more than any other crop, and most of that damage occurs immediately after planting when wild pigs excavate and consume planted seeds. We evaluated whether anthraquinone (AQ), a repellent, could be useful for protecting seed corn from consumption by wild pigs. Specifically, we conducted cafeteria-style tests at 16 bait sites for 6 nights using concentrations of: untreated, 0.5, 1.5, and 3.0% AQ by weight sprayed on whole-kernel corn in AL and …

Peptide Elisa And Fret-Qpcr Identified A Significantly Higher Prevalence Of Chlamydia Suis In Domestic Pigs Than In Feral Swine From The State Of Alabama, Usa, Md Monirul Hoque, Folasade Adekanmbi, Subarna Barua, Kh. Shamsur Rahman, Virginia Aida, Brian Anderson, Anil Poudel, Anwar Kalalah, Sara Bolds, Steven Madere, Steven Kitchens, Stuart Price, Vienna Brown, B. Graeme Lockaby, Constantinos S. Kyriakis, Bernhard Kaltenboeck, Chengming Wang

USDA Wildlife Services: Staff Publications

Chlamydia suis is an important, highly prevalent, and diverse obligate intracellular pathogen infecting pigs. In order to investigate the prevalence and diversity of C. suis in the U.S., 276 whole blood samples from feral swine were collected as well as 109 fecal swabs and 60 whole blood samples from domestic pigs. C. suis-specific peptide ELISA identified anti-C. suis antibodies in 13.0% of the blood of feral swine (26/276) and 80.0% of the domestic pigs (48/60). FRET-qPCR and DNA sequencing found C. suis DNA in 99.1% of the fecal swabs (108/109) and 21.7% of the whole blood (13/60) of …

Understanding Tolerance For An Invasive Species: An Investigation Of Hunter Acceptance Capacity For Wild Pigs (Sus Scrofa) In Texas, Hailey E. Mclean, Tara L. Teel, Alan Bright, Lauren M. Jaebker, John M. Tomecek, Maureen G. Frank, Rachael L. Connally, Stephanie A. Shwiff, Keith M. Carlisle

USDA Wildlife Services: Staff Publications

Invasive species and their establishment in new areas have significant impacts on the ecological, economic, and social well-being of our planet. Wild pigs (Sus scrofa) are one of the world’s most formidable invasive species, particularly in the United States. They cause significant damage to agriculture and ecosystems, and can transmit diseases to livestock, wildlife, and people. There is an inherent social dimension to the issue of wild pigs due in part to the fact that people hunt them. Hunting contributes to both the control and spread of this species. The objectives of this study were to: 1) determine hunters’ overall …

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) …

Loci Associated With Antibody Response In Feral Swine (Sus Scrofa) Infected With Brucella Suis, Courtney F. Pierce, Vienna R. Brown, Steven C. Olsen, Paola Boggiatto, Kerri Pedersen, Ryan S. Miller, Scott E. Speidel, Timothy J. Smyser

USDA Wildlife Services: Staff Publications

Feral swine (Sus scrofa) are a destructive invasive species widespread throughout the United States that disrupt ecosystems, damage crops, and carry pathogens of concern for the health of domestic stock and humans including Brucella suis—the causative organism for swine brucellosis. In domestic swine, brucellosis results in reproductive failure due to abortions and infertility. Contact with infected feral swine poses spillover risks to domestic pigs as well as humans, companion animals, wildlife, and other livestock. Genetic factors influence the outcome of infectious diseases; therefore, genome wide association studies (GWAS) of differential immune responses among feral swine can provide …

A Rapid Population Assessment Method For Wild Pigs Using Baited Cameras At 3 Study Site, Peter E. Schlichting, James C. Beasley, Raoul K. Boughton, Amy J. Davis, Kim M. Pepin, Michael P. Glow, Ryan S. Miller, Kurt C. Vercautern, Jesse S. Lewis

