Paul Cross
Biography
Education
Ph.D. Environmental Science, Policy, and Management. 2005. University of California, Berkeley
B.A. Environmental Science. 1998. University of Virginia, Charlottesville
Research Interests
My research focuses on applied wildlife disease, conservation and management issues around the Greater Yellowstone Ecosystem. I try to integrate multiple different scientific fields, but my specific background is in field ecology, behavior and mathematical modeling. There are two central themes in my research: (1) the integration of empirical data and mathematical modeling, and (2) the effects of host behavior on disease dynamics. Currently, my research focuses on brucellosis, chronic wasting disease, canine distemper and sarcoptic mange.
Science and Products
Moose and Winter Ticks in Western Wyoming
Moose are an important game species in Montana, Idaho and Wyoming but hunter opportunities have been reduced in many areas over the last two decades as populations have declined at this southern limit of the species’ geographic range. In the Jackson, Wyoming area moose populations have declined by an estimated 80% since the early 1990s. Rising temperatures, pathogens, and parasites represent...
Impacts of Disease on Wolves in Yellowstone National Park
In 1995 and 1996, wolves were reintroduced into the Northern Rockies where they have since established and spread. Within Yellowstone National Park, one of the core protected release sites, the unmanaged population steadily increased to high densities, producing a large wolf population susceptible to infections such as canine parvovirus (CPV), canine distemper virus (CDV) and sarcoptic mange...
Chronic Wasting Disease
Over the past 20 years, chronic wasting disease (CWD) in Wyoming has been spreading slowly outward from the southeastern corner of the state toward the Greater Yellowstone Area and Wyoming's elk feed grounds, where more than 24,000 elk are supplementally fed each winter.
Pneumonia in Bighorn Sheep
Bighorn sheep populations are often impacted by outbreaks of pneumonia that are suspected to come from domestic sheep and goats.
Quantitative Disease Ecology
Researchers at the USGS are working on developing new quantitative methods to study disease dynamics in wildlife systems as well as systems at the wildlife-domestic-human interface. Much of our work focuses on how host population structure affects disease invasion, persistence and control in wildlife disease systems. We tackle these issues with a combination of simulation and statistical...
Brucellosis
Brucellosis is a nationally and internationally regulated disease of livestock with significant consequences for animal health, public health, and international trade.
NOROCK Large Carnivore Research Program
NOROCK has substantial expertise in large carnivore research, primarily involving species listed as Threatened or Endangered. NOROCK’s Large Carnivore Research Program includes scientists from NOROCK’s Headquarters, West Glacier Field Station, and the Southern Appalachian Field Station. Studies are conducted in a wide variety of landscapes throughout the U.S., as well as international...
COMPLETED: Using thermal imagery to assess wolf hairloss from sarcoptic mange
Researchers at NOROCK and their partners used thermal cameras at the Grizzly and Wolf Discovery Center in Montana to assess the amount of heat lost under a range of environmental conditions with and without hair. These methods help scientists better understand how mange operates in wild wolves throughout the Greater...
Parsing the effects of demography, climate, and management on recurrent brucellosis outbreaks in elk
1. Zoonotic pathogens can harm human health and well-being directly or by impacting livestock. Pathogens that spillover from wildlife can also impair conservation efforts if humans perceive wildlife as pests. Brucellosis, caused by the bacterium Brucella abortus, circulates in elk and bison herds of the Greater Yellowstone Ecosystem and poses a...
Cotterill, Gavin G.; Cross, Paul; Merkle, J. A.; Rogerson, JD; Scurlock, BM; Du Toit, Johan T.
Chronic wasting disease—Research by the U.S. Geological Survey and partners
IntroductionChronic wasting disease (CWD) is the only transmissible spongiform encephalopathy, a class of invariably fatal neurodegenerative mammalian diseases associated with a misfolded cellular prion protein found in wild free-ranging animals. Because it has a long incubation period, affected animals in Cervidae (the deer family; referred to as...
Hopkins, M. Camille; Carlson, Christina M.; Cross, Paul C.; Johnson, Christopher J.; Richards, Bryan J.; Russell, Robin E.; Samuel, Michael D.; Sargeant, Glen A.; Walsh, Daniel P.; Walter, W. David Confronting models with data: The challenges of estimating disease spillover
For pathogens known to transmit across host species, strategic investment in disease control requires knowledge about where and when spillover transmission is likely. One approach to estimating spillover is to directly correlate observed spillover events with covariates. An alternative is to mechanistically combine information on host density,...
Cross, Paul C.; Prosser, Diann; Ramey, Andrew M.; Hanks, Ephraim M.; Pepin, Kim M. Ecological interventions to prevent and manage zoonotic pathogen spillover
Spillover of a pathogen from a wildlife reservoir into a human or livestock host requires the pathogen to overcome a hierarchical series of barriers. Interventions aimed at one or more of these barriers may be able to prevent the occurrence of spillover. Here, we demonstrate how interventions that target the ecological context in which spillover...