USDA Wildlife Services: Staff Publications

Reliable and efficient population estimates are a critical need for effective management of invasive wild pigs (Sus scrofa). We evaluated the use of 10‐day camera grids for rapid population assessment (RPA) of wild pigs at 3 study sites that varied in vegetation communities and wild pig densities. Study areas included Buck Island Ranch, Florida; Tejon Ranch, California; and the Savannah River Site, South Carolina, USA, during 2016–2018. Rapid population assessments grids were composed of baited camera traps spaced approximately 500 or 750 m apart. Two RPA grids were deployed per study site and each grid was deployed twice (4–6 months …

Effects Of Inactivated Mycobacterium Bovis Vaccination On Molokai-Origin Wild Pigs Experimentally Infected With Virulent M. Bovis, Pauline Nol, Morgan Wehte, Richard A. Bowen, Suelee Robbe-Austerman, Tyler Thacker, Kristina Lantz, Jack Rhyan, Laurie A. Baeten, Ramón A. Juste, Iker A. Sevilla, Christian Gortazar, Joaquín Vicente

USDA Wildlife Services: Staff Publications

The wild pig population on Molokai, Hawaii, USA is a possible reservoir for bovine tuberculosis, caused by Mycobacterium bovis, and has been implicated in decades past as the source of disease for the island’s domestic cattle. Heat-inactivated vaccines have been effective for reducing disease prevalence in wild boar in Spain and could prove useful for managing M. bovis in Molokai wild pigs. We designed an experiment to test this vaccine in wild pigs of Molokai genetics. Fifteen 3–4-month-old pigs were orally administered 10⁶–10⁷ colony forming units (cfu) of heat-inactivated M. bovis (Vaccinates; n = 8; 0.2 …

Economic Estimates Of Invasive Wild Pig Damage To Crops In 12 Us States, Sophie Mckee, Aaron Anderson, Keith Carlisle, Stephanie A. Shwiff

USDA Wildlife Services: Staff Publications

We report the results of a survey on invasive wild pig (Sus scrofa L.) damage and control in 12 US states (Alabama, Arkansas, California, Florida, Georgia, Louisiana, Mississippi, Missouri, North Carolina, Oklahoma, South Carolina, and Texas). The crops chosen for this study represent the “second-tier” in terms of economic importance after the six crops that were the subject of Anderson et al. (2016). The survey was distributed by the USDA National Agricultural Statistical Service (NASS) in the summer of 2019 to a sample of producers in each of the states (except California) of the following six crops: hay, pecans (Carya …

Mixed Ancestry From Wild And Domestic Lineages Contributes To The Rapid Expansion Of Invasive Feral Swine, Timothy J. Smyser, Michael A. Tabak, Chris Slootmaker, Michael S. Robeson Ii, Ryan S. Miller, Mirte Bosse, Hendrik-Jan Megens, Martien A.M. Groenen, Samuel Rezende Paiva, Danielle Assis De Faria, Harvey D. Blackburn, Brandon S. Schmit, Antoinette J. Piaggio

USDA Wildlife Services: Staff Publications

Invasive alien species are a significant threat to both economic and ecological systems. Identifying the processes that give rise to invasive populations is essential for implementing effective control strategies. We conducted an ancestry analysis of invasive feral swine (Sus scrofa, Linnaeus, 1758), a highly destructive ungulate that is widely distributed throughout the contiguous United States, to describe introduction pathways, sources of newly emergent populations and processes contributing to an ongoing invasion. Comparisons of high-density single nucleotide polymorphism genotypes for 6,566 invasive feral swine to a comprehensive reference set of S. scrofa revealed that the vast majority of feral swine were …

Effects Of Wild Pig Disturbance On Forest Vegetation And Soils, Steven M. Gray, Gary J. Roloff, Daniel B. Kramer, Dwayne R. Etter, Kurt C. Vercauteren, Robert A. Montgomery

USDA Wildlife Services: Staff Publications

In North America, wild pigs (Sus scrofa; feral pigs, feral swine, wild boars) are a widespread exotic species capable of creating large‐scale biotic and abiotic landscape perturbations. Quantification of wild pig environmental effects has been particularly problematic in northern climates, where they occur only recently as localized populations at low densities. Between 2016 and 2017, we assessed short‐term (within ~2 yrs of disturbance) effects of a low‐density wild pig population on forest features in the central Lower Peninsula of Michigan, USA. We identified 16 8‐ha sites using global positioning system locations from 7 radio‐collared wild pigs for sampling.Within each …

Low Secondary Risks For Captive Coyotes From A Sodium Nitrite Toxic Bait For Invasive Wild Pigs, Nathan P. Snow, Katherine E. Horak, Simon T. Humphrys, Linton D. Staples, David G. Hewitt, Kurt C. Vercauteren

USDA Wildlife Services: Staff Publications

An acute toxic bait is being developed to deliver micro‐encapsulated sodium nitrite (SN) to stimulate severe methemoglobinemia and humane death for invasive wild pigs (Sus scrofa), thereby providing a new tool for reducing their populations. During April 2016, we evaluated sensitivity to SN and outcomes of secondary consumption in the ubiquitous mammalian scavenger, coyote (Canis latrans), to determine secondary risks of consuming carcasses of wild pigs that died from consuming the SN toxic bait. At the National Wildlife Research Center in Fort Collins, Colorado, USA, we first evaluated whether coyotes fed carcasses of domestic pigs killed by consumption of SN …

Use Of Unmanned Aircraft Systems (Uas) And Multispectral Imagery For Quantifying Agricultural Areas Damaged By Wild Pigs, Justin W. Fischer, Kelsey Greiner, Mark W. Lutman, Bryson L. Webber, Kurt C. Vercauteren

USDA Wildlife Services: Staff Publications

Wild pigs (Sus scrofa) cause extensive damage to agricultural crops, resulting in lost production and income. A major challenge associated with assessing damage to crops is locating and quantifying damaged areas within agricultural fields. We evaluated a novel method using multispectral high-resolution aerial imagery, collected from sensors mounted on unmanned aircraft systems (UAS), and feature extraction techniques to detect and map areas of corn fields damaged by wild pigs in southern Missouri, USA. Damaged areas were extracted from orthomosaics using visible and near-infrared band combinations, an object-based classification approach, and hierarchical learning cycles. To validate estimates we also collected ground …

Movement Responses Inform Effectiveness And Consequences Of Baiting Wild Pigs For Population Control, Nathan P. Snow, Kurt C. Vercauteren

USDA Wildlife Services: Staff Publications

Wild pigs (Sus scrofa) damage agricultural and natural resources throughout their nearly global distribution. Subsequently, population control activities (e.g., trapping, shooting, or toxic baiting) frequently involve the deployment of bait to attract wild pigs. A better understanding of how wild pigs respond to bait sites can help maximize efficiency of baiting programs and identify any potential pitfalls. We examined the movement behaviors of 68 wild pigs during three stages of intensive baiting programs (i.e., 15 days each: prior, during, and post baiting) spread across two distinct study areas in southern and northern Texas, USA. We found that bait sites needed …

Widespread Detection Of Antibodies To Leptospira In Feral Swine In The United States, K. K. Pedersen, K. L. Pabilonia, T. D. Anderson, S. N. Bevins, C. R. Hicks, J. M. Kloft, Thomas J. Deliberto

USDA Wildlife Services: Staff Publications

As feral swine continue to expand their geographical range and distribution across the United States, their involvement in crop damage, livestock predation, and pathogen transmission is likely to increase. Despite the relatively recent discovery of feral swine involvement in the aetiology of a variety of pathogens, their propensity to transmit and carry a wide variety of pathogens is disconcerting. We examined sera from 2055 feral swine for antibody presence to six serovars of Leptospira that can also infect humans, livestock or domestic animals. About 13% of all samples tested positive for at least one serovar, suggesting that Leptospira infection is …