Sokolow, S. H.; Nova, Nicole; Pepin, Kim; Peel, A. J.; Pulliam, J; Manlove, Kezia R.; Cross, Paul; Becker, D.; Plowright, RK; McCallum, Hamish; De Leo, Giulio A. Risk factors and productivity losses associated with Mycoplasma ovipneumoniae infection in United States domestic sheep operations
Association of Mycoplasma ovipneumoniae with pneumonia in domestic small ruminants has been described in Europe, Asia, and New Zealand but has received less attention in the United States. In 2011, the US Department of Agriculture’s National Animal Health Monitoring Survey detected M. ovipneumoniae shedding in 88% of 453 domestic sheep operations...
Manlove, Kezia R.; Branan, M; Baker, K; Bradway, D; Cassirer, E. F.; Marshall, K.L; Miller, Ryan S.; Sweeney, Steven J.; Cross, Paul C.; Besser, T. E. Modeling elk‐to‐livestock transmission risk to predict hotspots of brucellosis spillover
Wildlife reservoirs of infectious disease are a major source of human‐wildlife conflict because of the risk of potential spillover associated with commingling of wildlife and livestock. In the Greater Yellowstone Ecosystem, the presence of brucellosis (Brucella abortus) in free‐ranging elk (Cervus canadensis) populations is of significant...
Rayl, Nathaniel D.; Proffitt, Kelly M.; Almberg, Emily S.; Jones, Jennifer D.; Merkle, Jerod A.; Gude, Justin A.; Cross, Paul C. Extreme value-based methods for modeling elk yearly movements
Species range shifts and the spread of diseases are both likely to be driven by extreme movements, but are difficult to statistically model due to their rarity. We propose a statistical approach for characterizing movement kernels that incorporate landscape covariates as well as the potential for heavy-tailed distributions. We used a spliced...
Wijeyakulasuriya, Dhanushi A.; Hanks, Ephraim M.; Shaby, Benjamin A.; Cross, Paul C. Estimating the risk of elk-to-livestock brucellosis transmission in Montana
Wildlife reservoirs of infectious disease are a major source of human-wildlife conflict because of the risk of potential spillover associated with commingling of wildlife and livestock. In Montana, the presence of brucellosis (Brucella abortus) in free-ranging elk (Cervus canadensis) populations is of significant management concern because of the...
Rayl, Nathaniel D.; Proffitt, Kelly M.; Almberg, Emily S.; Jones, Jennifer D.; Merkle, Jerod A.; Gude, Justin A.; Cross, Paul C. Challenges and opportunities developing mathematical models of shared pathogens of domestic and wild animals
Diseases that affect both wild and domestic animals can be particularly difficult to prevent, predict, mitigate, and control. Such multi-host diseases can have devastating economic impacts on domestic animal producers and can present significant challenges to wildlife populations, particularly for populations of conservation concern. Few...
Huyvaert, Kathryn P.; Russell, Robin E.; Patyk, Kelly A.; Craft, Meggan E.; Cross, Paul C.; Garner, M. Graeme; Martin, Michael K.; Nol, Pauline; Walsh, Daniel P. Hidden cost of disease in a free‐ranging ungulate: brucellosis reduces mid‐winter pregnancy in elk
Demonstrating disease impacts on the vital rates of free‐ranging mammalian hosts typically requires intensive, long‐term study. Evidence for chronic pathogens affecting reproduction but not survival is rare, but has the potential for wide‐ranging effects. Accurately quantifying disease‐associated reductions in fecundity is important for advancing...
Cotterill, Gavin G.; Cross, Paul C.; Middleton, Arthur D.; Rogerson, Jared D.; Scurlock, Brandon M.; Du Toit, Johan T. The ecology of movement and behaviour: a saturated tripartite network for describing animal contacts
Ecologists regularly use animal contact networks to describe interactions underlying pathogen transmission, gene flow, and information transfer. However, empirical descriptions of contact often overlook some features of individual movement, and decisions about what kind of network to use in a particular setting are commonly ad hoc. Here, we...
Manlove, Kezia R.; Aiello, Christina M.; Sah, Pratha; Cummins, Bree; Hudson, Peter J.; Cross, Paul C. Estimating distemper virus dynamics among wolves and grizzly bears using serology and Bayesian state‐space models
Many parasites infect multiple hosts, but estimating the transmission across host species remains a key challenge in disease ecology. We investigated the within and across host species dynamics of canine distemper virus (CDV) in grizzly bears (Ursus arctos) and wolves (Canis lupus) of the Greater Yellowstone Ecosystem (GYE). We hypothesized that...
Cross, Paul C.; van Manen, Frank T.; Viana, Mafalda; Almberg, Emily S.; Bachen, Daniel; Brandell, Ellen E.; Haroldson, Mark A.; Hudson, Peter J.; Stahler, Daniel R.; Smith, Douglas W.
CWD Simulation App
Chronic wasting disease (CWD) is a fatal disease of deer, elk, and moose transmitted through direct contact and via environmental contamination. This software provide tools to simulate CWD and harvest management scenarios. These models were developed by the U.S. Geological Survey (USGS) in collaboration with Montana Fish, Wildlife, and Parks.
Study Shows Pathways of Disease Transmission Between Elk, Bison and Cattle in the Greater Yellowstone Area
The U.S. Geological Survey and its partners have shown how brucellosis has impacted cattle, bison and elk in the greater Yellowstone area.
Study Shows Cold and Windy Nights Physically Drain Mangy Wolves
During winter, wolves infected with mange can suffer a substantial amount of heat loss compared to those without the disease, according to a study by the U.S. Geological Survey and its partners.